SP-1285 - Heating, Ventilation and Air-Conditioning (HVAC) Specification V07
SP-1285 - Heating, Ventilation and Air-Conditioning (HVAC) Specification V07
SP-1285 - Heating, Ventilation and Air-Conditioning (HVAC) Specification V07
0
Petroleum Development Oman LLC Effective: Oct-2021
Document ID SP-1285
Security Restricted
Version 7.0
Keywords: This document is the property of Petroleum Development Oman, LLC. Neither the whole
nor any part of this document may be disclosed to others or reproduced, stored in a retrieval system,
or transmitted in any form by any means (electronic, mechanical, reprographic recording or otherwise)
without prior written consent of the owner.
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i Document Authorisation
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ii Revision History
The following is a brief summary of the 4 most recent revisions to this document. Details of all
revisions prior to these are held on file by the issuing department.
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TABLE OF CONTENTS
i Document Authorisation .......................................................................................................... 3
ii Revision History ........................................................................................................................ 4
iii Related Corporate Management System (CMS) Portal ........................................................ 4
Section 1: Introduction ......................................................................................................................... 13
1 Introduction ........................................................................................................................... 14
1.1 Purpose........................................................................................................................ 14
1.2 User Guidelines ........................................................................................................... 14
1.3 Changes to the Specification ....................................................................................... 14
1.4 Specification Index....................................................................................................... 14
Section 2: General Requirements ........................................................................................................ 15
2.1 Introduction ........................................................................................................................... 16
2.1.1 Purpose........................................................................................................................ 16
2.1.2 Applicable Standards, Specifications and Codes ........................................................ 16
2.1.2.1 PDO Standards ............................................................................................................ 16
2.1.2.2 International Standards ............................................................................................... 17
2.1.3 Compliance with Standards ......................................................................................... 21
2.1.4 Product / Asset Warranty ............................................................................................. 21
2.1.5 Quality Assurance and Control .................................................................................... 21
2.1.6 Maintenance ................................................................................................................ 22
2.1.7 Factory Acceptance Test (FAT)................................................................................... 22
2.1.8 Guarantees .................................................................................................................. 22
2.2 Scope ...................................................................................................................................... 23
2.2.1 General ........................................................................................................................ 23
2.2.2 Units of Measurement ................................................................................................. 23
2.2.3 Shop Drawings ............................................................................................................ 24
2.2.4 Protection and Storage ................................................................................................ 25
2.2.5 Painting, Colour Coding & Identification ...................................................................... 25
2.2.6 Test Points & Instruments ........................................................................................ 27
2.2.6.1 Test Points & Instruments for Pipe Works .............................................................. 27
2.2.7 HVAC Yard .................................................................................................................. 28
2.2.8 Commissioning & Handover ........................................................................................ 28
2.2.8.1 Commissioning Programme ........................................................................................ 28
2.2.8.2 Pre-Commissioning .................................................................................................. 29
2.2.9 Testing, Adjusting & Balancing .................................................................................... 30
2.2.10 Test Report & Documentation Format ......................................................................... 31
2.2.11 Spares, As-Built & Manual ........................................................................................... 31
2.2.11.1 Maintenance Tools..................................................................................... 31
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3.4.5.1.5 Controls........................................................................................................................ 81
3.5 Central Direct Expansion Units (Condensing Unit) ..................................................... 81
3.5.1 General ....................................................................................................................... 81
3.5.2 Materials ...................................................................................................................... 81
3.5.2.7 Execution ................................................................................................................ 82
3.6 Unitary Air Conditioning Unit ....................................................................................... 82
3.6.1 Window Air Conditioners ............................................................................................. 82
3.6.2 Mini Split Units ............................................................................................................ 83
3.6.2.1 General ..................................................................................................................... 83
3.6.2.2 Evaporator Unit ........................................................................................................ 83
3.6.2.3 Condensing Unit ........................................................................................................... 83
3.6.2.4 Control ..................................................................................................................... 83
3.6.3 Cassette Type Fan Coil Unit ........................................................................................ 84
3.6.4 Packaged Air Conditioning Units ................................................................................. 84
3.6.4.1 General ........................................................................................................................ 84
3.6.4.5 Coils ............................................................................................................................ 85
3.6.4.6 Refrigerant Circuit and Components ....................................................................... 85
3.6.4.7 Filter Section .............................................................................................................. 85
3.6.4.8 Controls and Safeties .................................................................................................. 85
3.6.4.9 Motor ............................................................................................................................ 85
3.6.5 Variable Refrigerant Flow/Volume (VRF/VRV) System .............................................. 85
3.6.5.1 General .................................................................................................................... 85
3.6.5.2 Outdoor Unit ............................................................................................................ 85
3.6.5.2.1 Compressor ............................................................................................................. 85
3.6.5.2.2 Heat Exchanger ........................................................................................ 85
3.6.5.2.3 Refrigerant Circuit ..................................................................................... 86
3.6.5.2.4 Safety Devices ........................................................................................................... 86
3.6.5.2.5 Oil Recovery System ................................................................................................. 86
3.6.5.3 Indoor Unit ................................................................................................................... 86
3.6.5.4 Control ........................................................................................................................ 86
3.6.5.5 Central Remote Controller ........................................................................................... 86
3.6.5.6 Unified On/Off Controller. ........................................................................................... 86
3.6.5.7 Schedule Timer........................................................................................................... 86
3.7 Fans ............................................................................................................................. 87
3.7.1 General ........................................................................................................................ 87
3.7.2 Products ....................................................................................................................... 88
3.7.2.1 Centrifugal Fans ......................................................................................................... 88
3.7.2.2 Axial Flow Fans .......................................................................................................... 89
3.7.2.3 Propeller Fans ............................................................................................................ 90
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Section 1: Introduction
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1 Introduction
1.1 Purpose
The purpose of this document is to specify the minimum requirements for “HVAC
Works” and is intended for use by PDO and its nominated Consultants and Contractors
for the development and operation of Company facilities.
This specification is intended to:
- Set the Company standards for facilities along the facilities life cycle.
- Disseminate and record facilities related information, experience and
procedures.
1.2 User Guidelines
For all HSE requirements, the User should refer the CP-122 ‘Code of Practice for
Health, Safety and Environmental Protection’ and other documents referenced therein.
Custodian of this document is the Corporate Functional Discipline Head (CFDH) of Civil
Engineering. Any User of this document, who encounters an inaccuracy or ambiguity,
is requested to notify the CFDH using the SP user feedback form provided in UEV civil
function webpage at following path (Directorates > UED- Engineering Directorate > UEV
- CIVIL ENGINEERING)
Reviews and modifications or changes to the Specification will normally be made by the
CFDH every three years or earlier when justified.
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2.1 Introduction
This specification covers the General requirements for the design, furnishing
&installation of equipment, final testing, adjusting, and balancing of all heating,
ventilating and air-conditioning system.
2.1.1 Purpose
The purpose of this document is to specify the minimum requirements for “Heating,
Ventilating and Air Conditioning” (HVAC) Works and is intended for use by PDO and
its nominated Consultants and Contractors for the development and operation of
Company facilities.
This specification is intended to:
- Set the Company standards for facilities along the facilities life cycle.
- Disseminate and record facilities related information, experience and
procedures.
This part shall be read in conjunction with other services of the Building and Utility
Services specification.
2.1.2 Applicable Standards, Specifications and Codes
This document shall be read in conjunction with the latest revisions of the following
standards, Specifications and Codes.
2.1.2.1 PDO Standards
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The entire Works, executed under a particular contract, shall be guaranteed to meet the
specified technical specifications and its referred standards & specifications.
All apparatus shall be built and installed so as to deliver its full rated capacity at the
efficiency for which it was designed and without objectionable noise or vibration (not more
than 3.3 2 mm/s). The vibration shall be taken from fan bearing motor end side.
Any defects, identified within the maintenance period as per the contract specified or a
minimum of one year from the date of Provisional Acceptance Certificate, have to be
rectified or replaced by the Contractor at his own cost.
The Contractor shall prepare a repair procedure for the defects. No repair procedures
shall be performed without the prior approval of the Company.
2.1.5 Quality Assurance and Control
Contractors and Suppliers shall demonstrate to the Principal that they implement
quality control and Assurance systems, which conform to the ISO 9000 series.
All materials used on the project shall be brand new and of high quality. Obtain
approval of all manufacturers from the Consultant and the Company.
"New" is defined as newly manufactured, "state of the art," tested and proven item of
equipment. Items which have been held in stock for any extended period of time by
either the Manufacturer or the Supplier will be rejected.
All materials used on the project shall bear the third party quality assurance stamp like
British Standard kite mark, UL, FM, LPC and/or other quality assurance authority as
stated herein elsewhere.
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All materials shall conform to the requirements of the specified British Standards or to
other equipment North American, DIN or European Standards.
2.1.6 Maintenance
Contractor shall submit FAT procedures and associated documentation for review and
acceptance by Company at least four weeks before planned start of FAT
The following equipment “Chiller, Air handling unit, Pumps, HVAC control panel and
HVAC MCC where specified shall be required for factory inspections, pre-testing, and
performance testing at Manufacturer site.
The Contractor shall endure that any deficiencies or shortcomings found during Factory
Acceptance Testing are made good prior to releasing the equipment for shipment to
site.
FAT Procedure
The FAT shall fully demonstrate that the equipment achieves its specification and the
design basis. As with all testing, the intent is to demonstrate and document that the
equipment operates as intended. The test outcome should give the test team
confidence that the equipment behaves as expected under the full range of foreseeable
conditions, including misuse and error.
2.1.8 Guarantees
The Contractor will guarantee all material and workmanship for at least one year or
as per project specified, after the issue of final completion certificate issue and take
over by the Company. Compressors shall be under warranty for 5 years for free
replacement in case any defect or failure.
Instruct all Suppliers and Manufacturers that guarantees on equipment will
commence when the completed work is accepted and not from the date the
equipment is put into operation.
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2.2 Scope
2.2.1 General
This specification shall define the minimum requirements for Supply and Installation of
‘HVAC’ Works.
This document shall be read in conjunction with the Company’s General Conditions of
Construction Works and the Contract Specifications. The Contract specifications
contain:
- Scope of Work including Technical Design Parameters
- Particular Specifications
- Technical Schedules
- List of Drawings
Labour, materials, equipment and services to complete the work of the HVAC system
as further specified and as shown on the Drawings;
The manufacture, supply, delivery, erection, testing and adjustment of the complete
heat, ventilation air conditioning system;
All of the material to provide a complete and operational installation to the satisfaction
of the Company incidental component and appurtenance necessary for the proper
operation of the system shall be provided and installed as required whether or not they
were specifically mentioned in the Contract Documents.
This Specification shall define the physical characteristics of the suitable materials and
describes the Works based on product or a method of Specifications. This
Specification shall also define the type of testing requirements and test sheets to be
used.
Plant and non-plant buildings require climatic conditioning (i.e. air conditioning and
ventilation) in order to maintain the temperature, relative humidity and air quality within
defined limits. In this way reliable operation of electronic equipment and human working
conditions are enhanced.
HVAC systems are generally supplied by specialised Manufacturers as package units
or as single components. Standard industrial HVAC equipment should be used.
It shall be ensured that sufficient space in buildings is reserved for HVAC equipment
and its ducting.
Verify location and elevation of all services (Water, Electrical, Telephone, Sanitary,
Storm Drainage, etc.,) before proceeding with the work.
2.2.2 Units of Measurement
Current : Amperes : A
Dimension : metre, millimetre : m, mm
Electrical : Ohms :
resistance
Flow : litres per second : 1/s
Force : Newton : 0.9807 kgf
Frequency : hertz : Hz
Power : watt, kilowatt : W, kW
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Refrigeration : Kilowatt : kW
Voltage : Volt : V
2.2.3 Shop Drawings
Submit shop drawings and samples for all materials and equipment.
Provide transparencies wherever possible and provide printed copies in a number as
specified elsewhere in the contract documents.
Present a schedule of shop drawings after award of the contract and not later than what
is specified in the contract documents, indicating the anticipated date when the
drawings will be submitted for review. Assume full responsibility for timely submission
of all drawings.
Check for all pertinent information such as physical dimensions, make, performance,
electrical characteristics and indicate the intended use and location before submitting
these drawings. Use reference symbols or enumeration to correspond to the contract
drawings.
Assume responsibility for accuracy of equipment dimensions related to space
available, accessibility for maintenance and service, compliance with inspection
authorities codes. Ensure that shop drawings indicate the shipping and working weights
of all equipment.
The submission of samples will be subject to the same procedure as that of shop
drawings. One set of such samples shall be required to be brought to site and kept
there after approval till substantial completion.
Prepare drawings in conjunction with all trades concerned, showing sleeves and
openings for all passages through structure and all insert sizes and locations.
Prepare composite construction drawings, fully dimensioned, of piping and equipment
in tunnels, shafts, mechanical equipment rooms and areas, and all other critical
locations to avoid a conflict of trades.
Base equipment drawings upon shop drawings and include but do not necessarily limit
to, all details pertaining to access, cleanouts, tappings, sleeves, electrical connections,
drains, location and elevation of pipes, ducts, conduits, etc., obtained from consultation
with, and agreement of, all trades involved.
Prepare drawings of equipment bases, pump pits, anchors, inertia slabs, floor and roof
curbs, wall openings, trenches, pertaining to mechanical work.
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Furnish prints of the reviewed details to all other parties who may require them for
proper coordination of their work, and furnish all information necessary for the work as
a whole.
Obtain Manufacturers' installation directions to aid in the preparation of shop drawings.
Submit two copies of such directions to the Consultant/ Company for his use.
The Consultant’s/ Company’s review shall not relieve the Contractor from responsibility
for deviations from the Contract documents, unless he has, in writing, called the
Consultant’s /Company’s attention to such deviations at the time of submission of
drawings. The review shall be construed to apply to, and only to, general arrangements
and shall not relieve the Contractor from the entire responsibility. Any approval by the
Consultant/Company shall be on the understanding that any item submitted shall be
ordered with options and modifications to fully meeting the specification. Any
fabrication, erection, setting out or other work done in advance of receipt of stamped
drawings shall be done entirely at the Contractor's risk and cost.
2.2.4 Protection and Storage
Protect all mechanical & electrical works from damage. Keep all equipment dry and
clean at all times.
Cover all openings in equipment and materials. Cover all temporary openings in ducts
and pipes with polyethylene sheets or caps until final connection is made. The quality
of such cover must be determined with due regard to how long it may be until final
connection.
Be responsible for and make good any damages caused directly or indirectly to any
walls, floors, ceilings, woodwork, brickwork, finishes, services, roads, gardens, etc.
2.2.5 Painting, Colour Coding & Identification
Equipment shall have the manufacturer's standard finish, unless otherwise specified in
the Contract, which, on completion of installation, shall be in good condition or brought
up to original standard.
Ferrous pipe work, brackets, etc. shall be painted with two coats of zinc phosphate
primer. Alternatively, where steelwork is completely enclosed, a proprietary antirust
coating may be used. A finish coat may also be required.
Secondary Identification
Apply colour bands, 50mm wide, in accordance with BS 1710 and superimpose a
legend identifying circuit, direction of fluid or gas flow, nominal pipe bore and, where
appropriate, fluid or gas pressure.
Colour bands shall not be provided on pipes which are to be painted to match internal
decorations. Directional flow arrows shall be provided on straight pipe runs, changes
of direction and passing through floors and walls.
b) Water Chiller:
Full details of water flow rates and design temperatures, condensing and evaporating
temperatures and pressures, refrigerants and lubricants, compressor type and duty,
electrical connections, and any other pertinent information as may be required by the
Company. This plate shall also be securely fixed to each of units local control panel
and protected from the environment influences.
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c) Pumps:
Pump size, rpm, amperes, voltage, impeller diameter, lubricants, pump characteristics,
flows for the duty specified, the K factor of the orifice plate if applicable, and any other
pertinent information as may be required by the Company. This plate shall also be
securely fixed to the pump.
d) AHUs, Fan Coils and Fans:
Air flows for the duty specified, fan size, rpm, amperes, voltage, pulley sizes, belt sizes,
air flow, impeller diameter, lubricants, fan characteristics, coil type and characteristics
air and water inlet/outlet temperatures and any other pertinent information as may be
required by the Company. This plate shall also be securely fixed to the fan. An
engraved label shall be fixed to each filter stating the maximum permissible pressure
drop.
The same as above is applicable to any other single piece of equipment or units within
the HVAC systems.
e) Identification plates
In addition to the specification plates, each unit shall be provided with an identification
plate showing the code number for each unit as indicated on the system schematics.
This plate shall be securely fixed to the unit in a prominent position.
f) Valve Equipment Labels
Valves shall be clearly labelled, and colour coded in accordance with BS 1710. Labels
shall be 100 mm x 40 mm, Colour/Black/Colour, multi-layer laminated plastic both
sides, showing the tag number and the service. Labels shall be attached to valve
spindles using short lengths of chain.
A valve chart, indicating both duty and position of all valves, shall be provided, in a
glazed picture frame and located as approved by the Company. Copies shall be
included as part of the As-Built Drawings.
Equipment shall be clearly labelled to identify equipment tag number and/or equipment
name and service. Labels shall multi-layer, White on Black, laminated plastic, front-
engraved and securely fixed to equipment by stainless steel screws or blind rivets.
2.2.6 Test Points & Instruments
Test points shall be provided as required for commissioning, whether shown on the
Contract Drawings or not, generally as given below to allow in-operation temperature
and/or pressure readings.
2.2.6.1 Test Points & Instruments for Pipe Works
Pressure and temperature test points in pipe work systems shall be provided at all main
branches and on flow and return connection to all cooling coils, and on all connections
to 3-way valves.
Temperature test points for pipe work shall comprise a 100 mm long x 15 mm brass
diameter well or sealable measuring nipple.
Thermometers for pipe work shall be bi-metallic type with a 100 mm dial, black case,
chrome bezel, 100 mm long stem and 15 mm BSPT connections, calibrated in °C.
Pressure test points for pipe work shall comprise a 10 mm diameter female brass gauge
cock and brass plug or sealable measuring nipple.
Pressure gauges for pipe work shall be the Bourdon type with a 100 mm diameter,
black case, chrome bezel and 10 mm BSPT connection, calibrated in PSI.2.2.6.2
Test Points & Instruments for Ductwork
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Pressure and temperature test points in ductwork systems shall be provided before and
after all air handling units, cooling coils and at fresh air and re-circulation inlets, whether
shown on the Contract Drawings or not.
Pressure and temperature test points for ductwork shall be 25 mm diameter holes
provided with an effective seal.
Test plug for AHU shall be to suit the panel thickness, by adding a further nut at the
lower thread end the plug can also be used on insulated ducting. Plug body cap and
nuts are made of brass. Cap seal neoprene and strap ethylene propylene rubber.
Temperature and pressure sensor shall be used which provides excellent
accuracy,repeatability and stability.
Separate fencing for the HVAC yard is not required if it is located within the plant
fencing.
The fence for the HVAC yard shall be provided if the building(s) is located outside the
plant fencing or if it is specify in the project specification.
The HVAC yard shall be provided with interlock or cement tiles as per sketch no
2.2.8 Commissioning & Handover
This section of the document provides guidelines for planning, responsibility, resources
and documentation for commissioning system by system. Technical commissioning
requirements for each service are given in the relevant Parts of these Specifications.
The commissioning period should comprise the following activities and events.
- Pre-commissioning.
- Commissioning and Start up.
- Contractor Substantial Completion.
- Contractor Completion.
- Handover to Asset Custodian.
Commissioning & Handover Procedure
A comprehensive method statement for Pre-commissioning and Commissioning the
Works shall be submitted to the Company for approval, well in advance of the planned
start.
The Method Statement shall include, but not be limited to:
- Identification of all systems
- Details of tests and demonstrations
- Samples of documentation (check lists, test sheets, test reports etc.)
- Details of test instruments
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- Pre-commissioning completion.
- Commissioning completion.
- Substantial Completion
- Handover.
The Commissioning Programme should include:
- Step by step procedures.
- Planning and resources.
- Details of specialist requirements.
2.2.8.2 Pre-Commissioning
Before pre-commissioning starts, the updated drawings, manuals, certificates and
factory test data shall be made available.
Materials, instruments and equipment shall be provided as required to carry out the
tests adequately, efficiently and safely. Test instrument calibration shall be checked
before use.
Before commencing work, verify that systems are complete and operable. Ensure the
following:
a. Equipment is operable and in a safe and normal condition.
b. Temperature control systems are installed complete and operable.
c. Proper thermal overload protection is in place for electrical equipment.
d. Filters are clean and in place. If required, install temporary media in addition to final
filters.
e. Hydraulic systems have been flushed, filled, and vented.
f. Pump motors have been checked to verify rotation is correct.
g. Proper strainer baskets are clean and in place.
h. Service and balance valves are open.
I. Fan motors have been checked to verify rotation is correct.
j. Fire and volume dampers are in place and open.
k. Duct system leakage has been minimized.
l. Coil fins have been cleaned and combed.
m. Access doors are closed, and duct end caps are in place.
n. Air outlets are installed and connected.
o. Fans and motors have been lubricated.
p. Alignment of pulleys and belt tension has been adjusted on each fan.
q. Fire, volume, and splitter dampers are operable and linkages are lubricated.
r. Position indicators are visible.
s. Field mounted gauges are installed and calibrated.
t. Confirm operation of ESD (Emergency Shutdown System).
u. Identify all duct traverse locations on the as-built drawings. Number and identify each
on the drawing and in the field.
v. Check whether indications in DCS (digital control system) are available.
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Definitions
Systems testing, adjusting, and balancing is the process of checking and adjusting all
the building environmental systems to produce the design objective. It includes:
The balance of air and water distribution, adjustment of total system to provide design
quantities, electrical measurement; verification of performance of all equipment and
automatic control; sound and vibration measurement.
Test: To determine quantitative performance of equipment.
Adjust: To regulate the specified fluid flow rate and air pattern at the terminal
equipment (e.g. reduce fan speed, throttling)
Balance: To proportion flows within the distribution system (sub-mains, branches, and
terminals) according to specified design quantities.
Procedure: Standardized approach and execution or sequence or work operations to
yield reproducible results.
Report forms: Test sheets arranged for collecting test data in logical order for
submission and review. These data should also form the permanent record to be used
as the basis for required future testing, adjusting, and balancing.
Terminal: The point where the controlled fluid enters or leaves the distribution system.
These are supply inlets on water terminals, return outlets on water terminals, and
exhaust or return inlets on air terminals such as registers, grilles, diffusers, louvers and
hoods.
Main: Duct or pipe containing part of the system’s capacity and serving two or more
branch mains.
Branch main: Duct or pipe serving two or more terminals.
Branch: Duct or pipe serving a single terminal.
When satisfied that a system, or systems, complies with the Contract Documents, the
Contractor shall give the Company adequate notice, in writing, that it is ready for test
and demonstration.
If full load conditions are not available, a system may be commissioned on part load.
The Contractor shall, however, repeat the tests and demonstrations under full load
conditions at such time(s) as it may be possible to do so.
The Contractor shall finally demonstrate to the Company that all systems of the
installation, already commissioned separately, operate simultaneously in accordance
with the Contract Documents.
Requirements include measurement and establishment of the fluid quantities of the
mechanical systems as required meeting design specifications and recording and
reporting the results.
Test adjusts and balances the following mechanical systems:
Supply air systems, all pressure ranges, including variable volume system
Return air system
Exhaust air system
Noise and sound control
Water piping system
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Control system
2.2.10 Test Report & Documentation Format
Such special tools as are required for testing or dismantling and assembling items of
equipment shall be provided in each equipment room.
Spare Parts
Classification Description
Initial Spares Spares required for Commissioning and First Year operation.
As Built Drawings shall be prepared, coordinated and submitted to the Company for
approval prior to the issue of the Substantial Completion Certificate. As Built Drawings
shall have the words ‘AS-BUILT DRAWING’ clearly indicated adjacent to the title block.
As Built Drawings shall include but not be limited to:
- External layout drawings at 1:500 or 1:100 scales.
- General arrangement drawings to a scale of 1:50.
- Detailed layouts of all plant and equipment areas, motor rooms, switch rooms,
etc., at a scale of 1:20.
- Control and protection drawings, diagrams and schematics.
- Schedules of equipment.
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Particular attention must be paid to the proximity of electrical conduit and cable to
mechanical piping and equipment. Electrical conduits shall not touch or be
supported on pipe or duct.
Confer with all trades installing equipment which may affect the work of this division,
and arrange equipment in proper relation with that equipment installed under all
Divisions of the Contract.
Furnish all items to be built in by others, in time, complete with all pertinent information,
commensurate with the progress of the work.
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All changes and connections to existing services shall be made only in a manner and
at a time approved by the Company, so as to avoid any interruption of such services
during normal working hours. If necessary, changes and connections to existing
services shall be made outside of normal working hours, at no extra cost.
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2.3.1 General
The Building Services design shall include, but not be limited to, overall scheme design,
sizing of equipment, duct & pipe work and coordination with other service.
HVAC system shall be designed to provide temperature, air quality and humidity controlled
environments for personnel and equipment in accordance with design criteria given in this
document. The design of the system should cater for the adverse desert environments
with fine sand and occasional high humid conditions. Systems shall incorporate the use
of filtration, cooling, heating and humidification/ dehumidification as required meeting this
objective.
Detailed design shall be prepared using established design methods, as given in ASHRAE
Fundamentals Handbook. Loads should be calculated using ASHRAE, Carrier or CIBSE
methods.
HVAC design review shall be carried out during details design stage
The heat load calculation shall be carried out using the latest version of Carrier HAP
programme only.
Actual U factors shall be calculated based on Architectural drawings.
The HVAC system shall be selected as follow:
- If the building is not serving Hydrocarbon facility then the table 1 shall be used.
Table 1:
Package units with duty Heavy duty package Supply and return duct
and standby(n +1 units with duty and can be common
arrangement) standby(n+1 between the units or
arrangement arrangement) each unit can be ducted
arrangement separately
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- If the building is serving the hydrocarbon facility then table 2 shall be used.
Table 2:
Building with and without Building with battery Requirements
battery room room
(Group C)* (Group D)*
Condensing unit and Air Condensing unit and With all associated
Handling Unit Air Handling Unit facilities e.g. duct work,
control system ...
*During the FEED or details design of the project, the project team shall be submitting
all necessary data to technical safety (MSE4) in order to evaluate the necessity of the
ventilation requirement for the building(s).
tight shut off damper shall be as per EN 1751 class 3, air leakage of 30 l/(s.m2) for closed
blade leakage and 0.29 l/(s.m2) for case leakage for duct pressure of 1000 Pa and less.
The tight shut off damper high integrity damper shall be provided with actuator in order to
close the damper within two seconds as maximum.
Sand trap louver shall be sized on 1.5 m/s velocity for economically and efficiently.
Building Automation System shall be considered when specified, for evaluating, controlling
the HVAC system from a centralized location, the integration of HVAC control systems
and the Building Automation System shall be considered on project bases.
A separate toilet/locker exhaust system shall be provided in all cases where these facilities
are provided and shall in no case be clubbed with exhaust of other areas. All exhaust fans
shall be provided with thermistor to protect from overheating.
All necessary fire/smoke dampers shall be provided within the air conditioned ducts, return
and exhaust openings penetrating and/or passing through walls of and fire zones.
Air handling units to be designed as per ASHRAE HVAC system and equipment
handbook(Latest version) The AHU shall be housed inside a room with air conditioning if
it is located in the red or yellow zones or if it is specify in the project specification. Rooftop
locations are acceptable, if space availability is a concern but with proper accessibility to
the roof e.g. concrete stair case.
Minimum space of 1.5 meter shall be maintained all the way around each unit.
Safe access to be provided to reach the unit and its accessories e.g. proper bridging with
hand rail.
Providing dog house in case of slab cut-out or/and side wall entry in case wall cut-out as
per the sketches provided in this SP.
Provide duct support all around the duct if the height of the duct is more than one meter
from floor finish level of the roof.
Water tank (1200 gallons) with two taps (one for AHU area and the second one for the
DX/chilled system area) shall be provided for maintenance of the HVAC. Also power out
let shall be provided for both locations (as above). The tank can be shared with other
facilities e.g. Toilet
Duty/stand by air handling units shall be fitted with shutoff dampers (motorised damper) to
allow maintenance of the stand by unit when the other unit is running.
Access sections with doors shall be provided at each filter section as required for the
maintenance, filter cleaning and replacement.
Fresh air ventilation units for control buildings, Computer buildings & auxiliary rooms to bel
be provided as per ANSI/ASHRAE 52.1 with following paramenters
MERV 8 or higher for Human comfort;
MERV 11 or higher for Electrical products;
MERV 13 for Chemistry & Physics Lab;
MERV 14 or 15 for Biology lab
MERV 11 for polluntant
MERV 3 for Pre filter
ASHRAE Standard 52.2 MERV 13 is equal to 80% ≤ Em( Average Eff.) < 90%
M.E.(Minimum Eff): 35%
F7 of EN 779:2012
Cooling coil shall be designed to have maximum air face velocities 2.5m/s to prevent
moisture carry over. Cooling coil performance shall be rated in accordance with ARI 410.
Heater shall be U.L. listed for the appropriate service.
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Supply fans shall be centrifugal type, backwardly inclined and air foil blades. Fans to be
tested and rated in accordance with ASHARE standard 51 and AMCA 210. Fans to be AMCA
tested, certified and labelled. Fan and housing assemblies to be isolated from vibration and
insulated as required to maintain a maximum sound power level rating of the unit at 85 dB, in
accordance with AMCA standard 301.
In general, all AHU motor shall be the high efficiency type (IE3). Terminal box for motor cable
shall be provided in the AHU wall close to fan section and from the box to the motor the cable
shall run through closed cable tray.
Motorised dampers shall be provided at all air inlets and outlets. Motorized damper shall be
provided at inlet of fresh air.
Outside air ventilation rates to be provided in accordance with latest revision ASHARE
standard 62.1
Relief of air shall be accomplished with gravity operated relief air dampers. These dampers
shall be set to relieve at specified building pressurization requirements. This damper shall be
start to open at +12pa (0.05 in wg.) above the mentioned pressure.
Exhaust to be provided for rest room, photocopy machine room, toilets, kitchen, battery room,
laboratories, and similar areas (when applicable) as indicated in appendix –B and in ASHRAE
standard 62.1. Air shall be exhausted by dedicated exhaust fans.Exhaust outlets shall be
located away from all air intakes. Exhaust rates to meet minimum criteria as given in ASHRAE
standard 62.1
Condensate drains from indoor terminal units should discharge to nearest soak way. The
drain line shall be provided with open-able trap with water seal, cover with insulation and
metal cladding.
Pipe work shall not be directly buried, not chased in floors or walls, but shall be enclosed in
preformed ducts or voids.Refrigerant pipes shall be insulated as per standards with metal
cladding and run in a metal open tray.
The HVAC controls shall be interlocked with the fire and gas detection system. Activation of
a fire alarm shall cause the shutdown of air conditioning system, unless continued operation
of the system does not cause spread of smoke to outside the area where the fire has been
detected. In case of detection of H2S, Hydrocarbon or any flammable gases, the fresh air
intake motorized damper of air-conditioning system shall shutdown automatically to prevent
ingress of gases into the building through fresh air system and air conditioning system shall
be shutdown.
Where installations include evaporate water-cooling, the guidelines of CIBSE TM 13,
minimising the risk of Legionnaires disease, shall be followed.
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Design indoor conditions should be based on the ASHRAE standard, CIBSE Guide,
Section A1, Environmental Criteria for Design, and shall be subject to Company
approval.
Ventilation rates shall keep carbon dioxide concentrations below 1000 ppm to create
indoor air quality conditions acceptable.
Contractor to use actual equipment heat gains from the selected equipment in the
calculation. Humidity shall be controlled.
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The above limits may be exceeded in areas where space restrictions exist; it’s
subjected to approval from the company.
The length of the flexible duct shall not exceed 6 x diameter and supports to be provided
as per DW 144 section 30
All rectangular 45 to 90 degree elbows ductwork shall contain turning vanes. Kitchen
exhaust ductwork shall be welded stainless steel. See NFPA 96 for kitchen exhaust
ductwork design restrictions.
Balancing devices shall be provided at each supply branch connection. Balancing
devices shall also be provided at return air and exhaust air devices to obtain required
return and exhaust airflow. Pressure loss for each outlet on each ductwork branch or
run shall be approximately equal to ensure uniform air distribution.
Quick selection of air terminals shall be carried out based on a face velocity of 2.5 m/s
(500- FPM) and the velocity selection shall maintain the required noise level. Similarly,
air intake louvers shall be sized on a face velocity of 1.5 m/s (300 FPM) and extract air
louvers on a face velocity of 2m/s (400 FPM). Face areas shall be gross area and not
net free area.
Maximum noise criteria shall be as given in appendix –B of this specification.
All inlets in finished spaces shall be installed with an inlet air boot for appearance and
noise control. Air inlet/return devices should have volume control dampers.
Pressure sensor shall be installed in supply duct and link with the DDC to monitor the
duct pressure.
The Air-Conditioning & Ventilation system, materials and Equipment shall comply with
the section-3.
Air conditioning equipment shall be selected aiming for the highest operation efficiency.
The minimum Coefficient of Performance (COP) at 50°C for all Air Conditioner shall be
1.9 (integrated) for all types of compressors.
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Where items of equipment are interconnected to form an integral part of the complete
air conditioning installation, their characteristics of performance and capacities shall be
so matched as to give safe, reliable, efficient and economical operation of the complete
air conditioning installation.
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2.4.5 Kitchens
The guidelines given below address commercial catering installations, criteria for
domestic kitchens are given in Appendix-B.
Often it is not possible to achieve comfort conditions in kitchen cooking areas at all
times because of the extremely high expenditure involved. In such cases, it should be
sufficient to maintain acceptable working conditions with maximum of 24°C with 70%
RH.
Generally air should be extracted from cooking and subsidiary areas through stainless
steel double-skin hoods, minimum sheet thickness 18 gauge located over the main
cooking, Chapatti area, Bakery/Pastry and dishwashing equipment. Hoods should be
sized to overlap equipment by 150 mm each side, to have a minimum face velocity of
0.3 m/s and to have a minimum clearance of 1900 mm above finished floor level.
Vertical distance from lower lip of the hood and the cooking surface shall not exceed
1200 mm. The hood volume should suit the equipment covered. 80 – 85% of the
replacement air should be provided, as treated (cooled and filtered) outside air with
85% efficiency, at the internal perimeter of the hood. If this part of the replacement air
is supplied outside the hood, it should be 100% outside air-cooled to plenum conditions.
Ducted, re-circulating systems should not be used because of greasing problems. The
remainder of the replacement air should be drawn from adjacent areas so that a
negative kitchen pressure is maintained to contain odours but Kitchen pressure shall
be maintained positive against the atmospheric pressure.For commercial kitchens
Refer to ASHREA System and Equibment and UL Standard.
Extract ductwork shall be designed for ease of cleaning, with flanged joints and man-
size access doors, and shall be constructed of stainless steel sheet (type 316),
minimum thickness, 1.0 mm. Air velocities should be a minimum of 9 m/s. Extract fans
should be treated for moisture and heat, and attenuators should be avoided. A point of
grease and residue collection shall be provided at the base of each vertical rise. An
opening and drain trap shall be provided at each change in direction of the duct for
purposes of inspection and cleaning. This access door shall be made to be removed
without the use of tools.
The hood shall be equipped with stainless steel baffle type grease filter. The filter
housing shall terminate in a pitched, full length grease trough, which shall drain into a
stainless steel removable grease container. Any noise from the filter shall not be
acceptable. The drain line shall be provide and connected to drain point of hood. Hood
shall be provided with one (1) filter removal tool.
All external joints and seams are to be welded liquid-tight. The motor to an exhaust fan
is to be located outside the exhaust air stream. The ducts that terminate above the roof
has the discharge located a minimum 1000 mm above the roof surface and distance
should be 20 meter between the exhaust point and any supply air intakes. The
discharge terminal device should include a bird guard mesh (made of SS grade 316)
and protected from rain entertainment.
Comfort air conditioning should be provided by high level fan coil units.
The requirements for fire detection and protection in kitchens are included in SP-1075
Specification for Fire & Explosion Risk Management.
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2.4.6 Laboratories
Laboratory air conditioning design shall adher to ASHREA Application Standard.
However, the following guidelines should apply.
HVAC system for Laboratory working and solvent storage areas should be provided
with 100% outside air system (with treatment), which also provide adequate ventilation
to offset fume hood exhaust and exhaust air requirements. Laboratory supply air shall
not be re-circulated or reused for other ventilation needs. In interior Oman, heating
should be included for winter morning start up. Ancillary areas, such as offices, should
be provided with separate, re-circulating systems such as fan coil units. Mechanical
exhaust should be provided for chemical and material storage areas, typically at a rate
of 6 – 15 air changes an hour, depending on the items stored.
Fume cupboards for use with hydrocarbons should have an acid resistant 18/12
stainless steel internal fume chamber with integral bench top. The minimum air velocity
over a 400 mm deep sash opening should be 0.75 m/s.
Fume cupboards for general use should have 1 mm thick high-pressure plastic
laminate on the sides and solid epoxy resin bench tops. The minimum air velocity over
a 400 mm deep sash opening should be 0.5 m/s.
All fume cupboards should be provided with air foil sash opening profiles and high-level
by-pass grilles to ensure constant volume airstreams.
Fume cupboard exhaust ductwork shall be constructed of HDPE or stain steel 316 and
shall not contain fire dampers. Fire detection and alarm systems shall not be
interlocked to automatically shut down laboratory hood exhaust fan.
Exhaust air from fume hoods shall be sterilized before being exhausted to the outdoors
and meet the requirements of ASHRAE HVAC Application Handbook.
The internal fume chamber, exhaust ducting and exhaust fan shall be classified as
Zone 1 hazard.(To be finalised with technical safety team)The internal light fittings
therefore shall be separated from the fume chamber by an airtight glass plateSolvent
and gas bottle stores shall be classified Zone 2.
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2.5 Appendices
Appendix 2.5A: Glossary of Definitions & Abbreviations
Appendix 2.5B: Internal Environment Design Criteria
Appendix 2.5C: Standard Forms
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The Contractor : The party with which the Company has entered into a
Contract
Manufacturer : A Party responsible for the manufacture of equipment and
services to perform the duties specified by the Consultant or
the Company.
Vendor/Supplier: : A party responsible for the supply of equipment, materials or
product related services in accordance with the purchase
order issued by PDO or its nominated purchasing office.
Local Agent : An authorised agent of a Manufacturer in the Sultanate Of
Oman who can supply the product and services.
National Product : A product defined as a National Product, in origin
manufactured in the Sultanate Of Oman as per the General
Conditions of Contract.
GCC Product : A product defined as a GCC Product, in origin manufactured
in GCC country as per the General Conditions of Contract.
Works : The permanent Works to be executed and maintained in
accordance with the contract together with all temporary
works of every kind required in or about the execution or
maintenance of the Works.
Workshop : A defined place, approved by the Company, where the
Contractor executes fabrication works.
Worksite : The land and other places on, under, in or through which the
Works are to be executed.
the User : The Company, and/or Consultant, designate using this
document.
Temporary : Any member or structure which needs to withstand loads and
Structures forces of a temporary nature, such as scaffolding, erection
bracing, steel props, commissioning facilities, etc. The word
‘temporary’ shall be understood as a short period, limited to
maximum of 2 years.
Semi Permanent : Any member or structure which needs to withstand all
Structures meteorological conditions, loads and forces of a permanent
nature, but designed for a short period. The word ‘semi-
permanent’ shall be understood as a relatively short period,
limited to maximum of 4 years.
Permanent : Any member or structure which needs to withstand all
Structures meteorological conditions, loads and forces of a permanent
nature, but designed for a long period. The word ‘permanent’
shall be understood as a relatively long period, say 30 years
or more.
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2.5.A2 Abbreviations
The following abbreviations are used in this document.
ASME : American Society of Mechanical Engineers
BS : British Standard
CP : Code of Practice
FS : Full Size
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GI : Galvanised Iron
HOR : Horizontal
HP : High Pressure
HV : High Voltage
HW : Hardwood
JE : Junior Employee
JS : Junior Staff
LV : Low Voltage
MAX : Maximum
N : Neutral
No. : Number
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SP : Specification
SS : Senior Staff
STD : Standard
UV : Ultra Violet
VERT : Vertical
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Ref No Description
C.1 STD-2-1702-A01 : Pipe work Leakage Test
C.2 STD-2-1702-A02 : Exceptions List
C.3 STD-2-1702-A03 : Handover Report
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Notes: Pipe work leakage tests shall be conducted in accordance with Specification
WITNESSED
Sheet No: for Contractor: for PDO:
Date: Position: Ref Ind:
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Date By Date By
NOTES:
DISTRIBUTION
Update
Sheet No.
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3.1 Introduction
This specification covers the technical requirements for the furnishing &installation of
equipment, final testing, adjusting, and balancing of all heating, ventilating and air-
conditioning system.
3.2 Scope
3.2.1 General
This Specification shall define the physical characteristics of the suitable materials and
describes the Works based on product or a method of Specifications. This Specification
shall also define the type of testing requirements and test sheets to be used.
Plant and non-plant buildings require climatic conditioning (i.e. air conditioning and
ventilation) in order to maintain the temperature, relative humidity and air quality within
defined limits. In this way reliable operation of electronic equipment and human working
conditions are enhanced.
HVAC systems are generally supplied by specialised Manufacturers as package units or
as single components. Standard industrial HVAC equipment should be used.
It shall be ensured that sufficient space in buildings is reserved for HVAC equipment and
its ducting.
3.2.2 Abbreviations
General abbreviations are given in Section-2 Specification for HVAC Services – ‘General
Requirements’. The following additional abbreviations have been used in this document.
DB - Dry Bulb Temperature
HDPE - High Density Polyethylene
HRC - High Rupturing Capacity
WB - Wet Bulb Temperature
AHU - Air Handling Unit
3.2.3 Definitions
For the purpose of this Specification, the following definitions shall hold:
3.2.3.1 General Definitions
The Contractor is the party which carries out all or part of the design, engineering,
procurement, construction, commissioning or management of a project or operation of a
facility. The Principal may undertake all or part of the duties of the Contractor.
The Manufacturer/Supplier is the party which manufactures or supplies equipment and
services to perform the duties specified by the Contractor.
The Company is the party which initiates the project and ultimately pays for its design
and construction. The Company will generally specify the technical requirements. The
Company may also include an agent or consultant authorised to act for, and on behalf of,
the Company.
The word shall indicate a requirement. The word should indicate a recommendation.
3.2.3.2 Specific Definitions
Air Handling Unit (Re-circulation): HVAC equipment through which air is transported
and transformed to the required conditions by filtration, heating and cooling (including
humidification/dehumidification by means of condensation). Re-circulation air handling
units may form part of an HVAC ducting system.
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Air Handling Unit (Self-contained): An air handling unit, located in the space which it
serves, which re-circulates the air in that space to the required conditions. A self-
contained air handling unit does not normally involve a ducting system.
Chilled Water Unit (Air cool type): A unit similar to a direct expansion (DX) chiller but
including a heat exchanger which utilises the vaporising refrigerant's latent heat to cool a
chilled water circuit to the required temperature.
Direct Expansion (DX) Chiller: A unit consisting of a compressor and a condenser. The
refrigerant vapour is compressed to a certain pressure, condensed to liquid refrigerant
and then vaporised, thus utilising the vaporising refrigerant's latent heat in a cooling coil
(separate from the chiller). The vaporised refrigerant is returned from the coil to the
compressor.
(Dry-bulb) Temperature: The temperature of the air indicated by an accurate
thermometer.
Electronic/Electrical Equipment: Indoor electronic and electrical equipment, including
microprocessor based control, safeguarding, telecommunication, computer, power
supply and switchgear systems.
Fan Coil Unit: HVAC equipment through which air is re-circulated from the space in which
it is located. The purpose of this re-circulation is to cool or heat this air to the conditions
required for the space. This unit is normally connected to the chilled water system.
Fresh air Ventilation Unit: An air handling unit in which the fresh air is handled to the
required conditions and used as ventilation air.
Human Comfort: Is defined by the environmental parameters of temperature, radiation,
humidity and air movement necessary for thermal comfort and depends on the individual’s
clothing and activity level. In a control building occupants will typically be sedentary or
slightly active and wearing indoor clothing.
Humidity (Relative): The ratio of the weight fraction of water vapour present in the air to
the weight fraction of water vapour present in saturated air at the same temperature and
barometric pressure.
HVAC System: A heating, ventilation and air-conditioning system which maintains the
temperature, relative humidity and air quality in a room or building within defined limits.
Interruptible, Maintained Electrical Supply: A source of electrical power which is
backed up by a second (emergency) source of power to provide a supply of electricity
that may be interrupted for no more than 15 s.
Buildings: Buildings such as offices, all non-plant buildings, control buildings, field
auxiliary rooms (FARs), analyser houses, electrical substations and others (e.g.
dedicated flow metering buildings). Such buildings may contain different types of rooms.
HVAC electrical equipment shall be suitable for the applicable hazardous area.
Uninterruptible Maintained Electrical Supply. A source of electrical power, which is
backed up by a second (emergency) source of power to provide a supply of electricity
that may be interrupted for no more than 0.5 minutes.
Vital electronic equipment: Electronic equipment which, if failing in operation or when
actuated, can cause a process upset, an unsafe condition of the process and/or electrical
installation, can jeopardise life, or can cause major damage to the installation.
Vital HVAC system: A HVAC system meant for vital rooms only.
Vital rooms: Rooms containing vital electronic equipment (e.g. computer rooms,
instrument auxiliary room, electrical auxiliary room, telecommunications room) and
continuously manned rooms (e.g. control room).
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Units of measurement are listed in ‘General Requirements’ Section-2 and item 2.2.2 page
16.
3.3.1.1 General
Provide factory assembled and tested air-cooled liquid chiller, suitable for outdoor
installation, to operate at a wide range of ambient temperature from “-4ºC” to “55ºC”.
Chiller shall include but not be limited as compressors, evaporator, condensers,
electronic expansion valves, inter connecting piping & wiring and control panels. Engrave
plate and labelling shall be provided for each chiller components .Engrave plate shall be
of stainless steel.
The chiller shall be designed to cooling chilled water temperature as 4ºC to 12ºC. Chiller
capacity selection shall be based on a water side fouling factor 0.018 m² ºC/kw in the
evaporator tubes and the dry bulb temperature entering the air cooled condenser. The
unit shall be able to start with an evaporator entering high fluid temperature.
The chiller unit shall consist of two compressors minimum and minimum two independent
refrigerant circuits shall be provided. Compressor shall be mounted on a single welded
steel base.
Chiller shall be performance tests/run tested at the manufacturer’s works under simulated
design conditions. Such tests shall be witnessed and approved by the Company’s
engineer(s). Prior to shipment, the chiller automated controls test shall be executed to
check for proper wiring and ensure correct controls operation, the unit shall be pressure
tested, evacuated and fully charged with refrigerant.
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3.3.1.2 Fluids
Provide full operating charge of refrigerant, oil and all other fluids as required for proper
operation. Refrigerant shall not contain chlorine. The unit shall be charged with
environment friendly, ozone friendly and low global warming potential refrigerant.
Contractor shall evaluate the available environmentally friendly refrigerant and submit to
Company for approval during the design review and before ordering the chiller.
3.3.1.3 Housing
The casing of unit shall be made of zinc coated galvanized steel sheets which is
phosphatised and backed after an electrostatic powder coat of 60 microns. Use ASHREA
system and equipment standard
Base rail hall be of formed double thickness, painted galvanized plate steel or stainless
steel.
Provide removable panels and/or access doors of same material and same finishing used
for casing, for inspection and access to internal parts and components. Door shall be
provided with special gasket and locking device.
3.3.1.4 Evaporator
Provide shell and tube design with seamless copper tubes with minimum wall thickness
0.6-0.71mm, roller expanded into tube sheets. Design, test, and stamp for refrigerant side
working pressure of 1550 kPa minimum and water side working pressure of 1034 kPa
minimum in accordance with ASME pressure vessel code or equivalent European codes.
Provide one water pass with series of internal baffles. Provide 1034 kPa flanged water
connections. Provide water drain connection with stainless steel valve and bulb wells of
copper /brass for temperature controller and low temperature cut-out at 3- 4ºC.
Provide independent multiple refrigerant circuit’s gasket evaporator heads. The
evaporator shell shall be insulated with19- 25mm closed –cell with a maximum K factor
of 0.038w/m.ºK. Evaporator thermal insulation shall be flexible elastomeric complying
ASTM C 534, type II, apply adhesive to 100 percent of insulation contact surface to give
good rigidity, after adhesive apply two coats of protective coating to insulation, factory
apply insulation over entire surfaces of water chillers component, factory fitted with
aluminium cladding thickness 0.3mm minimum to provide mechanical protection and
ensure protection against UV rays.
In top of the insulation metal cladding of 0.55mm thickness shall be provided to the
evaporator and the suction line.
3.3.1.5 Condenser
Construction of condenser to comply to ASHRAE - HVAC system and equipment ( Latest
Revision)
Construct coils with copper headers and configured aluminium or copper/copper fins &
tube mechanically bonded to seamless copper tubing. Micro channel heat exchanger
(fully aluminium) is also acceptable. Provide integral sub-cooling circuit with liquid
accumulators.
Condensers coil (except similar materials) shall be coated with here-site or approved
equivalent to prevent corrosion. Coating shall be guaranteed for 5 years. The condenser
coils shall be leak-tested by nitrogen/helium gas detection at 1.5 times working pressure.
Provide removable guard factory mounted with wire mesh heavy gauge, electro-
galvanized or polyethylene coated to full unit.
Fan motors shall be rated for outdoor use IP 55 protection.
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3.3.1.6 Compressor
Construction of compressor to comply to ASHRAE - HVAC system and equipment (Latest
Revision)
Assembly to conform to ASME Boiler and Pressure Vessel Code. Assembly shall be sized
and rated for chiller capacity. Assembly shall function according to ASHRAE 15-1992,
Safety Code for Mechanical Refrigeration, Section 10.4.5.
Pressure switch shall have alarm contacts suitable for use with a remote audible, visual
alarm, or the building management/ DDC system.
The diagnostics display module shall indicate the safety lockout condition by a numeric
or other suitable coding at the control panel, and shall be able to scroll an explanation for
the coded condition. The diagnostic display module shall have the capability of displaying
the output (result) of run tests to verify operation of each chiller component (fan,
compressor, switch, etc.) before chiller is started.
Capacity control based on leaving chilled water temperature 5ºC with return chilled water
sensing.
Unit controls shall include a microprocessor board and 80 characteristic digit
diagnostic display as a minimum that is capable of achieving the following function.
Automatic changeover between compressors.
Limiting the chilled water temperature pull down rate at start up to an adjustable
range 0.1 to 1.1ºC per minute to prevent excessive demand spikes at start up.
Enable chilled water leaving temperature adjustment based on return water
temperature.
Provide a dual set point for the leaving chilled water temperature activated by a
remote contact closure signal
Control water pump operation
Enable automatic lead lag of two chillers in a single system
The interlock system shall be provided between the chillers and AHU’s.
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The chiller control system shall be suitable for the following remote control system
interface but not the limited from HVAC panel, DCS and Scada system:
3.3.1.12 Motors
Motors for all HVAC equipment to be in accordance and relevant standards IEC
60034-1 & IEC 60034-14.
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b) Pipes for chilled water installed above grade to be seamless black Mild steel,
heavy weight to BS EN10255 or equivalent with ASTM A53 Schedule 40.
c) Pipes shall be painted with two coats of red oxide primer prior to application of
thermal insulation.
65 mm and larger
i) Wrought carbon steel to comply ANSI B 16.9, butt-weld fittings.
50 mm and smaller
ii) Malleable iron to comply ASME B 16.3 with threads ends.
iii) Flare connections may be used on soft copper tubing where one end of the flare
connection is an integral part of the equipment or valve.
iv) Welding flanges for pipe 65 mm and larger: Steel to ASME B 16.5.
v) Unions for pipe 50 mm and smaller shall be Malleable iron ASTM A197, class 150,
with bronze to iron ground joint, ANSI B 16.3
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Isolating valves, size 50 mm and under, to be to BS EN 12288, bronze gate valves with
solid wedge, non-rising stem and screwed BSPT ends, approved by the Company.
Valve sets, sizes 15 mm to 50 mm, shall comprise bronze metering station, close coupled,
bronze double regulating valve located on the return, together with an isolating valve on
the flow.
Valve sets size 65 mm and above, shall comprise PN 16, cast iron metering station, close-
coupled, cast iron double regulating valve located in the return, together with an isolating
valve on the flow.
The test set shall comprise a single column type manometer connected to measure the
pressure difference across the metering station. The test set shall be supplied with
bypass and isolating valves and lengths of connecting tubing, terminating in probe units.
3.3.3.5 Strainers
Strainers to be according to ASHRAE Handbook-HVAC Application (Latest version)
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3.3.3.12 Fittings
Wrought-copper fittings, ANSI B16.22, ARI 710 and ANSI B16.26, as applicable,
streamlined pattern.
Provide automatic air vents at all high points on piping mains for chilled water systems.
Arrange all runs of piping to prevent interference and to achieve a satisfactory and
workman like installation of neat appearance. Run all piping parallel to walls. All valves
controls, equipment, expansion compensators, flexible connections, as far possible, all
piping shall be easily accessible for inspection, maintenance and operation.
Unless otherwise specified or instructed on site, all pipe work shall have a minimum
clearance of 25 mm between its finished face (including insulation) and the finished face
of any wall, pipe or other surface.
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Where pipe work passes through walls, floors or partitions etc., mild steel sleeves with
sufficient diameter shall be provided to allow the pipe work and its insulation to pass
through uninterrupted.
Provide adequate allowance for expansion and contraction of piping by providing
expansion joints.
Install drain valves at all low points for draining and locate where easily accessible.
Threaded joints shall be carefully reamed and jointed with compound on the male thread
only. Re-tighten flanged connections after the installation has been brought up to its
service temperature, after which operation, the insulation may be applied. Take care not
to over stress the material during construction.
Inaccessible pipes in chases, ducts, partitions and, where no easy access is available,
shall be welded irrespective of size. No joints shall be made in walls or floors, etc.
Provide strainers upstream of each pump suction and inlet of equipment.
Provide gate, globe, and check valves in all piping systems as required for satisfactory
operation and control of equipment. Provide shut-off valves wherever piping is connected
to any equipment.
Pressure gauges shall be installed on the suction connection & delivery of each pump
and in the feed and pressurization line to each system.
Condensate drains shall be provided to all equipment requiring same and shall be routed,
via a trap, to the nearest waste stack or floor drain as appropriate. Discharge condensate
drain indirectly to waste.
All ends shall be cut square and be well reamed or filed to ensure that the full bore of the
pipe is maintained.
Where branches are to be welded in, the ends of the branch pipes shall be correctly
shaped to the main pipe and the hole for the branch pipe cut in the main shall be the full
diameter of the branch pipe and shall be executed with the aid of a template. All loose
scale and oxide shall be removed from the inside of the main pipe before the branch boss
is welded into position.
Pipe welding operations shall be performed by welders holding a certificate from the
inspection agency for the class of piping to be welded. No superfluous material shall
restrict the internal opening of pipes and fittings.
When welding or cutting with a torch, take precautions to prevent fire.
Arrange piping to permit ease of equipment removal. Flanges or unions shall be provided
on all pipe connections to each piece of equipment. Install all valves in equipment rooms
in accessible locations from the floor.
Where ASTM are specified pipes shall have same specification as standards indicated
(BS) and contractor shall ensure that alternative standard submitted is equivalent to the
specified standard. All BS products shall carry kite mark seal.
Special care shall be taken to prevent the ingress of dirt or rubbish entering the open
ends of all pipe work during erection. Approved caps shall be used for this purpose, the
use of shavings, rags or paper will not be allowed.
All pipe work shall be tested to at least one and a half times the working pressure of
the systems. If any leaks be detected during the specified testing, the defective portion
of the weld shall be cut out and re-welded, and further tested until found satisfactory.
After the chilled water pipe work system has been completed, but before the final
connections to the fan coil units/ air handling units are made, the systems shall be
continually flushed through with clean water until the discharge water is clean. To
facilitate the fan coil connections shall be isolated and temporary loops made between
the flow and return connections on the end of each run.
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Cut refrigerant piping accurately to measurements established at the site, and install
without springing or forcing. Installed piping shall be sufficiently flexible to allow expansion
and contraction caused by temperature fluctuation inherent in its operation.
Do not conceal piping in walls and partitions, underground, or under a floor, except as
indicated. Do not conceal pipe joints within the building. Run insulated pipe as indicated
and as required, with sufficient clearance to permit application of insulation. Care shall
be taken to avoid interference with other piping. Run piping plumb and straight.
Refrigerant piping shall be joined by brazing. Free the inside of tubing and fittings from
burrs and flux. Clean the parts to be jointed thoroughly with emery cloth. Heat to a
temperature greater than the solder flow point, and keep heated until the solder has
penetrated the full depth of the fitting and the extra flux has been expelled.
Joints shall be air cooled; marks and traces of flux shall be removed. Protect the piping
from forming an oxide film on the inside.
Install refrigerant driers, sight glass liquid indicators, and strainers in refrigerant piping if
not furnished by the equipment manufacturer. Installed driers in liquid lines, with service
valves and valve bypass line.
Locate strainers near the equipment requiring protection. Install a strainer in the common
refrigerant liquid supply to two or more thermal valves in parallel if each thermal valves
has a built-in strainer. Install strainers with screen down and in direction of flow as
indicated on strainer body.
Install refrigerant charging valve connection for each remote type refrigeration system,
located on the reducing outlet of a full size tee in the liquid line, upstream from the
refrigerant drier and liquid indicator sight glass.
Install solenoid valves in horizontal lines, locate stems vertically, and indicate direction of
flow on the valves.
3.3.4.3 Trenches
Buried chilled water pipe work shall be laid on minimum 150 mm thick compacted bedding
and shall have a minimum cover of 800 mm. Backfilling shall be in 150mm thick layers,
the first layer being laid by hand.
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Bedding and backfill shall comprise of sand, excluding stones retained in a 25 mm sieve,
or other material equal and approved by the Company. Watering shall be minimal,
sufficient to dampen but not to flood. All buried chilled water lines shall be provided with
protection jacket as well as normal insulation and Cora cloth with paint.
Pipe work shall not be directly buried but be enclosed in pre-formed, unfilled ducts, and
sealed at building entry. In cases where proprietary metal clamps are used, pipe work
shall be insulated, using plastic tape, to prevent chafing and electrolytic action.
Each refrigeration circuit shall be supplied with a correctly sized thermostatic expansion
valve, liquid line solenoid valve with suitable coil, liquid line sight glass and moisture
indicator, and open able filter drier with shut-off valve. Refrigeration pipes shall be
protected by metal cladding (0.55mm) after insulation. Refrigeration pipes shall run in
Company’s approved a galvanized steel tray. Provide copper finished steel clamp or
plastic coated steel clamp or Company’s approved.
Vertical runs
Pipe work shall be clamped using hard wood clamping blocks or, subject to approval by
the Company, proprietary pipe work fixings. The maximum distance between clamps
shall be 1000mm and the minimum distance from a bend to a clamp shall be 300 mm.
Horizontal Runs
Pipe work shall be laid level without sagging, and supported by hard wood battens, or
proprietary fixings, and clamped. The maximum distance between clamps shall be 1000
mm and the minimum distance from a bend to a clamp shall be 300 mm.
Drain sizes shall not be less than the equipment drain pan connection size and shall
include a union, or similar, coupling located so that the equipment may be removed.
Traps shall be provided to ensure that a seal is always maintained from the drainage
system and between air-conditioned spaces. Traps shall be located to avoid drying out.
For this reason, condensate drain discharge should be above wash hand basin traps, or
similar
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fungal lagging adhesive. Rubber half sectional inserts shall be used where the support
clamps are fixed.
Exposed chilled water pipe-work insulation on roof, plant room and other areas shall be
provided with aluminium cladding. It shall be cladded using an outer covering of plain
aluminium sheet of 0.55mm or thicker.
3.3.6 Execution
Insulation on pipes and ducts shall not be applied without adequate application of
adhesives on the pipe/duct surfaces.
Insulate and finish valves and fittings in the same manner and same thickness as piping in
which such items are installed. Insulate and finish valves and fittings in the same manner
and same thickness as piping in which such items are installed.
Direct contact between pipe and hanger shall be avoided. Hangers shall pass outside of
the sheet metal protection saddle, which shall cover a section of high density insulation,
of sufficient length to support the pipe without crushing the insulation. The vapour barrier
shall be lapped over the saddle and securely cemented to it. Minimum thickness of metal
saddle is 1.5 mm. The insulation shall be installed in accordance with the manufacturer’s
printed instructions.
Internal piping shall be seamless black Mild steel, heavy weight to BS EN10255 or
equivalent with to ASTM A53 Schedule 40. All joints shall be butt welded for sizes 65mm
and larger and socket welded for 50mm and below. Straight sections, shall be supplied in
12M random length where it possible.
ii) Insulation
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The pipe insulation shall be with a material of insulation conductivity of 0.032 to 0.040
W/(m.K) for a fluid design operating tempeparture range of 4 to 16 °C and <4 °C.
The leak detection cable shall be factory installed and supplied by the prefabricated system
manufacturer. The leak detection/location system shall consist of microprocessor based
monitoring unit(s) capable of continuous monitoring of a sensor string for leaks/faults. The
units shall have a sensing range of 610meter to 1525 meter (2000) (5000) feet per cable.
The alarm unit(s) shall operate on the principle of pulsed energy reflection and be capable
of mapping the entire length of the sensor cable and storing the digitized system map in
non-volatile memory. An analogue system using an alarm threshold value, fixed for the
length of the cable, or a portion of the cable, will not be allowed as it will not detect a second
leak smaller than any acknowledged leak. The alarm unit(s) shall provide continuous
indication that the sensor cable is being monitored.
After proper acknowledgement of a minor leak, the leak detection/location system shall be
capable of monitoring the entire sensing string for additional leaks even if they are smaller
than the leaks previously acknowledged. The system shall be capable of accounting for
minor installation irregularities, static moisture and puddles (such as condensation) with no
loss in accuracy or sensitivity. The system shall locate the point of origin of the first leak or
fault within ±1.5 metre (±5 feet), whichever is greater. The monitoring unit shall report and
record, to non-volatile memory, the type of fault, distance, date, and time of an alarm.
The system manufacturer shall have at least seven years of experience with leak
detection/location sensor cable technology and provide a factory trained representative at
two on-site meetings for pre-construction and sensor/electronics installation.
The system shall have multi-level security passwords for access to operating functions with
recording of all password entries to non-volatile memory.
The alarm unit(s) shall be enclosed in a modified NEMA 12 enclosure and have a two line
by forty character display providing status and alarm data. The monitoring unit(s) (will be
field connected to any) (will have a factory mounted) alarm horn. The monitoring unit shall
be U.L. listed and FM approved to provide connections for intrinsically safe sensor circuits
for use in Class 1 Division 1, Groups C and D hazardous locations.
The system shall be tested and found to comply with the limits for a Class A digital device,
pursuant to Part 15 of the FCC rules and so labelled.
The system shall be evaluated by an independent third party according to the Third Party
Procedures developed according to the U.S. EPA’s “Standard Test Procedure for
Evaluating Leak Detection Methods: Liquid-Phase Out-of-Tank Product Detectors.” The
evaluation results shall verify the system manufacturer’s claims regarding sensitivity, range,
and other performance data.
Ability to locate a leak shall not depend on battery backed-up functions. In the event of
power failure, system conditions and parameters shall be stored in non-volatile memory
allowing the units to automatically resume monitoring, without resetting, upon restoration of
power.
The monitoring unit(s) power requirements shall be 240V, 50 Hz, single phase. Monitoring
units shall be equipped with an RS-232 communication port and a minimum of two SPDT
output relay, rated for 250 VAC, 10 amps.
The sensor cable, connectors, (probes) and jumpers shall be supplied by the manufacturer
of the monitoring unit(s). The cable sensing principal shall provide for continuous
monitoring while short lengths of the cable are in contact with liquids, without altering the
systems sensitivity and/or accuracy.
Software shall be provided that allows the user to remotely or on site interface thru the RS-
232 serial port for trouble shooting and diagnostics. Software shall have the ability to
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operate the PAL-AT monitoring units and retrieve each of the stored reference maps and
current condition TDR traces. Software shall also be including the above features and also
having auto call and continuous monitoring. The auto call will allow the PAL-AT, thru
PALCOM software to call a designated phone number and deliver a verbal message when
an event is detected.
iv) Protective Jacket
The outer casing protective jacket shall be high density polyethylene (HDPE) industrial
grade material and shall conform to ASTM D 1248, Type 3, Class C specifications. PVC,
or tape materials shall not be allowed as material for the jacket construction. The jacket
shall be seamless throughout. All fittings shall be factory welded, by butt fusion or extrusion
welding process. Hot air welding or taping shall not be allowed in the factory or in the field.
v) Anchors, End Seals, Gland seals and other accessories
All system accessories shall be factory manufactured water tight and designed to prevent
moisture from entering the insulated system.
Pumps shall be supplied with flanged connections to BS 4505 together with mating
flanges. Pump flanges shall be tapped for discharge and suction pressure/altitude
gauges.
The pumps shall be entirely suitable for continuous operation in ambient temperatures of
50°C under shade.
The pump and motor shall be aligned and shall be mounted on a manufacturer fabricated
cast iron steel base and the complete unit shall be with anti-vibration appropriate spring
mounted on a minimum 150mm thick reinforced concrete plinth with 50mm thick layer of
dense cork or other approved anti-vibration media surrounded by kerb and sealed with
bituminous compound to prevent ingress of moisture.
Suction connections shall include isolating valve, strainer, pressure gauge and cock,
drain cock and flexible connection. Delivery connection shall include isolating valve,
check valve if the pump is in parallel connection, pressure gauge and cock, and flexible
connection. Gland drip, if any, shall be piped to waste.
The chillers pumps shall operate on a duty/standby basis, with automatic changeover in
the event of pump failure, or to arrange equal operation time for each pump. Each pump
shall have hours run meter in the HVAC control panel.
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Fill the system with fresh water and add recognized approved cleaner (chemical)
sufficient quantities as recommended by the supplier taking necessary samples during
each flushing. Operate the system for at least six hours taking samples for analysis every
two hours. Temporary pumps shall be provided for this purpose, as required.
Thoroughly flush the system for as many times as necessary to remove all traces of pre
operational cleaning chemical and as.
Recommended by the supplier taking necessary sample for analysis during each
flushing.
Refill the system with fresh water and add oxygen scavenger and corrosion inhibitor in
adequate quantities as recommended by the manufacturer, to suit the overall system
volume.
The Contractor shall follow the written instructions of the manufacturer for the mixing of
all chemicals and a copy of these shall be kept on site.
System isolating valve to enable commissioning of the set prior to opening the
system.
All necessary interconnecting pipe work in high gauge copper to BS 2871, Table X
and non return valves etc.,
The entire system shall be controlled by a microprocessor with LCD Screen which must
give alternate pumps starting on two pump sets, pump start frequency/leakage detection
alarm to indicate a leak causing too many starts per hour, thus damaging the switchgear
etc., high and low pressure alarms manually set, a common alarm to shut down the system
if the pressure limits are transgressed, indication of transducer or transducer lead faults.
Volt free contacts must be provided for the following:
Common system alarm and system OK status, high pressure alarm, low pressure danger
alarm, pump start frequency. These volt free contacts for connection to a future BMS.
System expansion vessel(s) to be steel “water in bag” type of correct size to suit system
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parameters which an air cushion pressure to match “initial system pressure”. This vessel
shall be mounted external to enclosure.
Expansion Tank: The expansion tank shall be sized to suit the system water quantity
unless a larger size is required for proper functioning of the system.
The tank shall be fabricated from mild steel and shall be painted both inside and out after
completion of welding. The tank shall be rated for operation at 16 Bar NP in accordance
with the pressure test requirements of ASME or approved equal.
The tank shall have a neoprene rubber diaphragm rated for continuous operation at 16 Bar
NP.
The tank shall be complete with all tapings for inlet (which may also be the drain,) air
recharge, and pressure relief.
A spare diaphragm shall be maintained by the Contractor at site during the warranty period
and shall be handed over to the Owner in “as new” condition at the end of the warranty
period.
Installation shall be in accordance with the Manufacturer's recommendations.
The expansion tank shall be sized to suit the system water quantity as per ASHREA
standard in accordance with the pressure test requirements of ASME or approved equal.
The method of introducing these chemicals into the system shall be by means of
automatic dosing system. 2 x 100% dosing pumps shall be provided. Digital controller
with all sensors shall be used.
Before treatment, the complete chilled water system shall be flushed to the approval of
the Company and a final leakage test performed. Large bore (minimum 50mm) flush
points, at lowest sections of the system, shall be provided.
The system shall then be drained down, re-flushed and re-filled.
After refilling the sample shall be taken and tested in the lab. The results shall not
excessed the values in the table. If any of the results is not meeting the below requirement
then the re-flush to be done.
If the results are satisfactory as per table than dosing with a corrosion inhibitor and an
algae inhibitor shall be applied.
SI Quality Level
No
Parameter Description
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Table-chemical dosing below gives details for treatment subject to company written
approval.
3.4.1.1 General
Air handling units shall be draw through type; manufacturers of air handling units shall
have ISO 9001 certification, and performance of the unit shall be EUROVENT certified.
Provide as a complete system. Units shall be provided with vibration isolation.
3.4.1.2 Components
Electrical heater (thyristor type)
Volume control damper (VCD), Motorised damper (MD), none return damper
Sand trap louver with pre filter and VCD
Door safety limit switch shall be interlinked with DDC.
Internal inspection light with ON-OFF switch and with viewing provision (made of hard
plastic). Fan chamber 2 no’s; filter chamber 1 no; cooling coil chamber 1 no.
Weather hood, if unit install outside/open area: (if specified)
Moisture Eliminators.
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3.4.1.3 Casing
Service doors shall be provided with special gasket and locking device. A factory mounted,
weather resistance (enclosed and gasketed), vapour- tight incandescent light fixture shall
be provided for access and/or fan module. The fixture shall be complete with junction box,
globe, aluminium globe guard, receptacle, and bulb. Access doors shall be provided with
aluminium hinges with quick release latches having external and internal handles for
external and internal opening. Latch doors can be acceptable with the approval of the HVAC
engineer.
The inspection side of the coil section panels shall be assembled with bolts and nuts for
easy removal of coils. Panel air tightness and sections up to 2500 Pa as required in
EUROVENT 2/2.
The AHU manufacturer shall guarantee that no condensation shall take place on the
exterior of panels. In the event that any condensation problems appear after installation,
the Contractor shall undertake all remedial measures to rectify and to the satisfaction of the
Owner. Any stacked or double height coils shall have separate drain pans to reduce carry
over such pans will be piped to the main drain, not into the lower pan.
Cooling coils performance shall to be rated and certified to ARI 410 Standards. Coil shall
be air pressure tested in factory to a minimum 1.5 times of working pressure.
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3.4.1. 8 Humidifiers
Humidifiers shall be jacketed electrical dry steam units that provide full separation from
steam ahead of the jacketed control valve.
3.4.1.10 Filter
Filterto be according to ASHRAE Standard 52.1 section shall be supplied with the same
casing construction as the air handling unit.
Filter materials to be fire resistant in accordance with the requirements of BS 9999.
Aluminium Sand trap louver shall be provided for fresh air intake system with the sand
trap louver and damper.
Panel filters and bag filters shall be provided to each air handling unit. Pressure switch
with adjustable setting shall be provided for each type of filter with independent pressure
switch.
a) Panel Filter:
It shall have the minimum average synthetic dust weight arrestance by EUROVENT 4/5
(i.e. Grade EU3) /ASHRAE Standard 52.1 – 1992 and maximum initial resistance at 2.5
m/s face velocity.
Performance data for expanded aluminium filter panels oiled with a thixotropic adhesive
shall have the following minimum average synthetic dust weight arrestance by
EUROVENT 4/5 (i.e. Grade EU3) ASHRAE Standard 52.1 - 1992; minimum dust hold
capacity and maximum initial resistance at 2.5 m/s face velocity.
b) Bag Filter:
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The air filter shall be of high efficiency, extended area, deep pleated, disposable type.
The media shall be micro fine glass fibre, which is reinforced by a laminated synthetic
backing. It shall have a nominal width of 600 mm and the following average atmospheric
dust-spot efficiency by to EUROVENT 4/5 (i.e. Grade EU7) /ASHRAE Standard 52.1 –
1992 and initial resistance at 2.5 m/s face velocity. The air filter to be designed for the air
velocity of 1.0 to 3.5 m/s and shall operate to 250 Pa final resistance.
A complete set of all new filters shall be provided on every air handling unit at the time of
handing over.
A differential pressure switch shall be provided for each filter bank including the fresh air.
This section covers heat exchangers and installation of energy recovery wheels.
Whenever is required.
Quality Control: ASHRAE 84-78, Method of Testing Air-to-Air Heat Exchangers. ARI
Standard 1060-80. BS 5141 Part 1
Materials selection data to be submitted, Independent lab test report certifying
the cross contamination limit for recovery wheels.
(B) Rotor
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the vertical and radial run out does not exceed 1mm per 1000mm which will minimise
leakage/drag on the radial seals as well as fluctuations in the drive belt tension.
The spacing of the substrate around the rotor should be extremely consistent so that
uniform air flow and performance over the entire face of the air stream is ensured. In order
to achieve uniform pressure drop and air flow across the rotor face the flute height and
pitch should be consistent.
The media should be cleanable with compressed air, low pressure steam or water with
light detergent; without degrading the latent recovery.
(C) Purge Section
Built-in purge section should be provided in the unit to ensure maximum, separation of
fresh air from exhaust air to limit carryover of bacteria, dust and pollutants from exhaust
air to fresh air.
(D) Seal
The wheel cassette shall be supplied with four pass labyrinth seal. The seals shall not
make any contact with the rotating surface of the wheel. Seals shall be field adjustable to
ensure optimum performance. The seal and purge system shall limit cross contamination
to less than 0.04%.
At a given tilt angle, a 1 in. inside diameter heat pipe will transfer roughly 2.5 times as
much energy as a 5/8 in. inside diameter pipe. Consequently, heat pipes with large
diameters are used for larger-airflow applications and where level installation is required
to accommodate both summer and winter operation.
For full specification refer to ASHRAE Handbook - HVAC Systems and Equipment
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- The programming of control panel shall be open protocol type in order to communicate
(interface) with other disciplines.
- The control panel shall be equipped to accept the interface with other disciplines e.g. fire
and gas system,…. Etc.
- The alarm shall be generated in the DDC in case there is any type of fault in any fan
3.4.3.1 General
VAV control units shall be installed in association with a variable air volume system, having
control of the fan output relative to system demands or Variable air volume units shall be
pressure independent bypass type.
The VAV shall be design as per ASHRAE hand book section 4.11 & 4.12
The digital thermostat shall be furnished by the terminal unit manufacturer and include
teperature set point and velocity adjustments located in the thermostat.
Ref to ASHRAE hand book
3.4.5.1 General
a) The fan coil unit shall be single skinned if it is used in air condition space otherwise
double skinned.
Shop Drawings: Submit assembly-type shop drawings showing unit dimensions, weight
loadings, required clearances, construction details, and field connection details.
h) Wiring Diagrams: Submit manufacturer’s electrical requirements for power supply
wiring to fan coil units. Submit manufacturer’s ladder-type wiring diagrams for interlock
and control wiring. Clearly differentiate between portions of wiring that are factory –
installed and portions to be field- installed.
I) Maintenance Data: Submit maintenance instructions, including instructions for
lubrication, filter replacement, motor and drive replacement, and spare parts lists. Include
this data, product data, shop drawings, and wiring diagrams in maintenance manuals.
Unit Chassis
Horizontal/Vertical Base Unit with Plenum for concealed installation shall have a factory
installed, galvanized steel plenum section sheet metal thickness not less than 1.6 mm and
throw away/washable filter. Filters shall be washable type with minimum 15mm thickness
and shall have at least 60% efficiency as per BS 6540: part 1: 1985 No. 3 test dust.
The plenum shall be either bottom or rear return, lined with 12.5mm PUF insulation or
equivalent based on manufacturer standard and include a removable panel to provide an
access to the fan/motor assembly.
Ref to ASHRAE hand book
3.4.5.1.2 Coil
Coil shall be equipped with a 3 row coil (minimum) for installation in a 2 pipe system. Coils
shall have 7-12mm copper tubes, aluminium fins bonded to the tubes by mechanical
expansion and have a working pressure of 16 bars. Each coil shall have a manual air vent
and drain valve connection. Ref to ASHRAE hand book
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avoid the condensation. An extension drain pan shall be provided for installation at the
jobsite under the valve package.
3.4.5.1.5 Controls
Each or multiple fan coil units shall be controlled by the room thermostat. Where multiple
fan coil units are controlled by a single room thermostat, a DDC based controller with PID
control action to be provided. The DDC controller shall send the signal to the valve based
on the room temperature and room thermostat setting
Manual on/off switches shall be fitted on all units irrespective of the automatic controls
3.5.1 General
Central DX air-conditioning units shall comprise an outdoor air-cooled condensing unit
and matching indoor air handling unit with interconnecting refrigerant pipe work. Both
units shall be of the same manufacture unless specifically approved otherwise by the
Company.
The air condensing units shall be suitable for outdoor installation on the ground or roof
top. Units shall be completely factory-assembled and tested, piped, internally wired and
fully charged with CFC/HCFC free refrigerant.
Units shall be capable of operating as per ASHRAE hand book HVAC SYSTEM AND
EQUIPMENT
A separate local disconnect switch near each unit shall be provided.
3.5.2 Materials
3.5.2.2 Fans:
Condenser fans shall be as per ASHRAE hand book HVAC SYSTEM AND EQUIPMENT
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or micro channel condenser aluminium tube with aluminium fins with efficient heat
exchange arrangement.
Coils shall be factory leak tested at 1.5 times working pressure. The aluminium fins shall
be E coating for effective corrosion treatment. The vendor shall provide 5 year warranty for
this coating. Coil wire mesh guard shall be provided to avoid damage due to the elements
and vandalism.
3.5.2.4 Compressors:
The condensing unit shall be with 2 or more independent circuits with semi-hermetic or
hermetic type compressors. The HVAC engineer can accept single circuit if the project
requirement is not critical e.g. fresh air unit for resisdentional buildings. Compressors shall
be as per ASHRAE hand book HVAC SYSTEM AND EQUIPMENT.The vendor shall
guarantee the compressor for 5 years against failure.
i. Filter dryer.
ii. Thermal Expansion device.
iii. Solenoid valve
iv. Suction and liquid line service valves and gage ports.
v. Charging valve.
vi. Compressor discharge service valve.
vii. Condenser pressure relief device.
viii. Moisture and liquid indicator.
b) The control of the unit shall be designed to communicate with HVAC control panel
using open protocol.
3.5.2.7 Execution
a) Maintain minimum manufacturer's recommended clearances for service and
maintenance.
b) Install the units on a minimum 200mm height concrete base.
c) Interlock or cement tiles shall be provided for the yard of out door units.
3.6 Unitary Air Conditioning Unit
3.6.2.1 General
The split system shall be designed for continuous operation at outdoor ambient temperature
of 50 deg. C. The distance between indoor and outdoor unit shall not exceed 15 meters.
The refrigerant used shall be environment friendly CFC/HCFC free.
For specification refer to ASHRAE hand book HVAC SYSTEM AND EQUIPMENT
Floor mounting unit cabinet shall be enamelled steel with removable panels on front and
ends in colour selected by the company.
b) Ducted fan coil unit:
Generally, the ducted fan coil units shall comply with Sub-section of FCU unit
Specification with Direct expansion coils and controls. Indoor unit shall match with the
condensing unit.
For specification refer to ASHRAE hand book HVAC SYSTEM AND EQUIPMENT
3.6.2.4 Control
A control package shall be supplied with the unit with remote thermostat/fan speed/on-off
control facilities, which will control both units from within the conditioned space. Control
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shall be microprocessor type with on-off timer, room temperature indicator, energy saver
facility, with multiple fan speed and other features.
The split units shall be interfaced with the BMS system for monitoring the run status of the
units, Also to be interfaced with fire alarm for shut down of the unit in the event of fire.
3.6.4.1 General
The refrigrerent used in the package air-conditioning unit shall be environment friendly
CFC/HCFC free
For specification refer to ASHRAE hand book HVAC SYSTEM AND EQUIPMENT
3.6.4.2 Casing
Cabinet panels shall be easily removable for servicing. Filters shall be accessible through
an access panel.
3.6.4.3 Fan
a) Evaporator Fan: The fan shall be centrifugal type belt driven with adjustable
motor pulleys. The fan wheel shall be made from steel, be of the double inlet type with
forward curved blades, and have a corrosion resistant finish. It shall be statically and
dynamically balanced and tested at the factory. Fan shaft shall be mounted on two grease
lubricated ball bearing designed for 200,000 hours average life. Fan motor and fan
assembly shall be mounted on common base to allow consistent belt tension with no
relative motion between fan and motor shaft. Entire assembly shall be completely isolated
from unit and fan board by double deflection, rubber shear isolators.
b) Condenser Fan: The condenser fan shall be of the direct driven, propeller type,
with corrosion resistant blades riveted to corrosion resistant steel spiders. It shall be
dynamically balanced and discharge air vertically with protective grilles. Motor shall be
three phase with permanently lubricated ball bearing, built in current and thermal over-
load protection, and weather tight lingers over bearings.
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3.6.4.4 Compressors
For specification refer to ASHRAE hand book HVAC SYSTEM AND EQUIPMENT
3.6.4.5 Coils
Evaporator Coil seamless copper tubing mechanically bonded to heavy duty
aluminium/copper fins of configured design. Condenser coil configurated aluminium fin
surface shall be mechanically bonded to primary surface of seamless copper tubing or
micro channel heat exchanger. The coil shall be coated with air dry “phenolic”, thermally
set “here-site” or approved equal coating suitable for salty sea cost with SO2 environment
and shall be guaranteed.
3.6.5.1 General
Unit shall be air cooled, split type multi-system air conditioner consisting of one outdoor unit
and multi indoor units, each having capability to cool or heat independently for the
requirements of the rooms.
Up to ten different type and different capacity indoor units can be connected to one
refrigerant circuit and controlled individually. Maximum sixteen numbers of indoor units shall
be connected to a single refrigeration circuit.
Air conditioner shall operate continuously at the ambient temperature of 50°C. Both indoor
unit outdoor unit are assembled, tested, and charged with refrigerant at the factory.
3.6.5.2.1 Compressor
Each unit shall have two to three scroll compressors and be able to operate even in case
one of the compressors is out of order.
For specification refer to ASHRAE hand book HVAC SYSTEM AND EQUIPMENT
The address of the indoor unit shall be set automatically in case of individual and group
control.
3.6.5.4 Control
Computerized PID control shall be used to maintain a correct room temperature.
Unit shall be equipped with a self-diagnosis for easy and quick maintenance and service.
The LCD (Liquid Crystal Display) remote controller shall memorize the latest malfunction
code for easy maintenance.
For specification refer to ASHRAE hand book HVAC SYSTEM AND EQUIPMENT
It shall be able to control all zones or all groups (each group consists of Max. 16 units) of
indoor units with the following functions.
For specification refer to ASHRAE hand book HVAC SYSTEM AND EQUIPMENT
3.7 Fans
3.7.1 General
Furnished and installed the fan as per required schedule. Fan selection and installation
depends upon a variety of factors including the application, space availability, and noise
considerations.
Store fans in clean dry place and protect from weather and construction traffic.
Comply with manufacturer’s rigging and installation instructions for unloading fans and
moving them to final location.
3.7.2 Products
General: For belt-driven fans, fan and motor shall have one-piece base with
adjustable motor mount. Each fan shall be provided with fan sheave, motor sheave,
matched V-belts and belt guard.
Fan motors shall be totally enclosed fan –cooled (TEFC), IP 55, with class F insulation
type.
The battery room extract fans shall be provided with terminal box and isolation
switch. The terminal box and the isolation switches shall be explosion proof type
suitable for zone one.
All Fan resistances shall be checked by the Contractor before any equipment is ordered.
Noise levels of to comply with the room noise levels as pespecified in ASHRAE
standards.
Power supply wiring from power source to power connection on unit. Including starters,
disconnects, Interlock wiring between electrically operated equipment units and between
equipment and field installed control devices, required electrical devices, except where
specified as furnished, or factory installed by manufacturer.
Each fan assembly shall be supplied complete with lifting lug and earthlings boss.
An engraved nameplate shall be mechanically fixed to each fan. As a minimum, the
nameplate shall provide the following information:
a) Manufacturers name and address
b) Date of manufacturers
c) Equipment Tag No.
d) Design air flow rate
e) Design air system resistance
f) Impeller speed
g) Direction of rotation
h) Direction of air flow
i) Electrical supply
b) Fan casings shall be constructed of zinc coated steel sheet with angle stiffeners
and base angles to ensure freedom from drumming and shall be suitable for operation at
the maximum static pressure of the system. Fan casings shall be constructed so that
impellers can be easily withdrawn after installation. Outlets shall be flanged and inlets
shall be flanged or spigotted. A drain and plug shall be fitted to the fan casing at its lowest
point, an access door, for inspection and cleaning, shall be fitted to the casing in an
accessible position.
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c) All centrifugal fansshall have airfoil backward curved blades unless shown
otherwise. Impeller for high efficiency shall be made of steel or aluminium, statically and
dynamically balanced on their shafts after assembly.
d) Impellers shall be of steel or aluminium; the blades shall be secured to the hub
or the blades and the hub shall be formed in one piece. The hub shall be keyed to a
substantial mild steel shaft or of smooth polished stainless steel and the whole statically
balanced. Blades shall have an aerofoil section. Shafts shall be carried in two bearings
which may be ball, roller or sleeve type. Lubrication nipples shall be extended to the
outside of the casing. An access door of adequate size shall be provided. The fan shall
be equipped with an inspection opening through which electrical connecting and
changing of blades position can be done without difficulties.
e) Fan drive shall be V-belt type consisting of two endless anti-static type V-belts
capable of transmitting a power at least 75 % in excess of the rated brake horse power
(b.h.p.) of the motor and designed for trouble-free start-up and operating conditions even
if one of the belts is broken.
f) The fan motor shall be unit mounted, arranged on fan bases, designed for
extreme ambient conditions, maximum power consumption of the fan's characteristic
curve, three immediate starts one after another and 10 % power reserve at minimum,
including slide rails with clamping devices and adjustable belt tightness. A belt guard
consisting of an easily accessible and removable casing made of reinforced and stiffened
perforated steel sheets, spring or rubber vibration mountings, a drain device and wire-
mesh guards at the intake air cones of the fan casing shall be provided.
b) The cylindrical casing shall be made of galvanized or painted heavy gauge steel
sheet, reinforced and stiffened with connecting flanges. The length of the duct casing
shall be greater than the length of the fan(s) and motor(s), in such a manner that the
complete section may be removed without disturbing adjacent ductwork.
c) Casings shall be rigidly to obviate drumming and vibrations. Fabricated steel shall
be provided where necessary for bolting to the base or supports.
d) The fan shall be consisting of a impeller with profiled aero-foils blades for high
efficiency and designed of the variable pitch type, continuously adjustable at stoppage
and completely made of aluminium alloy, statically and dynamically balanced, and
combined with flexible and non-rotatable canvass connections, spring or rubber vibration
mountings, an electrical motor designed for maximum power consumption of the fan's
characteristic curve, including a separate water-tight and dust proof terminal box fastened
to the outside of the fan casing and connected with the motor terminal box by a cable
with outside protection tube and combined with a wire mesh, if so required.
e) Inlet and outlet ducts shall terminate in flanged rings for easy removal. Fans shall
be selected to operate at not more than 80% of maximum capacity.
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b) Impeller shall be of aluminium, the blades shall be fastened to the hub of the
blades and the hub shall be formed in one piece. The bearings may be of ball, roller or
sleeve type.
b) 415V/3 PH/ 50 HZ only shall be used in chemistry lab and battery room applications
c) All extract fans shall have louver and back draft damper at the end of the
discharge duct except small glass mounted fans which shall have built in exhaust side
shutters.
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3.8.1 General
Ductwork shall be off site pre-fabricated according to the requirement as specified in the
Particular Specification. The ductwork shall be fabricated from good quality full sized zinc
coated hot dipped galvanised flat steel sheet to BS EN 10142, coating type Z275 unless
otherwise specified in the Particular Specification or the Drawings.
Supply duct shall not be passing over or crossing any panels.
Where any part of the installation is not covered by the above, the recommendations of
the latest edition of “Ductwork Construction Standards" issued by the Sheet Metal and
Air Conditioning Contractors' National Association (SMACNA) Inc. USA shall be applied.
3.8.2 Materials
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d) Laundry extract ductwork shall be air and water tight construction manufactured
from aluminium sheets in accordance with BS 1470.
e) Reinforcement Shapes and Plates. Unless otherwise indicated, provide
galvanized steel angles for reinforcing where installed on galvanized sheet metal ducts.
For stainless steel ducts, provide reinforcing angles of compatible materials.
f) Tie-Rods. Galvanized steel, 8 mm minimum diameter for 900 mm length or less;
10 mm minimum diameter for lengths longer than 900 mm.
g) Hardware. Nuts, bolts, screws, rivets, and other miscellaneous fasteners used
for duct systems shall be compatible with the ductwork material. For galvanized steel,
hardware shall be galvanized cadmium-plated, shall have other corrosion-resistant finish,
or shall be made of a corrosion-resistant material.
h) All supports, stiffeners, flanges etc. used in ductwork construction and installation
shall be hot dip galvanized otherwise specified.
Dampers with side dimensions up to 300 mm shall have a single blade, not less than 1.6
mm thick, with 10 mm diameter pivot rods and rigid bearings.
Dampers with side dimensions over 300 mm shall have horizontally opposed multi leaf
blades, not less than 1.6 mm thick and blades no more than 250 mm wide, with 10 mm
diameter pivot rods set in rigid bearings and linked externally to a single operating lever
and quadrant.
Frame and Blades shall be constructed from the same material of the ductwork. Bearings
shall be of nylon material and the units shall be of low-leakage design by incorporation of
synthetic trailing edge seals and a peripheral gasket which shall be tested according to
BS 476 Part 6 and 7.
Unless otherwise specified, quadrants and operating handles shall be of die-cast
aluminium or other material approved by the company with the words 'OPEN' and 'SHUT'
cast on the quadrant.
Each air volume control damper in the ductwork shall be fitted with a non-corrodible label
stating the actual air flow in (m3/s) when in the fully open position, its overall cross
sectional area and the design or actual air flow.
Access openings with readily removable or connected with safety wire air sealed covers
shall be provided adjacent to all dampers, unless access is available through adjacent
equipment. Subject to limitations of ductwork size the dimensions of access openings
shall not be less than 450 mm x 450 mm and they shall be located so as to afford easy
access for inspection and maintenance.
After final commissioning, the position of all dampers shall be secured and indicated with
a durable mark on the quadrant.
Fire or Smoke dampers used singly or in combination shall have an overall fire rating not
less than that indicated and certainly not less than that for the wall or floor slab in which
they are situated Scope of supply of fire dampers should include necessary sleeves and
retaining angles for fixing.
Fire dampers made to British standard B.S. 476 or North American Standards or N.F.P.A.
90A, with minimum 2-hours rated, UL listed and shall be labelled by manufacturer. Each
Fire damper casing shall be air tight, continuously welded and clearly marked with a
permanent indication of the direction of air flow. All Fire dampers shall also be approved
by the civil defence/Fire Services Department.
Remote position indication of fire damper to be considered in DDC or local HVAC control
panel.
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Access panels with airtight gasket shall be provided to fire dampers enabling full
inspection of blades and the fusible links.
A least 2 Nos. fusible link shall be supplied as spare.
Fire dampers handling outside air shall be fabricated from stainless steel. A fire damper
installation frame shall be provided.
Smoke dampers shall be the low leakage type, rated under UL 555 S as leakage Class I.
Frame shall be of formed channel of not less than 1.6 mm (16 gauges) galvanised steel.
Blades shall be 2 mm (14 gauges), air foil shaped, double skin construction, opposed blade
type.
Damper actuators shall be factory furnished suitable for either 240 volt or 24 volt application
UL listed. Complete unit shall be factory tested in compliance with UL 555S and shall be
UL label.
The damper unit shall be supplied with a two position indicator switch linked directly to the
damper to provide the capability of remotely indicating damper blade position.
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Blade position indicator: Each combination fire smoke damper shall be equipped with
switch package which shall include two position indicator switches linked directly to the
damper blade to provide the capability of remotely indicating damper blade position.
Fusible link: Each combination fire smoke damper shall be equipped with a fusible link
which shall melt at 72-74°C causing damper to close and lock in a closed position.
Damper actuator selection shall be based on fail closed operation, in which the damper
closes when power is interrupted to the actuator. The damper shall be released to the
closed or fail-safe by an independent closure spring on loss of power supply, either by
genuine power failure or by the zone fire signal actuated by the smoke detection system.
The damper shall be automatically reset on resumption of power supply by built-in motor
of 220V AC or 24V AC/DC.
Provide Re-settable, re-usable link control device with high limit temperature sensor that
causes the damper to return to fire protection mode (closed) when temperatures reach
the operation limit of the damper/actuator assembly and meets all NFPA 92 A
requirements.
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Blade spindles shall be in stainless steel to BS 970 304 S11 supported in plain brass
bearings.
Shut off dampers shall have a leakage rate not exceeding 200 M3/hr/M2 at 1000Pa.
When mounting the actuator outdoor it has to be certain the actuator is protected against
direct sun exposure and rain. Actuator for hazardous area shall be explosion proof type.
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Select all diffusers to provide uniform air coverage without overlap. Air velocity up to a
height of 1.8m above the floor shall be 0.13 to 0.25 m/s (25 to 50 fpm).
Noise generated by outlet or inlet at peak volume shall be such that room sound pressure
level does not exceed the value specified in ASHRAE standards. Room attenuation; the
sound power level reference to 10-12 power watts.
All volume and air pattern devices shall be fully adjustable from the face of the diffuser,
register or grille.
All diffusers, grilles and registers shall be supplied completely factory powder coated.
Finish colour shall be to the approval of the Company. The interior of all grilles and diffusers
is to be factory painted matt black.
All supply and return grilles and diffusers will have opposed blade balancing dampers. All
will have foam rubber sealing band around the edge to seal to the structure. All pivots will
be round section, not of formed sheet, and not relying on a spring steel locking wire.
Unless otherwise specified basic grilles and diffuser materials shall be Aluminium extruded
sections. Sections in the airstream shall be carefully selected to minimize turbulence.
All grilles and diffusers shall be tested and rated in accordance with ASHRAE Standard
70-72, and ISO 3741.
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Pressure drop at 2 M/Sec average face velocity shall not exceed 120 Pascal.
The sand trap louver shall be as per EN 13181
Behind each louver shall be an insect mesh screen 76 x 6 mm made from 2 mm diameter
stainless steel (316) wire. The screen will be clamped by a 20 mm frame and will be firmly
fixed to the outer edges of the louver. The frame shall be hot dip galvanized after fabrication.
All ductwork shall be constructed, reinforced, supported and installed in accordance with
HVCA or SMACNA "HVAC Duct Construction Standards - Metal and Flexible', and the
specification herein.
All supply and return ductwork shall adhere to DW142 and 144.
Make all laps in the direction of air flow. Hammer down all edges and slips so as to leave
smooth finished surface inside the ducts.
All ducts shall be braced and stiffened and shall be tight so that they will not breathe,
rattle, vibrate or sag. Cross-break or transverse bead all rectangular ducts as per HVAC
or SMACNA standards.
Duct sealant such as mastic shall be manufactured by the approved manufacturer. Brush
joints with the compound before and again after assembly. Mastic sealant shall be applied
to all duct transverse joints and longitudinal seams.
Seal the bottom and side joints of fresh air ducts or plenums to be watertight.
Flexible duct connections shall be of Class 1, corrugated aluminium flexible duct suitable
for 1200C and 1.5 kPa and shall bear the 'building unit' label of Underwriters' Laboratories.
Flexible duct connections shall be insulated with 25 mm fibre glass insulation with density
of 24 kg/m3 complete with vapour barrier.
Bends in flexible ducts shall have centreline radius of not less than 1 1/2 x diameter.
Collars to which flexible ducts are attached shall be a minimum of 50 mm in depth. Metal
flexible ducts shall be attached using a minimum of three #8 sheet screws equally spaced
around duct. Ducts larger than 300 mm diameter shall have a minimum of five #8 screws.
Screws shall be located at least 12 mm from duct end. Insulation and vapour barriers on
factory-fabricated ducts shall be fitted over cone connection and supple- mentally
secured with a draw band.
Generally more durable and noise-resistant sheet metal ducts are preferable to flexible
ducts in connecting ducts to diffusers or boxes. However, flexible ducts may be used
under the following conditions:
If shown on drawings to allow easy location of diffusers. Does not pass through floors or
fire walls and does not exceed 1 m in length. Flexible ducts shall not be installed in
inaccessible locations, such as above gypsum board ceilings unless specific approval
from the Company is obtained.
Where ductwork passes through a wall or floor, other than when a fire damper is required,
pack around the duct using a fire resistant material to ensure a sound and air-tight joint.
Cover the opening with sheet metal flange of the same metal thickness of duct, overlap
opening on four sides by at least 38mm.
Install ducts with fewest possible joints. Locate ducts, except as otherwise indicated,
vertically and horizontally, and parallel and perpendicular to building lines; avoid diagonal
runs. Install duct systems in shortest route that does not obstruct usable space or block
access for servicing the building and its equipment.
Battery rooms shall be supplied with conditioned air at low level through droppers with
VCD for each dropper, motorised control damper (MCD) shall be provided in main supply
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duct. The actuator for supply duct of the battery room shall be designed for zone 1, T4
rating, Gas Group IIB/IIC. Exhaust shall be from the higher level from the opposite side
as describe in specialist areas battery rooms in section-2.
Install ducts with a clearance of 25mm (1 inch), plus allowance for insulation thickness.
Locate all sheet metal ducts where shown and size as shown. If changes of size or
location of ducts are found necessary because of building construction, make a specific
proposal for review by the Company engineer prior to proceeding with the change.
Make changes of direction of horizontal ducts with elbows having an inside radius not
less than the width of the duct, Make change of direction from horizontal to vertical duct
with elbows having an inside radius equal to the depth of the duct. Where this is not
possible due to the building construction, use turning vanes.
Provide access ports at convenient locations in all main ducts and main branch take offs
with airtight covers and extension sleeves through insulation to allow air meter readings.
Access ports shall be similar to 32 mm round openings as approve by the company.
Provide flexible connections as specified at each building expansion joint, air handling
unit and fan duct connection.
Paint visible internal surface behind each grille or register flat black.
Support horizontal ducts within 600 mm of each elbow and within 1200 mm of each
branch intersection. Support vertical ducts at a maximum interval of 4800 mm and at each
floor.
Upper attachments to structures shall have an allowable load not exceeding one fourth
of the failure (proof test) load, but are not limited to the specific methods indicated.
The ducting shall be supported from a structurally sound part of the building by galvanized
steel rods and galvanized steel angle brackets. The support angles, and rods shall be of
adjustable type.
The ducting shall not rest on the insulation at support locations. At the support locations
suitable insulated spacers of neoprene make shall be provided so that the insulation does
not rest on the supports. The spacers shall be minimum 25 mm in excess of insulation
depth and shall be securely fixed to steel support brackets.
3.8.4.3 Cleaning
Protect ductwork against entry of foreign matter during construction. Remove all dirt and
foreign matter from the entire duct system and clean diffusers, registers and grilles before
operating fans.
Provide temporary capping of ductwork to prevent entry of foreign matter during
construction.
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Clean duct systems with high power vacuum machines. Protect equipment which may be
harmed by excessive dirt with filters, or bypass during cleaning. Provide adequate access
into ductwork for cleaning purposes
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shall be fully sealed. Adhesive and sealers shall be approved by the company may be
used.
Access panels in ductwork shall be fitted with purpose-made rigid fibre, removable,
covers with quick release bands or fasteners.
Damper, test hole and instrumentation, connections etc. insulation shall be neatly cut and
sealed to allow permanent access.
Both adhesive and sealant shall be recommended by the Manufacturer for the purpose
and classified Class 1 flame spread in accordance with BS 476, Part 7.
Installation
Installation shall follow the manufacturer's recommendations.
Adhesive shall be applied with 100% coverage of the sheet metal surface prior to bonding
the glass fibre.
In addition, the insulation shall be secured to the sheet metal by mechanical fasteners.
Fasteners shall be adhered, not spot-welded, to the ductwork and pins shall be turned
over in the direction of airflow. Fasteners shall be fixed at not more than 350 mm centres,
shall start within 50 mm of open edges, i.e. sheet metal joints, and within 75 mm of corners
and longitudinal butts.
At open edges, the glass fibre shall be cut back and the facing turned under. The turned
facing shall be secured on both sides of the glass fibre by the fastener. At corners and
longitudinal butts, the glass fibre shall be cut back and the facing turned under. At lateral
butts, the upstream glass fibre shall be cut back and the facing overlapped on the facing
of the downstream slab.
Sealant shall be applied with 100% coverage of joints at edges, corners, longitudinal butts
and lateral butt facing overlaps. Sealant shall also be applied to repair all facing cuts and
tears.
Lateral and longitudinal butts shall be allowed only where the duct side is greater than
the glass fibre slab standard size.
The liner shall be fixed to ductwork sections in a sheet metal workshop, not in situ.
Lined sections of ductwork shall be subject to the Company's inspection on site before
installation and shall require the Company's approval, in writing, in position prior to closing
up.
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Liner adhesive shall comply with NFPA 90A and ASTM C 916. Adhesives shall be non-
oxidizing, water based and asbestos-free. Adhesive service temperature limits shall be a
minimum of -18°C to 82°C. Flammability: 100 °C (min). Water vapour permeance at 0.031
dry film thickness (DFT). Fire hazard classifications, as rated per UL 723, shall be a
maximum of 10 for flame spread and 5 for smoke developed. Surface burning
characteristics shall conform to NFPA 255 requirements and be tested per ASTM E84.
Tape Sealing System: Tape sealing system shall consist of a woven-fibre tape,
impregnated with a gypsum mineral compound and a modified acrylic/silicone activator
to react exothermically with the tape to form a hard, durable, airtight seal.
3.8.7 Fire-Stopping
Fire-Resistant Sealant: Provide one-part elastomeric sealant formulated for use in a
through-penetration fire-stop system for filling openings around duct penetrations through
walls and floors, having fire-resistance ratings indicated as established by testing
identical assemblies per ASTM E 814 by Underwriters Laboratories or other testing and
inspecting agency acceptable to authorities having jurisdiction.
At shop drawing stage, the contractor will undertake calculation for every unit and every
area and determine the insertion loss required to meet the stated noise criterion. Supply
and return duct noise must be considered.
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Materials of construction shall be hot dip galvanized sheet metal and mineral fibre
acoustic fill which is inorganic, inert, moisture and vermin resistant. Silencers shall be so
constructed as to prevent erosion of the acoustic fill.
The silencers shall incorporate a removable panel which provides complete access to all
internal surfaces for cleaning and also permits removal and replacement of acoustic fill.
Silencers shall be factory made, and shall have available certified test data concerning
insertion loss. This must be available when required, in advance of ordering units.
The static pressure loss of any required silencer must be considered in air handling
equipment original selection.
Silencers shall be flanged to exactly match the adjacent ductwork in which they are to be
installed.
This design criteria along with specifications, practices, and standards referenced herein
provides the basis for engineering and design of the HVAC control systems.
HVAC control and alarm systems shall be in line with the HVAC vendor's standards.
HVAC control systems should at least include the following:
(a) Temperature control
- For constantly manned rooms (e.g. control room, shift supervisor room);
- For certain rooms which are less frequently used (e.g. meeting rooms, mess
rooms etc.);
- For equipment rooms and buildings (e.g. instrument auxiliary room, electrical
auxiliary room, computer room, and electrical substations.
(b) Humidity control
- For all rooms and buildings.
(c) Pressure control switch
- For main duct of each AHU after motorised damper and before supply plenum
box. The sensor shall protect the duct from over the pressure. The HVAC control panel
shall trip the AHU supply motor if the duct pressure is accessed more than 10 percent of
the design working pressure.
HVAC alarms shall be individually displayed on local HVAC panels. Common HVAC
alarm signals generated by the HVAC control system and displayed on the DCS screen
in the main control room shall be routed either via potential-free contacts and interface
boxes or via software links.
Control signals coming from an HVAC control system cabinet and going to an HVAC
motor control centre (power) cabinet shall pass via an interface box. The HVAC
control/alarm cabinet and the motor control centre (power) cabinet shall be physically
separated. For central air handling units, both cabinets should be located in the HVAC
machine room.
3.9.2 Design
The HVAC Control system & all electrical components shall be designed and installed
per the following Design General Specifications:
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Electrical Design Guidelines, Power, Control, Lighting and Earthlings Cables, Instrument
and thermocouple Cables, Design General Specification - System Cables, Design
General Specification Instrument Design Criteria on Process Units.
Each building shall have a HVAC power and control panel. This panel shall be located
inside the AHU room. The suitable panel shall be provided with run/off/trip indications and
auto/manual/off switches and provisions to send fault signal to the Central control room.
The control system shall be designed such that each mechanical system will be able to
operate under stand-alone control. As such, in the event of a network communication
failure, or the loss of any other controller, the control system shall continue to
independently operate under control. The appropriate control system shall be so
designed to meet the requirements and operation needs of the building operation &
management team and the operation requirements of the end users in building(s).
The HVAC Motor Control Centre (MCC) shall be in full compliance with Company
Specification of Low Voltage Switchgear and Controls. Installation of this MCC shall be
in accordance with Electrical Design Guidelines Specification.
The HVAC system of each building shall be provided with a dedicated DDC or PLC based
control system.
The PLC/DDC shall be directly interfaced with the local MCC for control of electrical
HVAC equipment.
In addition the PLC/DDC shall, via suitable interface facilities, control all field mounted
HVAC equipment and be capable of receiving all field instrument and equipment control
inputs.
The control system shall be capable of operating during the maximum specified ambient
temperature and humidity without failure.
Operating pilot and indicating devices have to be situated on the front panel for easy
reading.
The HVAC control system shall be consist of the following but not be limited as below
• LCD screen for master controller shall be mounted at eye level of an average height
man
• Power lamps.
• Open/close indication for each motorized shut off damper and fire damper.
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• Fire alarm panel interlock for each AC and ventilation system and fire dampers shut
down.
• Duty selector switch for AC units, twin fans, chillers and pumps.
• Indication of running conditions e.g. on/off, fault, status, open/closed, etc., for all
applicable types of equipment (fans, pumps, chillers, heaters, dampers, etc...).
• HVAC control panel shall be interlinked with fire and gas panel.
The control panel shall be provided with running hours of each equipment e.g. AHU,
Heater, ACCU or Chiller and pump.
The selection switch in the HVAC control panel shall be provided with three position
(Hand-Auto-Off).
All the above mentioned points shall be shown on the master graphic screen. Full
graphics screen shall be visible on the outer face to the panel.
“Chiller fault” and “room temperature high” alarms shall be provided in the HVAC control
panel and same shall be repeated on the Distributed Control System (DCS).
The HVAC control panel shall be interfaced directly with the DCS of the control room for
communications.
Manual switches for HVAC units and associated items to be provided for manual
operation.
The HVAC control panel shall be interfaced directly with the F&G system for area
protection, isolation and shutdown purposes. The HVAC system shall initiate relevant
shutdown actions on receipt of F&G inputs as required and confirm such actions to the
F&G. The HVAC control panel shall send trip signal for the AHU motor(s) and close all
motorised fire and smoke dampers in case there is fire or smoke detection from F&G
system.
Access and manual control actions for the HVAC control system shall be via operator
DCS interfaces facilities (if required)
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HVAC Control Software Package (final mapping programme) shall be handed over to
Company for future use and Company personnel shall be trained for using the above
Software.
The unit control systems shall be DDC or PLC type capable of providing the degree of
thermostatic and/or humidity control specified.
The HVAC control panel shall be able to give command, status and alarm of the
following:-
• Ambient temperature
• Building temperature
• Temperature set point
• Supply air temperature
• Mixing air temperature
• Temperature differential or sensitivity
• Ambient Humidity
• Building Humidity
• Humidity set point
• Humidity differential or sensitivity
• Running Units
• Number of compressor running
• Extract fan running
• All damper open and close
• Valves
• Pumps
• Pressurization units
• Chemical dosing system
• Pressure duct switch
The control parameters are to be indicated on a LED or LCD display being part of the
controller or separate.
Detailed sequence of operation and control/power wiring diagram for the control system
shall be submitted by contractor for employer/engineer approval.
The control system shall incorporate all necessary safety interlocks for the successful
operation of the mechanical plant and systems. All of the individual control elements shall
be provided by the same manufacturer.
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3.9.4 Material
(a) Direct Digital Controller (DDC)
(I) Each controller shall operate as a standalone unit capable of performing its specified
control responsibilities independently of other controllers in the network.
(ii) Local keypad and display shall be provided for local viewing and operation.
(iii) Power Fail Protection – All system set point, control algorithm and other
programmable parameter should be stored such that power failure of any duration does
not necessitate reprogramming the DDC controller.
(b) Set point potentiometers shall be housed in a robust casing of high impact plastic
suitable for the decor of the area in which they are mounted, the control knobs shall have
markings in °C over the band specified and the knob shall be removable enabling the
setting to be fixed and enclosed under a dummy knob, rendering it tamperproof.
(c) Temperature sensors shall be of the resistance type using nickel based element
and shall be accurate to 0.5°C, over the range of 0°C to 60°C. The sensor resistance
shall be compatible with the measuring bridge of the matching control box.
For immersion temperature sensors, sensors shall be provided with immersion pocket.
The sensing range shall be of 0 °C to 120 °C.
(d) Humidity sensors shall be of the thin film capacitor or plastic strip type and cover
the range specified for control plus 02 % above and below.
(e) Duct sensors shall incorporate a 200mm long non-corrodible tube with the
sensing element mounted in a protective housing at the end of the tube.
(f) Step controller shall provide the required number of operational steps and shall
comprise a series of cam operated micro switches operated by means of an electric motor
or shall comprise the required number of voltage dependent relays switching in sequence
with the output voltage signal from the control box. The cut in points and switching
differentials shall be fixed at equal proportions of the operating range.
Provide room thermostat with flame retardant plastic (ABS) casing. The room thermostat
shall be provided with LCD screen and adjustable set point. The temperature range shall
be between 12° to 35°C.
The cooling &heating thermostat shall be provided with 3 position slide switch for manual
control of fan speed apart from auto mode position and cool/heat change over.
The room thermostat shall be provided with momentary override button to circumvent
day/night programming.
The thermostat shall have LCD display and key pads and shall conform to current industry
standards.
Provide 2 way /3 way modulating control valves for all chilled water coils. The response
time shall not be more than 45 second. Provide position indicators on valves and pilot
positioners on sequenced valves.
Select valves to have equal percentage characteristics. Size valves operators to close
valves against pump shut off head.
The cabinet shall be divided internally with sheet metal webs to separate low voltage
equipment from instruments and control equipment and to prevent overheating.
The control panel shall have adequate access doors to ensure ease of maintenance of
equipment. Access doors shall have concealed hinges, stops and interlocks where
required, and a dust excluding gasket contained in a rebate. Hinges shall be strong and
may be taken off only by the use of special tools.
Door handles shall be the rotating type closing onto ramps, of approved pattern, finished
in a black, hard wearing non-conductive material.
After fabrication, steelwork shall be cleaned, zinc sprayed and stove enameled with one
primer coat, two undercoats and one finishing coat, the surface being rubbed down after
each coat. The finish color shall be light grey or company approved.
The operating handles of each protective device shall project from cut outs in the front
door and all switching and protective devices shall have clear on / off identification.
The HVAC system serving the building shall be integrated with FCS/DCS, via HVAC DDC
panel.
The room temperature control is achieved by means of temperature controller mounted
in the HVAC control panel (DDC) located indoor. Return air duct temperature sensor
provides the actual return air temperature input to the temperature controller. Based on
the return air temperature and the set temperature, the controller gives the signal for the
compressors of respective condensing units to be switched On/Off depending on the load
conditions to maintain the room temperature conditions. To meet the inside conditions
during winter and after/during dehumidification, the controller provides the controlled
analogue output signal to operate AHU heater and maintain the design room
temperatures.
In event of increase in relative humidity the controller shall switch on the compressors for
dehumidification of supply air by overriding the temperature set point.
Air flow fail switch & dirty filter switches are provided on the AHU across the supply air
fan & across the filters to detect the air flow and cleanliness of the filters. The switches
are wired to provide visual indications on the HVAC control panel for “airflow fail” and
“dirty filter”. Motorised damper shall be installed for AHU supply and return air
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connections to isolate the standby AHU. Power to the HVAC equipment shall be provided
by HVAC MCC located in switchgear room building.
The supply air duct shall be connected to battery room through a dropper at a height of
300mm from bottom of the finish floor. Motorized fire damper shall be placed in the supply
air duct at the entry of the room.
AHU comprises of pre filter, bag filter, cooling coil, electrical heater and supply fan(s) and
interconnected to DX system with all necessary control items.
The AHU shall have differential pressure switches for Pre filter, bag filter, air flow failure,
On/Off type damper actuator in supply air duct, temperature & humidity sensor in the
return air duct and temperature & pressure sensor in the supply air duct. Temperature &
humidity sensor shall be provided for ambient air.
unit. The duct mounted common return temperature & humidity sensor measures the
temperature and humidity in the return air, feedback to HVAC Control panel to maintain
the set temperature and humidity. Supply duct temperature sensor is installed in the
common supply duct to monitor/control the temperature. Heater(s) will be controlled by
return air temperature and humidity sensor in return air duct.
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terminal. Individual DDC controller fail status signal will be sent to FCS/DCS through a
volt free contact.
In case of failure of both the explosion proof battery extract fan and/or motorized volume
control damper is not opening, then HVAC control panel shall send a signal to UPS to
inhibit the boost charging of the batteries.
a) Provide timers in the control circuits of all pumps to enable the pumps to continue to
run for a period after such-down of cooling plant.
b) On plant start up and shut down operation, control circuits shall be arranged for
staggered switching of motors to avoid simultaneous large electrical loads being
imposed on the power cabling and power plants.
c) Under normal operating conditions, the extract fan starters shall be interlocked with
their respective supply fan starters and stop locks.
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d) Humidifiers and electric heater batteries shall be interlocked with their associated
supply air fan to shut down the humidifier and electric heater battery when the supply
fan stops, or on power failure.
e) Fresh air inlet and discharge dampers shall close on normal plant shut down and
power failure. Operation from smoke detectors shall be as specifically required by the
local fire panel, or as per the detectable of the fire alarm and control system.
f) On full fresh air plants the air inlet dampers shall open before the fan can operate, by
use of damper motor end switches.
g) Where duty and stand-by pumps are provided, the selected duty pump shall start and
operate as required. Should the duty pump fail to start, a fault alarm shall be given
and the stand-by pump, after a pre-set period, shall operate. The same automatic
change-over sequence shall apply should a pump fail during normal running.
h) When electric heating batteries and cooling coils are to be operated in sequence a
dead zone shall be provided between each sequence.
i) Fire dampers shall be equipped with limit switches in order to shut down the
appertaining A/C ventilating systems as well as to close the appertaining fire dampers
of the above A/C ventilating systems automatically in order to prevent spreading of
fire or smoke through the building (appertaining system means all systems within the
same fire zone).
Microcomputer based remote control panels interfacing directly with sensors, actuators
and environmental delivery systems (i.e., HVAC equipment, plumbing and lighting
systems, etc.). The BMCS shall interface with the automation panels subject to company
approval.
The system shall have an inbuilt spare capacity of minimum twenty percent at all levels
of control and network to allow for future expansion.
Communication networks to allow data exchange between remote panels and the central
Building Management computer.
One personal computer (PC) based central and associated operator station(s) and
software functioning as the primary operator interface for the BMCS.
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Electronic and electric controls for all items indicated on drawings and described
hereinafter including sensors, control valves and thyristers.
Submittals, data entry and electrical installation, programming, interfacing with other
systems, start up, test and validation, instruction of Owner's representative on
maintenance and operation, as built documentation, and system warranty.
The BMS shall be a digital microprocessor based system of the latest proven technology.
It shall incorporate microprocessor based general purpose Direct Digital Controllers
(DDC) at the field level which shall interface directly with sensors, actuators, pneumatic
and electric controls, etc. The DDCs shall be provided on standalone basis and
individually for each area. Each DDC shall have real time clock, EEPROM, RAM, PEER
to PEER communication and shall be provided with a Portable Operator Terminal. The
BMS shall incorporate at the automation level System Controllers which shall have, but
not limited to, the following functions:
The cabling and wiring system shall comply with the requirements of the relevant Clauses
of electrical Specification.
Electrical sockets for maintenance works and water connection for cleaning of
condensers and water tap with hose adaptor for cleaning air filters are to be provided.
Cables and wiring shall comprise either PVC/SWA/PVC, laid in cleats or trenches/tray
work, or PVC drawn into galvanized conduits and trucking for control. Cables and wiring
for Power shall, however, be XLPE insulated.
Final connections to electric motors and all other items of plant subject to movement and
vibration shall comprise flexible cable in flexible conduit. Field isolators shall be provided
for all AC and ventilation equipment.
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Complete instructions shall be given to the operating personnel. Such instructions shall
be exclusive of the time required for regulating and adjusting.
* Notes:
* All components in the above water cooler units are to be lead free.
* All models must be U.L. approved.
* Water cooler unit specifications listed above may vary depending upon make and model
of unit being offered and should not be construed as the only units that may be accepted
within this package. The Company reserves the right to accept and/or reject units upon
inspection.
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The ice making machines to comply with the applicable requirements of Underwriters
Laboratories Standard No. 563 and ARI 810.
3.13 Refrigerator
General: A device described as a Refrigerator maintains a temperature a few degrees
above the freezing point of water.
Construction: Outer shell of refrigerator and freezer cabinets are now typically of stainless
steel or prepainted steel, thus reducing the volatile emissons that accompnay the finishing
process and providing a conssistantly durable finish to enhance product appearence and
avoid corrosion. Door shall be with latch arrangements and magnetic gasket duly fitted
with heavy duty stainless steel hinges. Standards typically require that refrigerator doors
and associated hardware withstand a minimum of 300,000 door openings. Stainless steel
legs with nylon adjustable bushes are provided at the bottom.
The refrigerator shall be equipped with separate freezer and refrigerator compartment
with separate access door.
The compressor compartment at the top/bottom shall be provided with stainless steel
finned or prepainted steel. It has to operate on single phase, 230 volts, 50 Hz of electric
supply. Refrigerator cabinet will have door operated light connection.
A separate stainless steel or prepainted steel sliding tray shall be provided at the bottom
of the cabinet to collect the defrost water. Vendor shall give 24 months warranty for the
Entire unit and compressor for 5 years.
Temperature Range: Refrigerator 1.11°C to 4.4 °C (30° F to 40° F), Freezer -17 °C to -
12 °C (0° F to 10° F)
Evaporator: The cooling system should be indirect fan cooling type. Frost free coil with
protective film with auto defrost cycle.
Freezer: Wrap around body with 3/8” copper coils of bright annealed surface from inside,
is soldered to the outer surface of the inner tank.
Body and door shall be made of 20 gauge 304 grade stainless steel sheets or prepainted steel.
High density PUF insulation. Deep freezer should have Temperature range of -20°C to -30°C.
Temperature, voltage input indicators should be in-built with alarm system and digital displays.
Microprocessor based control system with audio-visual alarm for temperature deviation.
Refrigerant shall be HFC (CFC & HCFC Free).
3.14.1 General
The general requirements for testing & commissioning and handover are given in
‘Section-1: General Requirements’. This chapter includes:
- Commissioning Method Statement
- Commissioning Programme
- Test Equipment
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- System Demonstration
- Pipe work Leakage Testing.
- Documentation
- Maintenance Tools
- Spare Parts
- As Built Drawings
- Operation & Maintenance Manuals
- Exceptions List Refer: STD-2-1702-A02 appendix C of section 2 page 16
- Handover Report Refer: STD-2-1702-A03 A02 appendix C of section 2 page
16
The commissioning of a chilled water air-conditioning system should normally be carried out in
the following sequence.
- Chilled water flush, test and dose.
(Since the pipe work circuit is usually available first).
- Chilled water pump start up. Pressurisation unit start up.
- Chilled water initial balance.
- Airside integrity check and fan start up.
- Air initial balance.
- Water chiller start up
- Control function check.
- Waterside and airside final balance.
- Control system calibration.
The standard Air conditioning Test Sheets included in Appendix B of this document, or
equal and approved by the Company shall be used to record measurements and
demonstrations.
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Work tests shall be carried out in accordance with the type normally associated with the
specified item of equipment and to the standards as laid down in the Specification and
the Contract.
3.14.3.5 Weld in Piped Services
The Company reserves the right to inspect at random the welded joints. Should any of
the above welds prove faulty in materials or workmanship, further removal of welds may
be ordered. If any of the welds fail the tests, it is sufficient to conclude that an operative
is not consistent in standard. The Company may order any number of the operative’s
welds to be removed. The contractor shall be responsible for cutting out and repair of all
such welds for inspection.
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3.15 Supervision
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4.1 Abbreviations
AC Alternating Current
ACB Air Circuit Breaker
Amp Ampere
AWA Aluminum Wire Armoured
CBCT Core Balance Current Transformer
Cu Copper
DC Direct Current
DDC Direct Digital Control
FCS Field Bus Control System
FGS Fire and gas system
Hz Hertz
IP Ingress Protection
IPF Instrumented Protective Function
kA Kilo-Ampere
kW Kilo-Watt
LBS Load Break Switch
LV Low Voltage
LSIG Long-time + Short-time + Instantaneous + Equipment Ground-fault Protection
MCC Motor Control Centre
MCCB Moulded Case Circuit Breaker
PVC Polyvinyl chloride
RCU Remote Control Unit
SCADA Supervisory Control and Data Acquisition
SFU Switch Fuse unit
SP PDO Specification
SWA Steel Wire Armoured
UPS Un-interrupted Power Supply
V Voltage
VSD Variable Speed Drive System
XLPE Cross-linked polyethylene
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4.2.1 General
HVAC equipment for building shall be fed from the HVAC MCC Or from LV
switchboard located inside the swichroom as per PDO electrical specification.
Company shall provide redundant incoming power supply to the HVAC MCC HVAC
MCC must be form4 type design. From HVAC MCC to all electrical downstream
system required for successful operation of the HVAC system shall be in scope of
HVAC Contractor / Vendor.
4.2.2 Voltage
Single point 240V AC, 50 Hz power supply shall be supplied to HVAC DDC (Direct
Digital Control) panel in addition to one normal 240V 50 Hz power supply required
for the utilities of DDC like heaters, fans, panel lights and sockets as applicable.
4.2.3 Others
Hazardous area classification shall be ‘safe’ and degree of protection shall be IP55
and IP45 for all outdoor and indoor electrical equipment respectively. However, for
battery room, the exhaust fans shall be suitable for Zone 1, Gas Group IIC, T4.
HVAC skid shall be provided with two earthing bosses diagonally located earth bar
Skid earthing bus bar shall be provided by the Vendor and equipment within the skid
shall be earthed to this skid earthing bus bar by vendor. All cable trays, JB’s,
instruments, motors, motor terminal boxes etc shall be earthed. Loop earthing to be
done for cable tray joints.
Following Y/G cu earth cable sizes shall be connected between respective equipment
and earth Bar:
a. LV Switchboards ,
b. Distribution boards - 70 Sq mm Y/G Cu conductor
c. HV Motors LV Motors, LV Motor terminal box,
d. Electrical RCU, Electrical JB’s,
e. Non conducive parts ( non-electrical conducting equipment) : 25 Sq mm Y/G Cu
conductor
The condensing units along with all electrical, instrumentation shall be suitable for
outdoor installation without sunshade.
All the electrical equipment viz. motors and instrumentation located outdoors shall
be suitable for 82°C black bulb temperature. All electrical equipment that are not in
the air conditioned environment like substation building shall be designed for an
ambient temperature of 50°C. All electrical equipment located in shade shall be
suitable for 50°C shade temperature. It is to be noted that shade effect shall not be
considered for some of the motors viz. fresh air fan motor, motors of volume control
dampers. Also Vendor to check and confirm that motors in condensing units and air
handling units are in sheet metal enclosure of respective units and hence can be
treated as “under shade”. Such motors shall be suitable for 50°C.
Final paint shade of all electrical equipment shall be RAL7035.
Make of all electrical equipment shall be as per Company approved Vendor list
(AVME) except those components which are part of AHU and DX or chiller unit.
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Cable entries to the 415V LV HVAC MCC shall be from bottom. 415V LV HVAC MCC
shall be provided with un-drilled gland plate of adequate size, for fixing cable gland.
415V LV HVAC MCC shall be provided with cable glands, lugs etc.
The draw out portion of all the modules of a particular type and rating shall be
completely identical and interchangeable.
The short circuit rating of the 415V HVAC MCC shall be min 50kA for 1 sec or as per
project specific requirement whichever is higher.
Power/control cables shall be supplied by HVAC Contractor / Vendor except incoming
power supply cable to HVAC MCC and 240V AC supply cable to DDC panel.
Power/control cables shall be Cu/XLPE/SWA/PVC type. Single core cables shall be
Cu/XLPE/AWA/PVC. Sizing of cables shall be done in such a way that steady state
and dynamic voltage drops shall not exceed the limits specified in IEC 60364
Power supply to Exhaust fans in Toilets /Bathrooms / Pantry shall not be powered from
HVAC panel. Same shall be powered from Lighting and Small Power Distribution
board. However, exhaust fans in Battery room, Mess & Kitchen shall be powered and
controlled from HVAC panels.
All Air Heaters wherever required shall be provided with local safety switch (for single
phase heater) or Load Break Switch (for three phase heater) pad lockable type in off
position for Isolation.
Local / Remote switch shall be provided in DDC panel. No Local / Remote switch shall
be provided in Motor modules. In local mode, it shall be possible to operate and
maintain any motor from local RCU and Load Break Switch as the case may be.
Corresponding to each AHU, dampers shall have on/off switches to enable local
maintenance of associated motors.
Load Break Switch / RCU for local Isolation (pad lockable type in off position) near the
unit shall be provided for following HVAC systems:
Window AC
Split AC - Local Isolation required for both Indoor unit as well as Outdoor unit
VRV Units ( Variable Refrigerant Volume) - Local Isolation required for both Indoor
unit as well as Outdoor unit
Package AC Units - Local Isolation required near the unit
Condensing Unit and AHU - Local Isolation required for condensing unit. Remote
control unit (RCU) is required for each AHU motors. If motors are provided with space
heater (>= 75kW) then safety switch near motor is also required for local Isolation.
Chilled Water System - Local Isolation required near the unit.
4.4 Motors
All independent motors (which are not part of a package e.g. condensing unit, AHU
motor,) shall be in line with SP-1119, SP-1103, motor data sheets and shall be
procured from PDO AVME list. All other motors shall comply with IEC 60034-1, IEC
60034-5, IEC 60034-12 and IEC 60034-14 and 60034-18.
The cage induction type motors forming part of an AC Variable Speed Drive System
(VSDS) shall comply with IEC 60034 as applicable.
Minimum efficiency at full load of LV motors shall comply with IE3 (High efficiency) of
IEC60034-30
Motor body shall be provided with two (2) diagonally opposite earthing bosses. The
motor terminal box shall have separate earthing arrangement.
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All motors shall be rated less than 160 KW and voltage levels shall be in line with SP-
1103 Appendix 2.
All independent motors (which are not part of a package e.g. condensing unit, AHU
motor and chiller) shall be in line with SP-1119, SP-1103, motor data sheet and shall
be procured from PDO AVME list. All other motors shall comply with IEC 60034-1, IEC
60034-5, IEC 60034-12 and IEC 60034-14 and 60034-18.
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5.0 Appendices
Appendix A: HVAC Typical and General Details
Appendix B: Standard Air Conditioning Test Sheets
Appendix C: SP User- Comment Form
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Figure – A 01
Figure - A02
Note: AHU room shall be provided with air conditioning.
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Figure - A 03
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Figure – A 04
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Figure – A 05
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Figure – A 07
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Figure - A 0 8
Figure – A 09
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h
Figure No: A14
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