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13. Lighting, Small Power and Ventilation

13.1 Scope

This section of the specification includes for the interior and exterior lighting, small power and ventila-
tion systems.

Whenever practicable, fixtures shall be sourced locally. All lamps, fittings, plugs, sockets and general
accessories of the same size and types shall be similar and interchangeable throughout the installa-
tion.

The lighting and small power equipment and installation shall comply with other sections of this Speci-
fication as appropriate.

All civil works associated with this section of the works shall be deemed to be included as part of the
works in this section. No additional payments will be made for such requirements.

The requirements of this section of the works are subject to the Main Conditions and Specifications
laid down in other sections of the Bid Document.

13.2 References

British Standards

• BS 7671 Code of Practice Regulations for Electrical Equipment in Buildings 15th Edition.
Institution of Electrical Engineers
• BS 6004 Specification for PVC insulated cables (non-armoured) for electric power and
lighting
• BS 6346 Specification for PVC insulated cables for electricity supply
• BS 6500 Specification for insulated flexible cords and cables
• BS 6121 Mechanical cable glands
• BS EN 60947 Specification for control gear for voltages up to and including 1000V AC and
1200V DC
• BS 4533 Luminaries
• BS 3677 Specification for high-pressure mercury vapour lamps
• BS 1363 Specification for 13A fuse plugs and switched and unswitched socket outlets
• BS 1362 Specification for general purpose fuse links for domestic and similar purposes
(suitable for use in plugs)
• BS 4568 Specification for steel conduit and fittings with metric threads of 150 form for
electrical installation
• BS 4066 Test on Electric cable under fire conditions
• BS 4434 Specification for safety aspects in the design construction and installation of re-
frigerating appliances and systems
• BS 5970 Code of Practice for thermal insulation of pipework and equipment
• BS 848 Fans for general purposes

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• BS 6540 Method of test for atmospheric dust spot efficiency and synthetic dust weight
arrestance
• BS 2871 Specification for copper and copper alloys: tubes
• BS 1470 Specification for wrought aluminium and aluminium alloys for general engineer-
ing purposes, plate, sheet and strip
Institution of Heating and Ventilation, Engineers Guide to Current Practice.
American Society of Heating Refrigeration and Air Conditioning, Engineers
Recommendations
Heating and Ventilation Contractors Association of U.K., Specification DW /
121

13.3 Defects Liability Period

The Contractor shall be responsible for the efficient and good working of the installations comprising
this section of the Specification for the agreed period as set out in the Specification document.

13.4 Approvals

The Contractor shall submit to the Engineer for approval copies of all his calculations forming the ba-
sis for the designs of the specified systems, which shall be shown on the working drawings, also to be
submitted for approval.

Any approvals shall not, however, relieve the Contractor of his contractual responsibilities which in-
clude obtaining local authority approvals for electrical wiring installations.

13.5 Lighting Requirements

The lighting installations shall be designed to give the standard service illuminations and shall incorpo-
rate emergency lighting where indicated. Control rooms, relay rooms, telecommunications equipment
rooms, offices and stores shall have the service illumination measured at 850 mm above finished floor
level. All other areas shall have the service illumination measured at floor level.

The installations shall also meet the limiting glare index requirements as set out in the specified codes
of practice. This section of work gives proposals for the types of lighting fittings to be used in the area,
type of control to be employed, number of socket outlets and the types of mounting expected to be
suitable for the respective areas. Where discharge and fluorescent light sources are to be used in are-
as containing rotating or reciprocating machinery, the fittings shall be allocated between the 3 phase
and neutral in such a manner as to avoid stroboscopic effects. When 3 phase lighting installations are
to be used, contactor switching controlled by pushbuttons located in the area to be illuminated is pre-
ferred.

In all rooms and corridors having two entrances the lighting installation shall have two way switching,
the switches being located in appropriate positions adjacent to the entrances.

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Emergency lighting shall be arranged to illuminate all stairways, exits and entrances and provide some
illumination in operational areas within the control building and the switchyard, e.g. circuit breaker and
transformer locations.

Security lighting shall be installed around the perimeter walls illuminating the external area and shall
be controlled from the gatehouse. The level of illumination for security lighting shall be measured at a
distance of 3 metres outside the boundary wall.

13.6 Schedule of Design Requirements

The lighting system shall include provision for ease of erection, maintenance, cleaning, lamp replace-
ment and future extension. Lamp replacement and maintenance should, unless otherwise approved,
be possible without necessitating outages on main plant items.

Lighting apparatus shall be of top quality, designed to ensure satisfactory operation and service life
under all variations of load, frequency and temperature. Sodium discharge lighting shall be used for
road and security lighting. Switchyard floodlighting shall use 500W Halogen lamps unless otherwise
specified.

Key to Abbreviations:
L Local switches
S1, S2, etc. Socket outlets or fused spur circuits
P.B Pushbutton for remote control
T.S Time switch control
C Ceiling mounted
W Wall mounted
P Pole or earth mast mounted
M Recessed modular mounting
D Suspended
F Flush installation
S Surface installation
A Automatic on mains failure.
BH Behind ceiling diffuser.

13.7 Coding Systems

The Contractor shall, when preparing drawings showing the respective designs, use a code to identify
each lighting fitting and socket outlet.

The code shall comprise letters and figures so compiled that the following information can be readily
identified:

1. The lighting distribution board to which the fitting or socket outlet is connected.
2. If connected to the normal supplies or to the emergency DC supplies.
3. The circuit number and phase of the distribution board to which the fitting is connected.
4. The sequence of the fitting in a particular circuit.

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13.8 Distribution Boards

The distribution boards and all component parts shall be manufactured and tested in accordance with
the latest standards and designed to suit the fault level of the transformers supplied. The Contractor
shall demonstrate by calculation that this has been complied with.

Each, current carrying component shall be so designed that under continuous rated full load condi-
tions in the climatic conditions at Site the maximum total temperatures permitted under the relevant
Standards are not exceeded.

Each distribution board shall have a rustproof metal case of sheet steel with either a galvanised or
enamelled finish. The colour of the enamel finish shall match the colour of other switchgear. The metal
casing is to be provided with a number of knock-outs or other approved form of cable entries, corre-
sponding to the circuit capacity of the distribution board, and a suitable screened brass earthing stud.
Busbars, including neutral bar, shall be of high conductivity copper supported to withstand all normal
and fault condition stresses.

All busbars, neutral bars and primary conductors are to be PVC sleeved in respective phase and neu-
tral colours.

Distribution boards for exterior use shall be galvanised and weatherproof.

Neutral bars shall have an appropriate number of ways relative to the size of the board. They shall
have a rating not less than that of the associated phase busbars.

The metal surface adjacent to any live part and all spaces between phases shall be protected by bar-
riers of fireproof insulation material.

The distribution boards shall be either single pole or triple pole and neutral types and shall be
equipped with means to provide overcurrent protection to each circuit. This protection may comprise
an HRC fuse or a miniature circuit breaker, both of which shall be removable without exposing live
connections.

Fuse bases and bridges, where used, shall be of an approved non- hygroscopic insulation suitable for
the receipt of HRC fuses.

Residual current circuit breakers shall be incorporated to protect all lighting circuits, socket outlets and
supplies to appliances, etc. These shall comply with the requirements of the main electrical part of this
Specification.

The current rating of the busbars in each distribution board is not to be less than the sum of maximum
current rating of all outgoing circuits. The neutral connection for each circuit is to be direct to the neu-
tral busbar.

Title labels of an approved type and inscriptions are to be fitted externally on the front cover of each
distribution board giving details of the points controlled by each circuit. The circuit lists shall be typed
or printed stating the location of the equipment served, rating of the protective unit and the circuit load-
ing. The lists shall be mounted on the inside of the cover door and shall be protected by an acrylic
sheet slid into a frame over the circuit lists. The lists and cover are to be easily removable to permit
circuit modifications.

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The cables feeding the distribution boards will be connected directly to the incoming isolator or neutral
bar as appropriate, unless otherwise indicated by the Specification.

Switch fuse units or isolators connected on the incoming side of a distribution board shall be mechani-
cally attached to the board with solid copper electrical connections between the units. A suitable insu-
lated barrier is to be supplied to prevent copper or carbon dust released under fault conditions passing
from one unit to the other.

Distribution boards for use on the direct current system shall be double pole types equipped with ade-
quately rated fuses.

Mixed capacity boards shall be employed and all contactors and time switches associated with the re-
spective outgoing circuits shall be accommodated within the distribution board.

13.9 Miniature Circuit Breakers

Miniature circuit breakers shall comply with the requirements of the main electrical part of this Specifi-
cation.

13.10 Cables

Cables shall be XLPE insulated, single wire armoured and PVC sheathed overall and be manufac-
tured and tested in accordance with the requirements of BS 5467, 600/1000V grade or equivalent. The
outer sheath shall be coloured black and incorporate flame retardant characteristics to meet the re-
quirements of BS 4066 and IEC 60332. Jute fillings will not be permitted. Cables shall comply with the
requirements of the cable section of this Specification.

Flexible type cables for pendant cords and final connections to fixed apparatus are to be butyl or sili-
cone rubber insulated and sheathed, manufactured and tested in accordance with the requirements of
BS 6500, 300/500V or 300/300V grade as applicable.

The conductor is to comprise multi-strands of 0.25 mm wire. The number of strands are to be not less
than 30 and in all cases of a number suitable for the protection rating of the respective circuits.

All cables used for lighting and small power shall have copper conductors.

The Contractor is to select conductor sizes for the respective final circuits to meet the following condi-
tions:

(a) That the minimum conductor size for lighting circuits is to be 1.5 mm² and for socket outlets
2.5 mm².
(b) That the size is to be adequate for the current to be carried as set out in the cable Manufactur-
er's specification.
(c) That the size is sufficient to keep the voltage drop in the phase and neutral conductor to the far-
thest lighting or power point, under normal full load conditions, to within the final circuit limit
specified in BS7671. Diversity will not be allowed.

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13.11 Cable Terminations

Terminations for cables shall comprise compression type glands with armour and bonding clamps to
meet the requirements of Type E1 to BS 6121, or equivalent, and are to be designed to secure the
armour wires, to provide electrical continuity between the armour and the threaded fixing component
of the gland and to provide watertight seals between the cable outer sheath and gland and between
the inner sheath and threaded fixing component. The glands are to project at least 10 mm above the
gland plate to avoid moisture collecting in the cable crutch.

Earth bond terminal attachments are to be provided.

Terminations for rubber insulated cables are to comprise compression type glands where the function
of the gland is to secure the outer sheath of the cable, in accordance with the requirements of Type A2
to BS 6121 or equivalent. A watertight seal is to be provided between the outer sheath and the gland.
Only one cable is to be terminated in each gland.

13.12 Sealing and Drumming

Immediately after the works tests, both ends of all cables shall be sealed against the ingress of mois-
ture, dirt and insects and the end projecting from the drum shall be adequately protected against me-
chanical damage during handling and shall be fitted with a pulling eye bonded to cores, sheath and
armours.

13.13 Conduit

All wiring shall be installed in screwed heavy gauge welded steel conduit or heavy gauge PVC con-
duit, at the discretion of the Engineer. No conduit less than 20 mm diameter will be permitted.

Surface mounted - steel - switchrooms, battery rooms, i.e. painted blockwork.

Flush mounted - PVC - relay control rooms which have a decorative finish.

Steel conduits shall be manufactured in accordance with BS 4568, Part 1 or equivalent, heavy gauge
screwed and welded Class B and shall be galvanised. Conduit fittings are to be manufactured of good
quality galvanised malleable cast iron and of small circular pattern to BS 4568, Part 2 or equivalent,
with internally tapped spouts minimum length 21 mm. threaded to the correct length at intersections,
tees, draw throughs and stop-ends.

Conduit fittings of PVC shall be of the plain bore pattern suitable for a push-on compression type joint-
and shall be sealed with a hard setting vinyl cement to prevent ingress of vermin, water, dust, etc. In-
spection bends, solid or normal bends, elbows or tees are not to be used except with the approval of
the Engineer.

Conduit runs shall, wherever possible, be concealed in ceilings, voids and walls, chases, etc., and in
rooms of secondary importance (with back outlet entries to switch boxes, etc. especially on fair faced
brickwork) otherwise the conduits shall be securely fixed to the surface of walls using heavy cast dis-
tance saddles. Where plastered finishes are called for, buried conduit systems shall be provided.

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Where the system of wiring is concealed, the 'loop-in' system of conduit shall be used and the 'loop-
ing-in' boxes shall conform to BS 31, Class B3.

A separate insulated earth conductor, coloured green and yellow, shall be run in PVC conduits and
such facilities shall be provided at all terminal points.

Wherever the installation is specified as being flame-proof, the conduit runs entering these areas shall
have a barrier box inserted in the run immediately before the conduit passes into the flame-proof area.
All conduit work inside the flame-proof area shall be carried out with solid drawn galvanised conduit
and all conduit fittings, sockets and accessories shall be galvanised and certified suitable for Group 1
hazard. At the completion of the wiring all machine faces on accessories shall be thoroughly cleaned
and greased, prior to the screwing or bolting of all accessory cover plates into their final flame-proof
secure position.

The ends of all steel conduits shall be reamered to remove all burrs or sharp edges after the screw
threads have been cut. All dirt, paint or oil on the screw threads, the conduit, sockets and accessories
must be removed prior to erection. All conduits shall be swabbed through prior to installation of cables.

The ends of the conduit shall butt solidly in all couplings. Where they terminate in fuse-switches, dis-
tribution boards, adaptable boxes or non-spouted switch boxes, they shall be connected thereto by
means of smooth bore male brass bushes, compression washers and sockets. All exposed threads
and all bends shall be painted with an aluminium spirit paint after erection.

All conduit and accessories, after being installed, shall be examined and all parts where the surface
has been chipped or scratched shall be painted.

All conduits shall be kept 80 mm clear of water, gas and other services. Should this prove impractica-
ble, then they shall be properly bonded by means of pipe clamps or other device ensuring mechanical-
ly sound, electrically continuous connection.

The method of installing PVC conduit and fittings shall conform strictly to the Manufacturer's recom-
mendation. These recommendations shall be submitted when seeking approval to the system pro-
posed. In general the clauses dealing with steel conduit shall apply.

PVC tube not exceeding 25 mm in diameter shall be bent cold by means of the appropriate spring and
the tube shall be saddled as quickly as possible after bending. When bending larger sizes of tube, the
tube must be heated in an approved manner until it is pliable. A 90˚ bend shall have a radius of not
less than five times the outside diameter of the tube.

Joints between conduits and conduit fittings shall be watertight and shall be made by means of a sol-
vent adhesive as recommended by the Manufacturer. Care shall be taken to ensure that the tube is
clean and free from damp and grease and in particular dust, mould and oil.

The Contractor shall provide PVC tube ends and flexible covers to prevent ingress of concrete grout
into the tubing and boxes.

All bends are to be made on Site to suit conditions and not more than two right angle bends will be
permitted without the interposition of a draw box. No tees, elbows, sleeves, either of inspection or solid
type, will be permitted. Generally long straight conduit runs from point to point shall have draw boxes
installed at maximum intervals of 10 metres.

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Deep boxes or extension rings on standard circular conduit boxes shall be used where necessary in
order to bring the front of each box flush with the surface of the ceiling or wall. Where conduits are laid
direct on the shuttering of the reinforced slab construction, conduit extension rings or deep boxes shall
be used to raise the run of conduit to between the top and bottom reinforcing. Galvanised draw wires
or other approved types shall be provided where conduits are not to be wired on completion or are to
be wired by others.

All draw boxes and junction boxes shall be of ample size to permit the cables being drawn in and out.
They shall be made of malleable iron or PVC approved type and the jointing surface machined to en-
sure a dust tight joint. All circular boxes shall be provided with long spouts internally threaded incorpo-
rating a shoulder for the proper butting of the conduit and a solid brass earth terminal tapped and
screwed into the base of the box.

All conduit boxes shall be screwed on or in walls, ceilings, etc. by countersunk wood screws of appro-
priate size. Holes in boxes shall be adequately countersunk to ensure the complete recession of the
fixing screws. All inspection and draw-in boxes shall be provided with covers fixed by round head
brass screws.

Where surface conduit is specified, it shall be fixed by means of distance saddles and shall terminate
in raised back pattern conduit boxes. Surface conduits shall not be bent or set to enter accessories,
and where they turn through walls back outlet boxes shall be provided. Conduits shall be fixed at
1200 mm centres on vertical runs and 900 mm apart on horizontal runs.

Vertical conduit runs shall have saddles at 300 mm maximum from their points of emergence from
floors or ceilings and the remaining saddles shall be fixed consistent with the requirements of spacing
and appearance. Saddles shall be fixed on each side of every bend at 300 mm maximum from the
point of intersection of the centre line conduit.

Conduits in ceiling cavities shall be supported independent of the suspended ceiling.

Where conduits cross expansion joints, the Contractor shall allow for the installation of expansion
couplers at the positions of the expansion joint and at right angles to it. He shall provide a bonding
earth wire between each terminal fitted in the nearest conduit box each side of the coupler.

All flexible metallic tubing shall be galvanised watertight pattern fitted with sweated brass adaptors.
External earth conductors, wrapped around the tubing, shall be provided.

Where conduits are laid in slab floor, etc., the Contractor shall arrange for a competent person to be in
attendance whilst the concrete pouting or screeding operation is being carried out, in order to avoid
damage being caused to the conduits and also to ensure that the conduit work is in sound condition,
properly and efficiently maintained during this installation period.

Particular care should be taken when setting out conduit runs to outlet points where they are to be fit-
ted to furniture, kitchen fittings, etc. The Contractor shall ascertain exact details of the furniture and fit-
tings construction in order that all conduit work shall wherever possible be concealed.

Conduits installed in chases of walls and floors shall be firmly secured by wrought iron pipe hooks or
crampets and these fixings shall in themselves be sufficient to hold the conduits in place. Conduits in-
stalled in chases shall be painted with one coat of bitumastic paint before erection and a further coat
shall be applied to all accessible surfaces including the hooks and the crampets after erection.

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Recessed conduits buried in plaster shall permit a full 6mm. depth of cover over its entire length. Pro-
vision shall be made for the tapping of condensed moisture.

Care shall be taken to prevent water, dirt or rubbish entering the conduit system during erection.
Screwed metal caps or plugs shall be used for protecting open ends.

All conduit systems shall be erected completely with all conduit accessories connected. They shall
then be offered for inspection and approval by the Engineer before any cables are installed. Conduit
boxes shall be fixed to the structure of the building independently of the conduit.

Where a conduit is exposed to different temperatures (either by surrounding air conditions or by virtue
of the surrounding medium with which it is in contact) at any particular time, the section of the conduit
at the higher temperature shall be isolated from the section at the lower temperature by means of a
conduit box filled with an approved permanently plastic compound, after completion and testing of all
wiring. Such a condition would arise if a conduit running in a warmed building is run to exterior points.

Where galvanised conduit is specified, all conduit, accessories, switch boxes and all associated appa-
ratus used in the installation must also be galvanised. Galvanised conduit shall be used when mount-
ed outside a building, installed in floor chases subject to dampness or accidental flooding, or buried in
the ground. Conduit systems shall be weatherproof when erected outside a building. Exposed conduit
threads shall be given a coat of zinc rich paint.

Conduit buried in the ground shall be wrapped with PVC self-adhesive tape half lapped. The taping
shall be extended for a distance of 150 mm beyond the point where the conduit emerges from the
ground. Joints in galvanised conduit systems shall be made watertight using lead, aluminium paint and
hemp and/or gaskets. The joints shall be partially screwed up before the paint and hemp are applied
to maintain continuity.

All adaptable boxes shall be grey iron pattern unless otherwise specified. Where adaptable boxes are
fitted flush, the cover plates shall be heavy gauge metal with 12 mm overlap on all sides. The internal
depth of a box shall be not less than 40 mm.

Covers shall be secured by a screw at each comer and by additional screws as necessary to provide a
maximum spacing of 300 mm between adjacent screws. Fixing screws shall be brass (round or
cheese head).

Covers for boxes shall be of the same material as the box. For boxes mounted in weatherproof situa-
tions, the cover shall have a machined surface around the perimeter mating with a similar machined
surface on the box and shall be complete with a gasket.

Every flush outlet box to which a luminaire pull cord switch or similar is to be fitted, shall be equipped
with an approved type of break joint ring.

13.14 Cable Trunking

Where trunking is specified it shall be constructed of 1.65 mm minimum thickness zinc coated mild
steel or PVC and shall have a removable cover throughout its length with centre screw latch fixings.

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Trunking shall be rigidly fixed and supplied complete with purpose manufactured fittings, connectors,
dividers, flanges, cable retaining clips, racks and copper earth continuity links. As an alternative, if ap-
proved, a proprietary brand of heavy duty plastic trunking may be acceptable. When submitting details
for approval, full installation instructions as recommended by the Manufacturer shall be included in the
details.

All cables installed in trunking shall be labelled and identified in an approved manner. Clips shall be at
600 mm from centres. Vertical cable trunking shall be fitted with cable pin racks arranged to avoid any
strain on the cables.

All trunking shall be rust proofed, primed and painted and fixed at intervals not greater than 1,000 mm.

13.15 Cable Trays

Cable trays, where required as part of the Contract supply, are to be the perforated galvanised sheet
type.

Trays are to have upturned edges and be of a width suitable for the number of cables to be supported
and are to be supplied with purpose- made galvanised steel brackets suitable for mounting from the
building structure. External cable trays shall be provided with covers.

Where site cutting of trays or support bracket steelwork is unavoidable, recutting bare steel shall be
protected with two coats of an approved zinc rich paint immediately after cutting.

13.16 Cable Jointing

The Contractor shall be responsible for the sealing and jointing of all cables supplied and installed as
part of this Section of the Contract. Straight jointing of cables is not permitted without the written con-
sent of the Engineer.

13.17 Contactors

Contactors shall comply with BS 5424 or equivalent and shall be of the electrically held-in types con-
tained in heavy gauge sheet steel cases suitable for panel mounting. Each contactor shall be continu-
ously rated and suitable for thirty inductive switching operations per hour.

13.18 Switches and Pushbuttons

Switches shall be rated for 15 amps, shall be single pole types and be provided with an earth terminal.
Switches shall be one way, two-way or intermediate as required and, where mounted together, they
shall be fitted in a common box.

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Switches for use in areas designated for surface installation shall be quick-make-quick-break fixed grid
industrial types mounted in galvanised malleable iron boxes with protected dolly and arranged where
necessary for multi-gang switching.

Switches for use in areas designated for flush installation shall be micro-break types fixed to white
plastic cover plates and mounted in galvanised steel flush type boxes.

Switch-boxes shall be galvanised and fitted with screwed stainless steel front plates having a 6 mm
overlap minimum for flush installations. They shall be suitably barriered and labelled where two phas-
es are connected in the same box.

Switches mounted externally shall be of weatherproof pattern to IP55 level fitted with machined box
and cover joint, brass operating handles, neoprene weathertight seals and external fixing feet.

Where DC emergency lighting circuits are to be switched, double-pole quick make, quick break
switches with pillar type terminals and earthing straps shall be provided.

Switches shall be mounted 1.4 m above finished floor level.

Pushbutton switches shall either be flush or surface types contained in galvanised steel boxes and be
single pole rated for 5 Amps. Pushbuttons shall be made of non-hygroscopic material, be non-swelling
and so fitted as to avoid any possibility of sticking.

The terminals for all switches shall be adequate to accommodate 2 conductors, each a minimum of
1.5 mm² in area.

13.19 Lighting Fittings

Illustrations and/or samples of all lighting fittings which the Contractor proposes to purchase shall be
submitted to the Engineer for approval before issuing any sub-orders.

Lighting fittings for interior and exterior use are to be manufactured and tested in accordance with the
appropriate sections of BS 4533, IEC 60162 or equivalent and together with all components are to be
suitable for service and operation in the tropical climate stated.

Each fitting is to be complete with all lamp holders, control gear, internal wiring, fused terminal block,
earth terminal and reflectors or diffusers as specified. The design of each fitting is to be such as to
minimise the effect of glare and such that the ingress of dust, flies and insects is prevented, where
open type fittings are used it is to be impossible for insects to become lodged therein.

The control gear for use with fluorescent lamps is to be quick or resonant start type without starters.

Chokes are to be impregnated and solidly filled with polyester resin, or other approved high melting
compound, are to be manufactured to restrict the third harmonic content to less than 17% of the un-
corrected current value, and are to be silent in operation.

The built-in ballast units shall comply with IEC 60082 and shall include radio interference suppressors
and capacitors to correct the fitting power factor to a minimum of 0.85 lagging. Control gear noise lev-
els shall be minimal.

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Fittings shall be supplied complete with closed end vitreous enameled metal reflectors or totally en-
closed opal plastic diffusers, which shall be fully interchangeable.

Dispersive reflector fittings suitable for mercury bulb fluorescent or tungsten filament lamps shall be of
heavy gauge sheet steel finished vitreous enamel. They shall be fitted with anti-vibrators and arranged
for conduit box mounting, direct or pendant, on galvanised ball and socket dome type lids.

Bulkhead fittings shall have cast bases tapped for conduit entry, hinged bezels, heat resisting pris-
matic glasses fitted with neoprene gaskets and porcelain lamp holders. Circuit cable shall not be con-
nected direct to bulkhead fittings but shall terminate in a fixed base connector mounted in a conduit
box adjacent to the fitting. Final connections to each fitting shall be carried out with silicone rubber
covered cable. All bulkhead fittings shall be watertight pattern.

Internal connections are to comprise stranded conductors not less than 0.75 mm² covered with heat
resistant insulation to the requirements of BS 6500 or equivalent. All internal wiring is to be adequately
cleated to the fitting casing with an approved form of cleat. The finish of fittings for interior use is to be
impervious to deterioration by atmospheric reaction. Fittings for exterior use shall have a vitreous
enamel, natural aluminium or galvanised finish according to the Manufacturer's standard product.

Lampholders for tungsten lamps up to 150 watts shall be brass or porcelain BC type and for higher
ratings shall be ES or GES type according to size. Fittings for housing tungsten lamps exceeding 150
watts rating are to be provided with an approved method of dissipating heat from the lamp cap and
terminal housing.

Lampholders as applicable are to be suitable for the lamp specified.

Lighting fittings are to be of the type description as generally set out in the schedule appended to this
section of the Specification. The type references used are to be repeated in the Schedules and on the
drawings.

13.20 Lamps

The Contract includes the supply and erection of all lamps and tubes necessary to complete the instal-
lation.

Fluorescent lamps shall be manufactured and tested in accordance with BS1853, IEC 60081 or equiv-
alent, shall be bi-pin types and shall have colour rendering values of X = 0.335 and Y= 0.342 (i.e.,
Colour 2) on the CIE chromaticity scale.

Tungsten lamps shall be manufactured and tested in accordance with BS 161 or equivalent and shall
be bayonet cap for lamps up to and including 100 watts. Lamps rated for 150 watts and higher shall
have Edison screw caps. Low wattage lamps used in exit signs and emergency lighting units may be
small or miniature Edison screw.

Discharge lamps shall be manufactured and tested in accordance with BS 3677 or equivalent. Mercu-
ry vapour lamps shall be fluorescent types having a 10% red ratio colour correction, whenever used.

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13.21 Socket Outlets and Fused Spur Outlets

Each socket outlet shall comply with the requirements of the BS 1363 or equivalent and shall be the
interlocked shuttered and switched types arranged for surface or flush mounting in single or multi-
gang units as appropriate.

Each fused spur outlet shall be equipped with double pole isolator, a fuse to BS 1362 or equivalent
and where required front entry for flexible connection.

Each socket outlet and fused spur outlet shall be equipped with a galvanised metal box with earth
terminal.

Each group of five socket outlets is to be provided with a matching fused plug top.

All socket outlets for exterior use shall be galvanised and weather- proof and be equipped with
screwed dustproofed cap attached to the socket by means of a chain.

13.22 Time Switches

Time switches for use with lighting systems shall be the synchronous motor wound types protected by
a suitably rated fuse for 230 volts operation with a nine hour reserve spring and are to be fitted with a
twenty-four hour hand set dial, two "OFF" and two "ON" levers and manual operation pushbutton. The
main contacts shall be rated for 20 Amps on a 230 Volt 50 Hz AC supply.

Time switches shall be suitable for mounting in the distribution boards supplying the circuits to be con-
trolled.

13.23 Poles

Lighting poles shall be tapered, of hot dip galvanised steel with bituminous preservative inside and
outside at the base and shall be approved by the Engineer.

Each pole shall be equipped with a base section compartment of 470 mm by 150 mm to house an in-
spection trap, lockable door, fused cut out, cable entry and terminations for both the incoming and
outgoing power cables and secondary cables feeding the light sources.

Poles for substation lighting shall support the floodlights at 11m above ground level and poles for ac-
cess roadway lights shall support the lanterns at 4.5m above ground level.

The Contractor shall ensure each pole is provided with foundations suitable for the ground conditions
occurring at each site.

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13.24 Interior Installations

Wiring for the lighting and socket outlet installations shall comprise PVC cables drawn into conduits at-
tached to walls, structural or roof steelwork or ceilings as appropriate (see chapters 13.13 and 13.14).

Surface and flush type installations are required according to the particular area as indicated in the
schedule appended to this section.

In areas where flush type installations are indicated the wiring shall be drawn into conduits buried un-
der wall finishes or concealed above ceilings as appropriate.

All fixings shall be of a type approved by the Engineer and all metalwork used shall be galvanised. Fix-
ings to structural steelwork shall be with purpose made brackets or clamps; the drilling of structural
steelwork will not be permitted.

Cleats with two screw fixings shall be used for supporting conduits at not greater than 2 m intervals.

All switchboxes, socket outlet boxes and items of a similar type shall be fixed with two screws or bolts.

Switches and pushbuttons for lighting circuits shall be mounted at 1400 mm above finished floor level.

Socket outlets shall be mounted 500 m above finished floor level but those for use with workshop
benches shall be mounted 150 mm clear of the bench working surface.

Lighting fittings shall be attached to ceilings, walls, trunking or roof steelwork or suspended therefrom
as appropriate.

Where fittings are to be suspended, rod type suspension units shall be employed.

Final connections to all suspended lighting fittings shall be with heat resistant flexible cable terminated
in porcelain clad connectors in the ceiling or junction box which shall also terminate the main circuit
cable. The cable length shall be such that the suspension unit supports the full weight of the lighting
fittings.

Where recessed type lighting fittings are to be installed suspension units shall be used to prevent the
weight of the fittings being applied to the suspended ceiling. It shall be possible to carry out mainte-
nance from the underside of the fitting without disturbing the false ceiling. To facilitate this need the fi-
nal connection to each fitting shall be with heat resistant flexible cable from a plug in type ceiling rose
mounted above the false ceiling.

All cables not contained within conduit for their whole route shall be terminated with a cable gland.

Where lighting fittings are mounted direct on walls or ceilings, the main circuit cables may be connect-
ed into the fitting terminal block. Where terminal blocks do not exist within the lighting fitting, flexible
heat resistant cable shall be used connected to a separate junction box.

Earth continuity shall be maintained throughout the entire wiring installation with separate insulated
earth continuity conductors of adequate cross-section ultimately connected to a common earth termi-
nal at the respective distribution board.

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Within the interior installation adequate provision shall be made for connection to small ventilating
fans, which are not energised from the central air conditioning control and starter panel.

Each and every trunking route shall be bonded across all joints with external copper bonding links
supplied for the purpose.

13.25 Exterior Installation

Exterior substation lighting fittings shall be attached to substation walls at high level or pole mounted
as appropriate. Security lighting round the perimeter wall/fence is to be provided.

When locating the floodlights for the switchyard lighting, the Contractor shall ensure that all floodlights
are outside safety clearance for the high voltage switchgear at the particular location.

Cables to exterior lighting shall be laid direct in ground, laid in concrete trenches or cleated to build-
ings structures as appropriate to the route requirement. The cables shall be terminated at a cut-out lo-
cated at the base of each support. Wiring between the cut-out and the control gear or lantern shall be
with multicore cable run within poles or with cable drawn into galvanised steel conduit attached to the
supporting structure.

13.26 Emergency Lighting

Emergency lighting shall comprise lighting fittings of the types indicated in the schedule appended to
this section of the Specification.

The system shall be so arranged that on failure of the normal a.c. supplies to the lighting installation
the emergency lighting system will automatically be switched on. Other than those of the "on demand"
type, all emergency lighting shall be switched "off" 5 minutes after restoration of normal supplies. Each
emergency lighting unit shall have a minimum 3 hour rating.

Sufficient fittings of Type E3 shall be provided in each room to enable the rooms and building to be
evacuated safely.

In addition, in designated working areas emergency manually switched lighting, to give not less than
30 lux, shall be provided utilising type E4 fittings. Switches shall be labelled to the approval of the En-
gineer.

The security lighting scheme shall illuminate the area to 6 metres inside the perimeter wall to the light-
ing level specified.

13.27 Telephone System

A complete conduit/duct system shall be provided throughout the building to enable the telephone ca-
bles to be run to the proposed extension points. This includes telephone wiring to operators' desks
and office in the control building.

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Telephone instruments, the PABX and connections to PTT exchange lines shall be carried out by oth-
er Contractor.

13.28 Schedule of Lighting Fittings and Socket Outlets

All lighting schemes are to utilise fittings and lamp types which are available locally in Bangladesh to
ensure that replacements are readily acceptable.

Lighting fittings described in this Schedule shall also meet the general requirements of the Clause for
Lighting Fittings of this Specification.

Type F1 Shall indicate a basic channel complete with control gear and lamp holders for one fluo-
rescent lamp, equipped with an open ended metal reflector having upward light slots.

Type F2 Shall indicate a fitting which shall comply generally with the description for Type Fl but be
equipped for use with two lamps.

Type F3 Shall indicate a recessed modular fitting suitable for mounting in a suspended ceiling and
equipped with a clear prismatic controller. The metalwork and trim are to comprise a rigid
welded unit so arranged as to be invisible when erected complete with controller. The fit-
ting is to be equipped with a pre-wired removable gear tray and adjusting facilities to en-
able levelling relative to the ceiling to be carried out after erection. The assembly is to be
complete with control gear and lamp holders for one 1500 mm long 65 watt fluorescent
lamp.

Type F4 Shall indicate a fitting which shall generally comply with the description F3 but with an
open type grid diffuser.

Type F5 Shall indicate a dust-tight, weatherproof and vapour resistant fitting, having a grey polyes-
ter fibre glass reinforced chassis containing the control gear and having lampholders for
one 1500 fluorescent lamp. The fitting shall be complete with a vacuum formed acrylic dif-
fuser which is secured to the body with injection moulded toggles and sealed with a neo-
prene gasket.

Type F6 Shall indicate a weatherproof bulkhead fitting with a cast aluminium base and vandal re-
sistant diffuser equipped with control gear and lampholders for two fluorescent lamps.

Type E1 Shall indicate a self-contained, self-sustained (normally off) emergency lighting unit,
complete with integral batteries and control gear, with the words "EXIT" in white letters on
red background in English and Arabic. It shall be energised from the batteries under
mains failure conditions. The mains failure device shall be sensed by an unswitched
phase connection from the local lighting circuit.

Type E2 Shall indicate a self-contained, self-sustained (normally off) wall mounted emergency
lighting unit comprising a pilot light and two 100 watt spotlights complete with integral bat-
teries and control gear. The pilot light shall be energised under mains failure conditions
with manual "on demand" switches for the spotlights. The mains failure device shall be
sensed by an unswitched phase connection from the local lighting circuit.

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Type E3 Shall indicate a self-contained, self-sustained (normally off) wall or ceiling mounted
emergency lighting unit complete with integral batteries and control gear. The lamps shall
be energised under mains failure conditions. The mains failure device shall be sensed by
an unswitched phase connection from the local lighting circuit.

Type E4 Shall indicate a 110V DC wall or ceiling mounted emergency lighting unit which shall be
manually switched and be similar to type E3.

Type H1 Shall indicate forward throw floodlight fitting comprising a sheet steel vitreous enamelled
or spun aluminium reflector housing a 500 Watt Halogen lamp. The fittings to be com-
plete with wall mounting bracket.

type H2 Shall indicate a semi cut-off roadway and perimeter security lantern with housing manu-
factured from a one piece LM6 aluminium alloy casting enamelled white internally and
equipped with reflector bowl of heat resisting glass, all suitable for housing the lamphold-
er and control gear for one 150 Watt sodium vapour lamp. The fitting to be equipped with
pole arm suitable to give an outreach of 1 metre.

Type S1 Shall indicate a 13 Amp single or double gang flush mounted switched socket outlet.

Type S2 Shall indicate a 13 Amp single or double gang surface mounted switched socket outlet.

Type S3 Shall indicate an ironclad one gang heavy duty 4 pole interlocked switched socket outlet
with scraping earth connection suitable for use on a 400V 3 phase 4 wire 50 Hz for 125A.
Each socket is to be supplied complete with cable box with 2 glands, suitable for termi-
nating a PVCWPVC cable and shall be fitted with a screwed dustproof cap attached to
the top of the socket by means of a chain. Matching plugs to be provided in each socket.

Type S4 Shall indicate a 15 amp 3 phase 4 wire switched socket outlet with plug flush mounted.

13.29 Schedule of Lighting Requirements

13.29.1 Control Building

Location Service Illuminance (Lux) Glare Index

Control relay room 400 25
Behind panels 100 -
Office 500 20
Battery room 100 -
toilet 100 -
Corridors, stairs 100 20

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13.29.2 Outdoor Areas

Location Service Illuminance (Lux) Glare Index

Switchyard floodlighting 20 -
Transformer compounds 120 -
Roadway lighting 20 -
Perimeter wall security 10 -
Control building exterior 15 -

13.30 Air Conditioning and Ventilation

13.30.1 Scope of Work

This Section of the works covers the design, supply, delivery, installation, commissioning and setting
to work of the ventilating systems for the control building.

All ventilating systems shall be fully automatic in operation and shall be capable of maintaining internal
conditions within the bands of temperature and humidity specified hereafter. the substations are nor-
mally manned and allowance shall be made for at least four persons on site in the design.

13.30.2 Air Conditioning

The following areas shall be air conditioned:

• Office
• Control & Relay Protection room
• Telecommunication/SCADA/PLC room
• AC 6 DC Auxiliary Power Supply room

Air conditioning shall be provided in the form of Air Cooled Split System Air Handling Units. The sys-
tems shall handle predominantly recirculated air with a controlled quantity of fresh air introduced either
at each unit or independently via a separate supply and extract system. Supply air distribution ducts
for the Control/Relay room shall be located in the false ceiling serving supply diffusers. Return (recir-
culated) air shall be drawn in through the front of each unit.

The cooling medium for the split System Air Handling Units shall be direct expansion provided by air
cooled refrigeration condensing units located on the roof of the building or wall mounted on building
exterior, and interconnected by refrigerant pipework to multi circuit direct expansion cooling coils.

Air conditioning system shall be thermostatically controlled to maintain internal conditions under con-
tinuous operation within the limits stated. Plant shall be arranged to facilitate maintenance and future
replacement of equipment.

13.30.3 Mechanical Ventilation

Supply and extract ventilation shall be provided to serve the following areas:

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• Battery room
• Toilets (extract only)
• Cable basement

Supply air handling plants shall consist of a sand trap fresh air intake louvre, insect screen, pre-filter,
bag filter, electric air heater battery, fan and distribution ductwork.

The air intake shall not face the prevailing wind.

Extract ventilation shall be provided by means of wall mounting fans, roof extract units or ducted sys-
tems with louvered discharges to atmosphere. Individual extract fans shall be provided for Battery
room and toilets.

Extract fans for battery room shall be corrosion resistant throughout, with a 4 mm PVC lining.

13.30.4 Basis for Design

(a) External Design Conditions

The external conditions for the calculation of duties for the mechanical services shall be with mean
monthly, maximum and minimum values as below:

• Maximum ambient shade temperature: 45 °C

• Minimum ambient shade temperature: 4 °C
• Maximum daily average temperature: 35 °C
• Maximum annual temperature: 25 °C
• Relative humidity: maximum 100%, minimum 80%
• Solar radiation: 100 mW / m²

All plant and equipment installed externally, or which can be affected by external condition shall be
capable of withstanding without damage or deterioration the effects of solar radiation, rain, wind, dust,
sand storms or other weather phenomena prevalent in the area in which particular building is located.

(b) Internal Design Conditions

Air conditioning systems shall be capable of maintaining internal l conditions in all air conditioned are-
as within the following bands or, if necessary for the satisfactory operation of the equipment housed,
more stringent requirements:

For substations 22 + 4 °C DB, 40 to 70% R.H.

The following air change rates/hour shall be provided in mechanically ventilated area:

Battery rooms 10
Toilets 12 (extract only)
Cable basement 6
Other general areas 4

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All air conditioning and ventilating systems shall be designed for continuous operation. Plant shall be
arranged to facilitate maintenance and future replacement of equipment.

The Contractor shall calculate heat gains and losses under the specified conditions for each part of
each building, taking into account solar radiation, thermal transmittance through roofs, walls, floors
and windows, fresh air requirements, heat emission from installed e1ectrical equipment and lighting,
personnel, infiltration and any other sources. The Contractor shall be responsible for determining the
heat transfer coefficients for all materials used in building construction. In the event of any change in
materials. design or method of building construction, the Contractor shall at all times be responsible
for rechecking the design of all systems to ensure that they are capable of meeting the specified de-
sign requirements.

13.30.5 Air Cooled Condensing Units

The cooling medium for the air conditioning shall be direct expansion refrigeration provided by air
cooled condensing units located externally.

The condensing units shall be of the fully packaged type requiring only site connection of refrigeration
pipework, isolated electrical supply and input from the control system.

The individual item of refrigerant equipment shall be matched such that the required performance of
the evaporator is achieved concurrently with the satisfactory operation of the compressor and ade-
quate heat rejection at the condenser. Each system as a whole shall maintain the correct duty at the
design ambient and operate at the maximum ambient conditions stated without exceeding the safe
operational limits of any individual item of equipment and without causing any safety device to oper-
ate.

All electrical equipment, control, magnetic coils and solenoids shall be manufactured specifically for
operation at the electrical characteristics specified herein and such items designed for any other char-
acteristics shall not be used.

Air cooled condensing units and air handling units that are inter-connected on site with refrigerant pip-
ing shall all be supplied by the same Manufacturer.

The casings of the condensing unit shall be weatherproof and shall incorporate adequate access and
inspection panels secured in place by rustproof fasteners.

The whole of the casing shall be treated for corrosion and weather resistance and ungalvanised mild
steel shall not be used (even if painted). The unit shall be finished in not less than two coats of weath-
er resistant finish, such as baked enamel of a light reflective colour.

The access panels shall be adequately sized for the service and removal of all working parts of l the
unit. All panels shall be stiffened and supported to prevent flexing and drumming.

Electrical equipment shall he contained in a fully weatherproofed enclosure with internal division be-
tween the power connections and equipment and the control connections and equipment.

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13.30.6 Refrigeration Systems

Liquid lines shall be insulated where they are in direct sunlight or where they pass though non-air con-
ditioned areas.

Suction lines shall be insulated over their entire length.

All insulation to refrigeration pipework shall be of flexible, closed cell l foam phenolic rubber type with a
temperature range of -40°C to +105°C. They shall have a thermal conductivity of 0.0375 w/m °C at 21
°C and a water vapour transmission of less than 6.0 ng/Ns.

The thickness of insulation shall be in accordance with the following tables:

Location Insulation Thickness for O.D. Pipe Size Range

Suction Lines
6-10 mm 12-22 mm
Exposed to weather 13 mm 19 mm
In air conditioned spaces 9 mm 19 mm
In non-air conditioned spaces 9 mm 9 mm

Liquid Lines
Exposed to weather and in non-air- 9 mm 19 mm
conditioned spaces

The refrigerant used shall conform to BS 4334 Group 1 or equivalent and shall be non-explosive, non-
combustive, non-toxic and non-irritating.

Packaged air conditioning plant items requiring interconnection with refrigeration piping on site shall
be leak tested by the Manufacturers and delivered to site with a holding charge of refrigerant.

13.30.7 Console Air Conditioning Units

Console model room air conditioners shall be of the slim-line pattern and complete with 4-way adjust-
able grilles, heavy gauge zinc coated stove enamelled sheet steel casing with single or two colour
decorative finish. Electrical-heaters shall not be fitted.

The casing and position shall be such as to protrude not more than 250 mm into the air-conditioned
space and no external projection beyond the building line will be permitted other than the fixing of the
condenser cooling air grille.

The units shall be extremely quiet ill operation, the noise level not being higher than 30 dB. All sec-
tions of the casing shall be acoustically and thermally insulated.

Compressors shall be of the fully hermetic type, fitted with resilient mountings and complete with ther-
mal overload protection and starting relays.

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Evaporators shall be manufactured of' copper tube with copper or aluminium fins mechanically bond-
ed.

The evaporator fan shall be of double inlet, double width type and complete with continuously rated to-
tally enclosed electric motor.

Filters shall be of the washable type, suitably positioned for easy access for cleaning.

Automatic control by means of an integral thermostat shall be provided, together with the safety con-
trol to prevent excessive cooling.

Motors shall be air-cooled and units shall be complete with internally mounted condenser cooling fans
with totally enclosed motors.

Fresh air shall be introduced separately by means of a central fresh air plant, where these units are
proposed to serve individual offices in a building.

Units shall be supplied as a whole and be suitable for easy removal and re-positioning should this be
desired at a later date.

13.30.8 Ductwork

All sheet metal ducting shall be manufactured and installed in accordance with the Institution of Venti-
lation Engineers Guide to Current Practice Section B 16, the American Society of Heating, Refrigera-
tion and Air Conditioning Engineers, or the Heating and Ventilating Contractors Association of United
Kingdom Specification DW/142 or equivalent international standards for sheet metal ductwork for low
velocity low pressure air system with air velocity of up to 10 m/s.

Ail ductwork and fittings serving hazardous areas, such as battery rooms where corrosive fumes are
expected, shall be of rigid PVC materials.

13.30.9 Condensate Drains

Provision shall be made for condensate to be passed into the rainwater drainage system. Condensate
drains must be routed directly into the drainage system or individual soakaways. Pipes discharging on-
to substation or building brick paving will not be permitted.

13.30.10 Extract Ventilation Units

This clause covers fan powered extract ventilation units for mounting in walls and windows, on roofs
and in plant rooms.

Extract units shall incorporate propeller. aerofoil, axial, centrifugal or hybrid type fans which shall be
constructed in accordance with the relevant sections of this Specification.

Roof units shall comprise a galvanised sheet steel base suitable for use as a weathering skirt, a mild
steel fan/motor mounting frame and a spun aluminium cowl. The sheet steel base shall be constructed
to support the fan/motor without distortion and where the fan is belt driven shall incorporate a rigid

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subframe for motor mounting. Fans shall be diaphragm mounted or fitted with a cylindrical casing de-
signed for removal from the unit from inside or outside the building without disturbing the weathering
skirt or cowl fixings. The cowl shall be weatherproofed and shall be hinge mounted to provide com-
plete access to the fad/motor.

Lubricating points shall be extended to a convenient access point. Stainless steel nuts, bolts and
washers shall be used for all fixings exposed to the weather.

13.30.11 Air Filters

All filter media hall be properly bonded and protected against filter fibre or particle migration. The di-
rection of air flow shall be clearly marked on all filter panels and on installation frames.

Access to filters shall be through removal panels fitted with quick release fasteners and rubber sealing
gaskets.

Each disposable panel filter system shall be provided with 4 complete spare sets for use during the
commissioning period. These sets shall be in addition to any filter cells supplied as spares in accord-
ance wit11 the general clauses of this specifications.

Filter performance shall, unless otherwise noted, be taken to mean the Overall Gravometric Efficiency
against BS 6540:Part I Duct Test or equivalent.

Filter media of all types and sizes shall be supported in rigid peripheral frames with internal or external
wire support of the media to ensure that the media shall not collapse under air flow. The
holding frames shall incorporate accurately sized channel sections to provide a good fitting for the fil-
ters.

The type of washable and/or disposal panel filters shall be subject to the Engineer's approval.

13.30.12 Grilles and Louvres

Grilles shall be of aluminium construction and shall be fixed by means of subframe with spring clips or
screw fixings.

The corners of front flanges of grilles and subframes shall be mitred and jointed to produce a clean
unbroken appearance and visible aluminium sections shall be free from extrusion marks.

Front flanges shall be at least 30mm wide and shall incorporate a lip of at least 4.5 mm and a felt gas-
ket. Blades shall be fixed at even centres with intermediate mullions giving support for blades of more
than 550 mm long. Grille finish shall be anodised natural aluminium colour except where otherwise in-
dicated.

All grilles shall be fitted with an opened blade damper for regulation purposes and shall be fitted with
acoustically lined inlet plenums where necessary in order to comply with the acoustic limits of this
Specification.

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Outdoor air louvres shall be of all extruded aluminium construction fitted with opposed blade dampers
in the connected ducting where necessary for air flow regulation, Movable blade louvres shall not be
used.

Louvres shall be weatherproof and shall incorporate an aluminium wire mesh screen on the inside sur-
face.

The dimensions of louvres for mounting in the building structure shall suit the concrete block or brick
modules and shall be fixed to a hardwood frame.

13.30.13 Control Equipment

Each item of shall be provided with local isolation and/or emergency stop buttons to facilitate mainte-
nance, inspection and emergency operation.

The control system shall be of the electronic type, capable of providing the degree of thermostatic con-
trol specified. The Contractor shall provide full wiring diagram of all control circuits giving terminal con-
nection reference.

The control system shall incorporate all necessary safety interlocks for the successful operation of the
mechanical plant and system. All of the individual control elements shall be provided by the same
Manufacturer.

Temperature sensors shall be of the resistance type using nickel based elements and shall be accu-
o o o
rate to + 1 C over the range of 0 C to 30 C. The sensor resistance shall be compatible with the
measuring bridge of the matching control box.

13.30.14 Electrical Connections

All electrical power control cables and wiring associated with the air conditioning and ventilation sys-
tems, including all connections between control panels, valves, thermostats, sensing probes and other
like items shall be supplied, installed and connected up as part of this Contract.

The cabling and wiring system shall comply with the requirements of the relevant clauses of this
Specification and be either surface or flush installation as appropriate.

Cables and wiring shall comprise either PVCWPVC laid in cleats or trenches, or PVC drawn into gal-
vanised conduits and trunking.

Final connections to electric motors and all other items of plant subject to movement and vibration
shall comprise flexible cable in flexible conduit.

13.30.15 Manufacturers

Wherever possible all air conditioning and ventilating plant shall be selected from a single Manufactur-
er's product range and origin. Where this is not possible, because of practical or technical constraints.
then the number of different sources of origin shall. be kept to a minimum. Local service facilities shall
be available for the equipment proposed.

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The Contractor shall provide, with his submission, illustrated technical literature covering all plant and
equipment offered.

13.30.16 Standards

All air conditioning and ventilation equipment shall conform to British Standards, Chartered Institution
of Building Services or ASHRAE recommendations or other recognised International Standards.

13.30.17 Approval

The Contractor shall submit to the Engineer for approval copies of all his calculations forming the ba-
sis for the selection of all air conditioning and ventilating plant, plant selection details and full working
drawings. Such approval shall not relieve the Contractor of his contractual responsibilities.

13.30.18 Maintenance

The Contractor shall be responsible for the maintenance of all installations covered by this section of
the Specifications for the period stated elsewhere in the Specification.

13.31 Earthing and Bonding

All equipment being supplied under this Section shall be effectively bonded to ensure earth continuity
throughout the system. Continuity may be provided by means of cable armouring but a separate earth
continuity conductor shall be included with all wiring in conduits. No reliance shall be placed on metal
to metal joints in conduits for earth continuity. The earth continuity conductors shall as far as possible
be in one continuous length to the furthest part of the installation from the controlling switchboard. The
earth conductor shall connect all metal cases housing electrical equipment. The branches shall be
connected to the main conductor by permanently soldered on mechanically clamped joints.

13.32 Testing and Commissioning

The Contractor shall be required to prove that the installed system meets the design requirements and
Specification to the satisfaction of the Engineer.

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