Petroleum Development Oman L.L.C.: Document Title: Drain Systems Specification

Petroleum Development Oman L.L.C.
Document title: Drain Systems Specification
Document ID SP-1126
Document Type Specification
Security UnRestricted
Discipline Engineering and Operations
Owner UEP/1P – Corporate Function Discipline Head
Issue Date June 2012
Version 3.0
Revision: 3.0
Petroleum Development Oman LLC Effective: Jun-12
This page was intentionally left blank
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.
Page 2 SP-1126- Drain Systems Specification Printed 27/06/12

The controlled version of this CMF Document resides online in Livelink®. Printed copies are UNCONTROLLED.
Revision: 3.0
i DocumentAuthorisation

Revision: 3.0
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.
Version No. Date Author Scope / Remarks

3.0 June 2012 Hussain Bakeer General Revision & SHALL [PS]
UEP/1P requirements identified
2.0 May 2004 A.C. Sluijterman UEP References updated and
intermediate flash vessel
requirements relaxed
1.0 May 1999 A.C. Sluijterman UEP/1 PDO-ERD-08-10 rewritten to new
format with minor comments
incorporated
iii Related Business Processes

Code Business Process (EPBM 4.0)
iv Related Corporate Management Frame Work (CMF)

Documents
The related CMF Documents can be retrieved from the Corporate Business Control
Documentation Register CMF.

Revision: 3.0
TABLE OF CONTENTS
i Document Authorisation........................................................................................................ 3
ii Revision History.................................................................................................................... 4
iii Related Business Processes................................................................................................. 4
iv Related Corporate Management Frame Work (CMF) Documents........................................4
1 Introduction........................................................................................................................... 6
1.1 Scope.............................................................................................................................. 6
1.2 Compliance with this Specification..................................................................................6
1.3 Process Definition........................................................................................................... 6
2 Drain Systems....................................................................................................................... 7
2.1 Objective of Drainage Systems.......................................................................................7
2.2 Classification of Drainage Systems.................................................................................7
2.2.1 Open Non-Hazardous Drain...........................................................................7
2.2.2 Open Hazardous Drain..................................................................................7
2.2.3 Closed Drain.................................................................................................. 7
2.2.4 Process Drains............................................................................................... 8
2.3 Sources and Destination of Various Drains.....................................................................9
2.4 Design Considerations................................................................................................... 10
2.4.1 Open Drain Systems....................................................................................10
2.4.2 Closed Drain System...................................................................................10
2.4.3 Instrument Drains......................................................................................... 11
2.4.4 Sample Drains............................................................................................. 12
2.4.5 Tank Drains.................................................................................................. 12
2.4.6 Closed Drain Vessel.....................................................................................12
2.4.7 Vent System.................................................................................................12
2.4.8 Drain Pumps................................................................................................ 13
2.4.9 Process Drains.............................................................................................13
2.4.10 Laboratory Drains........................................................................................14
2.4.11 Other Process Chemicals Drains.................................................................14
3 Related Business Control Documents.................................................................................15
Appendix A Glossary of Abbreviations..................................................................................16

Revision: 3.0
1 Introduction
1.1 Scope
The objective of this document is to specify the design/engineering requirements and
selection of drainage systems for on-shore oil and gas facilities. The drainage systems
are needed for maintenance of equipment, piping, and instruments and to reduce risk of
fire and environmental pollution.
Drainage streams are produced from many sources and these guidelines are for the safe
collections and disposal of these streams.
This specification does not cover domestic wash water or sewage drain systems for
accommodation areas, buildings and control rooms which SHALL[PS] be separate from
plant drain systems.
Compliance with this Specification

The user SHALL[PS] obtain written approval from the Corporate Function Discipline
Head (CFDH) Process Engineering for any deviation from this specification.
1.2 Process Definition
Open Non-Hazardous Drain This system provides drainage for areas, which are
classified as non-hazardous according with DEP
80.00.10.10-Gen. The drain system from these areas,
referred to as the Open Non-Hazardous Drain (ONHD),
handles fluids collected from open drip pans, tundishes
and floors in non-hazardous areas.
Open hazardous Drain This system provides drainage for areas, which are
classified as hazardous according with DEP 80.00.10.10-
Gen. The drain system from these areas, referred to as
the Open Hazardous Drain (OHD), handles fluids
collected from open drip pans, tundishes and floors in
hazardous areas.
Closed Drains These drains form a closed drain system and dispose of
liquids from closed equipment, vessels and pipework.
These drains can either drain into a blanketed vessel with
the drain system operating at slightly above atmospheric
pressure, or alternatively drain into an atmospheric vessel
by which the drain system operates at atmospheric
pressure.
Process Drains These drains are continuous discharges from process
systems due to normal operation of the plant.
Sour Service Refer PDO SP-1190 for sour service definition with
respect to personnel safety.
Sour Liquid The liquid, which can contribute to designate a facility as
sour service, as mentioned above shall be considered as
sour liquid in this specification.

Revision: 3.0
2 Drain Systems
2.1 Objective of Drainage Systems

Drain systems are required for safe collection and disposal of:
(1) Contents of process vessels, piping and equipment, prior to inspection and/or
maintenance.
(2) Liquids from knockout vessels for compressors, flares, etc.
(3) Liquids from instruments, level glasses, etc.
(4) Liquids from scraper traps.
(5) Surface liquids (rainwater, wash down water and waste oil).
(6) Fire-fighting water.
(7) Liquids from Laboratory.
For safety reasons, drains from process areas SHALL[PS] be totally separate from
control room or accommodation drains.
2.2 Classification of Drainage Systems

The drainage system of PDO on-shore oil and gas facilities can be classified as follows:
2.2.1 Open Non-Hazardous Drain

This system provides drainage for areas, which are designated non-hazardous. This
system SHALL[PS] be entirely segregated from all other open or closed drain systems.
Non-hazardous areas generally include storage vessel areas for utility materials such as
lubricating oil, diesel fuel, etc. The drain systems from these areas, referred to as the
Open Non-Hazardous Drain (ONHD), handle fluids collected from open drip pans,
tundishes and floors in Non-Hazardous areas.
2.2.2 Open Hazardous Drain

This system provides drainage for areas, which are designated as hazardous. These
generally include all process areas and locations where hydrocarbons are present in
significant quantities. The drain system from these areas, referred to as the Open
Hazardous Drain (OHD), handles fluids collected from open drip pans, tundishes and
floors in hazardous areas. Open drainage systems must only be used for draining
hydrocarbon fluids from process vessels (via tundishes) when such vessels have
undergone a maintenance preparation procedure.
2.2.3 Closed Drain

Many process vessels contain fluids, which, even after depressurising to the blow down
system, would release significant quantities of hazardous vapours, if they were
discharged via open drainage systems. A permanent pipe work connection and
collection header SHALL[PS] be routed to a drain vessel for the safe removal of
generated vapour. This systems, referred to as the Closed Drain (CD) system, handles
hazardous fluids from process vessels, keeping them out of contact with the
atmosphere. This system should be used where toxic materials are likely to be present.
Sour liquid drains (other than process drain) from any source SHALL[PS] be routed to
closed drain system.
Revision: 3.0
Hydrocarbon fluids shall be routed to a closed drain system from process vessels and
pipe works only after depressurisation to atmospheric pressure.
2.2.4 Process Drains

Some continuous process discharges, that are not further needed in the process
systems, e.g. gas compressor knock-out drums liquid are often discarded as drains.
These drains are generally discharged on level control from the source vessels. As the
liquid contains water and hydrocarbons it is often intended to recover the oil from these
drains.

Revision: 3.0
2.3 Sources and Destination of Various Drains

Table 1 lists the major sources of drain fluids, their contents and destination.
TABLE – 1
FLUID SOURCE AND DRAIN SYSTEM
DESTINATION
EXPECTED OPEN DRAIN

SOURCE
COMPONENTS CLOSED
NON- DRAIN
HAZARDOUS
HAZARDOUS
Oil,
Process equipment and lines
Condensate,
1 containing hydrocarbons for X+Y X (1), (2)
Water, Sand,
maintenance purpose
Gas
Turbine and compressor lube oil
2 Lube Oil X
tank
Compressor Seal oil tank, pump
3 Oil + Gas X (3)
seal drain
Spilt fuel/
Bunded areas containing fuel & chemicals,
4 X
chemical storage wash water,
drain water.
5 Atmospheric oil storage tanks Oil, water X+Y X
Floor drains in hazardous Spilt oil, wash
6 X
module water
Spilt oil, wash
7 Floor drains in Non-Hazardous X
water
Contaminated
8 Fire/Deluge water when used X
oil-water
9 Scraper barrel Oil X+Y X (1), (2)
10 Sample drains Oil, Water X X (1), (2)
11 Instrument drains Oil X X (1), (2)
12 Floating roof tank roof drains Oil, Water X
13 Flare knock-out drum Oil, Water X

Atmospheric flash vessel of
14 Oil, Water X
process drains
Discharge from thermal relief
15 Oil, Water X X (1)
valve in oil system
16 Laboratory drains Oil, water X (4)
Other process chemicals
17 Chemicals See Note (5)
systems

Revision: 3.0
Key:
X = Drain System to be used.
Y = Washing operation & discharge
Notes:
(1) Sour liquid to be routed to closed drain.
(2) Volatile hydrocarbons to be routed to closed drain.
(3) A local drain collection facility (tank/pot) should be provided if the
contents of the fluid are likely to partially vaporise. The drain from
this local facility is to be connected to Open Hazardous Drain by
piping with a normally closed isolation valve in between. Vent from
the local facility can either terminate locally at 1 metre above the
building roof or can be connected to the atmospheric pressure flare
system. Dispersion calculations shall be carried out f or sour service
in the case of local vent.
(4) Laboratory drains SHALL[PS] have local facilities to drain various
chemicals. Only oily-water drain can be connected to OHD via a
water-sealed pipe discharging into the OHD gully outside the
laboratory wall.
(5) Drains for different types of chemicals shall be independent. Disposal
of the contents of such drains shall depend on type of chemicals
handled.
2.4 Design Considerations
2.4.1 Open Drain Systems

For the design of Open non-hazardous and Open Hazardous drain systems DEP
34.14.20.31-General, Drainage and Primary Treatment systems shall be followed.
2.4.2 Closed Drain System

Discharge to the closed drain system SHALL[PS] be by hard-piped connections which
SHALL[PS] be positively isolated from the process during normal operation. The main
drainage header shall be fabricated from ANSI 150# rated piping class. The branch
connections from the vessels to the main header or up to the first pipe diameter
increase SHALL[PS] be rated for the same pressure as the vessel itself. This is
because, should the vessel be inadvertently drained under pressure, it is in the smaller
branch pipes that hydrates are likely to form. The need for hydro-testing the CD system
means that a flange must be installed at the spec break, so that the two pipe classes
can be isolated from one another. This specification break shall be recognised as
demarcation of process and drain system (see Figure 1).
Closed drains SHALL[PS] be routed to a drain vessel from which the gases shall be
flared.
For sizing the branch connection to the main header the following DEPs shall be
referred to:
- DEP 31.38.01.11-Gen, Piping General Requirements, Section 4.5 for Pressure
Vessel drain
vessels.
- DEP 31.40.10.13-Gen, Design of Pipe line Pig Trap System, Section 2.2 for Pig-
Trap drain lines.
For other equipment or piping system the line size shall be designed based on a realistic
time of draining the residual system hold up.

Revision: 3.0
The underground drain header shall be at least one size larger than the maximum drain
connection size used for the process side of equipment / piping.
Drain piping shall be adequately and continuously sloped at 1:200 minimum to eliminate
the possibility of creating liquid pockets. Elbows, bends and flanges should be avoided
as much as possible. Possibility of blockage by sludge/sand shall be assessed and
appropriate measures such as 45 bends, larger diameter pipe, etc. should be taken.
The drain connection SHALL[PS] be positioned at the bottom of the process vessel. A
back flushing connection on the drain line underneath the vessel should be installed if
there is a possibility of blockage from deposits of sludge, sand, wax, etc. in the vessel
(see Figure 2).
Sufficient rodding-points must be installed if sand/solids are expected. Water hose
connections may be fitted at the rodding points (see Figure 2).
There SHALL[PS] be no drain valve or any other means of isolation downstream of a
specification break, which could cause the drain system to be over-pressurised. The
single exception is the isolation valve installed at the drain header for drain vessel
maintenance, which shall be kept locked open during normal operation.
Guidelines provided in DEP 31.38.01.11-Gen. Piping General Requirements, section
3.4 shall be followed for general requirements for buried drain headers.
Closed drain systems and open drain systems SHALL[PS] not be interconnected.
The CD system SHALL[PS] be used only to empty equipment containing hydrocarbon
liquids prior to equipment maintenance. Liquid levels in equipment are lowered to the
minimum practical level using the normal process connections and it is essential that
the equipment is fully depressurised before draining via the CD system.
Depressurising may lead to cooling of the vessel contents which should be allowed to
regain ambient temperature before being admitted to the drain system. Only after this
procedure has been completed will the equipment be emptied to drain. To reinforce this
procedure, all closed drain lines must be isolated from equipment by double block
valves and intervening spade or spectacle blind A removable spool may be used where
draining is infrequent.
To avoid the possibility of heating up of contained hydrocarbon and cause flashing
inside the drain header, hot oil/fluid drains shall be routed separately to the Drain
Vessel.
Spent hot oil (dead oil) may be drained into OHD after it is allowed to cool down to the
ambient temperature or 45 Celsius, whichever is higher.
Remote facilities with small inventories i.e., remote manifolds do not need hard pipe to
closed drain system. A simple system to a pit in the final inventories with a vent and a
facility for vacuum truck would be sufficient.
2.4.3 Instrument Drains

Some instruments like level gauges and level switches need draining either for taking
readings or for maintenance. If the drained liquid is sour and/or volatile the drain
SHALL[PS] be hard piped to the closed drain system (see Figure 3). Drains for sweet
non-volatile service shall be drained to the open hazardous drain system via tundishes.
The drained liquid should be visible when the drain valve is opened (see Figure 4).
2.4.4 Sample Drains

Sample systems require draining for flushing purposes and to avoid splashing of the
sample fluid. Sample flushing lines SHALL[PS] be directly connected to closed drain
system (see Figure 5) for sour service and volatile hydrocarbons or when the flushing

Revision: 3.0
quantity is high. A sample draw-off point in sweet, non volatile service, may be
connected to the Open Hazardous Drain System, via a tundish (see Figure 6 & 7).
Samples from systems 600# and above SHALL[PS] be collected via a sample point
with a block and needle valve arrangement for filling the sample bottles.
2.4.5 Tank Drains

Tank drain may be routed to a closed drain if more desirable or convenient.
Any water drained from the roof of a crude oil or product storage tank inside the
bunded area shall be treated as contaminated and shall be taken to OHD. Floating
Roof Tank drains shall be piped into the open hazardous drain system and a sight glass
shall be installed in the drain line to allow checks to be made for any hydrocarbon
contamination due to leakage.
2.4.6 Closed Drain Vessel

Each drain vessel shall be sized to accommodate the largest expected volume of liquid
which remains in any vessel (excluding tanks) after it has been emptied to its lowest
liquid level prior to draining for maintenance.
The hold up volume of liquid in a drained vessel shall be calculated as between high
and low liquid level alarm settings The Hi-Hi-Liquid level shall be considered at 80% of
vessel diameter. Figure 8 represents the general arrangement / requirement of a Drain
Vessel.
Closed drain vessel SHALL[PS] have a design pressure of 350 kPa(g) or above to
withstand possible flame flashback from the vent.
A drains collection vessel shall have a weir to separate sludge and solids. The weir
height may be kept at about 40 per cent of the vessel diameter. Length of sludge catch
area may be kept about 40 per cent of the vessel tan to tan length.
A pump-out connection at pump side with an isolation valve shall be provided to
facilitate removal of the liquid. A dump connection with a valve can be provided at oil
inlet side of weir for dumping oil from external source and also to pump-out weir side
oil before maintenance.
A closed drain inlet header SHALL[PS] be provided with a locked open isolation valve
and a spectacle blind on the downstream side to isolate the drain vessel for
maintenance. A pit shall be provided for access to the valve and blind. Operating
procedures should take care of the possibility of over-pressurisation of the drain header
due to inadvertent opening of a drain valve in the plant system while the spectacle
blind is closed.
Cathodic protection shall be provided for the buried drain vessel and piping as per PDO
SP-1128.
2.4.7 Vent System

Gas from drain vessels should pass to lowest pressure flare system.
Due to the possibility of air ingress into the closed drain system a closed drain vessel
SHALL[PS] be purged continuously by inert or blanketing gas. The flow of purge gas
shall be through a restriction orifice which should be preceded by a locked open
isolation valve.
Provision of lightning protection SHALL[PS] be assessed as per DEP 33.64.10.10-Gen,
Electrical Engineer Guidelines, section 6.5.4.

Revision: 3.0
2.4.8 Drain Pumps

The facility to evacuate a drains vessel contents shall be provided by transfer pumps
and/or a pump out connection. Even when transfer pumps are installed, a pump out
connection is required to enable a drain vessel to be emptied to its lowest level, prior to
internal inspection and/or maintenance.
Liquids collected in a drain vessel should be pumped back into the production system.
Due consideration shall be given to the point at which drained liquids are pumped back
into the process, i.e. to avoid any possibility of over-pressuring drain piping in ESD and
PSD situations, or possible back flow to the drain vessel.
Pump capacity shall be higher than the maximum drainage rate.
A minimum of two pumps (one operating and one standby) shall be provided on the
drain vessel.
Operation of transfer pumps shall be by means of a level controller which gives
ON/OFF action.
On high level the stand by pump shall start automatically and it should stop when the
level comes back to normal.
Activation of station ESD SHALL[PS] stop drain vessel pumps. A manual override
should be provided to start the pump in ESD situation, if considered necessary.
2.4.9 Process Drains

Normally process drains should not be connected to a closed drain system.
If the process drain contains hydrocarbon and condensate but does not contain
undesirable toxic chemicals or materials, e.g. drains from compressor knock-out
vessels, then it can be routed to the closed drain system provided the following steps
are taken:
Process drain SHALL[PS] first be flashed to an intermediate flash vessel where
depressurising to atmospheric pressure should take place, unless the upstream
pressure and flowrate is low (e.g. first stage compressor suction scrubber).
Process drain is checked for flash temperature and the draining liquid temperature to
closed drain system is acceptable for the closed drain system material.
Process drain is checked for hydrate formation and adequately sized and protected.
Drain pipe to intermediate flash vessel is checked for breakthrough for process level
control valve failure in an open position and the vessel vent line is adequately sized to
restrict overpressure in flash vessel.
Gas outlet from intermediate flash vessel to be connected to flare or vent at such a
point that over-pressuring due to any reason cannot occur.
Drain from the intermediate flash vessel to the closed drain system is adequately
protected for gas breakthrough.
2.4.10 Laboratory Drains

Laboratory drains are used for the disposal of samples, chemical solutions, solvents
and chemicals.
Laboratory drains are independent drain systems. Only oil-water drain from the
laboratory may be connected via a water-sealed pipe into OHD gully outside the
laboratory well.
For various chemicals separate drain systems may need to be considered depending
on compatibility of the chemicals mixed.
Revision: 3.0
Drum collection of drains for different chemicals may be convenient.

The disposal of drains shall depend on type and properties of the chemicals and the
reagents used in the laboratory.
2.4.11 Other Process Chemicals Drains

Separate drains and disposal systems shall be considered for chemicals used in
process systems. The type of drain system shall depend on the properties of the
chemicals, compatibility with other chemicals, need for reclamation, etc.

Revision: 3.0
3 Related Business Control Documents
PDO Standards
PDO SP-1125 Isolation of Process Equipment Specification

PDO SP-1128 Cathodic Protection Design
PDO SP-1190 Design for Sour Services Specification
Shell Standards
DEP-31.22.05.11-PDO Gas Liquid Separator – Type Selection and Design

Rules
DEP-31.38.01.10-Gen Piping Classes Part I, Basis of Design
DEP-31.38.01.11-Gen Piping General Requirements
DEP-31.38.01.15-Gen EP piping Classes
DEP-31.40.10.13-Gen Design of Pipeline Pig Trap Systems
DEP-33.64.10.10-Gen Electrical Engineering Guidelines
DEP-34.14.20.31-Gen Drainage and Primary Treatment Systems
DEP-80.00.10.10-Gen Area Classification (Amendments/Supplements to IP-
15)
International Standards
IP Code Part 3 Refining Safety Code

API RP 521 Guide for Pressure – Relieving and Depressurising
Systems
API 2000 Venting Atmospheric and Low-pressure Storage tanks

Revision: 3.0
Appendix A Glossary of Abbreviations
CD Closed Drain
CFDH Corporate Functional Discipline Head
DEP Design and Engineering Practice
ERD Engineering Reference Document
ESD Emergency Shutdown
FIG Figure
IP Institute of Petroleum (UK)
kPa Kilo-Pascal’s
L Low Level (of liquid)
LC Locked-Closed or Level Controller
LG Level Gauge
LI Level Indicator
LIC Level Indicator and controller
LL Low-Low Level (of liquid)
LO Locked-Open
LZA Level Emergency Alarm
NC Normally Closed
ONHD Open Non-Hazardous Drain
OHD Open Hazardous Drain
PDO Petroleum Development Oman LLC
PSD Process Shutdown
PA Pressure Alarm
PG Pressure Gauge
RO Restriction orifice

Revision: 3.0
FIGURE 1.0 – PIPING SPECIFICATION BREAK FOR DRAINS

FIGURE 2.0 – BACK FLUSH AND END HEADER CONNECTION FOR DRAINS

FIGURE 3.0 – DRAIN HOOKUPS FOR LEVEL INSTRUMENTS IN SOUR SERVICE AND FOR VOLATILE HYDROCARBONS

FIGURE 4.0 – DRAIN HOOKUPS FOR LEVEL INSTRUMENTS FOR LOW-VOLATILE HYDROCARBONS IN SWEET SERVICE

FIGURE 5.0 – SOUR SERVICE AND VOLATILE HYDROCARBONS SAMPLE DRAIN CONNECTION

FIGURE 6.0 – SAMPLE DRAINS IN LOW PRESSURE TANKS, SWEET, NON-VOLATILE SERVICE SYSTEMS

FIGURE 7.0 – SAMPLE DRAINS IN LOW PRESSURE PIPELINE, SWEET, NON-VOLATILE SERVICE SYSTEMS

FIGURE 8.0 – CLOSED DRAIN VESSEL GENERAL ARRANGEMENT


Petroleum Development Oman L.L.C.: Document Title: Drain Systems Specification

Uploaded by

Copyright:

Available Formats

Petroleum Development Oman L.L.C.: Document Title: Drain Systems Specification

Uploaded by

Document Information

Original Title

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

Petroleum Development Oman L.L.C.: Document Title: Drain Systems Specification

Uploaded by

Copyright:

Available Formats

What is the purpose and scope of this document?

What is the purpose and scope of this document?

What are the main types of drain systems described in this document?

What are the main types of drain systems described in this document?

Petroleum Development Oman L.L.C.

Document title: Drain Systems Specification

Document Type Specification

Discipline Engineering and Operations

Owner UEP/1P – Corporate Function Discipline Head

Issue Date June 2012

This page was intentionally left blank

Page 2 SP-1126- Drain Systems Specification Printed 27/06/12

Page 3 SP-1126- Drain Systems Specification Printed 27/06/12

Version No. Date Author Scope / Remarks

iii Related Business Processes

iv Related Corporate Management Frame Work (CMF)

Page 4 SP-1126- Drain Systems Specification Printed 27/06/12

Page 5 SP-1126- Drain Systems Specification Printed 27/06/12

Compliance with this Specification

1.2 Process Definition

Page 6 SP-1126- Drain Systems Specification Printed 27/06/12

2.1 Objective of Drainage Systems

2.2 Classification of Drainage Systems

2.2.1 Open Non-Hazardous Drain

2.2.2 Open Hazardous Drain

2.2.3 Closed Drain

2.2.4 Process Drains

Page 8 SP-1126- Drain Systems Specification Printed 27/06/12

2.3 Sources and Destination of Various Drains

EXPECTED OPEN DRAIN

10 Sample drains Oil, Water X X (1), (2)

11 Instrument drains Oil X X (1), (2)

12 Floating roof tank roof drains Oil, Water X

13 Flare knock-out drum Oil, Water X

Page 9 SP-1126- Drain Systems Specification Printed 27/06/12

2.4 Design Considerations

2.4.1 Open Drain Systems

2.4.2 Closed Drain System

Page 10 SP-1126- Drain Systems Specification Printed 27/06/12

2.4.3 Instrument Drains

2.4.4 Sample Drains

Page 11 SP-1126- Drain Systems Specification Printed 27/06/12

2.4.5 Tank Drains

2.4.6 Closed Drain Vessel

2.4.7 Vent System

Page 12 SP-1126- Drain Systems Specification Printed 27/06/12

2.4.8 Drain Pumps

2.4.9 Process Drains

2.4.10 Laboratory Drains

Drum collection of drains for different chemicals may be convenient.

2.4.11 Other Process Chemicals Drains

Page 14 SP-1126- Drain Systems Specification Printed 27/06/12

3 Related Business Control Documents

PDO SP-1125 Isolation of Process Equipment Specification

DEP-31.22.05.11-PDO Gas Liquid Separator – Type Selection and Design

IP Code Part 3 Refining Safety Code

Page 15 SP-1126- Drain Systems Specification Printed 27/06/12

Appendix A Glossary of Abbreviations

Page 16 SP-1126- Drain Systems Specification Printed 27/06/12