Project Specification Job No. Doc.No. Rev.

RG6-S-00-1370-041 3
RasGas Onshore Expansion Project Phase 2 Date : Aug. 31. 2005 Sheet 1 of 6
(Train 6&7 EPC and AKG 2 EPC)
Prp’d : H. Okamoto
Pressure Relief Devices Chk’d : H. Ishii
App’d : K. Tanegashima

TABLE OF CONTENTS

1. SCOPE ....................................................................................................................................................................... 2

2. REFERENCES ............................................................................................................................................................ 2

3. GENERAL................................................................................................................................................................... 3

4. CONSTRUCTION ...................................................................................................................................................... 3

5. TEST AND INSPECTION .......................................................................................................................................... 5

6. SET PRESSURE ......................................................................................................................................................... 6

7. DATA/REQUIREMENT SHEETS ............................................................................................................................. 6

For
For Information For Review For Approval X For As Built
Construction

Rev Date Page Description Prpd Chkd Appd

E Aug.31,.‘05 Issued for Approval H. Okamoto H. Ishii K. Tanegashima
0 Jan. 26, ‘06 Issued for Construction H. Okamoto H. Ishii K. Tanegashima

1 Oct.12’06 Issued for Construction (Applied to AKG-2 also) A.Okonogi K.Okamura K.Matsukura
2 Feb.02’09 AS BUILT for AKG-2 Y.Kawano K.Okamura K.Matsukura
3 Apr. 6 ’09 AS BUILT for TRAIN-6 K.Tamura H.Ishii K.Tanegashima
RasGas Onshore Expansion Project Phase 2 (Train 6&7 EPC and AKG2 EPC) RG6-S-00-1370-041 Rev. 3
Pressure Relief Devices Sheet 2 of 6

1. SCOPE

This Specification provides guidance on the selection and design requirements for liquid and vapour
pressure relieving devices for RasGas Onshore Expansion Project Phase 2 (Train 6&7 EPC) and Al Khaleej
Gas Project Phase 2 (AKG 2).

2. REFERENCES

2.1 General

2.1.1 The following publications form a part of this Specification. The latest edition shall apply
unless otherwise specified herein.

2.2 Ras Gas Specifications

RG6-S-00-1351-001 Pressure Vessels-Design & Fabrication

RG6-S-00-1360-001 Piping– General Design
RG6-S-00-1360-002 Piping Materials and Service Classifications
RG6-S-00-1360-003 Piping-Fabrication, Erection, Inspection and Testing
RG6-S-00-1360-004 Piping - Process Equipment
RG6-S-00-1360-013 Piping-Testing of Valve for Service Temperature 0 to -196 ºC
RG6-S-00-1380-002 Certification and Marking of Materials
RG6-S-00-1390-001 Specification for Thermal Insulation – Hot Service
RG6-S-00-13A0-001 Specification for Painting – General Requirements
RG6-S-00-1520-004 Pressure Casting Inspection
RG6-S-00-1520-005 Pressure Containing Equipment – Welding and Weld Inspection
RG6-S-00-1520-007 Positive Materials Identification
RG6-S-83-1222-001 Loss Prevention General Specification
RG6-S-00-1222-007 Overpressure Protection Philosophy

2.3 API–American Petroleum Institute

API RP 520 PT I Sizing, Selection, and Installation of Pressure-Relieving Devices in

Refineries Part I - Sizing and Selection Sixth Edition; Errata - 1994
API RP 520 PT II Sizing, Selection, and Installation of Pressure-Relieving Devices in
Refineries Part II - Installation Fourth Edition
API RP 521 Guide for Pressure-Relieving and Depressuring Systems Fourth Edition
API STD 526 Flanged Steel Pressure Relief Valves Fourth Edition
API STD 527 Seat Tightness of Pressure Relief Valves Third Edition (R 1996)
API STD 620 Design and Construction of Large, Welded, Low-Pressure Storage Tanks
Ninth Edition; Addendum 1-1996; Additional Pages for Addendum 1-1997
API STD 2000 Venting Atmospheric and Low-Pressure Storage Tanks Nonrefrigerated and
Refrigerated Fourth Edition
RasGas Onshore Expansion Project Phase 2 (Train 6&7 EPC and AKG2 EPC) RG6-S-00-1370-041 Rev. 3
Pressure Relief Devices Sheet 3 of 6
2.4 ASME–American Society of Mechanical Engineers

ASME SEC I BPVC SECTION I Rules for Construction of Power Boilers Addenda - 1995;
Addenda - 1996; Interfiled (Boiler and Pressure Vessel Codes)
ASME SEC VIII D1 PVC SECTION VIII Rules for Construction of Pressure Vessels DIVISION 1
AB - SUBSECTION A – General Requirements (Boiler and Pressure Vessel
Codes)
ASME SEC VIII D1 PVC SECTION VIII Rules for Construction of Pressure Vessels DIVISION 1
BB - SUBSECTION B – Requirements Pertaining to Methods of Fabrication of
Pressure Vessels (Boiler and Pressure Vessel Codes)

2.5 NACE (National Association of Corrosion Engineers) Standard.

MR0175-2002 Material Requirements Sulfide Stress Cracking Resistant-Metallic Materials

for Oilfield Equipment.

3. GENERAL

3.1 The term "pressure relief device" applies to all types of devices that relieve pressure as required in
the ASME Code. For definitions of device types see Part I.

3.2 Pressure relief devices shall be sized in accordance with API RP 520, Part I,. Each device shall be
tagged with the tag number or other identification as specified on the purchase order. The data
may be stamped on the nameplate or on a separate corrosion resistant (stainless steel) tag that is
permanently attached to the device by pot rivets or stainless steel wire.

3.3 Venting and breathing equipment for low-pressure, aboveground storage tanks at less than 3 kPa
gage ( 0.44 psig) shall be sized as specified by API Std 2000, Section 1 through Section 3, or
API Std 620, Section 6.

3.4 When rupture disks are required for overpressure protection they shall meet API RP 520, Part I,
and ASME Section VIII, Division 1, Paragraph UG-127. Rupture disks shall not be considered
without prior COMPANY approval.

3.5 For pressure relief valves in water and steam services, appropriate sections of the ASME Code
shall apply. The ASME Code shall be the minimum acceptable where local codes do not cover
relief valves or are less stringent.

3.6 Pressure relief devices shall be stamped with ASME code symbol section I and VIII where
applicable standard for service of relief devices specifies so. e.g. NFPA for boiler.

4. CONSTRUCTION

4.1 (1) All pressure relief valves shall be the manufacturer's standard type recommended for specified
services. These valves shall conform to the following ASME and API standards: ASME Code,
Section VIII; API Std 526, for materials of construction and sizes of flanged valves; API Std 527,
for seat tightness.

(2) Materials shall be in accordance with the followings.

- Body and bonnet : per data sheets which shall be made based on Spec. RG6-S-00-1360-002
Piping Materials and Service Classifications
- Spring : API 526
- Pressure containing internal parts i.e. nozzle and disk: 316 stainless steel as a minimum.
- Other materials (bolts, gaskets, etc) : Vendors standard suitable for service conditions
RasGas Onshore Expansion Project Phase 2 (Train 6&7 EPC and AKG2 EPC) RG6-S-00-1370-041 Rev. 3
Pressure Relief Devices Sheet 4 of 6

4.2 Construction materials of valves for sour gas service shall conform to NACE MR0175. For
pressure relieving valves in unusually corrosive process conditions, body, bonnet, and trim
materials shall be approved by COMPANY. An example of unusually corrosive process conditions
is high-temperature production fluids containing high chloride levels in addition to acid gases.

4.3 For special services, such as hydrogen service at moderate temperatures, pressure relief valves
with soft seats or secondary O-rings may be used, subject to COMPANY approval.

Moderate temperatures for rubbers such as Buna-N and Butyl shall not exceed 93ºC (200ºF).
Moderate temperatures for fluoroelastomers shall not exceed 204ºC (400ºF).

Viton is not compatible with amine-based corrosion inhibitor at temperatures above 100 ºC in
continuous service.

4.4 Where required by local regulations, the pressure relief valve inlet and the mating flange of the
protected equipment shall be die stamped with the tag number.

4.5 Standard thermal relief valves and where the required flowrate is not specified in the data sheets
shall be ¾” orifice x1 inch flanged with a minimum orifice area of 0.71 cm 2.

4.6 (1) Bonnet type shall be closed type except for air and steam service where open type is required.

(2) Painting shall be in accordance with Spec. RG6-S-00-13A-001 and RG6-S-00-13A-004.

(3) Lifting lever shall be provided on pressure relief valves for air, water over 60 deg. C, and steam
service except for pressure relief valves specified as modulating pilot operated type, which are
fitted with a field test connection in lieu of the lifting levers.

(4) Screwed cap shall be provided for a conventional or balanced bellows type pressure relief valve
unless the pressure relief valve is specified with a lifting lever, which shall be provided with a
bolted cap.

(5) Test gag shall be provided.

(6) Flange

- Flange code : ANSI B 16.5

- Flange face shall be serrated or spiral finished with a roughness in the range of 125 to 250
micro inch. Checking of surface finish shall be judged by visual and factile comparison with
the rubber Microsurf 319 roughness comparison specimens, or flexitalic microsurf 319, or
comparison block measured by stylus type roughness meter.

(7) Mechanical restraints (Belleville washers, double-nuts, or tab-stops) shall be applied to spring
loaded pressure relief valves with inlet piping longer than 3 m., except for modulating pilot-
operated type, ASME Section 1 type and relief valves for thermal expansion cases.
These mechanical restraints will be fitted on each nut of the valve’s bonnet-bowl connection and
nuts on both sides of the inlet and outlet flange connection of the relief valve.

(8) Pilot operated pressure relief valves shall be provided with the following accessories:
a) field test connection
b) backflow preventer
c) auxiliary filter
RasGas Onshore Expansion Project Phase 2 (Train 6&7 EPC and AKG2 EPC) RG6-S-00-1370-041 Rev. 3
Pressure Relief Devices Sheet 5 of 6
5. TEST AND INSPECTION

5.1 General
The following test and/or inspection shall be performed as a minimum in accordance with
this specification and applicable code & standards

(1) Visual and dimensions

(2) Material test
- Chemical composition
- Mechanical properties
- Etc.
(3) Non destructive examination (NDE)
(4) Hydrostatic test
(5) Seat leakage test
(6) Function test including Popping test
(7) Positive material identifications (PMI)

5 .2 Non destructive examination (NDE)

All casting shall be in examined in accordance with Spec. RG6-S-00-1520-004 “Pressure

Casting inspection”.

5.3 Positive materials identifications (PMI)

PMI shall be performed for stainless steel body valves in accordance with Spec. RG6-S-00-
1520-007 “Positive Materials identification’.
Pressure relief valves are categorized as non-critical valves in the Spec.

5.4 Certification and marking of material

Certification and marking of materials shall provided in accordance with Spec. RG6-S-00-
1520-009 “Certification and Marking of Materials”.

5.5 Manufacturer's Shop Test

5.5.1 Pressure relief valves shall be tested after assembly with a gag (test rod to hold valve shut
where equipment is being given a hydrostatic test) in place. The gag shall be removed
prior to valve set pressure and leakage tests. The valve body shall be tested hydraulically
or pneumatically, depending on the valve's service, as follows:

(a) The inlet side shall be tested at 1.5 times the specified set pressure for casting
integrity.

(b) The outlet side shall be tested at 1.5 times the maximum allowable back pressure
specified by the manufacturer for casting integrity.

(c) The outlet side shall be tested at a minimum pressure of 345 kPa gage (50 psig) for
soundness of mating parts.

5.5.2 Pressure relief valves in liquid, vapor, and gas service shall be tested for set pressure and
seat leakage in the manufacturer's shop, using air, steam, or water. Cold differential set
pressures shall be given and stamped on the nameplate in accordance with API Std 526

5.5.3 Cryogenic seat leakage test shall be carried out as follows in addition to standard seat
leakage test.

(1) The test shall be performed for valves in cryogenic service where design temperature is
below –46 deg.C (line class: 1R0JL, 3R0JL, 3R0JLL AND 6R0JL).

At least 10% of each lot with a minimum of one valve for each size, type, and pressure
rating.

(2) In general, test procedure and aceptance criteria shall be in accordance with API 527.
RasGas Onshore Expansion Project Phase 2 (Train 6&7 EPC and AKG2 EPC) RG6-S-00-1370-041 Rev. 3
Pressure Relief Devices Sheet 6 of 6
Test pressure of seat leakage shall be 90% of set pressure and test temperature shall
be -196 deg C.

Spec. RG6-S-00-1360-013 Piping-Testing of valve for service temperature 0 to –196

deg.C shall be referenced where applicable.

(3) Vendor shall submit a detailed test procedure for approval.

5.5.4 Carbon content and carbon equivalent

The chemical composition of carbon steels (including low temperature carbon steels) to be
used for pressure containing parts shall comply with the followings.

(1) Carbon contents shall not exceed 0.25%.

(2) One of the following carbon equivalent requirements based on the ladle analysis, shall
be satisfied:

(a) Ceq = C+ Mn/6 + (Cr + Mo + V) /5 + (Cu + Ni) / 15 ,= 0.45%)

(b) Ceq = C= Mn/6 <= 0.42%

Formula (b) may be used if the material standard specified C and Mn only.
Otherwise, formula (a) shall be used.

5.5.5 Welding and weld inspection

(1) Welding and weld inspection shall be performed in accordance with Spec.
RG6-S-00-1520-005.

Pressure-Containing Equipment-welding and weld inspection:.

(2) Spec. RG6-S-00-1360-003 “Piping-Fabrication, Erection, Inspection and

Testing” shall be also met-for inspection of welding connection.

5.6 Field Testing

Prior to field installation, all pressure relief valves shall be tested as per Vendor’s recommended
field test method, in the approved field workshop (see specification RG6-S-00-1370-029), by
qualified personnel for set pressure and leakage. Pressure relief valves shall not be gagged to
permit hydrostatic testing of equipment or piping. Blinds shall be installed as required. After the
field workshop test has been carried out by Contractor and accepted by Company QC inspector, a
new engraved stainless steel hanging tag with set pressure and date of test will be fixed to the valve
by stainless steel wire.

Pressure relief valves shall be furnished with extended spindles to allow testing in place.

6 SET PRESSURE

A pressure relief device shall be set no higher than the maximum allowable working pressure
(MAWP) of the vessel(s) it protects, as specified in ASME Section VIII, Division 1, Paragraph
UG-125.

7 DATA/REQUIREMENT SHEETS

7.1 Delete

7.2 The final selection of all pressure relief devices shall be subject to COMPANY approval.