ISO 21013-4:2012
(Main)Cryogenic vessels — Pilot operated pressure relief devices — Part 4: Pressure-relief accessories for cryogenic service
Cryogenic vessels — Pilot operated pressure relief devices — Part 4: Pressure-relief accessories for cryogenic service
ISO 21013-4:2012 specifies the requirements for the design, manufacture and testing of pilot operated pressure relief valves for cryogenic service, i.e. for operation with cryogenic fluids in addition to operation at temperatures from ambient to cryogenic. It is restricted to valves not exceeding a size of DN 300 designed to relieve single phase vapours, gases, or mixtures of gases and/or vapours.
Récipients cryogeniques — Dispositifs de sécurité pour le service cryogénique — Partie 4: Dispositifs de sécurité pour la pression à pilotage automatique
General Information
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 21013-4
First edition
2012-06-01
Cryogenic vessels — Pilot operated
pressure-relief devices —
Part 4:
Pressure-relief accessories for
cryogenic service
Récipients cryogeniques — Dispositifs de sécurité pour le service
cryogénique —
Partie 4: Dispositifs de sécurité pour la pression à pilotage automatique
Reference number
ISO 21013-4:2012(E)
©
ISO 2012
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ISO 21013-4:2012(E)
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ii © ISO 2012 – All rights reserved
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ISO 21013-4:2012(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Requirements . 3
4.1 General . 3
4.2 Design . 3
4.3 Materials . 4
5 Qualification and testing . 5
5.1 Type approval . 5
5.2 Type approval tests . 6
5.3 Production testing . 8
6 Determination of the certified coefficient of discharge (K ). 8
dr
7 Set pressure tolerances . 8
8 Re-seating pressure . 8
9 Cleanliness . 8
10 Marking . 8
10.1 Marking on the shell body of the main valve . 8
10.2 Marking on the body of the pilot valve . 8
10.3 Marking on an identification plate . 9
10.4 Additional marking . 9
11 Sealing . 9
Bibliography .10
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ISO 21013-4:2012(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International
Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 21013-4 was prepared by Technical Committee ISO/TC 220, Cryogenic vessels.
ISO 21013 consists of the following parts, under the general title Cryogenic vessels — Pressure-relief
accessories for cryogenic service:
— Part 1: Reclosable pressure-relief valves
— Part 2: Non-reclosable pressure-relief devices
— Part 3: Sizing and capacity determination
— Part 4: Pressure-relief accessories for cryogenic service
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INTERNATIONAL STANDARD ISO 21013-4:2012(E)
Cryogenic vessels — Pilot operated pressure-relief devices —
Part 4:
Pressure-relief accessories for cryogenic service
1 Scope
This part of ISO 21013 specifies the requirements for the design, manufacture and testing of pilot operated
pressure-relief valves for cryogenic service, i.e. for operation with cryogenic fluids in addition to operation at
temperatures from ambient to cryogenic. This part of ISO 21013 is restricted to valves not exceeding a size of
DN 300 designed to relieve single phase vapours, gases, or mixtures of gases and/or vapours.
This part of ISO 21013 does not provide methods for determining the capacity of relief valve(s) for a particular
cryogenic vessel. Such methods are provided in ISO 21013-3.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced document
(including any amendments) applies.
ISO 4126-4:2004, Safety devices for protection against excessive pressure — Part 4: Pilot operated safety valves
ISO 15761, Steel gate, globe and check valves for sizes DN 100 and smaller, for the petroleum and natural
gas industries
ISO 21010, Cryogenic vessels — Gas/materials compatibility
ISO 21028-1, Cryogenic vessels — Toughness requirements for materials at cryogenic temperature — Part 1:
Temperatures below – 80 °C
ISO 21028-2, Cryogenic vessels — Toughness requirements for materials at cryogenic temperature — Part 2:
Temperatures between – 80 °C and – 20 °C
ISO 23208, Cryogenic vessels — Cleanliness for cryogenic service
ASME B16.34, Valves flanged, threaded and welding end
EN 12516-2:2004, Industrial valves — Shell design strength — Part 2: Calculation method for steel valve shells
EN 12516-3:2002, Valves — Shell design strength — Part 3: Experimental method
EN 12516-4:2008, Industrial valves — Shell design strength — Part 4: Calculation method for valve shells
manufactured in metallic materials other than steel
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
valve
complete assembly consisting of the main valve and its pilot valve
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ISO 21013-4:2012(E)
3.2
DN (nominal size)
alphanumeric designation of size for components of a pipework system, which is used for reference purposes
NOTE It comprises the letters DN followed by a dimensionless whole number which is indirectly related to the physical
size, in millimetres, of the bore or outside diameter of the end connections.
[SOURCE: ISO 6708:1995, 2.1]
3.3
pressure
algebraic difference between the absolute pressure and the atmospheric pressure
NOTE This is also known as gauge pressure.
3.4
rated minimum temperature
lowest temperature for which the pressure-relief valve is rated by the manufacturer
3.5
cryogenic fluid
refrigerated liquefied gas which is partially liquid because of its low temperature
NOTE 1 This includes totally evaporated liquids and supercritical fluids.
NOTE 2 In the context of this part of ISO 21013, the refrigerated but non-toxic gases and gas mixtures given in Table 1
are referred to as cryogenic fluids.
Table 1 — Refrigerated but non-toxic gases
Classification
a
Identification number, name and description
Code
Asphyxiant gases
1913 Neon, refrigerated liquid
1951 Argon, refrigerated liquid
1963 Helium, refrigerated liquid
1970 Krypton, refrigerated liquid
3 °A
1977 Nitrogen, refrigerated liquid
2187 Carbon dioxide, refrigerated liquid
2591 Xenon, refrigerated liquid
3136 Trifluoromethane, refrigerated liquid
3158 Gas, refrigerated liquid, N.O.S. (not otherwise specified)
Oxidizing gases
1003 Air, refrigerated liquid
3 °O 1073 Oxygen, refrigerated liquid
2201 Nitrous oxide, refrigerated liquid, oxidizing
3311 Gas, refrigerated liquid, oxidizing, N.O.S.
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ISO 21013-4:2012(E)
Table 1 (continued)
Classification
a
Identification number, name and description
Code
Flammable gases
1038 Ethylene, refrigerated liquid
1961 Ethane, refrigerated liquid
1966 Hydrogen, refrigerated liquid
Methane, refrigerated liquid or natural gas, refrigerated liquid with high
3 °F
1972
methane content
Ethylene, acetylene and propylene mixture, refrigerated liquid, containing
3138 at least 71,5 % ethylene with not more than 22,5 % acetylene and not more
than 6 % propylene
3312 Gas. Refrigerated liquid, flammable, N.O.S.
a
Classification codes, identification number, name and description according to the United Nations.
3.6
rated pressure
PR
maximum pressure difference between the inside and outside of any pressure retaining boundary for which it
is designed to be operated at 20 °C
NOTE PR of the valve is the lowest PR of any component of the valve.
3.7
type 1 valve
relief valve which will open below a specified multiple of set pressure (e.g. 1.3 × set pressure) with the pilot disabled
3.8
type 2 valve
relief valve which will not open below a specified multiple of set pressure (e.g. 1.3 × set pressure) with the
pilot disabled
3.9
valve category A
relief valve type which passed the test of the repeatability of seat tightness at re-seat of 1 000 cycles
3.10
valve category B
relief valve type which passed the test of the repeatability of seat tightness at re-seat of 20 cycles
4 Requirements
4.1 General
The valve shall satisfy all the requirements of ISO 4126-4 except in the event of conflicting or different
requirements, when this part of ISO 21013 shall take precedence over ISO 4126-4.
4.2 Design
4.2.1 Design temperature
The valve shall be suitable for operation at all temperatures between the rated minimum temperature and
+ 65 °C within the intended pressure range.
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ISO 21013-4:2012(E)
4.2.2 Disc guiding
The design of guiding shall avoid malfunction of the valve due to deposition and freezing of atmospheric
moisture on and within the valve during normal operation. The valve shall be sufficiently robust such that the
effectiveness of the guiding cannot be defeated by normal handling.
4.2.3 Inserts
Where a disc soft insert is used to ensure leak-tight shut off, the design shall be such as to prevent cold flow of
the insert to a degree that results in the valve failing to operate correctly.
4.2.4 Sublimating fluids service
Where the valve is specified as suitable for service with products that, when vented at valve operating conditions,
condense from gas or vapour directly to solid, e.g. CO , the design shall be such as to avoid the valve failing
2
to operate correctly due to deposition of solid product within the valve body or its outlet. In particular, the pilot
shall be provided with some means to ensure its safe operation in case of deposition of solids within it.
4.2.5 Electric continuity
For valves in flammable fluids service, the maximum electrical resistance shall not exceed 1 000 Ω with no more
than 28 volts between the ports in order to ensure electrical continuity to prevent build-up of static electricity.
4.2.6 Set pressure
Set pressure of the valve shall not exceed its PR.
4.2.7 Minimum shell thickness
The minimum shell thickness shall be as specified in ISO 15761, ASME B16.34 or EN 12516-2, EN 12516-3 or
EN 12516-4 as applicable for the pressure rating and size of the valve.
4.3 Materials
4.3.1 General
Material shall be in conformance with an internationally recognized standard and be compatible with the
fluid. Galling, frictional heating, and galvanic corrosion shall also be considered in the selection of materials.
Materials shall also be oxygen compatible if relevant (see 4.3.5.1).
Materials not listed in an internationally recognized standard shall be controlled by the manufacturer of the
pressure-relief valve by a specification ensuring control of chemical content and physical properties, and
quality at least equivalent to an internationally recognized standard. A test certificate providing the chemical
content and physical property test results shall be provided with the pressure-relief valve.
4.3.2 Metallic materials
Metallic materials to be used in the construction of cryogenic valves shall meet the requirements of ISO 21028-1
or ISO 21028-2 as appropriate for the rated minimum temperature.
These requirements apply only to the valve parts exposed to low temperatures in normal service. Metallic
materials which do not exhibit ductile/brittle transition, and non-ferrous materials which can be shown to have
no ductile/brittle transition, do not require additional impact tests.
Forged, rolled, wrought, and fabricated valve components from raw materials from these processes need not be
impact tested if the rated minimum temperature is higher than the ductile/brittle transition range temperatures
of the material. Castings meeting the requirements of one of the applicable mandatory Appendices I and IV
or II and III for forgings and rolled or
...
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