BS 6364: Withdrawn in 2015 — What a Cryogenic Valve Specification Should Name Instead

BS 6364:1984 was published on 29 February 1984 and withdrawn on 22 June 2015. A cryogenic valve specification that still calls for compliance with it is asking for a document that has not been current for eleven years.

Cryogenic valves do not leave service because a standard is retired, and the clause keeps appearing in project specifications because it was copied forward from an earlier template rather than chosen for the duty.

This article sets out what BS 6364 was, where its requirements went, and how to read a specification that still cites it.

Read it and you can tell a specification that means something by that clause from one that is repeating a template.

In an LNG receiving terminal, the cryogenic valves in the tank area sit at around −162 °C, are operated rarely, and are expected to stay tight through thermal cycling that would destroy a conventional packing.

Every one of those requirements is real. The document the specification names to enforce them is not, and it has not been for more than a decade.

What BS 6364 was, on the official record

Two things about that record matter more than the rest, and the second one is usually missed.

It was a supplementary document, not a standard. BS 6364 did not replace the product standard for a ball valve or a gate valve; it added requirements on top of one. A specification that says "valves to BS 6364" without naming the product standard underneath it was always under-specified.

Availability is not validity. The catalogue entry is still there, still priced, still shows the chapter structure. That is very often why people assume the standard is current.

The requirement areas it addressed

Four areas carried most of the weight:

Be aware of how this list is sourced. These are the requirement areas as reproduced consistently across public summaries of the standard. The primary text is not freely readable, so clause-level figures here are historical context. Where you need a number, take it from a standard that is current rather than from a withdrawn one.

Where the requirements went

The withdrawal did not leave a gap. It left four routes:

ISO 28921-1 also states, in its own scope, where its requirements differ from the valve product standard, its requirements prevail — which is the same precedence BS 6364 claimed as a supplementary document. The function carried over.

Note that the successor standard has already been revised once. BS EN ISO 28921-1:2017 was superseded by the 2022 edition on 21 July 2022. A specification that names the 2017 edition is naming a superseded edition of the right standard — closer to correct than BS 6364, and still not current.

Note also that ISO 28921-2:2015 is itself being revised. Its systematic review closed with the standard marked "to be revised", and the Edition 2 project was approved on 18 March 2026. So when a buyer asks what to specify instead, the honest answer carries a second clause: check the edition, because both parts of the family are moving.

And be aware of the exclusion inside the successor. ISO 28921-1 does not apply to cryogenic valves designed under ISO 21011 for use with cryogenic vessels, and it states a limit of its own — PN 250 and Class 1500 above DN100 / NPS 4 are outside it. A specification that assumes one standard covers every cryogenic valve in a plant is wrong in both directions.

Reading a specification that still names BS 6364

Four moves, in order.

1. Treat the clause as a signal of intent, not as the acceptance criterion. A BS 6364 clause has always been shorthand for three things: an extended bonnet, cavity pressure relief, and a documented low-temperature test. Ask for those three in the terms of a current standard.
2. Ask which edition. "BS EN ISO 28921-1" without a year is as under-specified as "ISO 15848 certified" without a part number. Both failures have the same root: a standard number used as a substitute for acceptance criteria.
3. If the specification is an EPC contract document, it governs its own contract. Note the divergence and say so in the enquiry rather than substituting silently. A template clause and a live standard can both be correct in their own context, and the buyer is the one who has to reconcile them.
4. Read the marking on the valve. A body marked with a withdrawn standard and a minimum service temperature dates the valve. That is useful information when you are evaluating existing stock, a spares order or a second-hand package.

What about a valve that was built to BS 6364?

A valve designed and tested to BS 6364 in 2010 was not wrong then, and may be sound now. Two things do change.

A supplier cannot declare new compliance with a withdrawn standard. If a datasheet issued today says "complies with BS 6364", there is no current standard behind that statement, and no test house will issue a fresh certificate against it.

A spares or replacement order that names BS 6364 will attract either a caveat or an unqualified answer, and the two look identical on a quotation. Ask for the current standard plus the criteria as numbers — the seat-leakage figure, the test temperature, the cycle count, the operating force. Numbers can be compared. Labels cannot.

When does this go to a human?

Five boundaries for cryogenic valve enquiries: any duty below −101 °C (−150 °F), where automatic coverage ends unconditionally; any enquiry where the specification names a withdrawn or superseded standard and the project cannot confirm which edition governs; any enquiry where two documents disagree; any duty whose acceptance criterion is stated only as a standard number; and any cryogenic vessel valve, where the vessel route applies instead.

• Any duty below −101 °C (−150 °F), where this site's automatic coverage ends unconditionally. LNG service at about −162 °C lands in that band. Every LNG cryogenic valve enquiry here goes to a person, and the testing regime is part of the reason
• Any enquiry where the specification names a withdrawn or superseded standard and the project cannot confirm which edition governs
• Any enquiry where two documents disagree — a datasheet that says BS 6364 and an RFQ that says BS EN ISO 28921-1
• Any duty where the acceptance criterion is stated only as a standard number and never as a number
• Any cryogenic vessel valve, where the vessel route applies instead and the size limit is different

What people assume, and what the record says

Common questions about BS 6364

Is BS 6364 still available to buy?

The catalogue entry remains, which is often why people assume it is current. Availability is not validity.

What should go in the specification instead?

Name the current edition of the design and production-testing standard for the valve type, state the acceptance criteria as numbers, and — if the valves are for a cryogenic vessel rather than a pipeline — use the vessel route instead.

My drawing says BS 6364. Do I have to redraw it?

No. What matters is whether the acceptance criteria are expressed in a document that is current. Redrawing is one way; restating the criteria in the current standard's terms is usually faster.

Why does the clause keep appearing if the standard is dead?

Because project specifications are inherited. A template written for an earlier project is copied into the next one, and the standard reference travels with it. This is a document-management problem, not a technical one.

Does the Chinese equivalent say the same thing?

Not the same numbers, and not the same temperature span. GB/T 24925-2019 is a self-developed Chinese standard covering −196 °C to −29 °C, with its own test table. GB/T 24925-2019: What a Chinese Cryogenic Valve Test Report Actually Contains opens it up.

What this article does not cover

Note that this article does not select a cryogenic valve, does not determine whether a valve or a specification complies with any standard or regulation, and does not provide certification or qualification advice. It records the status of BS 6364, names where its requirements now live, and states how to read a specification that still cites it.

Where the next constraint sits

Two questions follow a withdrawn standard. The first is what the Chinese supply side actually tests to, which is a different document, with a different temperature span and its own test table — GB/T 24925-2019: What a Chinese Cryogenic Valve Test Report Actually Contains sets it out clause by clause.

The second is what a low-emission specification is really asking for once a standard number has been replaced by class strings. ISO 15848 Explained: Reading BH, CO3 and SSA0 on a Valve Certificate decodes the fields that a cryogenic specification usually names without defining.

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