TB 16/20“-40 °C” Mark on Cylinders/Valves

The Transportable Pressure Equipment Directive permits countries where the ambient temperature “is regularly lower than – 20 °C” to mark pressure receptacles with “– 40 °C after the identification number of the notified body.

As a result, some countries in the Nordic region have a legal requirement to mark pressure receptacles with “- 40°C” to show they are not brittle at low temperatures.

This includes pressure receptacles constructed according to RID/ADR.

EIGA members understand the concern about low temperatures and embrittlement of steels. However, for gas cylinders there are a number of reasons why EIGA members do not consider it necessary to add this “-40°C”.

This Technical Bulletin covers the reasons in detail, and they are summarised as follows: - Aluminium alloy cylinders are not sensitive to low temperatures (cold embrittlement) and should not have to bear the”-40 °C” mark. - EN/ISO standards for seamless steel cylinders require good Charpy V values at -50 °C and the cylinders shall be stamped with the manufacturing standard.

Therefore they should not require the “-40 °C” mark. - Older seamless steel cylinders manufactured according to national standards that do not have the “-50 °C” requirement have been proven safe through long term use.

Impact tests carried out show that such cylinders are not sensitive to failure due to cold embrittlement.

Therefore it should not actually be necessary to mark these cylinders with “-40 °C”. Cylinders already marked with “-40 °C” would, of course, retain the mark.

This Technical Bulletin is intended to be used in discussions with Competent Authorities, to demonstrate that the “-40 °C” mark is not required.