New explosive gas atmospheres standard on the way

Industry is preparing for a new edition of AS/NZS 60079.10.1:2009, Classification of areas – Explosive gas atmospheres, due to appear later this year.

AS/NZS 60079.10.1:2009 is a modified version of the IEC 60079-10-1 standard, published in 2008. Since then there have been two updates to the IEC standard, in 2015 and 2020. The Standards Australia committee has considered the IEC 2020 version, and it is expected to be published, with modifications, as an Australian standard in late 2022.

Ben Adamson, F.AIRAH, who serves on committees with Standards Australia and the International Electrotechnical Commission, says that the new version of the standard will be of particular interest in Australia’s changing HVAC&R landscape.

“In the past, this standard has had little relevance to Australian HVAC practitioners, as flammable refrigerants have rarely been used in HVAC,” says Adamson. “The R fraternity have some interest in 60079.10.1 due to the use of ammonia, which is low flammability (class B2L) but the Australian annexes in AS/NZS 60079.10.1:2009 include specific provisions relating to ammonia, and the ammonia world is familiar with these. Other flammables, such as propane, have been used mainly in large systems for the oil, gas and petrochemical industries, where the use of flammables is common and has been practiced safely for many decades.”

But, as Adamson points out, flammable (A2L) HFOs and a flammable HFCs such as R32 are increasingly being used.

“Small systems with limited charges of A2Ls (typically <1kg) are covered under specific appliance standards,” he says, “but we are now seeing package chillers containing 100kg or more of R1234ze, R1234yf or R32, all A2Ls.”

Adamson notes that the A2L classification is not ecognized in Australia under flammable gas standards, and clause 5.14.1.1, in AS/NZS 5149.3:2016 states:

Machinery rooms with group A2L, A2, B2L, B2, A3 and B3 refrigerants, where it is possible for the concentration to exceed the practical limit or RCL (20 % of LFL), or for a flammable atmosphere to exist at any location, shall be assessed for hazardous areas in accordance with AS/NZS 60079.10.1.

“Any installation of a large package chiller for an HVAC application must conduct an appropriate design review and risk assessment in accordance with AS/NZS 60079.10.1,” says Adamson. “This will be a new experience for most HVAC practitioners in Australia.”

Adamson says there are a number of things practitioners can do to prepare.

“If considering an A2L installation, the designer and installer should read the current AS/NZS60079.10.1:2009, AS/NZS 5149.3:2016 and the latest IEC 60079.10.1(2020) and watch this space for more news later this year,” he says.

“If someone has already installed an A2L chiller without considering the flammability implications, that installation may be illegal or dangerous, or both. That carries major implications for insurance and liability, and should be reviewed as a matter of urgency.

“Finally, ensure that the person undertaking and signing off risk assessments is competent in the area of flammable gas atmospheres.”

Adamson recently presented on this topic at Refrigeration 2022, and is due to provide an update at the Future of HVAC 2022.