search.noResults

search.searching

dataCollection.invalidEmail
note.createNoteMessage

search.noResults

search.searching

orderForm.title

orderForm.productCode
orderForm.description
orderForm.quantity
orderForm.itemPrice
orderForm.price
orderForm.totalPrice
orderForm.deliveryDetails.billingAddress
orderForm.deliveryDetails.deliveryAddress
orderForm.noItems
REFRIGERANTS


Compliance vs safety


Professor Dick Powell of Refrigerant Solutions questions the guidance surrounding the use hydrocarbons.


L


ike other people, I was shocked by the pictures of Grenfell Tower in flames and the consequent loss of life. Although we must await the report of the public enquiry to fully understand the contributory factors, in the weeks immediately after the tragedy the flammability of the cladding panels was highlighted and led to extensive testing, the results being made public because of the safety implications for other buildings. Worryingly, the validity of the test procedures in BS8414, the British Standard relating to the safety of cladding materials, was questioned by the Association of British Insurers (ABI), which commissioned a study by the UK Fire Protection Agency (FPA) supported by the RISCAuthority membership. The information has been made available to Dame Judith Hackitt’s Review of Building Regulations and the Grenfell Inquiry. A key finding was that the procedures in BS8414 were deemed out-dated because materials and building technology had changed since the originally drafting, notably the greater use of plastic relative to wood.


So how could this affect the air refrigeration and HVAC industries, and also myself as a developer of refrigerant blends both fluorocarbon- and hydrocarbon-based? I am not an expert on refrigerant flammability, but I


36


am responsible for ensuring that my products are safe and compliant with the relevant regulations. Following Grenfell, I question whether ‘compliant’ and ‘safe’ are necessarily the same? Perhaps I should follow the Royal Society motto: “Take nobody’s word for it”? Providing information about flammability, like thermodynamic properties, is a fundamental requirement for selling a refrigerant. While small differences in, say, measurements of vapour pressure have little effect on its application, flammability can be assessed by a variety of methods, sometimes giving contradictory results. About 30 years ago the refrigerant industry therefore standardised on the ASHRAE 34/ASTM E681flammability test, which has been refined so that, in expert hands, it provides a reasonably reproducible distinction between flammable and non-flammable. But it does require attention to detail and careful interpretation of what constitutes flame propagation. For a zeotropic blend the effect of combined worst-case formulation and fractionation (WCFF) also must be determined to find the vapour blend that will actually be tested. The absence of fires or explosions associated with non-flammable-rated HFC refrigerants indicates that the ASHRAE 34/ASTM E681 test has proved itself a good safety screen, although


March 2019


www.acr-news.com


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72