The Institute of Refrigeration and British Refrigeration Association have collaborated to provide new guidance, allowing increased maximum allowable pressure for equivalent thickness of copper tube. The move has been hailed as ‘creating level playing field for the industry across Europe’
Revised guidance on the selection of copper tube and fittings for use in refrigeration and air conditioning systems has been agreed by two of the cooling industry’s leading bodies, the IOR and the BRA.
The changes, which have taken two years to implement, have implications for a number of key standards and practices used in the UK refrigeration and air conditioning industry.
The main change from the existing BS1306 standard to the relevant European standard EN14276 is a reduction in the safety factor, allowing the use of increased pressures for tube with the same wall thickness.
Gordon Adams technical manager at Climate Center, who played a key role in the revision, said: “It had been recognised for some time that the British Standard was very conservative. The revised guidance gives more latitude, allowing a stress value at 150 deg C to be used for discharge lines.”
The UK is ahead of the European standard in introducing the new design stress values - they will be introduced shortly in EN14276 as an amendment.
The strength pressure test required on copper tube under the Safety Standard BS EN378 has also been clarified, and now allows - subject to certain conditions being met - for the test to be carried out at 1.1 times the maximum allowable pressure.
The new guidance gives clear tables for the maximum allowable pressure of copper tube for the common diameters and wall thicknesses. It also highlights the minimum design pressures for commonly used refrigerants, bringing key information into a single reference point.
Mr Adams added: “Given the importance of the guidance for the safety and reliability of plant, we have gone through the data underlying the proposed changes extremely thoroughly. The key thing was to get it right, and ensure the industry could proceed to use the new approach with confidence. I would like to thank my colleagues from both the IOR and BRA, who have worked closely to evaluate and agree the changes.”
The guidance, “Selecting copper tube and fittings”, Institute of Refrigeration Guidance Note 25, is available from www.ior.org.uk