Posted By Robert S Woods I have been talking to an engineer (he carries out the ATEX assessments) who says he cannot see how any LEV would not be classed as zone 20: “There is a permanent presence of an explosive atmosphere”. This “fact” would mean an ATEX compliance assessment would need to be carried out on all LEV. The outcome being the possible upgrading of fans, filter units and any other possible sources of ignition in units installed pre July 2003. I had a similar problem in convincing an insurance company that a newly installed dust collection system. I rang the manufacturer who explained at first in technical detail then in idiot speak so I could understand that the amount of air pushed through the system and the type and quantity of product would not create an explosive atmosphere. Is there someone who can provide or somewhere I can get plain English guidance on ATEX compliance?

Posted By Dave Daniel The simple answer is no - there is no authorititive source of guidance. Having conspired in the production of DSEAR and ATEX the HSE have failed to realise the consequences of transforming good custom and practice into a regulatory framework. There are many areas where these issues exist and the main problem is that dilution levels generally mean that accepted zoning practices are extraordinarily conservative, and they were anyway based on guesswork or custom and practice only. You would probably have to have a very heavily blocked extraction system to generate an explosive atmosphere and you could detect this anyway.