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I read in sci.electronics.design that The Captain
wrote (in ) about 'CB Radios, Cellphones and Gasoline Vapor Ignition', on Thu, 18 Mar 2004: All handheld radios used on rigs are intrinsically safe, making them far more expensive than the standard variety. But do they NEED to be that costly or is that what the market will stand? I very much doubt that cell phones are buit to intrinsicly safe standards, and under those circumstances I would certainly not feel safe near someone yacking while filling. So, an interesting querstion is; does your phone conform to UL requirements for intrinsic safety? And if not, why are you using it in an area where an explosive gas air mixture is possible? We are effectively discussing whether there are any grounds for requiring cell-phones, non-intrinsically safe, to be switched off, or not used, at gas stations. So far, the numbers suggest that the hazard is minute and the risk is also minute. There is a relatively new philosophy being applied to safety standards, including UL standards. It's called 'hazard-based', and requires a logical chain of reasoning to justify every provision of a standard. This is likely to result in significant changes to such standards over the next decade or so. Many current standards have 'just growed' over many years, and in some cases no-one knows why a certain provision is included. -- Regards, John Woodgate, OOO - Own Opinions Only. The good news is that nothing is compulsory. The bad news is that everything is prohibited. http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk |