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Hi All, I have a query regarding 2L refrigerants and the application of DSEAR. After reading through EN378, it appears to suggest that for 2L refrigerants, any electrical equipment remaining energised if a high alarm is activated should be ATEX certified and any none ATEX equipment should be isolated. I know this is the case for ammonia, and is common practice but what about other 2L refrigerants? A hazardous area classification has been carried and as expected, only very low ventilaltion is required to achive a Zone 2NE. Does the detection system need to be ATEX certifed (as it does for ammonia) or am I missing something in EN378? Thanks in advance.
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Rank: Forum user
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Hi The quick answer if ever there could be one is if the DSEAR Assessment has acheived a hazardous zone of negligable extent then I can be managed as non-hazardous regarding DSEAR Explosion risk. The implications are that it has been established that the risk of damage or injury caused by the pressure rise due to an explosion is negligible. therefore you do not need to install ATEX equipment in the location. However you have to consider if the ventilation for the location is natural or mechancial. If it is mechanical and could potentially fail, then it should be interlocked in order to isolate either the gas supply or standard electrical equipment in the area when the required flow rate is not being acheived.
The same applies to gas detection it would normally alarm only around 25% LFL and activate isolations at 50% LFL for the flammable substance detected. These methods keep you around negligible extent when applied providing the rate of rise for gas isnt likly to be massive over a short duration such as a tank rupture or pipe fracture. We are assuming normal secondry sources or release from pipework for this to apply.
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1 user thanked John Elder for this useful post.
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