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How to convert PPMw (by weight) to PPMv(Volume) for H2S & moisture(H2O) in gas mixture?
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Submitted Chris Haslego, Nov 21 2011 11:21 AM | Last updated Nov 21 2011 01:29 PM

Category:	Safety
Question:	What design and safety aspects of tank design should be employed when storing dangerous chemicals such as methylene chloride?
Keywords:	v1i13,storage,tank,design,parameters,code,safety,hazardous,chemicals
Answer:	These types of chemicals should be stored remotely in a concrete paved area with a concrete wall or dike. Additionally, the storage tanks should be built to API650 standards as a minimum. The fluid should be stored under a pressurized nitrogen blanket of at least 1-2 psig.All tank nozzles should be located on the top of the tank. This eliminates all side and bottom nozzles with the exception of drains and clean-out connections which should be close-coupled, valved and blinded. This is done to eliminate any possibility of joint or gasket leakage around the tank. A vertical, roof-mounted pump is preferred, but if necessary a sealed (magnetic-drive) pump can be used if it is close-coupled to the tank and all piping is welded (or sealed, shrouded, and monitored). Level detection should be radar (or microwave) type. Pressure relief devices should be set to approximately 2.5 psig or the MAWP of the storage tank.Also, there should be a dedicated sprinkler system for the fire case on such a tank. All pumps, valves, and instruments should be remotely operated outside the dike area. Under normal circumstances, no operating personnel should be allowed inside the dike.Source: Mr. Art Montemayor