In certain circumstances exhaust treatment will be needed for equipment, experiments, or processes involving hazardous gases. Gas treatment is required for toxic or highly toxic gases if one half of the gas' Immediately Dangerous to Life or Health Level can be reached at the point of discharge to the atmosphere. Where treatment systems are used, they shall be sized to process the maximum worst case release of the gas based on the maximum flow rate of release and the total quantity from the largest cylinder or tank utilized.
Since the use of toxic and highly toxic gases at NCSU require gas cabinets (with sprinkler protection) and flow restricting orifices in the cylinder valve or CGA fitting, the worst case release will be assumed to be the flow of gas through the orifice. F or this reason, quite often gas treatment will not be necessary.
For those installations where gas treatment is appropriate, scrubbers must be carefully reviewed to assure they are installed properly with the appropriate safety devices in place. Improperly designed or equipped scrubbers can present an additional hazard of gas accumulation, exothermic reactions, etc which could result in fire or explosion.
If you are designing a new gas system or adding new hazardous gases to an existing system, please contact 515-6860 for assistance in determining whether gas treatment is appropriate for your installation and for other assistance with safety equipment design.
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