Alarm systems, toxic laboratories

All drains in a toxic laboratory with exception of those from the toilets should lead to a toxic sump. The toxic sump should be fitted with the wherewithal to permit addition of reagents, agitation, and sampling, as well as adequate indicators and alarms to highlight malfunctions. Valving should be convenient to operate and the system should feature parallel tanks so one batch can be treated while the lab continues to discharge to the other tank. Provision should be provided to pump out contents when untreatable. 

Toxic operations must be supported by a good communications system. In laboratories where communications are inadequate, workers will naturally use "runners" for communication needs. This practice results in avoidable traffic in and out of toxic areas which increases the opportunities for contamination to spread. In emergencies, a phone or intercom can help ensure that assistance is tailored to the actual need. An "all purpose" response to an alarm will normally be less rapid at a time when speed may be of the essence. Video cameras trained on critical operations add a measure of safety, but annoy the workers who may feel that the purpose of the system is to "spy" on them. As a minimum, the laboratory doors should have windows so that entering personnel don t blunder into a rapidly developing scenario. 

Those elements of conventional laboratory design that must be refined for facilities in which toxic chemicals will be handled are presented. Alarms, communications, construction materials, containment cabinets, filter systems, floor plans, security, compressed gases, and waste disposal are discussed. Emphasis is given to design considerations dictated by the use of large numbers of fume hoods. 

The entire system is maintained at 1 inch of water vacuum to prevent toxic materials from escaping into the laboratory. A compressed air ejector causes a negative pressure in the system. A pressure-sensitive alarm connected to the primary chamber sounds an alert if the pressure returns to normal. 

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