Alarm systems buildings, laboratories

The laboratory shall be equipped with a fire alarm system coimected so as to sound throughout the building (and in a central facility maimed 24 hours per day), an appropriate fire suppression sy stem, and be provided with one or more class 12 BC, or larger, fire extinguishers, or class D units... 

A ducted exhaust air ventilation system is to be provided. The system is to be designed so as to create directional airflow that draws air from clean areas into the laboratory toward contaminated areas. The exhaust air is notto be recirculated to any other area of the building, and is to be discharged to the outside with filtration and other treatment as needed. The outside exhaust must be dispersed away from occupied areas and air intakes. Laboratory personnel must verify that the direction of the airflow (into the laboratory) is proper (a static pressure gauge with an alarm between the laboratory and... 

Heat sensors and/or smoke detectors may be part of the building safety equipment. If designed into the fire alarm system, they may automatically sound an alarm and call the fire department, they may trigger an automatic extinguishing system, or they may only serve as a local alarm. Because laboratory operations may generate heat or vapors, the type and location of the detectors must be carefully evaluated in order to avoid frequent false alarms. 

Type B1 cabinets must be hard-ducted, preferably to their own dedicated exhaust system, or to a properly designed laboratory building exhaust. Blowers on laboratory exhaust systems should be located at the terminal end of the duct work. A failure in the building exhaust system may not be apparent to the user, as the supply blowers in the cabinet will continue to operate. A pressure-dependent monitor should be installed to sound an alarm and shut off the BSC supply fan, should failure in exhaust airflow occur. Since this feature is not supplied by all cabinet manufacturers, it is prudent to install a sensor in the exhaust system as necessary. To maintain critical operations, laboratories using Type B1 BSCs should connect the exhaust blow er to the emergency power supply. 

At Biosafety/Laboratory Containment Levels 3 and 4, the laboratory is maintained at a negative air pressure in relation to the external atmosphere. This ensures a continuous airflow into the laboratory. Exhaust air is not recirculated to any other area in the building but is discharged to the outside through a HEPA filter (or equivalent) and dispersed away from occupied areas and air intakes. Any equipment that may produce aerosols is contained in devices that exhaust air through HEPA filters. At Biosafety/Laboratory Containment Level 4 the differential pressure/directional air flow is monitored and alarmed to warn of any malfunction of the system. 

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