Air handling system isolation

Separate duct/fan systems shall be provided for incompatible vapors and air streams  

UMC 505.1 requires that ducts which convey explosives or flammable vapors, fumes or dusts (toxics are included in this group) shall extend directly to the exterior of the building, without entering other spaces. We believe it isunacceptableto connect gas cabinet exhaust to a woikstation or any other exhaust ventilation system. 

Wafer fabrication (H-6) air handling systems must be separated from one another. The retum-air system of one fib area shall not connect to another system within the building (UFC 5103.4.2). It is acceptable to provide supply air from a fab makeup air handling system to another area if the makeup air system utilizes a 100 percent outside air unit 

Similarly, the exhaust air duct system of one fabrication area shall not connect to another duct system outside that fabrication area within the building (UBC 1202.2.5). It is acceptable to connect the exhaust ducts for two separate fab areas together (or for a fab area and a non-fib area together) at a point outside the building. 

The exit corridors may not be used as a return air space for another area. Duct penetrations of fire-rated corridor walls must be provided with combination fire/smoke dampers (UBC 713.10 and 713.11). 

---