(a) control airborne concentrations, dust, and vapor to keep below
explosive or flammable levels
(b) control toxic particulates, gases, and vapors to keep below
exposure levels (TLVs) harmful to workers.
From Table 4-1, 50-100 fpm, use 100 fpm as recommended capture velocity.
cfm = 3 ft * 2 ft * 100 fpm = 600 cfm
Hood, duct, air cleaner, fan and stack.
(b) 0.05 grains/thousand ft3
(a) Capture, Face
(b) 16, 20
(c) (50 ft * 100 ft * 8 ft) * 60 changes/hr/60 = 40,000 cfm
(a) 4 ft * 8 ft * 100 fpm = 3,200 cfm (maximum)
= (3.1416 * 3 ft * 3 ft)/4 = 7.1 ft2
(a) Exhaust area in attic is not large enough
(b) Inlet opening area into building is not large