197 sq. in. (1,260 cm^2 ) as bare-minimum vent
area with a proper area (allowing for exten-
sive ducting) of 237 sq. in. (1,525 cm^2 ), plus
the addition of two 4-inch-diameter, 250 cfm
(10.2 cm dia., 7 m^3 /min.) exhaust blowers.
Minimum Vent Section Area
and End Fittings
In all cases, no ventilation duct can be less
than 3 sq. in. (19.3 cm^2 ) in cross-section area;
this means a pipe or tube must be at least
2 inches (50 mm) ID, a half-circle with a
radius greater than 1.38 inches (35 mm), a
square larger than 1.732 inches (44 mm) on
a side, or a rectangle larger than 1 inch by
3 inches (25.4 mm by 76.2 mm).
The end or terminal fittings (e.g., louver
grilles or clamshell vents) must have at least
80 percent of the minimum cross-section
area required under any of the preceding
requirements.Chapter 16:Ventilation of Machinery Spaces
Figure 16-7.
Minimum
gasoline vent
section area for
3 square inches
(19.3 cm^2 )
(Courtesy ABYC)