Section SPS 323.07 - Air distribution systems(1) SIZING. All air distribution systems shall be sized using the velocities and static pressure losses listed in Table 323.07. TABLE 323.07
DUCT VELOCITIES
Designation | Maximum Static Pressure Loss (in WG/100 ft) | Minimum Velocity (feet/minute) | Maximum Velocity (feet/minute) |
Main trunk duct | .10 | 700-900 | 800-1200 |
Branch duct | .10 | 600 | 700-1000 |
Branch riser | .10 | 500 | 650-800 |
Outdoor intake | .10 | 500 | 800 |
Grilles or openings | .10 | 400 | 600 |
Return air door undercuts | .10 | 200 | 300 |
Return air door or wall louvers | .10 | 200 | 300 |
(2) SYSTEM SIZING. The distribution system, including the evaporator coil, air filters (installed external to the heating unit), ducts, fittings, grilles and registers, shall be sized so that the total external static pressure shall not exceed the static pressure capacity of the fan at the system rated air flow.(3) CHANGES IN DUCT SIZE. Where duct sizes are changed, the slope angle of the transition duct shall not exceed 45°.Wis. Admin. Code Department of Safety and Professional Services SPS 323.07
Cr. Register, November, 1979, No. 287 eff. 6-1-80; correction in (1) made under s. 13.92(4) (b) 7, Stats., Register December 2011 No. 672.