HomeMy WebLinkAboutAtrium A 92B Exhaust EXHAUST METHOD
(Per IBC Section 909.8)
AXISYMMETRIC PLUMES
(Equations based on NFPA 92B -2005 Edition)
NFPA 92B - Eq. 6.2.1.1c: - Z <_ ZL
The Calculations are based upon the following:
Q = 5000.00 BTU/Sec
Q�= 3500.00 BTU/Sec
Z = 6.00 Feet
Z� = 13.94 Feet (0.533 Q�2�5 - Limiting Flame Height- NFPA 92B Eq. 6.2.1.1a)
Elevation = 8150.00 Feet
Smoke Temp = 250.00 °F
Since Z <_Z�, The following formula from NFPA 92B Section 6.2.1 will be used. Therefore:
Mp= �.�ZO8Q�3/5 Z
Mp= 0.0208 ( 3500.00 )3�5* ( 6.00 )
Mp= 16.70 Ibs/sec
From NFPA 92B Eq. 6.4:
V = 60 Mp/p
p = Density of air. The density used in these calculations has been
adjusted to the project's elevation and smoke layer temperature of:
8150 feet above sea level and corrected for a smoke layer temperature of:
250 ° F
0.043 adjusted density (Ibs/ft3)
V = 60 ( 16.70 ) / ( 0.043 )
V = 23,190 cfm (Required smoke control exhaust rate)