STANDPIPE SYSTEM
NFPA 14 Rules for Class 1 Standpipe Systems
An Excerpt from NFPA 14, Chapter-7, Cl. 7.10 – Flow rates
NFPA 14 requires the system to be capable of delivering 250 gpm from the most remote hose connection on the most remote standpipe plus 250 gpm from the second most remote outlet on the most remote standpipe. To this 500 gpm, an additional 250 gpm needs to be added from the most remote outlet on each of the other standpipes until a maximum flow
is reached.
Where a horizontal standpipe on a Class I or Class III system supplies three or more hose connections on any floor, the minimum flow rate for the hydraulically most demanding horizontal standpipe shall be 750 gpm (2840 L/min)
The maximum flow rate shall be 1000 gpm (3785 L/min) for buildings that are sprinklered throughout, in accordance with NFPA 13, and 1250 gpm (4731 L/min) for buildings that are not sprinklered throughout, in accordance with NFPA 13
Step – 05
Calculation for Pressure Loss between above ground and Underground Piping ( Call between Node T & U)
Above Ground piping Material : Sch. 40 Steel
Under Ground Piping Material : Class 52 Cement lined DI
We need to adjust Equivalent lengths of fittings (1 E + 1 T ) in the UG pipe because of two reasons here ;
- Change in the pipe materials, its DI ( C factor other than 120)
- Change in the internal diameter ( Other than those for sch. 40 steel)
Adjustmet for Inside Diameter:
Adjusted Eq. lenth of Elbow = Equivalent length of elbow x adj
for C x Adj for internal dia.
Total Adjustment for Elbow = 20 x 1.33 x 1.08
Adjusted Eq. lenth of Elbow = 20.1 ft.
Total Adjustment for Tee = 30 x 1.33 x 1.08
Adjusted Eq. lenth of Tee = 43.1 ft