PUMP OPERATIONS

The formula for calculating hydrant flows is: GPM = 29.83 x c x d2 x vP L/min = 0.0667766 x c x d2 x vP Note: "d" is the diameter of the hydrant or nozzle orifice in inches. "P" is the pressure in psi (kPa) as read on the gauge of the pitot at the orifice. "c" is the coefficient of discharge. The Coefficient will vary with the type of hydrant outlet or nozzle used. When using a hydrant, feel the inside contour of the orifice to determine which one of the three types will be used. The three types of hydrant discharges and their discharge coefficients are 0.70, 0.80, and 0.90. Conduct a hydrant test on your department’s hydrant. Use the formulas above to calculate the hydrant’s flow. Then plug the information into the following website and see how close they are. http://www.firehydrant.org/info/hycalc.html

Hydrant Calculations

FIREFIGHTER TRAINING

References:

Delmar Handbook 3rd edition, pages 310-312 J&B Fundamentals 2nd edition, pages 487-491 IFSTA Essentials 5th edition, pages 664-671, 695-696

NFPA 1001, 2008 JPR 5.3.15

Firefighter Daily Quick Drills - Easy Access to Training Topics

January 2010

Research and Program Development www.ncdoi.com/OSFM/RPD/rpd_home.asp