Fire flow = length X width ÷ 3 This formula is most easily applied if the estimated square footage of the entire structure is used to determine an approximate fire flow for the total structure and is then reduced accordingly for various percentages of fire involvement.

What is fire flow?

The flow rate of a water supply, measured at 20 pounds per square inch (psi) (138 kPa) residual pressure, that is available for fire fighting. FIRE-FLOW CALCULATION AREA.

What is fire flow requirement?

A Required Fire Flow (RFF) is the rate of water flow, at a residual pressure of 150 kPa and for a specified duration that is necessary to control a major fire in a specific structure or grouping of structures utilizing manual fire fighting measures in conjunction with built-in safety features of buildings.

How do you calculate gpm of a fire?

Example: For a 30′ x 50′ building that’s 25 percent involved, the flow would be 30 x 50 = 1,500 square feet, divided by 3 = 500 x 0.25 = 125 gpm. Based on that required fire flow, one handline pumped at the correct pressure should be able to produce the required gpm.

What is the formula for water requirement for fire fighting?

The basic formula in the schedule is: NFFi= (Ci)(Oi)(X +P)i Where NFFi = needed fire flow (NFF) in gal per min (L/min) Ci = a construction factor that depends on the construction of the structure under consideration Oi = an occupancy factor that depends on the combustibility of the occupancy (X = P)i = an exposure

How do I calculate GPM?

The formula to find GPM is 60 divided by the seconds it takes to fill a one-gallon container (60 / seconds = GPM). Example: The one-gallon container fills in 5 seconds, breakdown: 60 divided by 5 equals 12 gallons per minute.

How do you calculate fire load?

Safeopedia Explains Fire Load

1. A building’s fire load is a calculated value.
2. This yields the equation: Fire load = (Mass * Calories) / Area.

How do you calculate fire flow?

Required fire flow (gpm) = (length x width) ÷ 3. Using the same example, an IC arrives at a burning mercantile occupancy that measures 50 feet by 75 feet and is one story tall. The IC quickly determines that the area of the structure is 3,750 square feet.

How do you calculate K factor for sprinklers?

K-Factor formula for fire sprinklers

1. Q = AV.
2. Q = A√(2gh)
3. q = kp^0.5
4. k = q / p^0.5
5. p = ( q / k )²
6. for metric calculations: p = pressure in Bar. q = flow in litre per minute. k = discharge constant Lpm/Bar^0.5
7. and for imperial calculation: p = pressure in psi. q = flow in gpm. k = discharge constant gpm/psi^0.5

What is a fire flow test?

This test simulates Fire Brigade operations when firefighting – under the designed water flows & pressures. This test proves there are no obstructions or impediments between the booster arrangement, the fire pump bypass and the most remote hydrant valve.

What is PSI in fire fighting?

PSI stands for pressure per square inch, and GPM stands for gallons per minute. Both of these are vital in helping you choose what kind of firefighting pump you need, and it is very important to know about the PSI and GPM before buying any pump, regardless of the use.

What is the minimum flow rate for a fire hydrant?

The minimum fire flow from any individual fire hydrant shall be 500 gpm. The minimum flowing pressure at maximum flow shall be 20 psi.

What NFPA 291?

NFPA 291 provides guidance on fire flow tests and marking of hydrants in order to determine and indicate the relative available fire service water supply from hydrants and to identify possible deficiencies which could be corrected to ensure adequate fire flows as needed.