K-factor (fire protection)

In fire protection engineering, the K-factor formula is used to calculate the discharge rate from a nozzle. Nozzles can be fire sprinklers or water mist nozzles, hose reel nozzles, water monitors and deluge fire system nozzles.

K-Factors calculated in Metric units;

The flow rate of a nozzle is given by $q=K{\sqrt {p}}$$q=K{\sqrt {p}}$, where q is the flow rate in litres per minute (LPM), p is the pressure at the nozzle in Bar and K is the K-factor is given in units of $LPM/{\sqrt {\text{bar}}}$$LPM/{\sqrt {\text{bar}}}$.

K-Factors have also been calculated and published in English units of PSI and GPM. Within the United States, only English measurements are used.

Care should be exercised not to intermix K-factors from Metric and English units as the resulting factors are not equivalent or interchangeable.

External links

• k-factor calculator Calculate k-factor for a set of fittings, bends, valves etc. in a piping system.