What is K-Factor for Fire Sprinklers?

AGF’s TESTanDRAIN and Inspector’sTEST valves come in a range of k-factors to best meet your needs. But what is k-factor for fire sprinkler systems?

What is K-Factor?

K-factor helps to calculate the discharge rate from fire sprinkler heads. It’s calculated in imperial units for the United States by using the flow in gallons per minute (gpm) and the pressure in PSI. Metric calculations use the flow in liters per minute and pressure in bar.

Essentially, the k-factor is the orifice size needed for a particular flow and pressure. Low k-factors have a smaller diameter and restrict the flow while larger k-factors allow for more flow.

Meyer Fire offers a tool to compare pressure requirements and flow rates for different k-factors.

AGF offers a full range of orifice sizes to accommodate multiple k-factors for our TESTanDRAIN and Inspector’sTEST models.

Fractional Size vs K-Factor

The chart below shows the imperial and metric k-factor’s equivalent fractional size.

K-factor conversion chart
*Available on 1-1/4″, 1-1/2″, & 2″ size units only **Available on 1-1/2″ and 2″ size units only

Do you have more questions about K-factor? Contact us at 610-240-4900 to speak with a member of our technical staff.