K-Factor formula

The discharge from a sprinkler head can be calculated from the formula bellow. 

 

          

 

when           q = flow in L/min
          k = nozzle discharge coefficient or k-factor for head in L/min/bar^0.5 (metric)
          p = pressure in bar

 

This formula can be rewritten to give us:

          

 

We also use K-factors for many other applications in fire hydraulics such as flow from a fire hydrant, wet riser outlet, hose reel or foam monitor.  In fact the list is almost endless and this is why it is important to be familiar with the above formulas.