# Water Hammer Inlet Pressure

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

## Water Hammer Inlet Pressure Formula

 $$\large{ p_i = \frac{ 0.070 \;v \;l }{ t } }$$

### Where:

 Units English Metric $$\large{ p_i }$$ = inlet pressure $$\large{\frac{lbf}{in^2}}$$ $$\large{Pa}$$ $$\large{ v }$$ = flow velocity $$\large{\frac{ft}{sec}}$$ $$\large{\frac{m}{s}}$$ $$\large{ l }$$ = upstream pipe length $$\large{ft}$$ $$\large{m}$$ $$\large{ t }$$ = valve closing time $$\large{sec}$$ $$\large{s}$$