# Water Hammer Inlet Pressure

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

## Water Hammer Inlet Pressure Formula

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