A pump transfers from one tank to another, with check valves placed on either side of the pump and each tank is open to the atmosphere. This worksheet calculates the flowrate in the pipe by solving the Bernoulli equation for the system, taking into account the head added by the pump, and the head loss due to pipe friction and fittings. Friction factors are calculated using the standard equation for friction in laminar flow, or the Colebrook-White equation for friction in turbulent flow. A number of physical parameters can be specified, including the pipe roughness and the head loss coefficients for the valves.