I have considered 25% of developed length as compensation for valves and fittings if you know the fittings and values inside the piping then calculate actual pressure drop in fittings and values. Drop in EWH is already considered while designing hot water supply system, now we only designing hot water recirculation system.
@@ncengineeringtechnology3376 thanks for your reply, please clarify --- this 25% aditional is including 1. EWH pressure drop , 2. hot water return line 3. safety factor 4 . valves and fittings?
as thumb rule we consider 25% to 50% depending on the nature of piping route, if you know the piping rute, please calculate actual drop in piping, for recirculation piping design we do not consider EWH, it is not hot water supply pipe design, it is only for hot water recirculation network.
