Steam Pipe Sizing Calculator

This calculator converts Boiler Capacity into a steam mass flow rate, then sizes distribution piping and condensate handling from that flow. Steam Flow (lbs/hr) is Boiler Capacity divided by the latent heat of steam, which itself only drifts mildly with Steam Pressure (970 BTU/lb at low pressure, reduced by roughly half a BTU per PSI) -- so Boiler Capacity is overwhelmingly the driver of Steam Flow, and everything downstream of it: Condensate Load and Trap Capacity Needed both scale directly off Steam Flow.

Pipe Diameter is picked from a table of standard nominal sizes (3/4" up to 12") using a target steam velocity of 5,000 feet per minute -- because pipe stock only comes in those discrete sizes, a range of nearby boiler capacities can all round up to the identical recommended diameter, so don't read a stable Pipe Diameter reading as proof that capacity has no effect on it; a large enough change in Boiler Capacity or Steam Pressure will still push the recommendation to the next standard size. Pipe Run Length is collected as a project reference but never enters the sizing math at all -- this simplified model does not calculate the pressure drop that accumulates over a long run, so it has zero influence on Pipe Diameter, Steam Flow, Condensate Load, or Trap Capacity Needed.