I am trying to figure out how to calculate the total equivalent length of a loop with cast iron radiators. The pipes and fittings are easy to calculate because pipe is calculated linearly, and the fittings are just looked up in a table, but how should the radiators be included in this? How does one figure out how many feet of head to add to the loop to account for the radiators?
The standard way to treat a radiator is to pretend like it is a piece of straight pipe, so if the radiator is 4 feet long it counts as 4 feet of straight pipe.
I got this information when I asked a hydronic heating specialist how one does this calculation.