For other than one-pipe steam systems, each heat-distribution unit shall be supplied with a steam trap that is listed for the application.
Two-pipe steam system piping and heat-distribution units shall be sloped down at 1/8 inch per foot (10.4 mm/m) in the direction of the steam flow.
One-pipe steam system piping and heat-distribution units shall be sloped down at 1/8 inch per foot (10.4 mm/m) towards the steam boiler, without trapping.
Steam automatic air vents shall be installed to eliminate air pressure in heat-distribution units on gravity steam piping systems. Steam traps shall be installed on pump and receiver condensate systems to eliminate negative pressures in coils and heat exchangers on a low-pressure steam system. Air vents shall not be used on a vacuum system.
System piping shall be installed to allow condensate to flow from the steam trap to the condensate tank or steam boiler.
Where multi-row elements are installed in an enclosure, they shall be top fed and piped in parallel down to the steam trap. A single steam trap for each row of heating elements shall be installed. Where the size of the return header is increased by a minimum of one pipe size, a single steam trap shall be permitted to be installed for multiple rows. Where multiple steam unit heaters are installed, an individual steam trap for each unit shall be installed.