Air vent Requirement on Steam Main Line

Suchitapage

Hello,

I am working on this building (one-pipe system) where I came across this piping arrangement located in the boiler room itself. So the steam header is branched into many main steam lines and one of the lines is shown in the pictures attached.

We can clearly see the steam pipe coming from the right side of one viewing the picture. it separates into two risers and then we can see the condensate lines pitching downwards towards the left. Do we need an air vent on this location? Because I was not able to see one.

Fyi, this building has steam drum in it's distribution system which has steam trap feeding to feedwater tank.

Thank you.

Regards,

20250730_161505501_iOS.jpg

20250730_161508495_iOS.jpg

Steamhead

Can we get some pics of the steam drum and the trap?

109A_5

I would say , in general, no you don't need it there. Although it may not hurt depending on the length of the horizontal main, better venting may get the steam to the radiators faster. The pipe going off to the Left is just a drip for the horizontal main and condensate return for the risers (one pipe condensate return).

I would say you do need a main vent at the top of each riser if they do not already exist.

Suchitapage

https://forum.heatinghelp.com/discussion/comment/1861363#Comment_1861363

Sure. I have attached it below. This building has steam traps but it's a one-pipe system (all the radiators are one-pipe)

20250730_153304441_iOS.jpg

20250730_153306310_iOS.jpg

JUGHNE

The first picture looks to me like a feeder pump to return cond water to the boiler.

The second picture looks like a drop header with the drip F&T trap going into the feeder pump tank.

You may have a one pipe system and are the traps you refer to the ones at the tank?

I would call them end of main float & thermostat (F&T) traps going into the tank also.

Suchitapage

https://forum.heatinghelp.com/discussion/comment/1861386#Comment_1861386

Yes, I have a one-pipe steam system and the traps are near the tanks only.