Steam Mains Insulate or not?

bergensteamguy · February 20

Hey Everyone, I have a scenario to run by the pros. I have a part of my basement that I am finishing off. By this, I mean it will have partition walls built, which will be insulated. I currently have a one pipe steam system. The main will travel through this room and into the 'unfinished' part of my basement. Today, the entire steam main is insulated. I was thinking about removing the insulation on the steam mains once the room is finished, and only removing the insulation in the finished room. I would leave on the insulation in the unfinished parts of the basement. It would be just like any other interior room of the house that a steam pipe travels through. i.e. from 1st floor to second floor. My question, is there any reason to leave on the insulation? I was thinking the heat from the main could be used as a heat source for the room and it should not get to cold because the stat is all one zone and set at 68 degrees. so the room should never get much colder than that. Any thoughts on this is appreciated.

ethicalpaul · February 20

Your idea is sound. There is no reason not to remove the insulation if you want to increase the heat output into that finished room.

People will disagree. They will say that it causes "too much condensate". But remember, the main carries ALL of the condensate from every ounce of steam the boiler ever produces, so I find this point to be moot.

They might say it creates "wet steam". But remember, all the steam in every residential steam system is at the verge of condensing, and it is indeed constantly condensing all throughout the system.

Insulation in fact does not come into play at all when the main is room temperature, which can occur all throughout the shoulder seasons, and no one is concerned. They aren't concerned because the main is not affected by it. All throughout the main and in all other pipes as well, all year long there is constantly condensate and steam co-existing with no ill effect.

Long Beach Ed · February 21

Speaking theoretically, the same thing happens on a cold day when the system is working hard and the pipes are cool. The system should have been designed to handle this. When you remove heat into a very cold basement on a very cold day, you can be taxing the design without insulation.

You are replacing a certain amount of dry steam with steam of diminished latent heat by adding a radiator (the pipe) in series with the others.

RTW · February 21

Save the removed insulation as a back-up, so if removal creates a problem you can re-install ( its very expensive)

Regards,

RTW

Gsmith · February 21

I would leave the insulation on, then after the remodel is complete, see how comfortable the room is. If too cold, remove some insulation, in steps, until you reach a comfortable arrangement.

Intplm. · February 21

Im a BIG believer in insulation. However. Removing some to create a living space that works best for you is fine.

Make sure the insulation is fiberglass and not asbestos. If its fiberglass remove it yourself. If it's asbestos you should have a remediation company remove it, and have it removed first before remodeling. It can make a big mess.

Steam boilers need a mechanical room/basement for maintenance. Do not build your boiler in so tightly that when service is needed it will make a mess of the adjoining room(s). Not to mention your boiler needing the proper amount of air to function safely. People have died from building things too tightly. Suffield Ct. comes to mind. Many a rec. room has been ruined by having a boiler in an adjacent room.

ethicalpaul · February 21

You are replacing a certain amount of dry steam with steam of diminished latent heat by adding a radiator (the pipe)
in series
with the others.

My main has (x) number of radiator runouts on it. One of them is first. one of them is last. The first one is constantly pouring warm (not hot) condensate into the main. So is the second one, and the third one, and the fourth one and the (x-1) one

They are all in series. No one, least of all the main, cares because as I said above, in all our systems, warm condensate is constantly in contact with hot steam, all of which is close to condensing.

I assert that if a section of main is uninsulated, the tiny amount of condensate that forms on the walls of the pipe and runs down to the bottom of the main is a tiny fraction of what any radiator runout is adding to the mix.

We all know that a single pipe makes a crappy radiator. It's not enough EDR. Why when that pipe is a section of main are people suddenly thinking it's generating a massive amount of condensate that will somehow overwhelm the main's ability to deal with?

bergensteamguy · February 21

https://forum.heatinghelp.com/discussion/comment/1844012#Comment_1844012

Hi Long Beach Ed, the room should never get to a very 'cold' temperate. The room will be insulated well R23. No different from my living room above. Its a one pipe, 1 zone, system for the entire house. As long as the stat is set at a reasonable temp (i keep at 68 degrees). It should never get cold in the room, because it will be calling for heat when the room above starts to go below the desired temp.

bergensteamguy · February 21

https://forum.heatinghelp.com/discussion/comment/1844039#Comment_1844039

That makes a lot of sense Ethical Paul. Its ten feet of pipe. Some of the radiators probably produce a lot more condensate than that 10ft of pipe, especially the larger ones I have. Thanks for the feedback!

ethicalpaul · February 21

Any radiator produces/consumes more than 10 ft of pipe. Even a 3" main is only about 0.916 sq ft of surface area per lineal foot, in your case making an EDR of about 10.

It will be interesting to see if it gives you noticeable heat. If not, there are always space heaters, ceiling-mounted steam radiators, and hot water radiators that you might consider.

ARobertson13 · February 21

The president of my Coop removed about 13 feet of insulation in our basement meeting room to warm it up. The result was the steam took about 8 minutes to reach the 5th floor instead of 6 minutes. I put it back. I can't tell you what will happen in your situation. There are wall and ceiling radiators that can supply heating in those situations. The money and persons to install them may be a problem.

Good luck

Long Beach Ed · February 22

https://forum.heatinghelp.com/discussion/comment/1844111#Comment_1844111

When #6 Oil was 3-cents a gallon, do you really think the old-timers just spent money on insulation because they wanted the pipes to look pretty and to save money? They wanted the system to work right.

Long Beach Ed · February 22

Remember that a 2" steam main loses 224 BTU from each uninsulated foot when the temperature difference is 150-degrees.

Steam Mains Insulate or not?

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