Pipe Insulation

Matthias

Hey everyone. I work for a heating and AC company in Philadelphia and look at this steam heating job. I need some help estimating how long it would take to wrap the steam pipes. The people had asbestos removed and now are interested in insulating the pipe. It's a huge house (roughly 4000 square feet). The basement itself is roughly 2000 square feet. I measure about 45' of 3" pipe, 150' of 2.5" pipe. The header is 5" pipe. The pipe to the rads vary from 3/4" to 1.5". Do you guys have any idea of how to estimate the time it will take to wrap all this pipe? What about only straight pipe vs. fitting and valves? Thanks for the help.

The second question I have pertains to the picture attached. I am not sure what this item does or what it's called. The pipe coming out the top goes to a few radiators. Can someone help with that. Thanks much.

Matthias

If the runouts get wrapped, they'd only be in the basement as the others in the wall. Some runouts are quite long. Thanks Hatterasguy

Matthias

Roger. Thanks Hatterasguy

Steamhead

The device in the pic is a Trane Direct Return Trap. This is a Trane Vapor system. Vapor is a form of ultra-low-pressure two-pipe steam, and was the Cadillac of heating in its day. It's still one of the best systems out there.

The Return Trap is basically a steam-pressure-powered pump. If the boiler pressure got too high for the water to return by gravity, it went into the Return Trap. A float inside the trap would rise and open a valve which let steam into the trap. The steam pressure along with the height above the boiler's waterline was enough to make the water go back to the boiler.

See chapter 15 of Dan's book "The Lost Art of Steam Heating" for more details.

Steamhead

From what I've seen, the typical later Trane system had that Direct Return Trap and vacuum-type main vents on the steam mains and dry returns, and B1 or B2 traps on the radiators. It wasn't as fancy as some other Vapor systems, but it worked well. The most recent Trane installation I've seen dates to 1946.

Matthias

Great! Thanks for the knowledge Steamhead. I appreciate it. What does the pipe coming out of the trap do? When I followed it, it seemed to be going to radiators.

As far as the system is concerned, it has a commercial Burnham boiler in there that was converted to gas. Whoever did it, never mentioned to the homeowners that the chimney will need to be relined. Well, from what the homeowner told me, they are lucky to be alive. Crazy!!!

Steamhead

One of the pipes should go to the steam piping near the boiler- that provides the steam to operate the trap. The other goes to the dry (overhead) return to keep the pressure in the trap low while it is filling.

SWEI

Jim_R said:

We know someone resurrecting the vapor vacuum pressure system using old technology and developing/utilising todays technology.

This deserves its own thread IMO. Please, do tell more...

Steamhead

In this case, the house was designed just before World War 2 but not built until the war ended. They kept to all the original plans and specs.

JUGHNE

This may be too late of a posting, perhaps the job is already done. But if the pipe hangers in the picture are indicative of the entire system then it seems prudent to correct the hanging method before insulating. I've had a couple jobs like this and installed clevis/auto-grip hangers with 3/8" all thread rod. Makes it very easy to adjust slope before and after insulating.
Also doubled up on the number of hangers as old pipe develops a bow between hangers even if the recommended hanger spacings were originally installed.

Jason_13

I usually use 1-1/2" thickness for this

RobG

Hatterasguy said:

Jason said:

I usually use 1-1/2" thickness for this

The payback period is 13,300 hours based upon the cost difference of $1.33/ ft. between 1" and 1.5" and the heatloss difference of 10 BTU/hr/ft and fuel at $1.00/therm NG.

Is there something wrong with that? It would pay for itself in 3-4 years and keep paying back from there. (I used your numbers but I pay less than that)

RobG

I meant the payback on the difference between 1" and 1 1/2".