Steam pipe insulation DIY?

Zipper13

I have a two pipe steam heating system with say 60ish feet of main. I've seen a few sites break down estimates of heat loss and the associated energy cost so I'm convinced that we should probably insulate (although, I do kind of like how warm the basement is now when i go down there to move the laundry).

I understand that fiberglass insulation of 1" is the best bang for my buck.

My questions are:

Does fiberglass pipe insulation produce any kind of hazardous off gassing when heated by a steam main?

Fiberglass kind of absorbs moisture, right? Is there specific prep I should do to the pipes before wrapping them to prevent damage from moisture or is that a non issue if done right and sealed properly? Mine are painted black now, not really much visible rust.

I know we can't share prices here, but would I actually be saving real money on labor doing it myself or should I just have a pro do it instead of taking on another new project? How many hours might be a reasonable ballpark for a pro to wrap these up?

Jamie Hall

Question 1 -- no hazardous gasses or offgassing of anything, for that matter.

Question 2 -- not a problem. If any moisture should manage to get in, the heat from the pipe will drive it right back out the way it came in.

Question 3 -- You certainly would save money doing it yourself, and it isn't that hard to do. How many hours? Impossible to say without looking at the system.

mikeg2015

Wear a dust mask and long sleeves. Fiberglass sucks! It does have a paper jacket around it that increases it's effective R value by being reflective of infrared energy. I ordered a bunch from Zoro as local store don't carry it here. can also get the precut elbows too.

ChrisJ

http://buyinsulationproducts.com/ is where I bought all of mine.

Do it when it's cool so you don't sweat so the stuff won't stick all over you and make you itch. Also take a cold shower after you work with it followed by a warm shower. The cold shower is IMPORTANT, do not skip it.

Follow all recommended safety precautions when working with fiberglass insulation I.E. safety glasses, respirator etc. I'm not an expert and it's best to look up such information or contact the manufacturer.

KC_Jones

Use this stuff:
https://www.amazon.com/Blue-Magic-5215-Invisible-Protective/dp/B000BPEPA0?th=1
I worked in a fiberglass for a couple years and tried everything I could think of, but this was the only thing that seemed to work. I would rub this into my hands and forearms every morning and again at lunch. Made a huge difference.

JUGHNE

FWIW:
It is always advisable to check the naked pipe now for dips and sags. Old systems often have few hangers on the steam mains.
The ones I have worked had sags in the pipe itself between the hangers. An additional hanger was installed between the original ones with just a little lift applied for correction.
One insulated it is very difficult to check slope on the piping.

I would add the hangers and listen a few days of operation for any water hammer you might have introduced with minor changes.

Zipper13

JUGHNE said:

FWIW:
It is always advisable to check the naked pipe now for dips and sags. Old systems often have few hangers on the steam mains.
The ones I have worked had sags in the pipe itself between the hangers. An additional hanger was installed between the original ones with just a little lift applied for correction.
One insulated it is very difficult to check slope on the piping.

I would add the hangers and listen a few days of operation for any water hammer you might have introduced with minor changes.

Thanks for making this recommendation. I have a steam pro coming to do maintenance and to inspect the system in next couple of months. (We're new to the house and doubt the previous owners have done much). I was debating if I should wait to do this until after he was able to check it all out or if I should just go for it and insulate now. Sounds to me like it's worth delaying Insulation until he can look and confirm all is well.

JUGHNE

You yourself could stretch a taunt string along side the main for the length of the pipe. This would give you an idea of sags.
There are string hanging levels that could level your string.
Needs to be tight and you slide the little bubble along it to check level in a few places.
Imagine it being a drain pipe that you want all the water to completely empty out of. (usually running to the far end of the main into a return pipe).

Many contractors are pressed for time this time of year and just do a quick look and say it is OK.

Zipper13

Thanks, all. Great input. a couple other questions as i look into this more.

• Wherever I stop the insulation (on the down stream end of the main and a couple of the longer laterals) do I need to seal the exposed fiberglass end? I've seen photos with white paint on them. Mastik? is there a specific type of this product that I need to use for the heat of steam?
  

• For elbows and bends. I see PVC shells/sleeves to cover the fittings, but they do not appear to be insulated. Shall I just stuff them with spare pink wall insulation and then tape them up?
  
  

pecmsg

For Steam Pipes i would use 1 1/2 or 2" wall thickness.

Covers for ells and T's are also available from http://buyinsulationproducts.com/ as @ChrisJ stated.

Simple fiberglass wrap available from the local hardware or building supply also works but looks terrible.

ChrisJ

pecmsg said:

For Steam Pipes i would use 1 1/2 or 2" wall thickness.

Covers for ells and T's are also available from http://buyinsulationproducts.com/ as @ChrisJ stated.

Simple fiberglass wrap available from the local hardware or building supply also works but looks terrible.

1.5" and 2" is awfully expensive for so little gains over 1".....

pecmsg

ChrisJ said:

pecmsg said:

For Steam Pipes i would use 1 1/2 or 2" wall thickness.

Covers for ells and T's are also available from http://buyinsulationproducts.com/ as @ChrisJ stated.

Simple fiberglass wrap available from the local hardware or building supply also works but looks terrible.

1.5" and 2" is awfully expensive for so little gains over 1".....

I'll admit i havent priced it in a while.........

Is it that much more as apposed to the cost of fuel?

Zipper13

more than doubles for 2", about 50% more for 1.5" I think given the diminishing returns for thicker insulation and that maybe letting a little heat into the basement to keep it a little warm makes 1" the best option for me.

any thoughts on my most recent questions this morning, though? Do i seal the ends of the insulation? what shall I fill the PVC fitting covers with?

mikeg2015

You might use Rock Wool for a easy to handle high temp rated "fill" for the elbows under the PVC covers. Just a thought. The pre-cut elbows are crazy expensive. You can also just miter the fiberglass and get pretty close.

Also, neoprene elbows aren't too expensive. Its' only rated for 200F, but elbows won;t stay over 200F for very long and it's there's even a slight air gap and surrounding temp is maybe 90F, you should be fine. I haven;t had any issues at my house.

FriendlyFred

I did some rough calculations:
2.5" pipe has a surface area of .654 ft^2 for every 12" in length.
Let's assume a delta-T of 140 degrees (210-70).

Now, lets apply the formula [BTU lost per hour = (surface area * delta T) / R-value] to a selection of insulation at different thicknesses.

From the insulation supplier linked above, you can buy insulation for 2.5" pipes at the following [Thickness, $ per foot, R-values]:

1", $2.39, 5.6
1.5", $3.87, 11.5
2", $5.73, 15.6

Adding 1" insulation allows the release of 16.35 BTU/hr
Adding 1.5" insulation allows the release of 7.96 BTU/hr
Adding 2" insulation allows the release of 5.8 BTU/hr

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Continuing to swag at the calculations...

Assuming the cost of BTUs from natural gas as $1.15 per 100,000 BTU, ($.0000115 per BTU).

An engineering chart shows that bare 2.5" pipe loses 250 BTU ($0.002875 per foot, per hour).

The following insulation sizes should prevent the release of the following dollars per hour, per linear foot of 2.5" pipe:

1": $0.002686975
1.5": $0.002783460
2": $0.002808300

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Using these values to figure out the payback period now....

1": 889.47 hours
1.5": 1390.356 hours
2": 2040.38 hours of operation @ delta-T of 140.

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So, in conclusion, I agree with @ChrisJ

Zipper13

@FriendlyFred such a great break down! My gas costs are a bit different, but it's such a great illustration of the diminishing returns of insulation!

mikeg2015

The pipe stores heat and only radiates 250BTU/ft/Hr once it's heated to that temp in a steady state. So it's not in reality you sort have to pick an average delta T for the whole heating season.

To complicate matters more, much of that heat will warm the basement that will in turn heat up the 1st floor. Heating the basement stores some of the energy in the ground, so you use a little less heat in "shoulder season".

I think you'll find the payback is probably around 3 years in reality. The bigger benefit is reducing pickup factor, and the $500 you spend in insulation could save you $500+ when you go to replace the boiler if you can go 1 size smaller. Something to consider.

Jamie Hall

The main purpose of steam main insulation is to reduce condensation in the mains, particularly during warmup and, during warmup, to allow the iron to heat faster which allows the steam to move faster in the main. 1 inch will do that.

Reducing the heat loss during running is, in most applications we are going to see, just gravy -- nice to have, but it's the meat underneath which counts. Again, my feeling is that 1 inch is an acceptable balance.

IMHO, anyway.