How to Calculate for Pipe Freezing/Heat Loss?

8/7/2019

Does anyone know which calculation can be applied (or if there is a calculator available) to determine if an insulated pipe will freeze (or how long it will take to freeze)?

We have a scenario where we specified a heat trace system to be used on branch lines extending from the building to an exposed exterior soffit that is subject to freezing conditions. Due to cost concerns, the school/contractor want to remove the heat trace and just insulate the pipe. Thanks.

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8 Comments

Howard G. Gerber

8/7/2019 10:16:09 am

insulation only slows heat transfer, it does not stop it, given time the pipe will freeze. Install the heat trace. can you use a dry head in the soffit?

Douglas E. Colter

8/7/2019 12:29:16 pm

I have a resource publication from the American Society of Plumbing Engineers on pipe insulation and time-to-freeze calcs, reprinted from the 2012 Plumbing Engineering Design Guide Book. try www.ASPE.org

or send me an email and I will forward my copy.

Zachary Siegrist

8/8/2019 01:55:35 pm

Can you provide me a copy of the plumbing engineering design guidebook you referenced in the heat loss thread?

Steven Lopez

8/8/2019 11:39:51 am

They don't want to use a dry system for the exterior as it is intermittent. There are a few areas where branch lines extend to the exterior soffit.

Rusty Scott

8/7/2019 12:49:54 pm

I would give "nVent" Raychem commercial tech support 650-474-7709. They have a program called TraceCalc Pro2 that maybe can help. Their program may allow for you to see what would happen if the heat trace component was removed and insulation thickness is increased, I'm not sure it's worth a shot.

Howard G. Gerber

8/7/2019 12:58:56 pm

try this website:

https://www.wbdg.org/guides-specifications/mechanical-insulation-design-guide/design-objectives/time-freezing-fluid-insulated-pipe-calculator

Mike

8/7/2019 07:23:59 pm

Just one question.

Was this during design phase or construction phase?

Justin Stirling

8/9/2019 05:13:54 am

I was under the impression that there was not a UL/FM approved product on the market for branch line heat tracing (very similar situation with antifreeze solutions as well).

Has this changed?

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