Heat Loss Help

JimRafferty

Greetings,
Here's the particulars:
Local school had a fire sprinkler system installed.
The exposed mains run up inside an unheated brick stair tower.
15'w x 20'l x 4 stories high. Very loose old construction, no insulation, 2 interior walls, 2 exterior walls, (2) doors to exterior, (4) 12 sq ft single pane windows. Phila zip code.
We have been asked to provide enough heat to protect the pipes from freezing in winter. Maintain 40*?
We recommended insulation to protect the pipes, but any ideas how to calculate a load for this application?
Thanks.

Jamie Hall

Honestly, I'd do it the same way as any other Manual J -- although there are going to be some loosey goosey assumptions in there. You know the wall area and the construction; you can get an R value from that. You have the window and door areas and their R values. I'd assume fairly high infiltration (heck of a stack effect in there!). What I would do is either add a fudge factor to the final number -- or use a higher internal target temperature; say 45 or 50.

pecmsg

Ray Chem heat tape and insulation

pecmsg

https://www.nventthermal.com/

EBEBRATT-Ed

If the building is heated you don't have to consider the two interior walls. I would put the heat near the two exterior doors and most of the heat on the lower floors due to the stack effect. I would make sure the doors close tight and are weather stripped.

STEVEusaPA

40° doesn't give you much room for error.