Thread: Where to insulate plumbing lines?

Got questions on where to insulate the plumbing lines.
I looked into the IRC 2003 Plumbing Chapter, but couldn’t find much info on it
IRC 2003 only calls out fixture traps to be protected from freezing. I inspected a house on concrete blocks and traps in crawl space don’t have any insulation on them.
The plumber says it is OK in Houston.
I know it differs from region to region.
Any kind of help (post, article, URL) appreciated.

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I don't see how it could be "OK" in Houston if it ever freezes there, and apparently it does:
First and Last Freeze for Texas cities

Check this figure in the IRC.

FIGURE R301.2(1)

Then look here in the IPC.

APPENDIX D
DEGREE DAY AND DESIGN TEMPERATURES

Houston is shown as 32 degrees for the design degree day, and the code requires protection from freezing when the design degree day temperature is 32 degrees or lower.

Originally Posted by Jerry Peck

Check this figure in the IRC.

FIGURE R301.2(1)

Then look here in the IPC.

APPENDIX D
DEGREE DAY AND DESIGN TEMPERATURES

Houston is shown as 32 degrees for the design degree day, and the code requires protection from freezing when the design degree day temperature is 32 degrees or lower.

Per this code, is every single water pipe (hot or cold) in unheated attic and crawl space supposed to be insulated?
If so, that brings up another subject.... What is the R value of insulation?

Originally Posted by M Kelekci

What is the R value of insulation?

Whatever is needed to protect the pipe from freezing.

Could even require insulation AND heat.

Think exposure... Since you are in Houston (not Wisconsin-in), much different exposures.

Where are the pipes exposed? Where will the pipes be suceptable to freezing thru supply lines?

In a garage-- no. Not exposed to outside temperatures as a rule of thumb.

Attic-- no (see garage)

Exterior walls-- exterior hose bib supply lines that protrude out of the wall and not insulated can freeze.

Now, on older homes, the supply lines for exterior hose bibs come straight out of the ground, some with a full foot or more of exposure-- insulate'em.

Crawlspaces-- yes. I would say that these lines should be insulated, even in Hughston.

Originally Posted by Richard Rushing

Think exposure... Since you are in Houston (not Wisconsin-in), much different exposures.

Where are the pipes exposed? Where will the pipes be suceptable to freezing thru supply lines?

In a garage-- no. Not exposed to outside temperatures as a rule of thumb.

Attic-- no (see garage)

Exterior walls-- exterior hose bib supply lines that protrude out of the wall and not insulated can freeze.

Now, on older homes, the supply lines for exterior hose bibs come straight out of the ground, some with a full foot or more of exposure-- insulate'em.

Crawlspaces-- yes. I would say that these lines should be insulated, even in Hughston.

The below code from Jerry Peck's post on another thread. How would you interpret it.
Thanks,



From the IRC.

- P2603.6 Freezing.
In localities having a winter design temperature of 32°F (0°C) or lower as shown in Table R301.2(1) of this code, a water, soil or waste pipe shall not be installed outside of a building, in exterior walls, in attics or crawl spaces, or in any other place subjected to freezing temperature unless adequate provision is made to protect it from freezing by insulation or heat or both. Water service pipe shall be installed not less than 12 inches (305 mm) deep and not less than 6 inches (152 mm) below the frost line.

Originally Posted by Richard Rushing

Think exposure... Since you are in Houston (not Wisconsin-in), much different exposures.

Where are the pipes exposed? Where will the pipes be suceptable to freezing thru supply lines?

In a garage-- no. Not exposed to outside temperatures as a rule of thumb.

Correction - YES. Protection is needed outside the heated envelope of the structure, unless the garage is also heated.

Attic-- no (see garage)

See correction at garage.

Exterior walls-- exterior hose bib supply lines that protrude out of the wall and not insulated can freeze.

Now, on older homes, the supply lines for exterior hose bibs come straight out of the ground, some with a full foot or more of exposure-- insulate'em.

Crawlspaces-- yes. I would say that these lines should be insulated, even in Hughston.

Not JUST "supply lines".

Supply lines, DWV lines too. ALL plumbing lines through which water flows and their vents in the attic and waste lines in the crawlspace.

Now, if your area is *at* the 32 degree design temperature, not having protection from freezing will likely not result in noticeable problems, except possibly supply lines exposed to those temperatures.

However, if you are below that 32 degree design temperature, I would very much write those up, and the further below 32 degree design temperature your area is, the greater the need to write them up.

Originally Posted by Jerry Peck

Now, if your area is *at* the 32 degree design temperature, not having protection from freezing will likely not result in noticeable problems, except possibly supply lines exposed to those temperatures.

Jerry
Guess it is OK not to write it up (supply pipes in unheated attic, crawl space and garage). Did I understand your post correctly?

Originally Posted by M Kelekci

Jerry
Guess it is OK not to write it up (supply pipes in unheated attic, crawl space and garage). Did I understand your post correctly?

Yes, but I also said:

Originally Posted by Jerry Peck

Houston is shown as 32 degrees for the design degree day, and the code requires protection from freezing when the design degree day temperature is 32 degrees or lower.

and

Originally Posted by Jerry Peck

Now, if your area is *at* the 32 degree design temperature, not having protection from freezing will likely not result in noticeable problems, except possibly supply lines exposed to those temperatures.

Thus, you may get some backlash 'because it's never caused a problem before'.

While you would absolutely be correct as Houston 'is listed' *at* the 32 degree design temperature trigger, is it something you want to write up? (I would, but that does not mean you would - it's a personal choice. I did not mind making people think about what was not being enforced, and, after a while (and many discussions with code officials and inspector), many times it would start being enforced.)

I've always like this part of the code.
From the IRC.

- R104.1 General.

The building official is hereby authorized and directed to enforce the provisions of this code. The building official shall have the authority to render interpretations of this code and to adopt policies and procedures in order to clarify the application of its provisions. Such interpretations, policies and procedures shall be in conformance with the intent and purpose of this code. Such policies and procedures shall not have the effect of waiving requirements specifically provided for in this code.


I.e., the Building Official is remiss in their required duties IF THEY DO NOT enforce that section.

Have fun with it, I would.

Thanks Jerry.
Just didn't want to be the only one who writes up the uninsulated pipes in unheated spaces.