Insulation clearance to direct vent chimney - InspectionNews

Eric Shuman · #1 (**permalink**) 05-12-2008, 05:45 PM

I know most metal chimney manufacturers require a 1-2 inch clearance to insulation but I cannot find specifics for the Secure Vent Direct Vent Chimney. It passes throught the wall with a horizontal installation and has fiberglass wall insulation in direct contact. My gut says this isn't right but the manufacturer's installation instructions do not address insulation contact specifically as I have seen with other metal chimney manufacturers. Any thoughts?

Thanks,

Eric

John Arnold · #2 (**permalink**) 05-12-2008, 05:56 PM

http://www.eccohtg.com/links/Product...%20-%204-5.pdf

On page 5 under Attic Radiation Shield, a one inch clearance is mentioned.

John Arnold · #3 (**permalink**) 05-12-2008, 06:04 PM

Also see page 7:
http://www.lennoxhearthproducts.com/...V-3328(II).pdf

Randy Clayton · #4 (**permalink**) 05-12-2008, 06:26 PM

I agree with John at least 1" clearance should be made.
However,I was in class last week and there is a new type of vent coming that is three wall type that requires zero clearance; have not yet seen it in the field yet.

Eric Shuman · #5 (**permalink**) 05-12-2008, 06:36 PM

Thanks for the responses!

Eric

Jerry Peck · #6 (**permalink**) 05-12-2008, 07:05 PM

Except that those two references are relating to vertical vents.

Page 9 in this one of the links addresses horizontal vents: http://www.lennoxhearthproducts.com/...V-3328(II).pdf

See the table "Minimum Clearances Inches (millimeters)" on page 9, at "Vent" it shows 3" Top and 1" Sides and Bottom, the 3" Top has an "*" behind it which goes down to "*Note: 3 in. (75 mm) above any horizontal/inclined vent component."

Bob Harper · #7 (**permalink**) 05-13-2008, 05:22 AM

If the vent is listed for use with a specific appliance model then the listed instructions of the appliance apply. However, all gas direct vents will require listed firestops, which keep insulation off the pipe, frame it to maintain clearances and support it.

Also, most state increased clearance required off the top of a horizontal pipe. For instance, unless otherwise stated, all HHT DVP products carry a 1 inch clearance around a vertical direct vent; 1 inch off the sides and bottom, 3 inches off the top of horizontal vent.

Historically, going back to the first gas direct vent, which Heat & Glo (Ron Shimek) invented in 1987, they have maintained these clearances for some 300+ models plus their revisions. Other mfrs, have require 1-2 inches off the top but I doubt that has worked for so many model styles. Some units run cooler than others while some run very hot. They engineer their units so they don't exceed these clearance requirements but in reality, many would pass with less clearance. It keeps life simpler to harmonize the clearances across so many models.
Bob

David J. Smith · #8 (**permalink**) 05-13-2008, 09:51 PM

This company has an excelent web site with all their installation manuels at

http://www.securitychimneys.com/PDF/...SECUREVENT.PDF

A radiation shield is required for a horizontal installation. The reason I looked it up is because in our cold northern climite if you where to leave a 1" air gap on a exterior wall for any reason you going to have other problems such as drafts and condensation.

Jerry Peck · #9 (**permalink**) 05-14-2008, 01:34 PM

Quote:

Originally Posted by David J. Smith

A radiation shield is required for a horizontal installation.

David,

This is what I read in there: "4. If using a wall radiation shield" ... " *IF* " using the radiation shield ...

Bob Harper · #10 (**permalink**) 05-14-2008, 04:07 PM

Again, you are reading from just the vent mfr. You also need to cross check it with the appliance installation instructions. May be the same but might not be.
Bob

Eric Shuman · #11 (**permalink**) 05-14-2008, 04:08 PM

Thanks all, for the input.

Pretty simple fix for the builder but I like to have documentation on everything when I present repair issues as some folks are prone to arguing about even the simplest things.

In most cases these chimney pipes have a sticker posted on them that is very specific about insulation clearances but for this particular brand's direct vent I have never seen a clearance sticker as I have on the others.

Thanks again,

Eric