proximity of ges vent to roof vent.

cory nystul · 01-14-2015, 09:06 PM

is there any kind of code on how close a roof vent can be to a gas vent?

DSCN6500.jpg

**Lon Henderson** · 01-15-2015, 07:51 AM

The issue is more the height of the flue than the proximity to the roof vent which will be exhausting warm attic air. That flue should be at least 3' above the peak.

BTW, pretty shoes.

**Jerry Peck** · 01-15-2015, 12:07 PM

Originally Posted by Lon Henderson

That flue should be at least 3' above the peak.

It should? Where is that stated?

**Lon Henderson** · 01-15-2015, 03:31 PM

Originally Posted by Jerry Peck

It should? Where is that stated?

Yeah, I got that wrong. It is 3' above roof line or 2' for B vent and minimum of 2' within any part of the roof within 10'.

**Jerry Peck** · 01-15-2015, 04:12 PM

Originally Posted by Lon Henderson

Yeah, I got that wrong. It is 3' above roof line or 2' for B vent and minimum of 2' within any part of the roof within 10'.

No see-gar for you on that answer either.

Chimneys are 3 minimum above the roof and/or 2 feet higher than any part of any structure within 10 feet.

Type B gas vents are 1 foot minimum (with the minimum going higher as the slope of the roof increases) and not within 8 feet of any vertical obstruction (wall, chimney, etc.), if there is a vertical obstruction within 8 feet then the gas vent is 2 feet minimum higher than any such obstruction within 10 feet (paraphrasing the requirements, not word for word).

**Lon Henderson** · 01-15-2015, 04:19 PM

Originally Posted by Jerry Peck

No see-gar for you on that answer either.

Chimneys are 3 minimum above the roof and/or 2 feet higher than any part of any structure within 10 feet.

Type B gas vents are 1 foot minimum (with the minimum going higher as the slope of the roof increases) and not within 8 feet of any vertical obstruction (wall, chimney, etc.), if there is a vertical obstruction within 8 feet then the gas vent is 2 feet minimum higher than any such obstruction within 10 feet (paraphrasing the requirements, not word for word).

Not according to my Code Check Manual

**Jerry Peck** · 01-15-2015, 06:39 PM

Originally Posted by Lon Henderson

Not according to my Code Check Manual

Post what your Code Check manual says, I'll follow with posting the code - we can see if this is another error in the Code Check books or if it is an error in something else.

**Lon Henderson** · 01-15-2015, 07:13 PM

I scanned in the page. Quality is so-so.phpqYEVgGPM.jpg

**Jerry Peck** · 01-16-2015, 10:03 AM

Originally Posted by Lon Henderson

I scanned in the page. Quality is so-so.phpqYEVgGPM.jpg

From the 2012 IRC (unchanged for many years/decades):
- G2427.6 (503.6) Gas vents. - - Gas vents shall comply with Sections G2427.6.1 through G2427.6.11. (See Section G2403, Definitions.)
- - G2427.6.1 (503.6.1) Installation, general.
- - - Gas vents shall be installed in accordance with the terms of their listings and the manufacturer’s instructions.
- - G2427.6.2 (503.6.2) Type B-W vent capacity.
- - - A Type B-W gas vent shall have a listed capacity not less than that of the listed vented wall furnace to which it is connected.
- - G2427.6.3 (503.6.4) Gas vent termination.
- - - A gas vent shall terminate in accordance with one of the following:
- - - - 1. Gas vents that are 12 inches (305 mm) or less in size and located not less than 8 feet (2438 mm) from a vertical wall or similar obstruction shall terminate above the roof in accordance with Figure G2427.6.3.
- - - - 2. Gas vents that are over 12 inches (305 mm) in size or are located less than 8 feet (2438 mm) from a vertical wall or similar obstruction shall terminate not less than 2 feet (610 mm) above the highest point where they pass through the roof and not less than 2 feet (610 mm) above any portion of a building within 10 feet (3048 mm) horizontally.
- - - - 3. As provided for direct-vent systems in Section G2427.2.1.
- - - - 4. As provided for appliances with integral vents in Section G2427.2.2.
- - - - 5. As provided for mechanical draft systems in Section G2427.3.3.

This is what you said "It is 3' above roof line or 2' for B vent and minimum of 2' within any part of the roof within 10'." and why I said "No see-gar for you on that answer either.":
- It's not "above the roof line" (which indicates either above the ridge as you first stated or above the eave), it is above the roof (measured from the roof for a flat roof and from the high side for a sloped roof).

And, yes, I was also not clear either when I said "if there is a vertical obstruction within 8 feet then the gas vent is 2 feet minimum higher than any such obstruction within 10 feet (paraphrasing the requirements, not word for word)." as that could have indicated '2 feet higher than any vertical obstruction within 10 feet' instead of '2 feet higher than any portion of the building within 10 feet'.

**Lon Henderson** · 01-16-2015, 02:12 PM

Instead of roof "line," I should have said roof "surface" as measured from the upper side of the flue base. But in any event, since the roof pitch is a factor in determining the flue height, I was still wrong.

**Rich Goeken** · 01-19-2015, 03:54 AM

Jerry, Just a suggestion. When quoting something could you quote in italics. It makes it easier to separate the wind (not that I am saying that you are windy) from the chaff.

**Michael Bronner** · 01-19-2015, 05:52 AM

Ditto to what Jerry has posted. This is one of the most common issues I see with the exterior of a home; gas vents that are too low in relation to the roof pitch or if within 8 feet of a vertical wall or obstruction (now, define obstruction in this regard). Second only are improper flue caps (not listed) on newer installed gas appliances.