vent clearance

**wayne soper** · 10-02-2009, 03:04 PM

Is there a minimum clearance required here. Condensation is heavy and dripping onto the crown.

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**Scott Patterson** · 10-02-2009, 03:49 PM

Originally Posted by wayne soper

Is there a minimum clearance required here. Condensation is heavy and dripping onto the crown.

What is it? Looks like a gas flue pipe terminating in decorative shroud?

Whatever it is the "B" vent pipe does not have an approved cap on it.

**wayne soper** · 10-02-2009, 03:56 PM

It is a metal vent in a block chimney with a slate cap. Could not see down the liner. Not enough clearance.Oil fired furnace.Could not determine if b vent or not.

**Jerry Peck** · 10-02-2009, 05:10 PM

You mean other than th entire thing being wrong?

No required termination, combined with an unlisted structure around and over it?

**wayne soper** · 10-02-2009, 05:58 PM

So if we remove the slate cap and put a listed cap on it we should be Ok correct?

**Jerry Peck** · 10-02-2009, 06:44 PM

Originally Posted by wayne soper

So if we remove the slate cap and put a listed cap on it we should be Ok correct?

Correct.

As long as the supports were removed too, along with adding a proper storm collar, etc.

**Bob Harper** · 10-02-2009, 08:01 PM

You have an unlisted shroud over a listed vent system. It is also missing the listed termination and storm collar. If this is, indeed type B-vent, then it must be removed and replaced with type L vent. B-vent is NOT approved for oil.
Really curious how they managed to put a metallic cover inside a masonry chimney.

**wayne soper** · 10-02-2009, 08:17 PM

I think they used a cement sleeve seen in photo and then ran the vent inside it. Thanks for the replies guys. Pretty sure we have L vent as it looks shiny like stainless where b vent is galvanized appearance.
To be honest, the 6th sense of "that looks wrong" kicked in and I just took a bunch of photos to research after the inspection.
but can't imagine why or how, this install would be cheaper or better, than a typical clay liner install.

**Bob Harper** · 10-03-2009, 06:35 AM

"cheaper or better than clay tile"??? Not this particular abortion of an install but just as a heads-up comparison:

type L, B, or special gas venting or factory chimney are engineered and listed; masonry products are not. This means predictable performance.

these engineered vents have specific tested duty ratings; masonry products do not

these engineered vents have specific tested resistance to corrosion; masonry products do not

these engineered vents are backed by long term warranties by large mfrs.; masonry products are unwarranted

Engineered vents have listed firestops to maintain stated clearances; masonry products rely on 'the other guy', who never firestops according to the code requirements.

Engineered products have step by step installation instructions; masonry products do not

Engineered vents come with terminations tested for performance while resisting animal and rain intrusion; masonry chimneys don't get caps unless the mason feels like it and when they do, they block proper access for inspection and service, do not provide adequate protection against animals & leaves (unless they use metallic aftermarket caps or top dampers which is rare).

vents have tight fitting joints that do not rely on dissimilar materials installed by technicians under unsupervised field conditions; masonry products do

I could go on but you get the idea. Masons cannot construct a masonry fireplace and chimney 100% to the applicable codes. Show me a mason who has any training, certification, and a copy of the current building code who is not associated with the chimney/ hearth industry and I'll buy him dinner. Show me a building inspector who knows ALL the relevant code requirements for constructing a masonry fireplace and chimney and I'll take him and his family out to dinner. So, what about engineered vents and chimneys?----read the listed installation instructions included with the product, cross-check with state and local codes for any requirements that exceed the listing without violating the listing and you're done.

Oh, yes: one man can carry engineered venting under his arm on site and install in an hour or so. Try that with masonry. Yes, engineered venting is usually much cheaper than masonry, too.

Both types have a limited service life. Vents require relatively simple replacement while the other requires major expensive surgery to repair/ replace. If the venting classification or sizing requirements change with new equipment, the vents can be easily changed to meet this need--masonry requires major surgery or abandonment.

Certain vents are approved for positive flue gas pressure from mechanical venting; masonry chimneys are NOT.

These are just a few comparisons btw product categories but you get the idea. ANY product or system installed improperly, misued, neglected, damaged or abused is a problem/ hazard. No system is bulletproof.

HTH,
Bob
(gee, do you think I'm biased just a little?) ;-)

To learn more about these products and their applications, attend training from The F.I.R.E Service Fireplace Investigation, Research and Education Service - Fire Technology Prefabricated Fireplace or programs sponsored by the International Association of Fireplace and Chimney Inspectors at IAFCI : International Association of Fireplace & Chimney Inspectors : Professional Fireplace, Chimney & Venting Inspectors : Home

**wayne soper** · 10-03-2009, 06:49 AM

Bob, That's why I said " I can't imagine it being cheaper or better"!
By the way, I am trying to get info on granite used in firebox in another post. Did you see that post?