Tape on furnace vent pipe

[Justin Fehl]

Hey guys, new to site and looking for some help.

I looked around on this site but am having a hard time getting a straight answer. I am a certified chimney sweep who moved from New England to Illinois recently and have started my own chimney company. In the past I have gone back and forth with my old boss on whether or not pipe tape is ok for furnace pipe. He says it is ok. I've seen others on this site say tape is only used for duct work (hvac duct, dryer duct, etc). But I can tell you that in the northeast we see tape all over the joints on furnace pipe (oil and gas. Especially oil). HVAC guys do it all the time and so do all the chimney companies I know of. I've never seen this cause a problem, not even the adhesive melting off. So is there a certain grade of metal tape that can be used on furnace vents? Or is it all off-limits?

Thanks a lot!

Justin

[Jerry Peck]

For "chimney" or "vent", although I doubt that really matters?

"Vent" - single wall needs three screws at each joint, no tape; Type B gas vent (double wall) locks together and does not need screws.

"Chimney" - double wall and triple wall all lock together at each joint, so tape would not be needed.

BOTH of the above require proper support and strapping, in which case neither would need tape anyway.

Now, an unasked question is: Would tape 'be harmful'? Possibly not, not unless a flammable tape was used ... pointless and unnecessary, sure, but people do pointless and unnecessary things all the time, and as long as they are 'not harmful', "no harm, no foul".

Where if Bob H. when we need him? :)

[Justin Fehl]

Jerry, thank you for taking the time to respond to this. Good info!

Justin



For "chimney" or "vent", although I doubt that really matters?

"Vent" - single wall needs three screws at each joint, no tape; Type B gas vent (double wall) locks together and does not need screws.

"Chimney" - double wall and triple wall all lock together at each joint, so tape would not be needed.

BOTH of the above require proper support and strapping, in which case neither would need tape anyway.

Now, an unasked question is: Would tape 'be harmful'? Possibly not, not unless a flammable tape was used ... pointless and unnecessary, sure, but people do pointless and unnecessary things all the time, and as long as they are 'not harmful', "no harm, no foul".

Where if Bob H. when we need him? :)

[BARRY ADAIR]

For "chimney" or "vent", although I doubt that really matters?

"Vent" - single wall needs three screws at each joint, no tape; Type B gas vent (double wall) locks together and does not need screws.

"Chimney" - double wall and triple wall all lock together at each joint, so tape would not be needed.

BOTH of the above require proper support and strapping, in which case neither would need tape anyway.

Now, an unasked question is: Would tape 'be harmful'? Possibly not, not unless a flammable tape was used ... pointless and unnecessary, sure, but people do pointless and unnecessary things all the time, and as long as they are 'not harmful', "no harm, no foul".

Where if Bob H. when we need him? :)

Jerry, Bob previously posted about tape #20
http://www.inspectionnews.net/home_inspection/heating-ventilation-air-conditioning-hvac-home-inspection-and-commercial-inspection/14441-furnace-vent-foil-taped.html

[Jerry Peck]

Jerry, Bob previously posted about tape #20
http://www.inspectionnews.net/home_inspection/heating-ventilation-air-conditioning-hvac-home-inspection-and-commercial-inspection/14441-furnace-vent-foil-taped.html

"Last time I checked, tin tape, even if listed to UL 181, is NOT an approved vent connector material."

But what about other types of tape?

And, permanent magic marker is not UL approved for use as labeling on vents, but is it harmful? That is the other part of the question.

Is it okay to using something which is not needed provided that it is not harmful (my "no harm, no foul" comment).

[Gary Burnett]

Works great if you don't have a reducer connection on the truck!

[Lon Henderson]

I have done some research into this because I have such a boring life. No where is cloth duct tape allowed. In most of the country, foil tape is not allowed. 3M has a high temperature tape rated to 600 degrees. I called 3M and spoke to one of their techs about it (did I mention how boring my life is?) who told me that their tape was specifically designed for metal flues on standard efficiency furnace, water heater, and boiler flues.
Then, I spoke with 3 of the AHJs in the Denver metro area. None were familiar with 3M's product, but said it didn't matter to them, because tape masked the connection and made it difficult to see the appropriateness and quality of the connection. Indeed, just a week ago, I saw a taped connection where I could see over an inch of fluting at the single wall connection through the foil tape, telling me that the tape was the only thing holding the two ends.

However, you need to familiarize yourself with what your local AHJ wants to see, because I recently had a student who was a HVAC tech in Kansas City tell me that their AHJ requires foil tape on all flue connections. Interestingly, he was unfamiliar with 3M's tape.

[Jerry Peck]

3M has a high temperature tape rated to 600 degrees. I called 3M and spoke to one of their techs about it (did I mention how boring my life is?) who told me that their tape was specifically designed for metal flues on standard efficiency furnace, water heater, and boiler flues.

I found that 3My high temperature tape too ... but I didn't call 3M ... so I guess I have a little life? :D

[Justin Fehl]

I have done some research into this because I have such a boring life. No where is cloth duct tape allowed. In most of the country, foil tape is not allowed. 3M has a high temperature tape rated to 600 degrees. I called 3M and spoke to one of their techs about it (did I mention how boring my life is?) who told me that their tape was specifically designed for metal flues on standard efficiency furnace, water heater, and boiler flues.
Then, I spoke with 3 of the AHJs in the Denver metro area. None were familiar with 3M's product, but said it didn't matter to them, because tape masked the connection and made it difficult to see the appropriateness and quality of the connection. Indeed, just a week ago, I saw a taped connection where I could see over an inch of fluting at the single wall connection through the foil tape, telling me that the tape was the only thing holding the two ends.

However, you need to familiarize yourself with what your local AHJ wants to see, because I recently had a student who was a HVAC tech in Kansas City tell me that their AHJ requires foil tape on all flue connections. Interestingly, he was unfamiliar with 3M's tape.


This was very helpful and makes a lot of sense. I guess if you have a good connection you shouldn't need tape anyway....

[Bob Harper]

It isn't just the temp. rating. You're covering the vent, which masks corrosion and damage. No coverings of any kind on vent/ chimney connectors-period. When you see where someone sprayed silver paint over galvanized steel connector call it out because it was obviously applied to mask corrosion.

Don't over think this.

You don't need tape on joints because its a negative vent pressure system. The tape is unnecessary. Air will be entrained in through micro gaps in joints just like a venture. Just like test holes for draft and combustion analysis testing.

[Vern Heiler]

I think the picture shows single wall vent in the attic and am sure that is not right. Retired in 2018 so might have lost my marbles 😬

[Eric Barker]

Justin - Taping the furnace vent joints is not a common practice here in N. IL. Only if I suspect that the tape may have been applied due to vent deterioration will I comment on it.