Replies

1. 
   Hubedube | Dec 18, 2004 08:36pm | #1

    In order to shorten a length of B vent, you have to first remove the "spacer ring" from the one end. (lower end)

    it could be either rivetted or spot welded in place. Then after removing the spacer ring just cut the outer and inner (one at a time) pieces to the necessary length and reinstall the spacer ring (pop rivets)

    Savvy?

   
   

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   Edited 12/18/2004 12:39 pm ET by Hube

2. 
   mike4244 | Dec 18, 2004 08:47pm | #2

   You can buy a shorter piece, comes in one foot increments from one foot up to five feet.

   mike

3. 
   Pierre1 | Dec 18, 2004 09:33pm | #3

   What Mikek says. 'B' vent is a UL rated fire protection device. Tampering with it may void your fire insurance policy. There are shorter pipe increments available; you may also shift the entire chimney run up or down to get the optimal adjustment, so long as the overall length meets code. Talk to a building inspector who is also certified to inspect combustion appliance installations.

   
   

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   Edited 12/18/2004 1:44 pm ET by Pierre1

4. 
   bobtim | Dec 19, 2004 12:58am | #4

   I wouldn't recommend any field modifactions.

   It would be mighty hard to cut it and still maintain the integrity of the flu. It was also not be allowed under the uniform mechanical code several years ago (I have no clue as to its present code status, but I can sure guess it ain't allowed).

1. 
   rjw | Dec 19, 2004 02:24am | #5

   >>I wouldn't recommend any field modifications.I'll note a very small (tiny) exception:I have been told that the meter manufacturer Bacharach has obtained letters from the B-Vent manufacturers allowing drilling a 1/4" inch hole through both sleeves of B-Vent for inserting probes.(I mention this because every now and again I get a homeowner getting worked up about my CO testing procedures which can include drilling such a hole.)I don't know about yours, but my church isn't a hotel for the holy, it's a hospital for sinners

   Sojourners: Christians for Justice and Peace

1. 
   Hubedube | Dec 19, 2004 11:42pm | #10

    Probe holes? no problem.Removeable  plug covers are available. Same as Pitot tube covers for air ducts when balancing systems.

2. 
   Hubedube | Dec 19, 2004 11:38pm | #9

    Approval wise, no its not allowed. But its been done hundreds of times by tin- smiths and furnace installers in a pinch.   No problem.At the most, it takes approx 15 minutes to alter a length. And the same goes for the class A ( insulatedwood stove)  type pipe. No problem.

   Pipe Classess A-B-C-L, they can all be altered in the field if necessary.

1. 
   rich1 | Dec 20, 2004 03:02am | #11

   NO PROBLEM???????????????????????????

    

   Can you say "NO INSURANCE"??????????????????????

5. 
   davidmeiland | Dec 19, 2004 02:24am | #6

   You can buy adjustable nipples in B vent, and they telescope to give you the length you need. Go to metalbestos.com and check out the B-vent materials they make, including the adjustable length sections.

   They should have them at any decent sheet metal supplier. They probably do not have them at Ace Hardware. Maybe at HD, I dunno, I don't go there.

   Don't cut it. Ignore the guy that says cut it. And don't put it together with sheet metal screws.

6. 
   MSA1 | Dec 19, 2004 06:45am | #7

   What brand is it? I used to sell "Selkirk Metalbestos" and "Amerivent". Both came in a variety of sizes. If you need to go an odd length they make an adjustable length. Bottom line.....you shouldnt cut it.

7. 
   SteveL | Dec 19, 2004 07:33am | #8

   B vent is NOT to be trimmed to length. You must use pieces intact. There are adjustable length pieces to "fill the gap". I prefer Simpson Duravent over others since it has an easy to operate twist-lock connection - you usually will mangle Amerivent beyond repair if you need to take it apart.