Author Topic: Bvent outside ?  (Read 687 times)

Offline Gasguy79

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Bvent outside ?
« on: May 01, 2017, 04:55:53 PM »
Was at a call today noisy furnace upon taking a quick look around started to notice multiple code infractions anyways long story short gas is off to both a cv water heater and fan assisted mid furnace .
Question I have is bvent is inside of the home ect is there a max allowed length to be outside above the roof or no ?

Also no way to drop a liner to both appliances so pitched him on hi eff firm and new pv tank
Anyone else ever run into this sad thing is the furnace is only 5 yrs old but major venting issues have caused damage inside unit another fly by night guy burned a customer again

Offline Admin

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Re: Bvent outside ?
« Reply #1 on: May 01, 2017, 06:31:56 PM »
Are you asking how long in total the B-vent can be or how high above the roof it must extend?

Clause 8.14.4 - A chimney shall extend not less than 3 ft (900 mm) above the highest point where it passes through the roof of a building and not less than 2 ft (600 mm) higher than any portion of a building within a horizontal distance of 10 ft (3 m).

You would use Table C.3 or Table C.4 to size the venting.  You would need to know the diameter of the existing B-vent and the chimney height, as well the BTU's of each appliance vented up the chimney.

The topic says B-vent outside, but you mentioned the B-vent being inside of the home.

Download Director's Order FS-051-04 - Here

Keep in mind Director's Order FS-051-04 was revoked and replaced by Annex N in both the B149.1-10 (FS-212-14) and B149.1-15 (FS-225-17) Code books.

Download Director's Advisory FS-052-04 - Here

Offline bster352

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Re: Bvent outside ?
« Reply #2 on: May 04, 2017, 02:36:24 PM »
Don Park B-vent is max 6' above roof line if that is your question.