New guy with venting questions.

Re: New guy with venting questions.

PostBy: I'm On Fire On: Thu Dec 22, 2011 3:22 pm

Rob R. wrote:
I asked a long-time code office about it once. He said it came about after the early 70's oil crisis when everyone added wood stoves/boilers to their existing chimneys. When a wood-burning appliance is connected to the same flue as an oil or gas appliance, the flue temps tend to be lower from the additional air pulled through the oil/gas unit's draft control. That increases creosote formation...and when there is a chimney fire, the draft control opens and feeds lots of air to the chimney fire. Many homes were burned down from this, and many more had the chimneys damaged or destroyed.


Apparently, its still allowed in Canada.

The National Standard of Canada, Installation Code for Solid-Fuel-Burning Appliances and Equipment, CSA-B365-01 clause 5.2.9 states that:

Two or more appliances shall not be connected to the same chimney flue unless:
a) The appliances are located on the same storey;
b) A negative pressure is maintained at the flue collar of each appliance;
c) Each appliance is provided with a means to control the rate of flow of air or flue gases through the appliance combustion and heat exchanger chambers. Where limitations on flue pressure (draft) are contained in the manufacturer’s instructions, such means shall be capable of maintaining at the flue collar, the pressure specified by the appliance manufacture;

NOTE: For the purpose of this Clause, draft controls include ash pit air control dampers, dampers or draft slides wherever located, over fire and flue key pipe dampers, and check draft controls located on or in the flue pipe.
d) The flue pipes of the appliances are connected to a manifold as close to the chimney as practicable or directly to the chimney in the following order:

(i) If only solid fuel is used, the flue pipe from the smallest appliance shall be on top (downstream);
(ii) If different fuels are used as permitted in Clause 5.2.7, the oil flue pipe shall be on top (downstream); and the solid fuel flue pipe on the bottom (upstream); and
e) The chimney flue is capable of venting the flue gas by natural draft when all appliances not interlocked to prevent simultaneous firing are firing at their maximum rate at the same time.


Not sure if this answers any of our questions though. I'm still looking for an answer as to "WHY" its not allowed. Seems like the creosote answer you gave makes the most sense when applied to wood. But it'd be nice to get an answer from an official source...like a town or code book...maybe even a few examples. Although, I feel we may be grabbing at straws ultimately.
I'm On Fire
 
Hand Fed Coal Stove: DS Machines DS-1600 Hot Air Circulator

Re: New guy with venting questions.

PostBy: CapeCoaler On: Thu Dec 22, 2011 10:00 pm

Canada rule make sense...
Use common sense and you will be fine, but not to 'code'...
Yep, fire would be a good reason to change code...
Everything worked fine before the change...
Bunch of wood burners not cleaning the flue and burning crappy wood...
During an energy crunch...
Who did not do it before...
Would be a problem...
CapeCoaler
 
Stoker Coal Boiler: want AA130
Hand Fed Coal Stove: DS Machine BS#4, Harman MKII, Hitzer 503,...
Coal Size/Type: Pea/Nut/Stove

Re: New guy with venting questions.

PostBy: Bobbart On: Fri Dec 23, 2011 6:49 am

Thanks for the help guys. Hopefullly going to the dealer today to ask a few more questions then I will make my decision on what to get. He sells hitzer, alaska and I think keystoker.
Bobbart
 
Stove/Furnace Make: Hitzer
Stove/Furnace Model: 50-93


Re: New guy with venting questions.

PostBy: Chuck_Steak On: Fri Dec 23, 2011 9:36 pm

The bottom line is that it is against code to vent a solid fuel appliance into the same flue as an oil fired appliance.


Actually in Maine it is not against the code. Exactly.
Several years ago, they changed it, so that it was up to the individual juristictions,
to set the requirements.
More so, to grandfather those that had been doing it.
That alone says that you can do it. Or else they would say you can't, no exceptions..

I've known people that have used one chimney for two fuels
for decades.

Sure... there have been accidents.
But mostly for neglect, or misuse, and not "just becasue" there are two fuels...
There are tons of chimney/house fires every year using just wood.

Wood is one thing, coal is another..
I wouldn't sweat it at all using coal and oil.

Dan
Chuck_Steak
 
Coal Size/Type: mostly nut, sometimes stove, Santa brand
Stove/Furnace Make: Harman
Stove/Furnace Model: Mark III

Re: New guy with venting questions.

PostBy: Discobubba On: Fri Dec 30, 2011 12:26 pm

I'm On Fire wrote:
The National Standard of Canada, Installation Code for Solid-Fuel-Burning Appliances and Equipment, CSA-B365-01 clause 5.2.9 states that:

Two or more appliances shall not be connected to the same chimney flue unless:
a) The appliances are located on the same storey;
b) A negative pressure is maintained at the flue collar of each appliance;
c) Each appliance is provided with a means to control the rate of flow of air or flue gases through the appliance combustion and heat exchanger chambers. Where limitations on flue pressure (draft) are contained in the manufacturer’s instructions, such means shall be capable of maintaining at the flue collar, the pressure specified by the appliance manufacture;

NOTE: For the purpose of this Clause, draft controls include ash pit air control dampers, dampers or draft slides wherever located, over fire and flue key pipe dampers, and check draft controls located on or in the flue pipe.
d) The flue pipes of the appliances are connected to a manifold as close to the chimney as practicable or directly to the chimney in the following order:

(i) If only solid fuel is used, the flue pipe from the smallest appliance shall be on top (downstream);
(ii) If different fuels are used as permitted in Clause 5.2.7, the oil flue pipe shall be on top (downstream); and the solid fuel flue pipe on the bottom (upstream); and
e) The chimney flue is capable of venting the flue gas by natural draft when all appliances not interlocked to prevent simultaneous firing are firing at their maximum rate at the same time.


From all the stuff I've read before I got the impression the flue pipes went the other way around when in these situations. Ex. Oil burner flue below the stove flue. Anyone have any opinion on this particular detail?

As I pointed out in a thread I created before the previous owner of my house had it set up that way but with a wood stove instead. Dunno if he was the one to have the flue put in but it's a few inches above the oil burner one on the opposite side. It's also too close to the ceiling/wood joists in the basement according to code. If the Canadian code above is correct, perhaps I should look into having someone close up the stove flue and relocate BELOW the oil burner one.

Also, I've never noticed a discussion about it on the forum here but has anyone thought about proposing to the NFPA to change their code?
Discobubba
 

Re: New guy with venting questions.

PostBy: I'm On Fire On: Sun Jan 01, 2012 11:02 pm

Discobubba wrote:Also, I've never noticed a discussion about it on the forum here but has anyone thought about proposing to the NFPA to change their code?


I deal with NFPA code a lot at work and from my understanding the only way to get code changed is to be on the board. Just writing a letter to petition for code change is probably not going to help. It's not easy to change NFPA code.
I'm On Fire
 
Hand Fed Coal Stove: DS Machines DS-1600 Hot Air Circulator