Exhaust fan in boiler room.

Jeff Krawic

I have what appears to be an easy question but my knowledge of locations of codes are at a loss on this one. Where can I find the code requirements that specifically state you cannot exhaust a boiler room?? I have a job at 4 buildings for the Air National Guard, where they are doing exzctly this. The contractor involved does not believe me when I explained to him the "bad" way of exhausting the air. Believe it or not, in one of the buildings, he interlocked the exhaust fan with the burner operating controls too! And even uses the proving switch for the EXHAUST to be used as a "Running Interlock" I have to show him in print, the error of his ways and I cant seem to locate it in the BOCA book. Anyone out there that can help???? In the words of the Duke,........ Much Obliged. Jeff Krawic

Uni R

When common sense fails...

I would still be tempted to try and trigger his common sense first, rather than codes. Codes usually don't show the rationale, just the requirements. Obviously, he has his some reason for his thinking (probably concerns over potential emission leakages from the boiler) but once he sees the rationale I'm sure you'll win him over.


Maybe just explain to him how the rooms are fairly tight boxes. When the boilers are running, it exhausts out the flue and has to pull extra air in from outside the box for combustion. When you run the fan, the fan is competing with the boiler for the makeup air and also for the chimney to actually be able to vent outside when the exhaust fan is trying to pull it back down. Hopefully, he will see how that could be catastrophic.

Jeff Krawic

Thanks Uni and believe me,..... common sense to me is NOT common to some others! I believe I am learning its OK to exhaust a boiler room as long as there is "adequate replacement" air provided by any means. (BOCA Article 10, Section M-1000.0) Darn,.......even BOCA doesnt seem to spell out the common sense of exhausting a room with fossile fuel combustion! NFPA ANSI Z223.1 Part5.3.6 states "Operation of exhaust fans, ventillation systems, clothes dryers, or fireplaces may create conditions requiring special attention to avoid unsatisfactory operation of installed gas utilization equipment" Now tell me, does THIS sound even a little vague????? LOL I appreciate the response. Am frustrated at how generic this issue appears to be in writing. I have ALOT to learn!! Thanks again Jeff Krawic

Kal Row

before you jump on him - are the boilers sealed combustion?

if the burner has a fan that takes outside air via it's own pipe and power vents the flu gasses, out another sealed vent then the boiler room air pressure is of no matter

it the boilers are natural draft - measure the draft with the fans on = maybe something was causing too much draft and he is using the fan for balance

but if there really is open flue spillage, then be a good citizen and disable the boilers, let him take you to court, you will win

sometime you just have to explain yourself - had someone with oil smell use a fan with burner – but I made him reveres the fan, and now with plenty of induction air, the whole show no longer smells – and the chimney doesn’t smoke

Jeff Krawic

Nope, I should have been more specific. I am mostly interesated in finding WHERE it is written that a boiler room cannot be exhausted. I am not so sure there is even a code to cover this to be honest. Now as for the jobsite. Burnham V-912 (NOT V-9A) and using PowerFlame burners. It is a pressurized combustion boiler but it is NOT a sealed combustion application where a negative in the room would not affect the operation of the combustion process. Thanks for making me be more specific! Jeff K.

JimGPE_3

Code requirements

IMC 1998 Paragraph 1004.2 requires that the boiler be installed in accordance with the manufacturer's instructions. Check with the manufacturer to see if they prohibit this practice.

1997 UMC paragraph 706 addresses the operation of exhaust systems relative to boiler operation but does not prohibit their simultaneous operation.

Note that the operation of an exhuast fan in the room is not prima facie evidence that someone is going to die. There are lots of ways to operate an exhaust fan and a boiler in the same room, you just need to be very careful.

Jeff Krawic

exhausting learning.. LOL

Huge thanks Jim. I did not even think to check the International Mechanical Code! Burnham as far as I know does not address then issue directly to exhausting a boiler room. For some unknown reason, I have had it stuck in my thick head that it was against code to exhaust a boiler room without make-up equivalent to the exhaust CFM, PLUS combustion air requirements. I am learning that it is probably NOT a written code, but more of a "common sense" issue. Having said that, I thank everyone for their help and between the Carbon Monoxide issues that need to be addressed and the exhausting of combustion rooms, I think there will be a host of new topics to be debated before the writing of the updated codes in our near future. Lets at least HOPE so for the benefit of all humanity. Be safe out there, watch your keister and be well. Jeff Krawic

Joe_30

Is there a combustion air makeup device that has two speeds so that it blows in so much air for the boiler when firing, and so much more when the drier is also on in the same room. And vice versa. And which closes when both are off.? Hmm, maybe just two small fans side by side in through-the-wall tubes , one keyed to boiler, other to drier, independent of each other?

Weezbo

ok so the guys burner has been \"fixed\" \"tuned\"and it Still

Doesnt seem right. the 200 X80 furniture store remanufacturing shop just hates the black smoke and fire that shoots back in the room..."i just had it "Tuned" well, whats up with that? here is whats up with that...they have a small helicopter main rotor in the paint shop....so i make it so when the fan is turned on the furnace shuts off.with a relay. done deal.exhaust What? when the fan previously turned on if the door was left open it would open the metal door at the end of the building ) seems some things blow right by the previous repairmen...really in all fairness how the heck are they supposed to have known that was the reason the burner guy was constantly being called over to fix the thing right this time...?

Pat K

Boiler room venting

At my job we have large commercial/industrial boilers that run on Oil and gas the gas company requires our boiler controls to be interlocked with the exhaust fans.We have large air intakes in the boiler room to provide make up air. This can get chilly in the winter so we have several steam coil type heaters to keep the space warm.

STEVEN MARKS

The system that I have seen most often.
Set of OA dampers open, end swithch on dampers closes allowing fresh air supply fan to start. The boilers are interlocked with fresh air supply fan and will not start until supply fan starts. Reheat coil may or may not be needed.