Hi,
I'm creating a boiler room in the basement.
My 9year old Burnham MPO147 has an optional "fresh air intake kit" (part #611280031 Burnham Air Intake) that consists of a 4" dia metal duct piped to the burner. The intent, I understand, is to continue this 4" dia duct (i.e. a rigid metal clothes dryer duct) to the outside. In my case, I would want to go 6ft up, 90degree turn, and 15ft horizontal to an exterior wall (that I know is not prone to snow drifts).
But, if I look at the New York State building code:
http://www2.iccsafe.org/states/new_york/NY_Residential/PDFs/Chapter 17.pdf
. under combustion air, Section M1703.2.1 says:
"When communicating with the outdoors by means of vertical ducts, each opening shall have a free area of at least 1 square inch per 4,000 BTU/hr .... [and where] horizontal ducts are used, each opening shall have a free area of at least 1 square inche per 2,000 BTU/hr...."
The MPO147 = 147,000BTU/hr.
So, the manufacturer is suggesting that a 4" duct is sufficient, but the code is saying I'd need a [147,000/2,000 = 73.5; sqrt(73.5*4/3.14) =10"] 10" dia duct.
A couple of questions:
1. Which duct sizing method is appropriate?? Seems to contradict eachother.
2. If I choose to skip the outdoor air intake, and just leave a louvered vent into the main basement room, the same code says I must provide 1" per 1,000BTU/hr for a vent at the bottom, and top, of the wall. That's roughly 12"x12" square openings at bottom and top of my wall. But... I just spent effort to put up 5/8" fire rated sheetrock and a fire rated door in order to be code-compliant. I truly understand the need for combustion air, but aren't these vents negating all my required fireproofing efforts? Is this seemingly obvious contradiction just something we all accept?
3. Fire rated doors come in several hourly ratings. How do I know which to choose?
Thanks
Theodore
I'm creating a boiler room in the basement.
My 9year old Burnham MPO147 has an optional "fresh air intake kit" (part #611280031 Burnham Air Intake) that consists of a 4" dia metal duct piped to the burner. The intent, I understand, is to continue this 4" dia duct (i.e. a rigid metal clothes dryer duct) to the outside. In my case, I would want to go 6ft up, 90degree turn, and 15ft horizontal to an exterior wall (that I know is not prone to snow drifts).
But, if I look at the New York State building code:
http://www2.iccsafe.org/states/new_york/NY_Residential/PDFs/Chapter 17.pdf
. under combustion air, Section M1703.2.1 says:
"When communicating with the outdoors by means of vertical ducts, each opening shall have a free area of at least 1 square inch per 4,000 BTU/hr .... [and where] horizontal ducts are used, each opening shall have a free area of at least 1 square inche per 2,000 BTU/hr...."
The MPO147 = 147,000BTU/hr.
So, the manufacturer is suggesting that a 4" duct is sufficient, but the code is saying I'd need a [147,000/2,000 = 73.5; sqrt(73.5*4/3.14) =10"] 10" dia duct.
A couple of questions:
1. Which duct sizing method is appropriate?? Seems to contradict eachother.
2. If I choose to skip the outdoor air intake, and just leave a louvered vent into the main basement room, the same code says I must provide 1" per 1,000BTU/hr for a vent at the bottom, and top, of the wall. That's roughly 12"x12" square openings at bottom and top of my wall. But... I just spent effort to put up 5/8" fire rated sheetrock and a fire rated door in order to be code-compliant. I truly understand the need for combustion air, but aren't these vents negating all my required fireproofing efforts? Is this seemingly obvious contradiction just something we all accept?
3. Fire rated doors come in several hourly ratings. How do I know which to choose?
Thanks
Theodore
Last edited:
