Combustion Air and the IFGC

[jar546]

We saw this all the time when people finished their basement.

You're tasked with ensuring compliance with the International Fuel Gas Code (IFGC) for a residential basement where a 120,000 BTU boiler is installed. Initially, the basement met the code's combustion air requirements. However, after a remodeling project, the available space has been reduced.

Question:

1. Calculate the compliant cubic feet of indoor air required for the original 120,000 BTU boiler installation, based on the IFGC standard method (304.5.1).
2. After the remodeling, the available space has been reduced to 400 cubic feet. Does this reduced space meet the compliance requirements for the 120,000 BTU boiler, based on the IFGC? If not, explain why and discuss potential solutions to ensure compliance.

 

[klarenbeek]

Not even close to compliant. 6000 cubic feet of space is required. 400 cubic feet is only good for 8,000 BTU. Options are either:
1. Transfer openings to a space with minimum 5600 cubic feet (for the additional 112,000 BTU). If connecting a space on the same level, one high opening and one low opening, each with a free area of 112 square inches. If connecting to a space on a different level, one opening with 224 square inches of free area. IFGC 304.5. This would work only if you don't access the boiler room through a bedroom or bathroom.
2. Outdoor combustion air in accordance with IFGC 304.6. Best option in a basement would probably be one opening of minimum 37.3 square inches free for the remaining 112 BTU (3000 BTU/ sq. inch).
3. A combination of the two above methods. IFGC 304.7
4. mechanical combustion air interlocked with the boiler including a failsafe safety of minimum 42 CFM. IFGC 304.9.

Frankly, if the boiler is getting older, the best option would be upgrade to a high efficient direct vent boiler, eliminating the need for additional combustion air.

 

[jar546]

Not even close to compliant. 6000 cubic feet of space is required. 400 cubic feet is only good for 8,000 BTU. Options are either:
1. Transfer openings to a space with minimum 5600 cubic feet (for the additional 112,000 BTU). If connecting a space on the same level, one high opening and one low opening, each with a free area of 112 square inches. If connecting to a space on a different level, one opening with 224 square inches of free area. IFGC 304.5. This would work only if you don't access the boiler room through a bedroom or bathroom.
2. Outdoor combustion air in accordance with IFGC 304.6. Best option in a basement would probably be one opening of minimum 37.3 square inches free for the remaining 112 BTU (3000 BTU/ sq. inch).
3. A combination of the two above methods. IFGC 304.7
4. mechanical combustion air interlocked with the boiler including a failsafe safety of minimum 42 CFM. IFGC 304.9.

Frankly, if the boiler is getting older, the best option would be upgrade to a high efficient direct vent boiler, eliminating the need for additional combustion air.

This happened all the time in Pennsylvania. They needed to add outside combustion air.

 

[steveray]

There used to be a great free online calculator for volume of combustion air called house of craig that is gone now....Anyone have one or a link they can share?

 

[jar546]

There used to be a great free online calculator for volume of combustion air called house of craig that is gone now....Anyone have one or a link they can share?

I use these for accuracy and they work wonders:

 

[steveray]

I use these for accuracy and they work wonders:

View attachment 12093View attachment 12094View attachment 12095View attachment 12096

I get it, but this one all you had to do was plug in the input BTU's and it would give you the areas with I think 3 different ceiling heights you would need and the openings to adjacent spaces....Something I could do in 5 seconds and I could get customers to use it which really saved time...It's not about ability, it's about time....

 

[klarenbeek]

L x W x H x 20 will give you how many BTU the space is good for.