Mass gas code question

Mechanic

How many cubic feet must boiler room be per 1000 btus?
thanks

Nick L. in Vt

up here

beleive it's 50 per 1000 but i don't have my nfpa 54 in the house. buried under all my crap in van, sorry


They call me "Hot Pipe"

Mitch_6

50 cubic feet per 1,000 btu

but when you try to get air from other areas with grills and ducts the formulas have changed a little.

I just put in a fan in the can when ever I can.

Mitch S.

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Brad White_9

The 50 CF per 1,000 BTU's Rule

addresses the volume of contiguous space for purposes of taking all combustion air from indoors, not necessarily the volume of the boiler room itself. (Boilers can be installed in closets which illustrates this. Otherwise a 100 MBH boiler would need a 25' x 25' x 8 ' high room. There goes the rumpus room

Key to this is that you have sufficient louver area high and low between the enclosure and the contiguous area. One square inch per 1,000 BTUH input for all appliances in the enclosure, IIRC.

[EDIT: I consider the product of that equation to stand for EACH louver. For example if I need 40 square inches, I specify 40 Sq. in. high and 40 Sq. in. low.]

There is a presumption that the house is not too tight and has leakage of at least 0.40 ACH (again, IIRC).

By illustration of this, you could not have a boiler/furnace/water heater in a closet if such could be isolated by a door from the greater volume of the house, if closing that door reduced the near-appliance volume below the 50 CF/1,000 BTUH rule. Nor can you take combustion air from a bedroom which you already know.

Massachussetts recognizes and adopted NFPA-54/ANSI Z223.1 with certain modifications, none of which change the combustion air requirements.

As Mitch (and Martha Stewart) says, A Fan in a Can is 'a good thing'.

Hope this helps-
Brad

Nick L. in Vt

fannies in a can

i really dislike finding fannies that were never wired in series with burner. fannie fails, burner still runs and sooty hilariousness ensues.



They call me "Hot Pipe"

J.C.A._3

Brads got it !

The boiler clearences are listed in the I and O manual. The required air for combustion is what you're looking for, and what all other answers addressed.(1 sq. in/1000btu)

Depending on the inspector and or town, they seem to find it different for some reason. (one wants the total area split high and low, one wants it directly from the outside, another may not even check!)

Be safe and go above and beyond the stated code. Too much air for a boiler room is NEVER a bad thing IMHO.(fan in a can, GOOD IF needed,just another thing to break if it's not!) Chris

Mechanic

Thank you

Exactly what I needed thanks.