Jeff Remas Posted December 31, 2008 Report Share Posted December 31, 2008 You are inspecting a 20 year old home that is not considered to be unusually tight construction. The family has recently finished the basment and has framed around the utility area creating a separate, nice size utility/mechanical room of 12'x12' with 8' ceilings. The room has an energy rating and is sealed. All combustion air comes from within the room. In the room is an electric hot water heater and a gas fired hot water boiler for the hot water baseboard. The boiler has a 60,000 BTU input rating and a 52,000 BTU output rating. Is there enough combustion air in the room? Quote Link to comment Share on other sites More sharing options...
exploreparadise2 Posted December 31, 2008 Report Share Posted December 31, 2008 The Fuel Gas Code provides the following calculation when all combustion air must come from a room that does not communicate with another space. G2407.5.1 The minimum required volume shall be 50 cubic feet per 1,000 Btu/h. A 60,000 Btu/h furnace will require 3,000 cubic feet. The volume of that room is 12X12X8=1,152 cu. ft. Quote Link to comment Share on other sites More sharing options...
Jeff Remas Posted December 31, 2008 Author Report Share Posted December 31, 2008 Blair, you are fast and you are good. Have Mike give you a prize! Quote Link to comment Share on other sites More sharing options...
MTL_Inspet_Man Posted January 1, 2009 Report Share Posted January 1, 2009 No ! Quote Link to comment Share on other sites More sharing options...
energy star Posted January 2, 2009 Report Share Posted January 2, 2009 Are you going to get the combustion air from a larger room in the home or from outside? You need so many square inches per 1000 BTU. Quote Link to comment Share on other sites More sharing options...
hausdok Posted January 3, 2009 Report Share Posted January 3, 2009 Originally posted by energy star Are you going to get the combustion air from a larger room in the home or from outside? You need so many square inches per 1000 BTU. Uh huh, see #2 above. OT - OF!!! M. Quote Link to comment Share on other sites More sharing options...
energy star Posted January 3, 2009 Report Share Posted January 3, 2009 That is telling us, yes he needs more combustion air. But, the openings can be of different size if he gets the air from outside or a bigger room in the home. And, is he going to tell the home how many square inches of free air space they need for the furnace in that room? Quote Link to comment Share on other sites More sharing options...
Jeremy Posted January 3, 2009 Report Share Posted January 3, 2009 Originally posted by energy star That is telling us, yes he needs more combustion air. But, the openings can be of different size if he gets the air from outside or a bigger room in the home. And, is he going to tell the home how many square inches of free air space they need for the furnace in that room? A furnace with dimensions of 20w x 22d x 36h would need 440 square inches of space.[^] ?? Quote Link to comment Share on other sites More sharing options...
StevenT Posted January 3, 2009 Report Share Posted January 3, 2009 In the original description it states that the room is sealed. If that is the case, shouldn't you be more concerned with the amount of make up air and not the dimensions of the room? Quote Link to comment Share on other sites More sharing options...
energy star Posted January 3, 2009 Report Share Posted January 3, 2009 That is what I'm saying. Quote Link to comment Share on other sites More sharing options...
Jeremy Posted January 3, 2009 Report Share Posted January 3, 2009 15 square inches. That's 1 square inch per 4000 Btuh. 30 inches if by horizontal ducting. Seems a little drafty doesn't it? Quote Link to comment Share on other sites More sharing options...
hausdok Posted January 3, 2009 Report Share Posted January 3, 2009 Maybe a little discussion about thread etiquette is in order, Energystar, your user name tells us that you probably instantly knew the answer to Jeff's question. It's clear that Jeff knew the answer before he posted the question. I think he was just trying to get someone to think about something we encounter all the time but which many inspectors - private as well as AHJ's as well as HVAC guys - seem to overlook. Anyway, the question wasn't, "If you have a gas burning appliance in a sealed room how must you get sufficient combustion air for it and how big are the necessary openings?" Jeff asked, "Is there enough combustion air in the room?" and the respondent in #2 provided the proper citation for determining whether there is or isn't sufficient volume in a space to provide enough air for combustion and the respondent in #4 ans wed the question more succinctly. If you take what's obviously someone's pop quiz and turn it on it's ear you'll confuse those who don't necessarily understand the question or the answers. Isn't it better to allow the initial poster to guide the thread to the point where the question has been answered to the initial poster's satisfaction before posing the next problem? That way, those inspectors who're brand new to this gig and still trying to apply everything they learned in training to the real world will have the opportunity to exercise that new found knowledge and work it out in their own heads or will pull out their texts and look it up. Jeff, to avoid confusion, so that we experienced hands don't jump in and ruin it, how about announcing it when you're going to be dropping a pop quiz? ONE TEAM - ONE FIGHT!!! Mike Quote Link to comment Share on other sites More sharing options...
Terence McCann Posted January 3, 2009 Report Share Posted January 3, 2009 Perhaps a "New to the business" corner or some such forum addition. BASHI has something akin to it. Quote Link to comment Share on other sites More sharing options...
energy star Posted January 3, 2009 Report Share Posted January 3, 2009 You need a HVAC quiz section. I did not know we would have a pop quiz as such the way that was posted. To me, I thought I needed to complete the answer. I probably don't need to tell you the free square area is different if it's from a larger room in the house or from outside. I will learn the members in here after a while. I never wanted to to step on anyones toes. Quote Link to comment Share on other sites More sharing options...
Jeff Remas Posted January 4, 2009 Author Report Share Posted January 4, 2009 Will do Mike, thanks. Quote Link to comment Share on other sites More sharing options...
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