Thread: Furnace in Garage

The furnace and WH heaters were installed in the garage (yes two water heaters one gas and one eletric tied together... don't ask... nobody knows). I know the gas WH needs to be lifted of the floor... I also know there are thickness requirements about the sheet metal used for the ducts in the garage and no supply/return openings, etc. But what about the furnace itself ('94 Trane - Metal Flue)? I personally think this is a terrible place for a furnace... I think enclosing this area with an access door would be the best option, but not sure if necessary. Opinions?

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That electric water heater needs to be off the floor as well. Also the furnace needs to be off the floor and protected with bollards. If you enclose the furnace you have to worry about makeup air.

David, not familiar with bollards.... could you elaborate?

Bollards are generally metal poles/pipes located in front of the furnace and/or water heater when the appliances are in direct line with a vehicle. Intended to protect the appliances from damage.

90% of the newer houses I inspect have furnaces in the garage... there's nothing wrong with it. I think the thickness of steel required is 26 gauge. And, you're right, no openings into the garage. Also, check the fire taping/sealant around the ductwork... it's almost always missing somewhere. As for recommending they build an enclosure around it.... no codes or common practices to support you.

Some gas and some electric water heaters need to be elevated... not all.

A bollard is a post to keep a car from driving into mechanical equipment, usually gas appliances/piping or an electric meter.

Andrew I don't know how long you have been inspecting homes. It is very common to install the furnace and water heater in the garage. Most new homes in my area put the water heater and furnace in the garage 90% of the time. If you recommend enclosing the furnace you will look like a fool in my opinion. If the furnace and water heater are in direct path of the vehicle a pipe bollard will need to be installed. Also water heaters may need to be 18" off ground. However not all types of water heaters need to be raised off ground. Some do not need to be raised. Check with local codes and water heater manufacture info.

Originally Posted by Trent Tarter

Also water heaters may need to be 18" off ground.

Gunnar's drawing also shows it incorrectly.

The water heater does not need to be 18" above the floor, the source of ignition does.

The source of ignition on gas appliances would be the lowest pilot, flame, or igniter, and on electric water heater the lowest source of ignition is typically the bottom element as the bottom element thermostat is above it.

Originally Posted by Jerry Peck

Gunnar's drawing also shows it incorrectly. The water heater does not need to be 18" above the floor, the source of ignition does. The source of ignition on gas appliances would be the lowest pilot, flame, or igniter, and on electric water heater the lowest source of ignition is typically the bottom element as the bottom element thermostat is above it.

Yeah, the strap is incorrect as well. I think I stole this pic from someone on this site. However, in my opinion, constructing the platform 18" above the floor leaves no margin for error and less chance for an argument with a building inspector.

Andrew:

If there is a metal vent (connector); it needs to be a 'B' vent. A garage is an unconditioned space.

Jerry:

Couldn't a blower motor be considered a source of ignition?

Originally Posted by Darren Miller

Jerry:

Couldn't a blower motor be considered a source of ignition?

You mean a blower on a furnace? Yes, but how many are mounted down within 18" of the floor?

Also a receptacle mounted down low for a hot water circulation pump, we've all seen burned and arced receptacles and plugs.

Not sure about the hot water circulation pump itself, probably yes now that I think about it (I've found a few which were within 18" but didn't think about them - usually the motors are higher with the receptacles being lower, also, don't forget that those receptacles require GFCI protection when lower than 6'8" above the floor.

Another problem with furnaces/AHU installed in the garage is the return air filter location/intended location in the unit itself - those doors/covers are not sealed and allow air from the garage to be drawn into the return air stream, which is not only 'not a good thing', but is specifically prohibited by code). *ALL* opening, seams, joints, duct connections, etc., to the furnace/AHU require sealing and taping to make sure the garage air does not get drawn into the air stream.

In my opinion, it is 'just dumb' to install a furnace/AHU in a garage. Code does not address 'just dumb' things.

Here is a picture of a bollard,this should help. And yes, I should of said not all water heaters need to be above the floor. not sure where I got photos from.

David,

Your first photo shows the right way to do a bollard, your second photo shows the wrong way to do it.

but Jerry it's got duct tape

Originally Posted by Jerry Peck

David,

Your first photo shows the right way to do a bollard, your second photo shows the wrong way to do it.

Why?

There is no pan under the left one. Is that why it is wrong?

Does the bollard have to be embedded into the concrete as gunner's(post#4) illustration shows and not bolted to the floor?

Originally Posted by David O'Keefe

Does the bollard have to be embedded into the concrete as gunner's(post#4) illustration shows and not bolted to the floor?

It should be, yes.

Many are posts with flat mounting plates and anchored with concrete fasteners (Tapcons, etc.) and they will not resist much force before pulling out and tipping out.

The steel posts should also be filled with concrete.

Used to be in the code but was lost when the codes went to the ICC, now it is up to the engineer.

Those are intended to stop the car from hitting the water, those bolted down ones will not do a very good job of that if the car is going faster than you can push it. I've seen some embedded and concrete filled bollard bent, someone hit those things with quite a bit of force, if those had been the Tapcon anchored ones they would have just tipped right over.

The one on the right is incorrect. They are supposed to be embedded into and filled with concrete, not hollow and bolted down.

Thanks for the education. I won't be using that photo anymore. Unless I'm trying to show how not to do it!

Ya'lls eyes are better than mine. I could not tell from the pic that that was a hollow post and I could not tell if there were bolts in that flange.

Originally Posted by Richard Stanley

I could not tell if there were bolts in that flange.

Of course you could not see the bolts, the duct tape is covering them.

Originally Posted by Wayne Price

The one on the right is incorrect. They are supposed to be embedded into and filled with concrete, not hollow and bolted down.

Originally Posted by Jerry Peck

The steel posts should also be filled with concrete.

Used to be in the code but was lost when the codes went to the ICC, now it is up to the engineer.

Wayne,

Do you have a current code reference for that? I know it used to be in the old SBCCI Building Code (I think that is where it was) but do not recall seeing it in the ICC codes.

Would be nice to have 'official documentation' support that, otherwise I just get accused of it being 'Jerry's Code'. Really, though, it is in this code ... the code of 'common sense'.

A friend at the local building office told me my area doesn't require them to be filled with cement so there is likely some variation there.

As for them being anchored versus poured into the cement.... I didn't realize they were meant to stop the car. I thought it was just supposed to be a warning device as you were arriving home

Greetings from COSA, the CARBON MONOXIDE SAFETY ASSOCIATION
Phone 1-800-394-5253 Website: The Carbon Monoxide Safety Assoc

I realize most of you as inspectors are followers of the codes adopted in your area and I viewed several good postings on having code support, common sense and your ideas.
Code (in whatever code model is adopted in your areas) does not necessarily address performance based or tested installations. Some code models are more intune with the mechanical function than others, and sometimes there are conflicts in differenct or changing code models. Officials may of maynot have practical experience in all area.
Yet testing for potential problems is rarely done on each installation. (like whole house testing under load conditions) however it is becoming more practiced and validated, more inspection professionals are doing it.
Furnaces (and Water Heaters) in Garages and other locations that cause concern, as well crawl spaces and attics present problematic installation concerns. Even when allowed (code) and building practices are accepted, potential problems are often missed due to lack of testing.
Good points about ignition sources and code location allowances of them.
Ductwork in the Garage space and sealing seams and air leakage areas.
Type of Venting material allowed in unconditioned spaces. B-venting of gas fired appliaces becomes a requirement where temperatures
below 37 degree F. are possible. B-vent has about twice the heat retention of single wall material.
I also had to review bollards, the same type item used to protect gas meters in driveway, alley and other motor travelled paths.

Since the installations of fuel burning applainces is allowed in residentail garages, and seem to be widely accepted as what you are indicating what is being allowed in many area, I will refrain from getting into the "how dumb is this" type of reply.
But, I will add that open combustion flames present a hazard for combustion gases and by-products (Carbon Monoxide for one) to reach the inhabitants of the dwelling you are inspecting. Forced air furnaces and other Air Handlers that have ductwork in garages can be the pathway to draw in these hazards.
Further, the 18" above the floor rules are an attempt keep vapor (gases) released from flamable liquids like gasoline away from ignition sources.
Last, combustion systems that use air from inside buildings vs. outside the building envelope for combustion are less ideal. Rather ones using a sealed combustion systems design or isolation of the appliances for these residental applications, would be a much better, and safer practice.

Some practices that codes allow are changed because we learn they don't work as well as once perscirbed. Solutions are often the result of you asking Why are we allowing it.

Let me know if our group can be of further help,
Ken Kimball, COSA - Director of Operations
Carbon Monoxide Safety Association The Carbon Monoxide Safety Assoc

I can be reached at directly at 605-393-8368 or kenkimball@coafety.org

Both the furnace and hot water heater need to be protected from low lying flammable gas vapors. One way to do this is to raise the water heater and furnace eighteen inches off the garage floor. A second way to to accomplish this would be to build a wall around the furnace and water heater in order to kepp flammible gas vapors from reaching the burners. The existing condition that you speak of is unsafe and must be corrected. I see this problem on occasion in New Jersey but its not too common. Maybe I see it every fifty inspections or so. Good call on the problem. New Jersey Home Inspector - NJ Home inspections by LookSmart Home Inspections, LLC - John Martino, Licensed Home Inspector in NJ Rockaway, NJ 07866

Actually John, your second option is incorrect:

"Appliances having an ignition source shall be elevated such that the source of ignition is not less than 18 inches (457mm) above the floor in garages. For the purpose of this section, rooms or spaces that are not part of the living space of a dwelling unit and that communicate with a private garage through openings shall be considered to be part of the garage." M1307.3 of the 2006 IRC mechanical code.

Actually, the first option is not entirely correct, either. It's worth repeating: The source of combustion should be 18" off the floor. I see gas warm air furnaces installed directly on the garage floor. The BURNERS are already 18" off the floor, by design.

Neal:

According to the 2006 IRC- Ignition Source- 'A flame, spark, or hot surface capable of igniting flammable vapors or fumes. Such sources include appliance burners, burners ignitions and electrical switching devices.'

There is room for debate, but a blower motor could be considered an ignition source. The blower compartment is 'usually' the lowest part of the furnace.

Originally Posted by Darren Miller

There is room for debate, but a blower motor could be considered an ignition source. The blower compartment is 'usually' the lowest part of the furnace.

I and many others would consider it as such, but ... at what height is it already above the garage floor ... 9" or so?

If so, then "the furnace" only needs to be raised the rest of the way to achieve the 18".

*ANYTHING* than can arc or spark (or is hot or has an open flame) can be considered an "ignition source".

If the homeowner brings it in, not much we can do about it - besides, when the homeowner (i.e., "seller") moves, they take that with them, but ... if it is a 'built-in' item, it should be on the report. It also would not hurt to mention the homeowners items in your report to clue them in ... such things as ... my air compressor in our garage is on the floor, with the motor within an inch or two of the floor, and it cycles on by itself ... the refrigerator we have in our garage ... things like that.

Here's a picture of a single wall vent I found last week in an attic; same conditions apply to a garage.