View Full Version : Inspector Says Bad Installation

J Love
11-14-2007, 03:28 PM
I have a brand new installation of a high-efficiency, upflow, natural gas furnace in my garage that is attached to my house.

The inspector says that I have to have it elevated 18" above the floor.

My furnace guy (consultant, I do most work myself) has told me that the inspector is wrong and because all of the ignition and burner areas are 30+inches above the floor, that I don't need to worry about it.

The inspector calls the wiring connections and switches and the electrical connections that the fan connect to "ignition sources" and says that THEY need to be 18" above the floor.

My permits use the 1997 UMC because they're old (I got them in '03).
SECTION 303.1.3
"ELEVATION OF IGNITION SOURCE: Equipment which has a flame, generates a spark or uses a glowing ignition source open to the space in whidh it is installed shall be elevated such that the source of ignition is at least 18 inches above the floor..."

The inspector quoted the 2006 UMC because that's what he had in his truck:
"ELEVATION OF IGNITION SOURCE: Equipment and appliances having an ignition source and located in hazardous locations and public garages, private garages...shall be elevated such that the source of ignition is not less than 18 inches above the floor surface on which the equipment...rests"

In the 1997 UMC there is NO definition for "ignition source" and it's worded in such a fashion that I read that "ignition source" means the place where the furnace ignites the gas in the course of operation.

In the 2006 UMC there IS a definition:
"IGNITION SOURCE: A flame, spark or hot surface capable of igniting flammable vapors or fumes. Such sources include appliance burners, burner ignitors and electrical switching devices"

Is the inspector right? If not, how do I contest this? If so, why does the HVAC guy say that he's installed 'hundreds of them' like that with no problems?

Thanks, everyone, for your opinions on this subject. I'm likely going to go to the city and argue this one.

To see my furnace pictures, look here:
--some are sideways pics online and they're big files--




Thank you very much.


11-14-2007, 04:09 PM
First, the inspector is ALWAYS right.
Second, in my experience, an electrical switch, like a thermostat on an electric WH, has been considered an ignition source.
Third, the inspector is ALWAYS right.

11-14-2007, 05:08 PM
I just wanted to add that the inspector is always right. They get to interpret code and arguing can be functionally equivalent to using only biological resources to wet a rope to a few feet off the floor. Generally speaking you do not want to annoy the inspector.

Switches cause sparks and are an ignition source unless they are specifically rated for use in an explosive atmosphere.

Connectors in the steady state do not usually make sparks; although a faulty connector could do so. One personal experience is a microwave oven I have. 10+ years old and it suddenly failed. The source of failure was a melted interlock microswitch. It melted because the assembler did not properly insert the insulated spade connector. Instead of going over the matching terminal post it went to the side. The heat from years of sparking and burning finally melted the switch. Disregarding this problem (and code tends not to disregard even low probability issues) if you connect or disconnect a powered connection when an explosive atmosphere is present, they can spark and make an annoying whole house bang.

The fuel source they are addressing here is gasoline vapors in the garage. Natural gas will go up. If you have LP, that will go down and be the same problem as gasoline vapor. You may not like it, and sometimes it is hard to understand why codes require what they do, but this actually is a fairly reasonable requirement. Newer gas hot water heaters are equipped with a flame front barrier to eliminate this problem in these devices that do not use electrical power.

J Love
11-28-2010, 09:15 AM
OK, here's what happened: The inspector showed me the code book and he was right (a sure surprise to those who posted replies above).
However, the code which was in place when my permits were issued (the previous year), the verbiage was not a clear and I argued that and he agreed.
So, I was able to leave the installation as is and have him sign off on it. Yay!

11-28-2010, 09:26 AM
Thanks for follow up on the three year old thread! Around here, as for water heaters, although they accept the FVIR as not requiring elevation, they use another section of the building code requiring a water heater to be protected from being bumped by the cars, and you can do that with bollards....or by leaving it elevated!