Gas Appliance Installation Requirements – This article is being written as a training topic for home inspectors. We will cover what things should look like when gas service is installed at the property with gas appliance in use like water heaters, fire places, etc. Here is an example report for reference throughout this article: REPORT_Gas_Inspection
Let’s start with gas water heaters. Since these are rare to see in South Florida, let’s go over how these should be installed and what issues to look for. In the code diagram shown here you can see many of the requirements, though not all are enforced in every South Florida municipality.
- Make sure there is a flex connector with some slack on it where the gas piping connects to the appliance.
- There should be a drip leg or sediment trap to prevent clogging of the gas valve inside the appliance.
- The gas piping should have an electrical bond wire. Current standards require bonding to be attached to both water pipes and the gas piping in the event that the water piping is metallic.
- The gas venting should have a vent hood that is attached to the top of the water heater and centered over the gas exhaust opening.
- Type B metal ducting should be attached to the vent, should slope only upward, and should have a minimum of 1 inch clearance to any combustible materials. This clearance should be checked in the attic at the roof sheathing and roof framing as well as with insulation and the ceiling drywall.
- You’ll notice strapping to secure the water heater. I always recommend this though this is often not required by municipalities that are not located in an area threatened by earthquakes.
- It is VARY important to check the vent termination over the roof or at the exterior wall. During home inspections, I commonly find this is wrong when gas water heaters are installed in South Florida. This should be a type B vent termination that extends adequately past the roof as shown in the IRC code diagram below. This vent exhaust should not be installed within 3 feet of an operable window or any openings into the home or attic. An improper vent hood can allow back-drafting of carbon monoxide back into the interior. We’ll discuss how you can tell this is happening.
You may run into different types of gas venting that use plastic pipes rather than metal type B flues. In this case the standards in this diagram do not apply. We can discuss direct vent gas appliances and high efficiency gas appliances in a separate article.
Water Heater Example Photo
In the photo to the bottom right you can see a gas water heater installed behind the cabinetry.
What’s wrong with the gas venting?
Gas Furnace Example Photo
In the photo below, What is wrong with this furnace and the drip leg connected to it?
Home Inspection Example Photo
Flex gas connectors cannot be installed through a wall of any kind.
When gas fireplaces are in use, there are ventless gas fireplaces that have no venting by design. However, when a gas log set in installed at a fireplace originally intended for wood burning, check to make sure a clamp is installed on the fireplace damper to prevent completely closing the damper. By doing this a home owner would inadvertently close the gas venting which could result in carbon monoxide poisoning.
Carbon Monoxide detectors
These should ALWAYS be installed in gas service is installed, when there is an attached garage, or when any other fossil fuel burning appliances are installed like a fire place. I recommend to my clients to have these detectors installed in the same room as every fuel burning appliance, near the garage passage door, at each floor level, and in every bedroom. Here are some common CO detectors you may come across. Again, During South Florida home inspections you will notice that these are almost never installed as gas safety requirements are very lax in this area.
A Few More Requirements to Look Out For
- Make sure there is a shutoff valve installed at every gas appliance.
- Make sure fireplace shutoff valves are not installed inside the firebox.
- Make sure approved piping is in use as gas piping and that this piping is properly secured.
- If CSST piping is installed, MAKE SURE there is an electrical bond wire attached to the gas piping. This flex pipe material is highly susceptible to damage and explosion from lightning strikes.
- Note if you see that metal gas piping is installed below grade or in concrete without being properly wrapped. This will require eventual replacement as the iron or steel pipe will eventually rot out.
- If plastic gas pipe is installed underground, confirm there is a copper wire wrapping the pipe for location in the event of digging near the area.
- If a propane tank is installed, there are requirements that it be installed a minimum distance from the home, that it be properly secured and protected from vehicle impact.
- Any gas tanks, meters, or relief valves are required to be a minimum of 3 feet away from electrical panels, AC condensers, and other electrical equipment.
- Last of all, the obvious. Be a-tuned to any odors that would indicate a gas leak. True, near gas relief valves, you will smell gas from time to time; but if you smell gas consistently near any gas piping or appliances, this should be reported so that the gas utility provider can inspect for gas leaks. Some inspectors carry a gas leak detector to attempt and find gas leaks.
Things to Disclaim In The Inspection Report
- Underground gas tanks are not inspected and should be regularly inspected by the propane gas supplier or qualified gas contractor.
- Gas leakage testing or pressure testing is not performed by the home inspector.
- Note the location of the main gas shutoff valve, the propane tank or gas meter, the type of piping, and type of gas appliances.
- Note that the function of CO (carbon monoxide) detectors are not verified and that carbon monoxide leakage testing is not performed.
Well that is my summary of what I am generally looking for when performing a home or commercial inspection where a gas system is involved.
Some Additional Reference Articles to Help in Inspecting Gas Installation During a Home Inspection
- I strongly recommend reading and understanding this article by Carson Dunlop and studying similar information in the Home Reference Guide by Carson Dunlop.
- Gas Pipe Bonding, by Structure Tech
- Gas Appliance Connectors, by Structure Tech
- Where to Look for Gas Leaks, by Structure Tech