Appliance Red Tagging

Wanted to get some other thoughts out there about red tagging appliances. Occasionally we come across stoves that either gas is detected while the oven is running or the CO is higher than the 009 PPM allowable standard, or leaks from water heaters/boilers/furnaces. Our company’s thought is to start red tagging these appliances if the levels are higher than the industry standard. We understand they essentially hold no authoritative weight but for awareness about the appliance, more so informing the homeowner/real estate agent about the gas detected. On the red tag we would identify who we contacted about the leak and our contact info. Just looking if this new practice for us would be worth it, if anyone out there does this or if there is a better way?

Thanks in advance,
Rob Bishop, CMI

What do you mean? You would contact someone other than the homeowner?

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For our area and per the local gas/energy company, they want to be notified anytime we detect CO over 009 anywhere in the home or if gas is detected anywhere along the gas line or the appliance. We would also anyone know who could be effected (tenant, family member etc.)

Cool…who are you going to contact when the pool is not properly bonded, the smoke detector battery has expired, the oven service wire is undersized, the water heater is too hot, the top stair is broken, the light switch cover is missing, the spa tub is not GFCI protected, the gas fireplace damper does not have a damper block, the deck ledger board is rotted?


I presume you are implying that if we red tag and notify about the gases then why stop there and tag/notify about other safety defects?

How the hell long are you operating those ovens??!!!


You got it. I think your intentions are honorable. Just where does it begin and end? And, where does the increased liability for you end and begin? Would it be “gross negligence” to notify the impending doom of a bad oven and ignore 10 other safety issues?


At the end of the inspection I leave a notice thanking the homeowner for allowing me entry into their home. On that notice I have wording and space for listing any important safety issues found. I leave that on the kitchen counter AND take a picture of it on the way out. Obviously these are noted in the report as well. What the owner does is on them as I can’t force them to do anything.

Beyond that I don’t raise alarming red flags unless the condition is so significant neither I nor anyone else should even be near it. That’s only happened twice in my almost 20 years. One was a major gas leak and the owner was there during the inspection and was very grateful for bringing it to their attention and they did verify it. We both left the home and he called 911 immediately. The other was a repo so filled with mold, growths, human bodily fluids including blood (terminally ill person’s last stand) there was NWIH I was going to walk around inside with all of that going on. On that one I politely told both the client (an investor), their REA and the seller’s REA I had stopped the inspection and why. No idea what happened on that one and don’t really give a damn either! We don’t get paid enough to contract something nasty!!


I really like the idea of leaving the note for the homeowner, thank you for that Emmanuel!


Very good point that I didn’t consider, thank you for your feedback Brian. Liability is king!

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IMO that would be appropriate.

Dear Home Owner, I did come across a few safety issues and this one really stood out to me because it is (invisible, hidden, especially egregious, etc.) I am notifying you as a courtesy because I want everyone to be safe and sound. I hope you have the opportunity to address this problem right away. Thank you for the privilege to inspect your home.

Kind regards,


Since you are ignoring my previous post, perhaps you would care to elaborate on where the hell you get your “standards” from… BEFORE an inexperienced inspector gets his ass in legal trouble!??

Carbon Monoxide Poisoning: Gas-fired Kitchen Ranges (AEN-205) - Department of Agricultural and Biosystems Engineering.

Was the entire room at that level, or simply what your tester reached at the range/oven itself??


Yup, who set the this 009 standard on a range? Not going to happen based on the information you have provided.

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According to Building Performance Institute standards, building CO should not be above 9ppm. The time for alarm, by BPI standards, is 35ppm in the building air. You need to leave at that time. This is different than appliance CO levels.

You need to use a CO measuring device that has a readout and alarm. Home CO devices won’t meet that need.

Above 9ppm will pass if you test the air above the range burners. 100ppm generally is the CO level of concerned, measuring undiluted exhaust gasses. You need a diffeerent device to measure undiluted gasses.

BPI has a Combustion Appliance Zone Test work/flow sheet that has those levels for various appliances and flue configurations. Measuring at the appliance can give you readings above 9ppm, but still meet BPI standards.

Personally, I watch for that 9ppm and 35ppm CO level in building air. Red flagging; that’s an issue you need to research more. Follow up with Combustion Appliance Zone (CAZ) test videos and training. BPI training/certification will be very beneficial for understanding when to call this issue out.

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Let me apologize for not writing you sooner Jeffery, I wasn’t simply ignoring you. To be honest I am trying to track that down now where we got the 009 PPM standard from. It has been company policy for quite some time and I know two local plumbing/HVAC companies use that standard. We test by running the stove for 30 minutes leaving our detector in the kitchen, typically across the room from the stove, with the vent on. If we detect an average of 009 PPM during that duration we recommend the appliance get serviced. Do you test for CO from stoves? If so what are your testing parameters and allowable CO levels?

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That’s probably a good procedure and recommendation. You’ll catch a range that probably needs service.

Thank you for directing me to the BPI; for everyone this is what I found…

ANSI/BPI-1200-S-2017 Standard Practice for Basic Analysis of Buildings If the CO instrument indicates an ambient CO level of 70 ppm or greater, the
auditor shall immediately terminate the inspection and notify the
homeowner/occupant of the need for all building occupants to evacuate the
building. The auditor shall immediately leave the building and the
appropriate emergency services shall be notified from outside the home. If the CO instrument indicates an ambient CO reading in the range of 36
ppm-69 ppm, the auditor shall advise the homeowner/occupant that
elevated levels of ambient CO have been detected. Windows and doors
shall be opened. The auditor shall recommend that all possible sources of
CO be turned off immediately. Where it appears that the source of CO is a
permanently installed appliance, the auditor shall recommend that the
appliance be turned off and the homeowner/occupant shall be advised to
contact a qualified professional. If the CO instrument indicates an ambient CO reading in the range of 9 ppm35 ppm, the auditor shall advise the homeowner/occupant that CO has been
detected and recommend that all possible sources of CO be checked and
windows and doors opened. Where it appears that the source of CO is a
permanently installed appliance, the homeowner/occupant shall be advised
to contact a qualified professional.

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There must be more. Help me fill in the blanks. What conditions? All appliances running, All burners on and the stove, none running, all running with all exhaust running, windows open, windows closed?

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That particular section only addresses “ambient” building/home air. There is another section that specifically address measuring the CO in the flue/ventilation method which is way beyond what we would do. I can’t find anything in InterNACHI relating to this specifically, unless someone could direct me to it? I guess bottom line is we are testing for high levels of CO in the kitchen that someone could be exposed to when cooking. At the end of the day we are simply suggesting the stove get serviced. Would be good if the InterNACHI moderators might we able to weigh in??

Building air is one thing, as Robert aptly quoted. This primarily is inspector safety, occupant safety. BPI doesn’t specify more than just that in this standard, building air. It covers all the conditions you mentioned, all/one appliance operating, windows closed/open. It also means if a home CO alarm sounds, you leave the home now.

The other is undiluted combustion gas CO levels. That’s the real test of proper appliance combustion. BPI Building Analyst training includes this testing. It’s a separate standard from building air.

I think his agency is trying to create a simple way to detect possible appliance CO issues, using 9ppm as their alert level. As a home inspector, I make sure to emphasize CO alarm presence and placement.

As an edit; I also make sure to be aware of back drafting. A tight house also has concerns, especially if there are two bath fans, a vented range hood, a dryer. Down draft range vents are always an issue. There are depressurization limits for various combustion appliances. A gas fireplace can often be a hazard, as can a wood fireplace, even with outside combustion air source. It gets complicated and NACHI doesn’t have training in the nuiances of these issues. It’s outside the SOp, but can be a worse case safety issue.

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