Gas oven carbon monoxide - InspectionNews

Linda Swearingen · #1 (**permalink**) 10-30-2009, 07:27 AM

It seems like gas ovens all discharge carbon monoxide (except the ones with automatic vent fans to the outside, which isn't many). Is there any sort of industry standard as to how much is too much? I realize that they can't burn 100% until they warm up some, but I've seen some that don't back down to under 8 or 10 ppm, and a few that were so high (200+ppm) that they are absolutely unsafe to operate as they are. But where do we draw the line?

John Dirks Jr · #2 (**permalink**) 10-30-2009, 09:28 AM

I always recommend that CO detectors be installed whenever any fossil fuels are used in a home.

If for whatever reason the CO levels get high enough to present a hazard, the alarm should warn the occupants.

.

Bob Harper · #3 (**permalink**) 10-30-2009, 12:10 PM

ANSI Stds. allowd for up to 800ppm from gas ovens. Any you just thought it was the tryptophan from the turkey making you sleepy at Thanksgiving.....

John, the operative words in your post were "should" warn and "high enough to present a hazard".

Present stock off the shelf CO alarms listed to UL 2034 are proven unreliable at best. So much for the *should* part. They are designed to ignore levels under 70ppm leaving you exposed. They even state on their packaging if you are elderly, have small infants or children or certain medical conditions, you may need "additional protection". So why am I buying this piece of junk in the first place?

There are two low level CO monitors on the market that are reliable and provide adequate protection, thus they are NOT listed to UL 2034 for single station monitors or UL 2075 for central station monitoring (which use the same alert levels): The CO Experts and the NSI 3000.

Try this test: crack the door to the oven then set to 'broil' and monitor CO. All that cool room air rushing into the top of the heat spreader plate will cool the gases causing CO formation. You can also demonstrate the effects on a range top with a pot of cold water.

yes, ovens and ranges *should* be ventilated but unfortunately they don't *have* to be.

Bob

DavidR · #4 (**permalink**) 10-30-2009, 04:16 PM

Quote:

Originally Posted by Bob Harper

yes, ovens and ranges *should* be ventilated but unfortunately they don't *have* to be.

Bob

They should be banned IMHO.

No place for them in any type of construction anymore.

Gunnar Alquist · #5 (**permalink**) 10-30-2009, 04:34 PM

Quote:

Originally Posted by DavidR

They should be banned IMHO. No place for them in any type of construction anymore.

David,

Ummm... ovens and ranges? How are we supposed to cook?

DavidR · #6 (**permalink**) 10-30-2009, 04:48 PM

Quote:

Originally Posted by Gunnar Alquist

David,

Ummm... ovens and ranges? How are we supposed to cook?

I get by just fine on electric.

Rick Hurst · #7 (**permalink**) 10-30-2009, 06:03 PM

A true Chef or someone who really enjoys cooking knows that gas is the only way to cook.

rick

Gunnar Alquist · #8 (**permalink**) 10-30-2009, 06:12 PM

Quote:

Originally Posted by Rick Hurst

A true Chef or someone who really enjoys cooking knows that gas is the only way to cook.

Right On! Ban the electric wimps!

Dennis Krouse · #9 (**permalink**) 10-31-2009, 06:23 AM

Thank you Rick and Gunnar. I couldn't agree more!

Rick Cantrell · #10 (**permalink**) 10-31-2009, 06:56 AM

Bob
It has been years since I read up on CO detectors, so my opinions are likely to be out of date.
My understanding of CO detectors is that they are unreliable, and pretty much useless in the home, even the professionally installed type that I have access to. I don't recommend them.
You said "There are two low level CO monitors on the market that are reliable and provide adequate protection".
Which two?

Thanks

DavidR · #11 (**permalink**) 10-31-2009, 07:26 AM

So you guys that use gas have made sure your ovens are operating safely and have low level CO monitors installed?

If they are vented and operating safely not a problem, otherwise I fail to see why you would want one in a building.

A real chef uses an open flame but I don't bring that inside either.

Bob Harper · #12 (**permalink**) 10-31-2009, 08:27 AM

Quote:

Originally Posted by Rick Cantrell

Bob
It has been years since I read up on CO detectors, so my opinions are likely to be out of date.
My understanding of CO detectors is that they are unreliable, and pretty much useless in the home, even the professionally installed type that I have access to. I don't recommend them.
You said "There are two low level CO monitors on the market that are reliable and provide adequate protection".
Which two?

Thanks

Rick, finish my sentence. Both I refer to ARE very reliable, unlike the listed alarms and they do alert at low levels unlike listed alarms. The NSI 3000 is available only if you take Day 1 of the NCI Co & Combustion Course. You can buy the CO Experts online from George Kerr.

Guys, understand where DavidR is coming from. Aside from teaching the NCI CO & Combustion course, he is a practicing professional HVAC tech who does check gas ovens so he knows first hand what he's talking about. I've tested a few dozen and found CO issues to one degree or another with all. Understand the ventilation is needed on electric ranges and ovens as well. The aerosolized food particles and humidity should be exhausted to the outdoors regardless of fuel burned.

Those professional chefs cook over professional ovens and ranges with massive exhaust fans rated in the thousands of CFMs sucking that kitchen inside-out. Ever tried to open a door to a commercial kitchen? Some of the worse depressurized spaces in the world. I've had commercial kitchen fans affect direct vent gas fireplaces. Had to install a $10K makeup air system.

The lack of a proper interlock with the gas burner was a direct cause of a CO poisoning event near me that sent people to the ER twice from the same grocery store caused by the same bake oven. What saved the day was the personal CO monitor/ alarm carried by the paramedics who responded to an old lady collapsed at the bake counter. It went off at 35ppm. I have carried a personal CO monitor for years and it has alerted me to hazardous environments, including being in traffic. How do you know you are not walking into a toxic environment every day? You guys should be wearing a personal 4 in 1 alarm: % LEL, CO, O2, H2S. That's what my next personal alarm will be.

Bob

Bob

JORY LANNES · #13 (**permalink**) 10-31-2009, 09:01 AM

Great subject however I think a bigger question needs to be asked. HOW MANY INSPECTORS CHECK FO CO LEVELS?

In a informal study of my ASHI chapter less than 50% of the members check for carbon monoxide as part of there standard inspection.

Testing for CO is not an Illinois or ASHI standard of practice.

I have found over the years several unsafe hot water heaters and furnaces only because of my CO tester.

Should the SOP be changed?

Rick Cantrell · #14 (**permalink**) 10-31-2009, 09:11 AM

"Rick, finish my sentence. Both I refer to..."
Sorry Bob, I was reading it wrong. When you said CO Experts I thought that meant, people that are carbon monoxide experts in general and NSI3000 was a standard.
Thanks for clearing that up.

DavidR · #15 (**permalink**) 10-31-2009, 09:50 AM

Quote:

Originally Posted by JORY LANNES

Great subject however I think a bigger question needs to be asked. HOW MANY INSPECTORS CHECK FO CO LEVELS?

In a informal study of my ASHI chapter less than 50% of the members check for carbon monoxide as part of there standard inspection.

Testing for CO is not an Illinois or ASHI standard of practice.

I have found over the years several unsafe hot water heaters and furnaces only because of my CO tester.

Should the SOP be changed?

Yes the SOP should be changed Jory, kudos to you for being proactive and testing without being made to!

You're setting a good example for those in your chapter that aren't aware of what they could be walking into.

DavidR · #16 (**permalink**) 10-31-2009, 09:53 AM

Quote:

Originally Posted by Bob Harper

Rick, finish my sentence. Both I refer to ARE very reliable, unlike the listed alarms and they do alert at low levels unlike listed alarms. The NSI 3000 is available only if you take Day 1 of the NCI Co & Combustion Course. You can buy the CO Experts online from George Kerr.

Guys, understand where DavidR is coming from. Aside from teaching the NCI CO & Combustion course, he is a practicing professional HVAC tech who does check gas ovens so he knows first hand what he's talking about. I've tested a few dozen and found CO issues to one degree or another with all. Understand the ventilation is needed on electric ranges and ovens as well. The aerosolized food particles and humidity should be exhausted to the outdoors regardless of fuel burned.

Those professional chefs cook over professional ovens and ranges with massive exhaust fans rated in the thousands of CFMs sucking that kitchen inside-out. Ever tried to open a door to a commercial kitchen? Some of the worse depressurized spaces in the world. I've had commercial kitchen fans affect direct vent gas fireplaces. Had to install a $10K makeup air system.

The lack of a proper interlock with the gas burner was a direct cause of a CO poisoning event near me that sent people to the ER twice from the same grocery store caused by the same bake oven. What saved the day was the personal CO monitor/ alarm carried by the paramedics who responded to an old lady collapsed at the bake counter. It went off at 35ppm. I have carried a personal CO monitor for years and it has alerted me to hazardous environments, including being in traffic. How do you know you are not walking into a toxic environment every day? You guys should be wearing a personal 4 in 1 alarm: % LEL, CO, O2, H2S. That's what my next personal alarm will be.

Bob

Bob

I really like the idea of the 4 in 1 Bob, Christmas might come early.

The other item with commercial kitchens and the pressure imbalances due to improperly balanced hoods is the effect they have on the water heaters sitting in those very kitchens.

Many kitchen fires and CO poisonings have been attributed to this depressurization.

Bob Harper · #17 (**permalink**) 10-31-2009, 03:30 PM

Just another example why you should wear a 4 in 1 monitor: BREAKING NEWS !!!! - Two badly burned in gas explosion - Carmi, IL - The Carmi Times

This was two HVAC techs who were injured. One is a grizzled veteran and friend of a frequent contributor over on HVAC-Talk.com where I found this. There was an LP tank in the yard to a furnace in the crawl space. He thought he had the tank shut off. No shutoff within 6ft. of appliance (now you know why code requires this). They went under to service and light pilot. 3rd degree burns on face and hands but they think he will live. They did not smell the gas so they ASSumed they were ok. Either the gas was below their noses or it was a case of 'odor fade'. Regardless, a 4 in 1 set to alert at 20% of the LEL could have warned them of the hazardous environment where they could have escaped unhurt. BTW, for LP gas, the LEL is about 4,300 ppm.

If there is a venting problem to where CO2 is being released into the room it will displace the O2 so an oxygen deficient space is a problem for people and combustion.

With all the busted stink pipes/ traps in basements and the low IDLH & PEL for hydrogen sulphide, this is cheap protection.

Bob

John Dirks Jr · #18 (**permalink**) 10-31-2009, 06:00 PM

So, who believes it's a bad idea to recommend CO detectors/alarms?

Dennis Krouse · #19 (**permalink**) 10-31-2009, 06:18 PM

So why were they trying to light the pilot if they thought the tank was off???

JORY LANNES · #20 (**permalink**) 11-01-2009, 11:08 AM

What is a personal 4 in 1 alarm: % LEL, CO, O2, H2S.? Who is the manufacture,where are they sold, approx price?

Thanks

Jory

mathew stouffer · #21 (**permalink**) 11-02-2009, 10:11 AM

Well said Rick, gas is king.

DavidR · #22 (**permalink**) 11-06-2009, 03:58 PM

None of you guys that are for the Kevorkian cooking style have said if you've tested your gas ranges yet.