Carbon Monoxide, and Naps

It may not be the Turkey that makes you sleepy.

Carbon monoxide from an electric oven

Cooking the turkey for hours can introduce considerable amounts of carbon monoxide to the home during the cooking process.  Turkey has a component that has been attributed to that nap after dinner.  Others hypothesize it is just eating too much that leads to sleepiness.  It is also possible that exposure to Carbon Monoxide is a contributor.

If carbon monoxide is a culprit, it is not only related to gas ovens. 

I am not sure how much CO is given off in an electric oven during the cooking of a turkey, but certainly some amount is likely. I will have to wait until Thanksgiving to get more information on that.

Considerable is created when using the self-clean function of the oven. 

My own oven gives off between 28 and 3 PPM for the first 1-1/2 hours of the 3 hour cycle.  After that time, whatever was creating the CO was successfully incinerated and CO levels dropped to normal. 

These amounts are perhaps not enough to kill you, but certainly enough to affect a person–especially infants that might be around.

In the first 15 minutes of operation, my own oven gave off about 28 PPM, after about half an hour it settled down to 12 PPM and after about an hour it was down to 5 PPM.  At the one-hour mark, ambient CO levels in the kitchen 10 feet away from the oven hovered around 3 PPM—with the exhaust fan on and a window open.

I suspect the amount of CO will depend on what the oven is burning off in the cleaning mode, and levels likely could be considerably higher, and for longer periods of time, if the oven is not cleaned very often.  I clean min probably twice a year.  I may start doing it more often now.

Of course your ordinary CO alarm is “not allowed” to alarm, per its listing, at these low levels, so most of the time you will have no idea why you need a nap.

I think the lesson here is to clean your ovens regularly–don’t wait until you can see the bottom of the oven.  You should also run the kitchen exhaust hood the whole cleaning cycle and keep a window open.

Perhaps I will go take a nap, while I wait for the oven to finish.

Charles Buell, real estate inspections in Seattle

The dark side of Carbon Monoxide Detectors

Carbon Monoxide detectors have been in the news a lot lately and with good reason. Given that the gas is colorless, odorless and can kill you while you sleep are all good enough reasons for me to pay attention. The building codes themselves require them, and in addition, many states have made laws requiring them.

There is a dark side to CO detectors that is not discussed very much however, and I have blogged about this issue with Carbon Monoxide Detectors in the past.carbon monoxide detector

This missing information can leave the consumer with a false sense of security.

Most of the CO detectors required by state laws and the building codes are quite good at detecting Carbon Monoxide in relatively acute doses. Acute doses are large levels of exposure over relatively short time periods. They are not very good at detecting Carbon Monoxide at chronic levels—low levels of exposure over longer periods of time.

In fact, the CO detectors required in your home are NOT ALLOWED to signal a problem at levels below 30ppm in order for them to obtain the UL listing necessary to meet the codes (UL 2034). It is interesting to note that most of these alarms are designed to sound at or below 70ppm within 60 to 240 minutes (I do not think that this information should make anyone feel protected).

There is a stream of emerging data (see HUD: Healthy Homes Issues: Carbon Monoxide) that there are health risks associated with low levels of CO exposure—levels below what is considered safe by the EPA. According to the EPA levels of CO below 9 ppm over an 8 hour period, or 35ppm for one hour are considered “safe.” Research is beginning to show that the elderly, the very young, the unborn and some other individuals experience negative physical, cognitive and emotional effects with exposures below these levels.

There is technology available for detecting low levels of CO. These devices do not meet UL 2034 and therefore cannot be “substituted” for the poorer performing listed devices but must instead be used as supplements to the required detectors.

One such device is the “Defender” CO detector. It is capable of detecting levels as low as 5 ppm for less than a minute. It has a wide range of sensitivities with different alarms and visual read-outs to display different levels of concern. These seem like a prudent device for any home. These devices also attempt to deal with the issue of when they have reached the end of their expected life. They come with a sealed in place battery so when the battery is dead you simply replace the whole device. I wonder how many regular detectors will continue to give their false sense of security long after the batteries are dead or when batteries are replaced when the units are well past their expected life.

Also keep in mind that there is no substitute for regular servicing of all combustion appliances in the home. Proper servicing is an essential part of any CO mitigation/detection system installed in the home.

By Charles Buell, Real Estate Inspections in Seattle

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So you think you know everything there is to know about CO detectors?

I sure did not and still do not.

In recent years the push to install CO detectors in homes has resulted in them being required in many jurisdictions and certainly any jurisdiction that has adopted the 2009 or later IRC Building Codes will require them in New Construction. Washington State currently requires them on each floor level and in the vicinity of each sleeping area when a home is sold. In most homes this means there will typically be two of the devices but with large sprawling homes with basements and/or multiple stories there could be several more.

CO detectors for residential construction must meet the requirements of UL 2034.

What is not commonly understood about these detectors and UL 2034 is that they are “not intended to alarm when exposed to long-term, low-level carbon monoxide exposures or slightly higher short-term transient carbon monoxide exposures, possibly caused by air pollution and/or properly installed/maintained fuel fired appliances and fireplaces.”

carbonmonoxide(please reread the previous quote and the information below VERY carefully as it is counter-intuitive)

Following these standards, the alarms are: 1, not “allowed” to alarm when CO is lower than 50 parts per million; 2, they are required to alarm within 50 (yes you are reading that correctly) minutes at levels up to 150 PPM; and, 3, they are required to alarm within 15 minutes at Carbon Monoxide levels up to 400 PPM.

What the standards do not address is the fact that some individuals are greatly affected by being exposed to lower levels of CO over longer periods of time.

The Kidde user’s guide states: “While anyone is susceptible, experts agree that unborn babies, small children, senior citizens and people with heart or respiratory problems are especially vulnerable to CO and are at the greatest risk for death or serious injury.

INDIVIDUALS WITH MEDICAL PROBLEMS MAY CONSIDER USING WARNING DEVICES THAT PROVIDE AUDIBLE AND VISUAL SIGNALS FOR CARBON MONOXIDE CONCENTRATIONS UNDER 30 PPM.”

They go on to state: CO alarms provide early warning of the presence of carbon monoxide, usually before a healthy adult would experience symptoms.

So does this mean that those most in need of protection are not in fact protected?

Other alarm makers have similar recommendations.

This next caution from Kidde is very important, as I can attest to, from an incident at a recent inspection: “CAUTION: THIS ALARM WILL ONLY INDICATE THE PRESENCE OF CO GAS AT THE SENSOR. CO MAY BE PRESENT IN OTHER AREAS.”

When I turned on the oven at the inspection and it had been operating for just a couple of minutes, I started to experience some of the symptoms of CO poisoning. (Once you have experienced these symptoms you can almost become your own CO detector—but unfortunately human beings sleep, and then there is the problem that you might not notice very low levels of CO and thus be no more effective than UL 2034.) My “real” CO detector found over 600 PPM and yet the CO detector plugged in at the countertop on the other side of the kitchen did not go off and would not (under UL 2034) be required to go off until the unit experienced 400 ppm for as much as 15 minutes. Depending on air currents in the home, the unit might never see appropriate levels–even after the person using the stove succumbed to the gas.

The biggest concern that I have with all of this information is: “Who reads the instructions?” Are we creating an awareness of CO detectors where people are assuming they are protected when they in fact are not? While I still think installation of these alarms is probably a good idea, and that perhaps more appropriate residential CO detectors may be forthcoming, I think it is at least as important to better educate people to recognize the symptoms associated with Co poisoning as well as to be aware of what these detectors do and don’t do.

Again from Kidde: “Be aware of the symptoms of carbon monoxide poisoning: – headaches, dizziness, weakness, sleepiness, nausea, vomiting, confusion and disorientation.

Recognize that CO poisoning may be the cause when family members suffer from flu-like symptoms that don’t disappear but improve when they leave home for extended periods of time.”

Carbon Monoxide in homes is a serious issue, and legislation/codes do not adequately address all the concerns associated with it. It is in all likelihood dangerous to assume that they do–if we and our families are to be safe in our homes. This is especially true as homes become tighter in relation to becoming more energy efficient.

By Charles Buell, Real Estate Inspections in Seattle

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