Carbon Monoxide (CO) Part 1


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This is old stuff

It’s winter again, and again I feel a need to address the dangers of carbon monoxide.  It seems like I’ve been doing this every winter since I can remember.  Certainly, it didn’t start with me.  The dangers go way back to the dawn of the early Hvac-Man.  If you go into the catacombs beneath 200 Shirlington Road (B3 in the elevator) in Arlington, Virginia, you will see hieroglyphics scribbled on the walls like the ones in Figure 1.

Since I am an expert in the art of the early Nesca people (from the Pre-Acca Period), I can interpret those etchings for you.  It means that one of the products of complete combustion is CO2 (carbon dioxide), which has two oxygen atoms.  However, if this CO2 is used to support combustion again, only one atom of oxygen will remain, and that is real bad stuff.  In the real world it often looks a lot like the picture in Figure 2.

A flame that rolls out of a combustion chamber is in search of oxygen.  In Figure 2, that source would have been the flu pipe connected to the water heater alongside of the boiler, as well as the boiler’s own venting system.

The facts

Carbon monoxide is a by-product of incomplete combustion.  It is produced when flammable fuels such as natural gas, propane gas, heating oil, kerosene, coal, charcoal, gasoline, or wood burn with insufficient oxygen.

Every year, about 15,000 people visit the ERs in our country due to prolonged exposure to carbon monoxide.  Of those, about 500 souls will perish each year.  The vast majority (79%) occur in a residential setting, and most (84%) occur during the winter months and involve a heating system.

Carbon monoxide is a national concern.  It doesn’t just happen during the winter in the north.  Only 17% of the deaths in our country occur in the northeast (probably due to heightened awareness), 33% in the South, 30% in the Midwest, and 20% in the West.

I live in Tampa, Florida.  We had a bad storm blow through the Tampa Bay area this August which caused scattered power outages.  Three elderly ladies died as a result of using a portable electrical generator in their garage (with the garage door closed) during the night.  They lived no more than a five-minute car ride from my home.

It’s ubiquitous

Carbon monoxide (CO) is a colorless, odorless, and tasteless gas that is poisonous and potentially lethal.  CO has a similar specific gravity (.9657) as air (1.0).  Which means that it is everywhere, and that it mixes well with the air.  So, the answer to the question, where within a room should I locate my CO detectors, is, it doesn’t matter because it is everywhere.

The International Association of Fire Chiefs recommends a carbon monoxide detector on every floor of your home, including the basement. A detector should be located within ten feet of each bedroom door and there should be one near or over any attached garage. Each detector should be replaced every five to six years.

When we breathe air containing carbon monoxide, it is absorbed through the bloodstream where it displaces oxygen and bonds with the hemoglobin in your blood.  Carbon monoxide has a greater affinity to hemoglobin than oxygen; CO bonds to hemoglobin about 250 times better than oxygen.  Without oxygen, vital organs, like your heart and brain, become deprived and will begin to deteriorate.  To compensate, your heart rate increases, breathing may become difficult, and in the most serious circumstances, cardiac trauma, brain damage, coma and even death will result.

The symptoms

CO poisoning is difficult to diagnose because its symptoms are similar to illnesses such as the flu or the start of a cold.  Early warning signs of carbon monoxide poisoning are headache, dizziness, nausea, and fatigue.

If exposure to carbon monoxide continues, symptoms will often become worse and include severe headaches, mental confusion, vomiting, vision and hearing impairment, and eventually unconsciousness.

It is the HVAC technician’s responsibility to make sure that the proper amount of oxygen is present to avoid the creation of carbon monoxide.  In Part 2, we will deal with the questions of how much oxygen is required, and how to properly satisfy that requirement.


Posted In: ACCA Now, Technical Tips

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