The school electrician entered the boiler room one morning to diagnose the electrical problem for one wing of the school. A short while later, the school principal asked the secretary to check on the progress of the electrician. When she opened the door to the boiler room, she saw the electrician passed out on the floor.

Rather than rushing to the fallen man, she sprinted to the office and called 911. The first responders tested the space and found highly elevated levels of carbon monoxide. They evacuated the man and rushed him to the hospital. The man survived thanks to the quick thinking of the secretary and the first responders.

I was asked to visit this boiler room a few weeks later to ascertain the cause of the accident. The source of the incident was two-fold. The first cause was the flue for the boilers was improperly installed and allowed flue gases to vent inside the boiler room. The second cause was the boilers were not maintained properly and the fuel-to-air ratio of the burners was out of calibration, spilling high levels of the toxic gas into the boiler room.

The ironic part about this accident is that the equipment room did have a carbon monoxide detector but it was not connected to an alarm. When I arrived, the digital display was showing a flashing error code.

Each fall, the media is filled with stories about the dangers of carbon monoxide in homes and businesses — sad stories about people who have been overcome by the dangerous gas. The majority of these accidents could have been avoided.

Carbon monoxide, or CO, is an invisible, odorless gas that can only be detected with sophisticated instruments. My uncle, a third-generation coal miner, used to regale us with stories about how the old miners would take a canary in a bird cage into the coal mines when they worked. If the bird stopped singing, the coal miners would run for the exit because the carbon monoxide was elevated to a dangerous level. The bird was a precursor to today’s CO detectors. Thankfully, we now have safer methods to test for it.

Carbon monoxide is dangerous because it displaces oxygen in the blood’s hemoglobin and forms carboxyhemoglobin. Since the oxygen is replaced by it, the body’s organs are starved for oxygen and nutrients, suffocating them.

The standard measurement for carbon monoxide is parts per million or ppm. To understand how small a ppm is, consider this. One part per million is equal to:

  • One day in 2,739 years;
  • One interception in 7,692 football games; or
  • One inch in 16 miles.


Recovery and testing

It has been theorized that the body actually prefers CO to oxygen, which is why it is difficult to remove from the body. Carbon monoxide has a half-life of five hours, which means the level of toxic gas will drop to half its current level after five hours and drop in half again after an additional five hours.

However, exposure to a high level of CO could take too long to be removed naturally. In severe instances, a person may have to be inserted inside a hyperbaric chamber, which uses pressure and oxygen to force the carbon monoxide from the hemoglobin. The table (pictured above) illustrates how deadly CO can be in only a few minutes.

Carbon monoxide is formed due to either an incorrect fuel-to-air ratio arrangement, improper flame patterns or inadequate draft. The fuel-to-air ratio should be tested on a regular basis as part of all boiler checks. The draft or flame pattern of the fuel-burning appliance could be affected by exhaust fans in the building or temperature of the water.

The safest way to test for carbon monoxide presence in an equipment room is to use a calibrated CO detector. For proper operation, the detector should be calibrated yearly. A technician at one of my seminars told me he used a plug-in-type CO alarm he purchased at a big-box store for CO testing. I informed him that he may be risking his life and he asked why. I explained there were two issues with using a system such as that.

The first reason comes from the CO detector manufacturer Kidde, “The CO alarm is designed to act as a monitor; it is not designed for use as a short-term testing device to perform a quick check of the presence of CO.”

The other more critical reason is the response time. According to UL 2034 standards, the plug-in-type carbon monoxide detectors will take 4 to 15 minutes to react when the CO levels are above 400 ppm. If you look at the table, death occurs within 1 to 2 minutes if the level is above 12,800 ppm. A burner can go from 0 to several thousand ppm in seconds.

When I am testing for carbon monoxide, I like to simulate the worst-case scenario. In a commercial building, I will make sure all the fuel-burning appliances are operating. This may require opening the hot water valves to start the water heater. I will energize the exhaust fan and any fans inside the boiler room. I will test around all fuel-burning appliances such as the water heater, boilers and pool heater.

If I am inside a home, I try to simulate the worst case by starting all the exhaust fans in the house including kitchen and bath, clothes dryer and oven. One of the most common causes of CO production in residential buildings is the oven.

Make sure you have the proper tools to test for carbon monoxide and to repair the problem. Stay safe inside the boiler room.