Looking at the combustion air grilles, we found they faced a field and some woods so nothing on that side of the building could be putting CO into the room. Furthermore, there was nothing in the plant making CO.
For some reason I can’t explain, I placed the analyzer probe in the combustion air grille and measured 150 ppm of CO coming into the room. We later determined that CO was migrating across a flat roof, coming down the wall of the building, and re-infiltrating the mechanical room.
Through investigation, we discovered that CO can become heavier than air below 32’F. This later explained confusion caused in other buildings where there were poisonings, yet CO was found on the opposite side of the building rather than where the equipment was located.
Case 4: Surprise! You’re Poisoned!
In the last scenario I actually got poisoned, making me sick. I was teaching a Combustion/CO class on the roof of a maintenance building that had two packaged units on it.
The first unit tested was making well over 2000 ppm of CO. Fortunately, I was able to insert and secure the analyzer probe in the vent without holding it, which let me keep my distance from the flue and kept me from breathing any CO.
The next packaged unit was not so easy. I had to hold the probe in the vent for five to 10 minutes. This unit was producing CO over 1500 ppm and, without realizing it, I was inhaling more than I thought. The rest of the class was standing back and safe.
Climbing back down from the roof when finished, I found myself getting quite nauseated and made a small mess in their parking lot.
I did get over it very quickly and finished the class.
Who would have thought that using a personal CO monitor on a roof would be necessary?
The meter I had used previously was back at the factory getting repaired, but I was on a roof. This was a military base where five people died from CO poisoning, but not from this building.
Danger, Will Robinson!!
CO poisonings, explosions, fires, electrical shocks, and so on, are all things that must not be ignored on the job.
Today we have excellent tools at our disposal to help warn us of these dangers well in advance of it becoming harmful to us and others ‘ much like the Robot in Lost in Space did for the Robinson family.
Safety is always the first concern. That is why it is extremely important to be aware of the surroundings in our working environment.