By Captain David Tharp
Gainesville Fire Rescue
One incident call that I still cringe over after 23 years of service is the dreaded "I smell smoke." The cringe is from the hundreds of calls that I have been on and remembering from experience that it is not always easy finding the source of the odor. For the most part, these incidents do not provide an easy road map for firefighters to follow to the source of the odor.
One call I agonized over for almost two hours one Saturday afternoon was an odor of smoke in a two story residential structure. We rolled out to the residence and were met by an excited woman who stated that she smelled smoke in her house. I went through the usual questions on my mental checklist: Have you been cooking? Is your air conditioner working properly? Do you smoke? Have lights or electrical appliances been experiencing electrical interruptions? The only yes was to the question do you smoke. That is usually where the answer to the problem exists. You must carefully listen to what is being said to you. It is much like going to the doctor’s office. The doctor will usually ask what’s been going on with you. He will listen while you explain your symptoms and perform some test in order to confirm what is suspected from the symptoms you have described. We as firefighters must listen carefully to the symptoms that are given to us by our customers. I could have saved a lot of time if I would have simply asked a simple question. We will come back to this later.
While entering the home the engine company smelled an odor of something burning. The odor was very faint and no smoke was visible. The odor would come and go and it was low and high inside and outside of the front of the residence. We checked every component in the residence from the lowest point to the roof. The home was thermal imaged, the circuit breaker box checked, as well as the HVAC unit, appliances, electrical outlets, and even the cushions of furniture. We were at a dead end, but the odor still persisted. I was at my wits end on this one. I even had a second engine respond to get fresh eyes and ideas of what the source could be. They were clueless and just as frustrated as I was.
The two engine companies gathered and we sat on the front porch scratching our heads. One of the firefighters said, "I think the odor is coming from this plant." I grabbed up the plant and smelled it and sure enough there was an odor of smoke. I took it out in the roadway and dumped it. Out came the plant, dirt, and around thirty cigarette butts. The occupant smoked outside on the front porch and used the soil in the plotted plant to extinguish her cigarette butts. She would push them far down in the dirt where unsightly cigarette butts would not be seen. The cigarette butts had been smoldering next to the roots. The roots began to smolder and put off the odor of the smoke.
The lesson I learned that day was to always follow up on questions that are answered with confirmation. She had stated that she smoked; I should have followed up by asking where do you smoke and extinguish your cigarettes.
Experience has taught me to smell the odor of the smoke. Is it a burning electrical odor or wood odor? This is a valuable tip in where to start your investigation. If it is an electrical odor start tracking it down by where the odor is strongest, use the thermal imaging camera and look at the electrical panel for tripped breakers. HVAC units can throw you off, especially when they are mounted on the roof. There can be an odor of smoke in the building but no clear source. Check to see if the thermostat is on, then listen and feel for air coming from a vent. If no air is present this is a good indicator to move to the next step of finding the fan motor. Most of the time the electrical motor has gone out or a bearing is going out in the motor. Be sure to always turn the breaker to the off position when investigating electrical equipment. Often short circuits can occur and electrical grounding to a metal case or cabinet can occur. The fan often will not turn if a bearing has seized up or the motor will show a significant heat signature with a thermal imaging camera. In addition nine times out of ten a distinct burning electrical odor will be present.
Remember we do not have the luxury of leaving without finding the source, once we are called it is our responsibility to find the source no matter how long it takes. Use your senses, hearing, smell, sight, and common sense. Do not become to focused on one aspect, review all aspects of possible sources. Beware of tunnel vision, if all else fails sometimes you just have to sit down and scratch your head and maybe it will come to you.