Bedbug Extermination Gone Bad
One of the things I have always enjoyed about being a forensic engineer is the occasional assignment that seems to come from way out in left field. Most of my work is related to HVAC, plumbing and fire suppression system failures and construction defects. But once in a while, my background in these areas crosses over nicely into other industries.
Such was the case when I got a call asking if I knew anything about bedbug extermination. Fortunately, I had no previous experience at the time. The adjuster on the call went on to explain that bedbugs are one of the most difficult pests to get rid of because they will hide themselves and their eggs in every nook and cranny of a house; they will even get into the wall cavities. He explained that in recent years, exterminators have been using heat treatments to eradicate bedbugs in homes. They seal-off the exterior doors to the house, connect large propane heaters to temporary ducts and blow the hot air into the house. They slowly raise the temperature inside the house to a level that cooks all the bugs (for a more detailed explanation: https://buglord.com/bed-bug-heat-treatment-guide/).
This all got a lot more interesting when the adjuster said, “In this instance, they melted the house.” My mind instantly conjured an image of a house that had collapsed into an amorphous heap oozing across the front yard. In reality, as the adjuster would go on to clarify, the house itself had not exactly melted. Rather, many of the plastic elements of the house and various plastic contents were damaged. Unfortunate to my curiosity, I was not able to visit the house. However, I was supplied with numerous photographs of the damage. The formerly straight, clean lines of the vinyl window frames were transformed into organic undulations. Framed family photos looked as if they had been soaked in water. And flat panel television screens were no longer flat.
The extermination crew had claimed that it was a blustery day when they performed the heat treatment. They explained that the wind caused surges in the heaters and after fighting it throughout the morning, the whole operation got away from them. They reportedly lost control of the heat inside the house, which caused all of the damage.
I was tasked with inspecting and testing the heaters to see whether there were any equipment defects that would account for the reported problems. Prior to the inspection, I did some research on the subject equipment. The crew was using two 500,000 btu/hr propane heaters to raise the temperature in the single story house. Inside the house, they had positioned 8 high-temperature fans at ground level to help circulate the air and equalize the temperature between rooms. Using an eight-channel digital thermometer, they were monitoring the temperature of six rooms inside the house and the discharge temperature of each heater. The equipment manufacturer provided a heat treatment procedure to achieve the best and safest results. The procedure explained that a home’s interior air temperature should be slowly raised to between 120°F and 140°F, then maintained at that level for 4 hours to ensure that the wall cavities are also brought up to that temperature range. The procedure stated that, following initial equipment setup, the process should take 7 to 8 hours to complete.
I inspected the heaters and ran each for a period of 10 minutes while monitoring the discharge temperature. Incidentally, it was very windy during the inspection. There were some fluctuations due to the wind, but overall, the discharge temperatures were within an acceptable range. I then reviewed the temperature data from the subject heat treatment. The technicians had recorded temperature data every 30 minutes throughout the operation. The data revealed that the temperature inside the house exceeded 140°F by noon and continued to climb to near 200°F in many of the rooms before the operation was shut down at about 3pm.
I spoke individually with each of the three members of the extermination crew. I got a number of conflicting stories about what had happened during the failed heat treatment. Finally, I went back to the foreman and told him that, given the testing and the data, it looks to me like you and your crew took a nap after lunch and when you woke, the house was overheated.
Perhaps a bit insulted by my suggestion, what he said next finally started making sense. He explained that the manufacturer’s instructions state that the heat treatment should take 7 to 8 hours. In addition, they found that it takes over an hour to setup and another hour to tear-down the equipment. He further stated, “If you do the math, that can add up to over 10 hours. Well, we work an eight hour day. So, we figured if we increase the temperature some, maybe we could reduce the time to 5 or 6 hours.” The subject house was the first test of their theory. He assured me that, given the outcome, they unanimously decided to abandon any further attempts to dial in their revised procedure.
I am certain that there are many well trained and professional exterminators out there. Many of them reasonably have plenty of experience running a bedbug heat treatment. Nevertheless, should I find myself with an undesirable need to eradicate bedbugs at my home, I will be having a conversation with the exterminator about his heat treatment procedure, just to make sure.
One of the things I have always enjoyed about being a forensic engineer is the occasional assignment that seems to come from way out in left field. Most of my work is related to HVAC, plumbing and fire suppression system failures and construction defects. But once in a while, my background in these areas crosses over nicely into other industries.
Such was the case when I got a call asking if I knew anything about bedbug extermination. Fortunately, I had no previous experience at the time. The adjuster on the call went on to explain that bedbugs are one of the most difficult pests to get rid of because they will hide themselves and their eggs in every nook and cranny of a house; they will even get into the wall cavities. He explained that in recent years, exterminators have been using heat treatments to eradicate bedbugs in homes. They seal-off the exterior doors to the house, connect large propane heaters to temporary ducts and blow the hot air into the house. They slowly raise the temperature inside the house to a level that cooks all the bugs (for a more detailed explanation, see: https://buglord.com/bed-bug-heat-treatment-guide/).
This all got a lot more interesting when the adjuster said, “In this instance, they melted the house.” My mind instantly conjured an image of a house that had collapsed into an amorphous heap oozing across the front yard. In reality, as the adjuster would go on to clarify, the house itself had not exactly melted. Rather, many of the plastic elements of the house and various plastic contents were damaged. Unfortunate to my curiosity, I was not able to visit the house. However, I was supplied with numerous photographs of the damage. The formerly straight, clean lines of the vinyl window frames were transformed into organic undulations. Framed family photos looked as if they had been soaked in water. And flat panel television screens were no longer flat.
The extermination crew had claimed that it was a blustery day when they performed the heat treatment. They explained that the wind caused surges in the heaters and after fighting it throughout the morning, the whole operation got away from them. They reportedly lost control of the heat inside the house, which caused all of the damage.
I was tasked with inspecting and testing the heaters to see whether there were any equipment defects that would account for the reported problems. Prior to the inspection, I did some research on the subject equipment. The crew was using two 500,000 btu/hr propane heaters to raise the temperature in the single story house. Inside the house, they had positioned 8 high-temperature fans at ground level to help circulate the air and equalize the temperature between rooms. Using an eight-channel digital thermometer, they were monitoring the temperature of six rooms inside the house and the discharge temperature of each heater. The equipment manufacturer provided a heat treatment procedure to achieve the best and safest results. The procedure explained that a home’s interior air temperature should be slowly raised to between 120°F and 140°F, then maintained at that level for 4 hours to ensure that the wall cavities are also brought up to that temperature range. The procedure stated that, following initial equipment setup, the process should take 7 to 8 hours to complete.
I inspected the heaters and ran each for a period of 10 minutes while monitoring the discharge temperature. Incidentally, it was very windy during the inspection. There were some fluctuations due to the wind, but overall, the discharge temperatures were within an acceptable range. I then reviewed the temperature data from the subject heat treatment. The technicians had recorded temperature data every 30 minutes throughout the operation. The data revealed that the temperature inside the house exceeded 140°F by noon and continued to climb to near 200°F in many of the rooms before the operation was shut down at about 3pm.
I spoke individually with each of the three members of the extermination crew. I got a number of conflicting stories about what had happened during the failed heat treatment. Finally, I went back to the foreman and told him that, given the testing and the data, it looks to me like you and your crew took a nap after lunch and when you woke, the house was overheated.
Perhaps a bit insulted by my suggestion, what he said next finally started making sense. He explained that the manufacturer’s instructions state that the heat treatment should take 7 to 8 hours. In addition, they found that it takes over an hour to setup and another hour to tear-down the equipment. He further stated, “If you do the math, that can add up to over 10 hours. Well, we work an eight hour day. So, we figured if we increase the temperature some, maybe we could reduce the time to 5 or 6 hours.” The subject house was the first test of their theory. He assured me that, given the outcome, they unanimously decided to abandon any further attempts to dial in their revised procedure.
I am certain that there are many well trained and professional exterminators out there. Many of them reasonably have plenty of experience running a bedbug heat treatment. Nevertheless, should I find myself with an undesirable need to eradicate bedbugs at my home, I will be having a conversation with the exterminator about his heat treatment procedure, just to make sure.
One of the things I have always enjoyed about being a forensic engineer is the occasional assignment that seems to come from way out in left field. Most of my work is related to HVAC, plumbing and fire suppression system failures and construction defects. But once in a while, my background in these areas crosses over nicely into other industries.
Such was the case when I got a call asking if I knew anything about bedbug extermination. Fortunately, I had no previous experience at the time. The adjuster on the call went on to explain that bedbugs are one of the most difficult pests to get rid of because they will hide themselves and their eggs in every nook and cranny of a house; they will even get into the wall cavities. He explained that in recent years, exterminators have been using heat treatments to eradicate bedbugs in homes. They seal-off the exterior doors to the house, connect large propane heaters to temporary ducts and blow the hot air into the house. They slowly raise the temperature inside the house to a level that cooks all the bugs (for a more detailed explanation, see: https://buglord.com/bed-bug-heat-treatment-guide/).
This all got a lot more interesting when the adjuster said, “In this instance, they melted the house.” My mind instantly conjured an image of a house that had collapsed into an amorphous heap oozing across the front yard. In reality, as the adjuster would go on to clarify, the house itself had not exactly melted. Rather, many of the plastic elements of the house and various plastic contents were damaged. Unfortunate to my curiosity, I was not able to visit the house. However, I was supplied with numerous photographs of the damage. The formerly straight, clean lines of the vinyl window frames were transformed into organic undulations. Framed family photos looked as if they had been soaked in water. And flat panel television screens were no longer flat.
The extermination crew had claimed that it was a blustery day when they performed the heat treatment. They explained that the wind caused surges in the heaters and after fighting it throughout the morning, the whole operation got away from them. They reportedly lost control of the heat inside the house, which caused all of the damage.
I was tasked with inspecting and testing the heaters to see whether there were any equipment defects that would account for the reported problems. Prior to the inspection, I did some research on the subject equipment. The crew was using two 500,000 btu/hr propane heaters to raise the temperature in the single story house. Inside the house, they had positioned 8 high-temperature fans at ground level to help circulate the air and equalize the temperature between rooms. Using an eight-channel digital thermometer, they were monitoring the temperature of six rooms inside the house and the discharge temperature of each heater. The equipment manufacturer provided a heat treatment procedure to achieve the best and safest results. The procedure explained that a home’s interior air temperature should be slowly raised to between 120°F and 140°F, then maintained at that level for 4 hours to ensure that the wall cavities are also brought up to that temperature range. The procedure stated that, following initial equipment setup, the process should take 7 to 8 hours to complete.
I inspected the heaters and ran each for a period of 10 minutes while monitoring the discharge temperature. Incidentally, it was very windy during the inspection. There were some fluctuations due to the wind, but overall, the discharge temperatures were within an acceptable range. I then reviewed the temperature data from the subject heat treatment. The technicians had recorded temperature data every 30 minutes throughout the operation. The data revealed that the temperature inside the house exceeded 140°F by noon and continued to climb to near 200°F in many of the rooms before the operation was shut down at about 3pm.
I spoke individually with each of the three members of the extermination crew. I got a number of conflicting stories about what had happened during the failed heat treatment. Finally, I went back to the foreman and told him that, given the testing and the data, it looks to me like you and your crew took a nap after lunch and when you woke, the house was overheated.
Perhaps a bit insulted by my suggestion, what he said next finally started making sense. He explained that the manufacturer’s instructions state that the heat treatment should take 7 to 8 hours. In addition, they found that it takes over an hour to setup and another hour to tear-down the equipment. He further stated, “If you do the math, that can add up to over 10 hours. Well, we work an eight hour day. So, we figured if we increase the temperature some, maybe we could reduce the time to 5 or 6 hours.” The subject house was the first test of their theory. He assured me that, given the outcome, they unanimously decided to abandon any further attempts to dial in their revised procedure.
I am certain that there are many well trained and professional exterminators out there. Many of them reasonably have plenty of experience running a bedbug heat treatment. Nevertheless, should I find myself with an undesirable need to eradicate bedbugs at my home, I will be having a conversation with the exterminator about his heat treatment procedure, just to make sure.