“1. List and discuss the heat sources identified by the NFPA as being the primary causes of ignition for residential fires.
2. Define stratification, and explain how this phenomenon is predicted. How can stratification be defeated? How are fires detected where stratification is predicted to occur?
This week I have chosen to discuss common heat sources identified by the NFPA in being common causes of ignition in home fires. The NFPA published the Home Structure Fires report in October of 2019 that outlines these fires and supports the conclusions with data from 2018. The following heat sources were listed as common denominators in home structure fires:
Electrical distribution and lighting
Home fires are responsible for seventy-nine percent of fire fatalities and seventy-three percent of fire injuries (Ahrens, 2019). These ignition sources have proven to be the most prevalent forms of starting these types of fires. In addition, it was reported that most fire fatalities were males over the age of 55 (Ahrens, 2019). These fires are generally occurring in the colder months between November and March during the hours of 5 PM to 8 PM when, “… many people are coming home from work, are preparing dinner, or are engaging in other household activities” (Ahrens, 2019).
These ignition sources are common in many households. Cooking fires can vary greatly from stove tops, ovens, grease, toasters, empty coffee pots on heaters, tea pots, etc. Smoking materials, however, are isolated to pipes, cigarettes, and their associated equipment (lighters, matches, etc.). Heating sources, just like cooking fires, have several different ignition source types to include furnaces, stoves (pellet, gas, oil, etc.), chimney ignition, etc. Electrical distribution and lighting malfunctions or surges caused roughly 7 percent of home structure fires and accounted for ten percent of residential deaths (Ahrens, 2019). Lastly, intentionally set residential fires accounted huge amounts of property loss and resulted in 380 fatalities, sixty four percent were linked to suicide (Ahrens, 2019).
It is critical that during home fire safety visits and non-emergent medical calls that fire departments take the time to address these matters with their citizens. Most fire deaths occurred while victims were asleep, are physically disabled (mostly geriatric), or impaired by alcohol or drugs (Ahrens, 2019). These fires are preventable and should be addressed in the public setting when appropriate.
This week is closer to what I deal with on the front lines. My departments district is 95 % residential. By the NF PA the leading reasons for home fires are Cooking, Heating, electrical distribution and lighting, Intentional and Smoking Materials.
Cooking – We see thing a lot in my area. people are cooking and forget about it. when they have the Oh Crap moment is when the smoke is rolling in to a second room. We once had someone put a pizza in the oven. but said pizza was still in the box.
Heating – This is either a issues with a wired in unit like a central forced air or a secondary unit. The secondary unit could be a Jet heater with a fuel source, or a kerosene heater that has been brought in due to the cold. this fires are more common in the lower income areas.
Electrical Distribution and lighting – This could be as simple as a shirt that has been thrown on a lamp. yep that is all it could take. the other issue is wiring of High Hat lights in to a ceiling. The wire could become punctured with a nail and the heat could spark off the insulation.
Intentional – This is usually when people run out of money. We in our district have seem more of these in past years. our area is being built up, the builders or homeowners run out of money. It could also be revenge or other reasons. This is when someone sets a home on fire with out the use of the other topics. there is usually a Gas or excellerant used.
Smoking Materials – People smoke all over the place. This is when someone falls asleep with one lit up. or someone thinks that the spark is out, but it slow burns in the mulch in the front yard.
There is a category that we have seen that is not in the NFPA data. In proper discarded Fire place materials. this happens when the ashes are taken out of the fire place and just dumped in the yard close to the house. We have seen more and more of these fires in the past winters.
Stratification is when the heat, smoke and gasses stop moving up and away from the seat of the fire. The best way for a fire department to defeat this is to use ventilation. Venting a structure can give the heat and gases somewhere to go other than banking down back in to the room. But that is a tool that we can use when we arrive on scene. Something to look at before the arrival of the FD is having lower Smoke alarms or incorporating them in to a system. Something else that would be helpful to use is the CO2 home dectors.
The reason for both of these is to have the lower levels monitored and have a front line of defence. if Stratification was to happen then the lower smoke detectors would catch some of the issue, The CO2 alarm would be a secondary device that would have high readings. the only problems would be the heat. These dectors might be exposed to higher levels of heat due to the level that they are at.
Fires where Stratification has happened is usually found by someone that sees smoke, or the dectors going off before the banking down of the gasses, heat and smoke.