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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?
#1
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:
Cooking
Heating
Electrical distribution and lighting
Intentional
Smoking materials
Home fires are responsible for seventy-nine percent of fire
fatalities and seventy-three percent of fire injuries (Ahrens,

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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.
#2
This week is closer to what I deal with on the front lines. My

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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

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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.