Flammable and combustible products are used for a wide variety of
purposes and are commonly found in the home. Gasoline is
the most common, but there are other flammable and combustible liquids
and gases used in the home including:
- paint solvents
- lighter fluid
- dry cleaning agents
- spray paint
- diesel fuel
- nail polish
Many households use natural gas, propane or fuel oil heating. Each
product poses a serious health or fire danger if not used and stored properly.
A flammable liquid in its liquid state will not burn. It only will
ignite when it vaporizes into a gaseous state. All flammable liquids
give off vapors that can ignite and burn when an ignition source such as
a lighted cigarette or spark is present.
To understand the dangers associated with flammable liquids, it is
useful to be familiar with the terms used to describe their
chemical properties. They are:
- Flash point
- Flammable/combustible liquids
- Flammable range
- Ignition temperatures
- Vapor density
Flash point - The temperature at which a particular flammable liquid
gives off vapors (vaporizes) and therefore can ignite. The
flash point differs for each type of flammable liquid. Kerosene has a
flash point of 110 degrees Fahrenheit. Gasoline has a flash
point of -40 degrees. This means that at 110 degrees or higher kerosene
gives off flammable vapors and can ignite. However,
gasoline requires a temperature of only -40 degrees to vaporize to cause
an explosion or fire. This means that when the
temperature is freezing, gasoline still vaporizes and can cause an
explosion and/or fire. At the same temperature, kerosene
cannot ignite. Liquids such as gasoline with a flashpoint below 100
degrees are called flammable liquids. Kerosene and other
liquids with a flash point above 100 degrees are referred to as
Flammable range refers to the percentage of a flammable liquid, in its
gaseous state, to air to create an explosive mixture. This
varies with different flammable liquids. Gasoline has a flammability
range of 1.4 to 7.6 percent. This means it will ignite when
there is 1.4 parts of gasoline mixed with 100 parts air. With this in
mind, 1.4 percent is known as the lower flammable limit and
7.6 percent is the upper flammable limit of the flammable range. A
product mixed with air below the low end of its flammable
range is too lean to burn. A flammable liquid which exceeds its upper
flammable limit is too rich to ignite. Ethylene oxide is
extremely flammable. It has a flammable range of 3.6 to 100 percent.
This means it can burn even if there is no air.
Gasoline has a narrow flammable range and is metered precisely in a
vehicle's carburetor to obtain the desired flammable range.
A vehicle will have trouble operating if the carburetor meters too much
gasoline. This is referred to as a rich mixture, which is
too concentrated for ignition by the spark plugs. Too little gasoline in
a vehicle's carburetor is called a lean mixture, which is too
diluted for ignition.
The ignition temperature is the temperature required for a liquid to
continue to emit vapors that can sustain
combustion. Gasoline will ignite when a heat source or electrical spark
of at least 853 degrees comes in contact with it. Natural
gas (methane) needs an ignition temperature of around 1000 degrees and
paint thinner 453 degrees.
Vapor density is the weight of a vapor relative to the weight of air.
The vapor density of natural gas causes it to be lighter than
air and will rise when exposed in the open. The vapor density of
gasoline is heavier than air and will seek low points when it is
exposed to the air. Products with a high vapor density (heavier than
air) behave much like carbon dioxide gas escaping from a
block of dry ice. (Dry ice is frozen carbon dioxide gas.) A term used in
the fire service is BLEVE. It is an acronym for "Boiling
Liquid Expanding Vapor Explosion." A BLEVE occurs when a confined liquid
is heated above its atmospheric boiling point.
The vapors expand and suddenly the container will explode.
Gasoline and Other Flammable Liquids and Gases
Gasoline is the most common flammable liquid found in the home. Used
carelessly or improperly, it is the main cause of burn
injuries among teenage boys. Gasoline is highly volatile due to its low
flash point and easily vaporizes when exposed to air.
Because it is heavier than air, it can seek out ignition sources such as
a pilot light from a water heater, an electrical spark from a
hand tool, or a lit cigarette dropped on the ground. Use care when
filling lawn mowers, chain saws and other power tools with
gasoline. Don't refill a power tool with the engine running or while the
manifold is hot. Use a funnel to pour the gas to avoid
overfilling and spilling. If gasoline is spilled, allow it to vaporize
completely. This will maintain a dry surface and reduce the
chance of ignition. Never fill gasoline in a confined space, indoors or
in a closed garage.
Never smoke around gasoline or other flammable liquids. Do not use it as
a cleaning solvent or to remove grease and oil from
automotive parts, your hands or clothing. Many people are seriously
burned each year from these mistakes. Do not pour
gasoline or other flammable liquids down the sink or into a storm drain.
This creates an explosion potential.
Do not store gasoline in the house. It should be kept in a detached
garage or in an outside storage area. Be absolutely sure it is
clear from any ignition source such as a water heater, washer or dryer.
Do not put gasoline in a cup, glass jug or old bleach
bottle. It should be stored in an approved container, which is of heavy
duty construction, has a spring-loaded, self-closing
handle and is equipped with a safety-relief plug.
Don't store gasoline in the trunk or back of the car. If you need to
carry fuel, make sure the cap is tightly closed, and fill the can
only three-fourths full, leaving an air space for vapor expansion.
Kerosene heaters are commonly used in many homes and businesses during
colder months of the year to provide warmth.
Kerosene is not as flammable as gasoline but just as dangerous. Fill a
kerosene heater outdoors using a fill spout. Never fill a
heating unit while hot and be sure the area is ventilated. Kerosene
should be stored away from the home and any heat or
ignition sources. It should be stored in an approved container like
Other flammable liquids and gases
For health and safety reasons, paint should be used in a ventilated
area. It should be stored in a secured can when not being
used. Spray paint and paint solvents such as lacquer thinner, and paint
brush cleaner are highly flammable and should be stored
away from heat or ignition sources. Other cleaners such as naptha and
toluene can be ignited by static electricity from one's
clothing. These products should be stored in secured containers away
from the home in a detached storage area.
You may have a good reason to have benzine in the house - as a dry
cleaning fluid or as a fluid for your cigarette lighter. Even
then, you should keep the smallest quantity possible on hand...in a
tightly capped container...stored securely away in a cool
place. Benzene (with an "e"), otherwise known as benzol, is a very
serious fire and health hazard (a known carcinogen). Do not
use or store it under any circumstances.
Denatured alcohol may be required for some uses in the home, perhaps as
a rubbing solution. While it is not quite as dangerous
as some of the others, it is nonetheless highly flammable and should be
used and stored with as much caution as any other
Many pesticides are not only poisonous, but are highly flammable. When
using pesticides, be sure you are away from any heat
or ignition source. Always keep pesticides in their original containers.
Rags which have been used to wipe or clean petroleum products may
spontaneously ignite. Cleaning rags soaked in oil,
furniture polish, turpentine, or paint should be kept in a
tightly-sealed metal container or thrown away immediately after use.
Survival Actions Regarding Flammable Liquids
Even if you have a small spill involving a flammable liquid, immediately
open your windows to ventilate the area. Do not use fans
or other electrical devices, which might provide an ignition source and
cause an explosion. If you get some of the liquid on your
skin, remove the affected clothing and wash your skin with soap and
water. Soak your clothes in water before washing them. If
a large spill occurs, evacuate the area immediately and call 9-1-1.
A small fire involving a flammable liquid can be controlled with a class
B fire extinguisher. Never try to extinguish a flammable
liquid fire with water. This could cause the fire to spread. Do not try
to control a fire involving compressed gases such as butane
or propane. They are extremely dangerous. For a large fire involving a
flammable liquid, evacuate the area and call 9-1-1.
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