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Fire Hazards Defined
Fire hazards are conditions that favor fire development or growth. Three elements are required to start
and sustain fire: (1) oxygen; (2) fuel; and (3) heat. Because oxygen is naturally present in most earth
environments, fire hazards usually involve the mishandling of fuel or heat.
Fire, or combustion, is a chemical reaction between oxygen and a combustible fuel. Combustion is the
process by which fire converts fuel and oxygen into energy, usually in the form of heat. By-products of
combustion include light and smoke. For the reaction to start, a source of ignition, such as a spark or
open flame, or a sufficiently high temperature is needed. Given a sufficiently high temperature, almost
every substance will burn. The ignition temperature or combustion point is the temperature at which a
given fuel can burst into flame.
Fire is a chain reaction. For combustion to continue, there must be a constant source of fuel, oxygen,
and heat (see Figure 19–1). The flaming mode is represented by the tetrahedron on the left (heat,
oxidizing agent, and reducing agent) that results from a chemical chain reaction. The smoldering mode is
represented by the triangle on the right. Exothermic chemical reactions create heat. Combustion and
fire are exothermic reactions and can often generate large quantities of heat. Endothermic reactions
consume more heat than they generate. An ongoing fire usually provides its own sources of heat. It is
important to remember that cooling is one of the principal ways to control a fire or put it out.
Figure 19–1 Fire tetrahedron (L) and fire triangle (R).
Figure 19–1 Full Alternative Text
All chemical reactions involve forming and breaking chemical bonds between atoms. In the process of
combustion, materials are broken down into basic elements. Loose atoms form bonds with each other
to create molecules of substances that were not originally present.
Carbon is found in almost every flammable substance. When a substance burns, the carbon is released
and then combines with the oxygen that must be present to form either carbon dioxide or carbon
Carbon dioxide is produced when there is more oxygen than the fire needs. It is not toxic, but it can be
produced in such volumes that it seriously reduces the concentration of oxygen in the air surrounding
the fire site. Carbon monoxide—a colorless, odorless, deadly gas— is the result of incomplete
combustion of a fuel. It is produced when there is insufficient oxygen to burn the fuel present efficiently.
In general, most fires have insufficient oxygen and therefore produce large quantities of carbon
monoxide. It is important in any intentional industrial fire that the fuel be consumed as completely as
possible. This will reduce ash and minimize smoke and gases, including carbon monoxide.
Hydrogen, found in most fuels, combines with oxygen to form water. Synthetic polymers, found in
plastics and vinyls, often form deadly fumes when they are consumed by fire, or when they melt or
disintegrate from being near fire or high heat. Burning, melting, or disintegrating plastic at a fire site
should be presumed to be releasing toxic fumes.
Liquids and solids, such as oil and wood, do not burn directly but must first be converted into a
flammable vapor by heat. Hold a match to a sheet of paper, and the paper will burst into flames. Look
closely at the paper, and you will see that the paper is not burning. The flames reside in a vapor area just
above the surface of the sheet.
Vapors will burn only at a specific range of mixtures of oxygen and fuel, determined by the composition
of the fuel. At the optimum mixture, a fire burns, generates heat and some light, and produces no other
by-products. In an unintentional fire, the mixture is constantly changing as more or less oxygen is
brought into the flames and more or less heat is generated, producing more or fewer vapors and
Remove the fire’s access to fuel or remove the oxygen, and the fire dies. Although a spark, flame, or
heat may start a fire, the heat that a fire produces is necessary to sustain it. Therefore, a fire may be
extinguished by removing the fuel source, starving it of oxygen, or cooling it below the combustion
point. Even in an oxygen-rich, combustible environment, such as a hospital oxygen tent, fire can be
avoided by controlling heat and eliminating sparks and open flames (see Figure 19–2). The broken lines
in the tetrahedron and the triangle indicate that the necessary elements are removed.
Figure 19–2 The broken tetrahedron and broken triangle.
Figure 19–2 Full Alternative Text
An explosion is a very rapid, contained fire. When the gases produced exceed the pressure capacity of
the vessel, a rupture or explosion must result. The simplest example is a firecracker. The fuse, which
usually contains its own source of oxygen, burns into the center of a firecracker. The surrounding
powder ignites, and the heat produced vaporizes the balance of the explosive material and ignites it.
The tightly wrapped paper of the firecracker cannot contain the expanding gases. The firecracker
explodes, in much less time than was required to read about it.
Heat always flows from a higher temperature to a lower temperature, never from a lower temperature
to a higher temperature without an outside force being applied. Fires generate heat, which is necessary
to sustain the fire. Excess heat is then transferred to surrounding objects, which may ignite, explode, or
decompose. Heat transfer is accomplished by three means, usually simultaneously: (1) conduction; (2)
radiation; and (3) convection.
Conduction is direct thermal energy transfer. On a molecular level, materials near a source of heat
absorb the heat, raising their kinetic energy. Kinetic energy is the energy resulting from a moving object.
Energy in the form of heat is transferred from one molecule to the next. Materials conduct heat at
varying rates. Metals are very good conductors of heat. Concrete and plastics are poor conductors,
hence good insulators. Nevertheless, a heat buildup on one side of a wall will transfer to the other side
of the wall by conduction.
Radiation is electromagnetic wave transfer of heat to a solid. Waves travel in all directions from the fire
and may be reflected off a surface, as well as absorbed by it. Absorbed heat may raise the temperature
beyond a material’s combustion point, and then a fire erupts. Heat may also be conducted through a
vessel to its contents, which will expand and may explode. An example is the spread of fire through an
oil tank field. A fire in one tank can spread to nearby tanks through radiated heat, raising the
temperature and pressure of the other tank contents.
Convection is heat transfer through the movement of hot gases. The gases may be the direct products of
fire, the results of a chemical reaction, or additional gases brought to the fire by the movement of air
and heated at the fire surfaces by conduction. Convection determines the general direction of the
spread of a fire. Convection causes fires to rise as heat rises and move in the direction of the prevailing
All three forms of heat transfer are present at a campfire. A metal poker left in a fire gets red hot at the
flame end. Heat is conducted up the handle, which gets progressively hotter until the opposite end of
the poker is too hot to touch. People around the fire are warmed principally by radiation, but only on
the side facing the fire. People farther away from the fire will be warmer on the side facing the fire than
the backs of people closer to the fire. Marshmallows toasted above the flames are heated by convection
(see Figure 19–3).
Figure 19–3 Campfire with convection heat.
Figure 19–3 Full Alternative Text
Spontaneous combustion is rare, but it can happen. Organic compounds decompose through natural
chemical processes. As they degrade, they release methane gas (natural gas), an excellent fuel. The
degradation process—a chemical reaction—produces heat. In a forest, the concentrations of
decomposing matter are relatively minimal, and both the gas and the heat vent naturally.
A classic example of spontaneous combustion is a pile of oil-soaked rags. A container of oil seldom
ignites spontaneously. A collection of clean fabrics seldom bursts into flames. Rags soaking completely
within oil are usually safe. One oil-soaked rag is unlikely to cause a problem. However, in a pile of oilsoaked rags—especially in a closed container—the chemistry is quite different.
The fibers of the rags expose a large surface area of oil to oxidation. The porous nature of rags allows
additional oxygen to be absorbed, replacing the oxygen already consumed. When the temperature rises
sufficiently, the surfaces of the oil on the rags vaporize.
Hypergolic reactions occur when mixing fuels. Oxidizers produce just such a rapid heat buildup, causing
immediate combustion at room temperature with no apparent source of ignition. Although the term
hypergolic originated with rocket propellants, the phenomenon has been around for a long time.
Pyrophor hypergolic fuels are those that self-ignite in the presence of oxygen found at normal
atmospheric concentrations. One example is white phosphorus, which is kept underwater. If it starts to
dry out, the phosphorus erupts in flames.
Sources of Fire Hazards
Almost everything in an industrial environment can burn. Metal furniture, machines, plaster, and
concrete block walls are usually painted. Most paints and lacquers will easily catch fire. Oxygen is almost
always present. Therefore, the principal method of fire suppression is passive—the absence of sufficient
heat. Within our environment, various conditions elevate the risk of fire and so are termed fire hazards.
For identification, fires are classified according to their properties, which relate to the nature of the fuel.
The properties of the fuel directly correspond to the best means of combating a fire (see Figure 19–4).
Figure 19–4 Classes of fire.
Without a source of fuel, there is no fire hazard. However, almost everything in our environment can be
a fuel. Fuels occur as solids, liquids, vapors, and gases.
Solid fuels include wood, building decorations and furnishings such as fabric curtains and wall coverings,
and synthetics used in furniture. What would an office be without paper? What would most factories be
without cardboard and packing materials such as Styrofoam molds and panels, shredded or crumpled
papers, bubble wrap, and shrink wrap? All these materials easily burn.
Few solid fuels are, or can be made, fireproof. Even fire walls do not stop fires, although they are
defined by their ability to slow the spread of fire. Wood and textiles can be treated with fire- or flameretardant chemicals to reduce their flammability.
Solid fuels are involved in most industrial fires, but mishandling flammable liquids and flammable gases
is a major cause of industrial fires. Two often-confused terms applied to flammable liquids are flash
point and fire point. The flash point is the lowest temperature for a given fuel at which vapors are
produced in sufficient concentrations to flash in the presence of a source of ignition. The fire point is the
minimum temperature at which the vapors continue to burn, given a source of ignition. The autoignition temperature is the lowest point at which the vapors of a liquid or solid self-ignite without a
source of ignition. Other important terms relating to flammable and combustible liquids as defined in
OSHA’s 29 CFR 1910.106 are (1) lower flammable limit—the percentage of vapor in the air above which
a fire cannot occur because there is insufficient fuel (the mixture is too lean); (2) upper flammable
limit—the percentage of vapor in the air above which there is insufficient air for a fire (the mixture is too
rich); (3) vapor density—the weight of a flammable vapor compared to air in which air = 1; and (4) PEL—
the permissible exposure limit of a vapor expressed in parts of vapor per million parts of contaminated
air (important because many vapors present inhalation hazards as well as fire hazards).
Flammable liquids have a flash point below 37.7°C (99.8°F). Combustible liquids have a flash point at or
higher than that temperature. Both flammable and combustible liquids are further divided into the
three classifications shown in Figure 19–5.
Figure 19–5 Classes of flammable and combustible liquids.
As the temperature of any flammable liquid increases, the amount of vapor generated on the surface
also increases. Safe handling, therefore, requires both knowledge of the properties of the liquid and an
awareness of ambient temperatures in the work or storage place. The explosive range, or flammable
range, defines the concentrations of a vapor or gas in air that can ignite from a source. The auto-ignition
temperature is the lowest temperature at which liquids spontaneously ignite.
Most flammable liquids are lighter than water. If the flammable liquid is lighter than water, water
cannot be used to put out the fire.1 The application of water floats the fuel and spreads a gasoline fire.
Crude oil fires burn even while floating on fresh or sea water.
Unlike solids (which have a definite shape and location) and unlike liquids (which have a definite volume
and are heavier than air), gases have no shape. Gases expand to fill the volume of the container in which
they are enclosed, and they are frequently lighter than air. Released into air, gas concentrations are
difficult to monitor due to the changing factors of air, current direction, and temperature. Gases may
stratify in layers of differing concentrations but often collect near the top of whatever container in
which they are enclosed. Concentrations found to be safe when sampled at workbench level may be
close to, or exceed, flammability limits if sampled just above head height.
The products of combustion are gases, flame (light), heat, and smoke. Smoke is a combination of gases,
air, and suspended particles, which are the products of incomplete combustion. Many of the gases
present in smoke and at a fire site are toxic to humans. Other, usually nontoxic, gases may replace the
oxygen normally present in air. Most fatalities associated with fire are from breathing toxic gases and
smoke and from being suffocated because of oxygen deprivation. Gases that may be produced by a fire
include acrolein, ammonia, carbon monoxide, carbon dioxide, hydrogen bromide, hydrogen cyanide,
hydrogen chloride, hydrogen sulfide, sulfur dioxide, and nitrogen dioxide. Released gases are capable of
traveling across a room and randomly finding a spark, flame, or adequate heat source, flashing back to
the source of the gas.
The National Fire Protection Association (NFPA) has devised the NFPA 704 system for quick
identification of hazards presented when substances burn (see Figure 19–6). The NFPA’s red, blue,
yellow, and white diamond is used on product labels, shipping cartons, and buildings. Ratings within
each category are 0 to 4, where 0 represents no hazard; 4, the most severe hazard level. The colors refer
to a specific category of hazard:
Figure 19–6 Identification of fire hazards.
White= Special information
Although we do not think of electricity as burning, natural and generated electricity play a large role in
causing fires. Lightning strikes cause many fires every year. In the presence of a flammable gas or liquid
mixture, one spark can produce a fire.
Electrical lines and equipment can cause fires by a short circuit that provides an ignition spark, by arcs,
or by resistances generating a heat buildup. Electrical switches and relays commonly arc as contact is
made or broken.
Another source of ignition is heat in the form of hot surfaces. It is easy to see the flame hazard present
when cooking oil is poured on a very hot grill. The wooden broom handle leaning up against the side of a
hot oven may not be as obvious a hazard. Irons used in textile manufacturing and dry-cleaning plants
also pose a heat hazard.
Space heaters frequently have hot sides, tops, backs, and bottoms, in addition to the heat-generating
face. Hotplates, coffee pots, and coffee makers often create heated surfaces. Many types of electric
lighting generate heat, which is transferred to the lamp housing.
Engines produce heat, especially in their exhaust systems. Compressors produce heat through friction,
which is transferred to their housings. Boilers produce hot surfaces, as do steam lines and equipment
using steam as power. Radiators, pipes, flues, and chimneys, all have hot surfaces. Metal stock that has
been cut by a blade heats up as the blade does. Surfaces exposed to direct sunlight become hot surfaces
and transmit their heat by conduction to their other side. Heated surfaces are a potential source of fire.
Fire Dangers to Humans
Direct or near direct contact with flame, also known as thermal radiation, is obviously dangerous to
humans. Flesh burns, as do muscles and internal organs. The fact that we are 80 percent water, by some
estimations, does not mitigate the fact that virtually all the other 20 percent burns. Nevertheless, burns
are not the major cause of death in a fire.
NFPA statistics show that most people die in fires from suffocating or breathing smoke and toxic fumes.
Carbon dioxide can lead to suffocation because it can be produced in large volumes, depleting oxygen
from the air. Many fire extinguishers use carbon dioxide because of its ability to starve the fire of oxygen
while simultaneously cooling the fire. The number one killer in fires is carbon monoxide, which is
produced in virtually all fires involving organic compounds. Carbon monoxide is produced in large
volumes and can quickly reach lethal dosage concentrations.
Figure 19–7 shows the major chemical products of combustion. Other gases may be produced under
some conditions. Not all these gases are present at any particular fire site. Many of these compounds
will further react with other substances often present at a fire. For example, sulfur dioxide will combine
with water to produce sulfuric acid. Oxides of nitrogen may combine with water to produce nitric acid.
Sulfuric acid and nitric acid can cause serious acid burns.
Figure 19–7 Major chemical products of combustion.
Detection of Fire Hazards
Many automatic fire detection systems are used in industry today. Many systems can warn of the
presence of smoke, radiation, elevated temperature, or increased light intensity. Thermal expansion
detectors use a heat-sensitive metal link that melts at a predetermined temperature to make contact
and ultimately sound an alarm. Heat-sensitive insulation can be used, which melts at a predetermined
temperature, thereby initiating a short circuit and activating the alarm.
Photoelectric fire sensors detect changes in infrared energy that is radiated by smoke, often by the
smoke particles obscuring the photoelectric beam. A relay is open under acceptable conditions and
closed to complete the alarm circuit when smoke interferes.
Ionization or radiation sensors use the tendency of a radioactive substance to ionize when exposed to
smoke. The substance becomes electrically conductive with the smoke exposure and permits the alarm
circuit to be completed.
Ultraviolet detectors or infrared detectors sound an alarm when the radiation from fire flames is
detected. When rapid changes in radiation intensities are detected, a fire alarm signal is given.
The Occupational Safety and Health Administration (OSHA) has mandated the monthly and annual
inspection and recording of the condition of fire extinguishers in industrial settings. A hydrostatic test to
determine the integrity of the fire extinguisher metal shell is recommended according to the type of fire
extinguisher. The hydrostatic test measures the capability of the shell to contain internal pressures and
the pressure shifts expected to be encountered during a fire.
Reduction of Fire Hazards
The best way to reduce fires is to prevent them. A major cause of industrial fires is hot, poorly insulated
machinery and processes. One means of reducing a fire hazard is the isolation of the three triangle
elements: fuel, oxygen, and heat. In the case of fluids, closing a valve may stop the fuel element.
Fires may also be prevented by the proper storage of flammable liquids. Liquids should be stored as
In flame-resistant buildings that are isolated from places where people work. Proper drainage and
venting should be provided for such buildings.
In tanks below ground level.
On the first floor of multistory buildings.
Substituting less-flammable materials is another effective technique for fire reduction. A catalyst or fire
inhibitor can be employed to create an endothermic energy state that eventually smothers the fire.
Several ignition sources can be eliminated or isolated from fuels:
Prohibit smoking near any possible fuels.
Store fuels away from areas where electrical sparks from equipment, wiring, or lightning may occur.
Keep fuels separate from areas where there are open flames. These may include welding torches,
heating elements, or furnaces.
Isolate fuels from tools or equipment that may produce mechanical or static sparks. Other strategies for
reducing the risk of fires are as follows:
Clean up spills of flammable liquids as soon as they occur. Properly dispose of the materials used in the
Keep work areas free from extra supplies of flammable materials (e.g., paper, rags, boxes). Have only
what is needed on hand with the remaining inventory properly stored.
Run electrical cords along walls rather than across aisles or in other trafficked areas. Cords that are
walked on can become frayed and dangerous.
Turn off the power and completely de-energize equipment before conducting maintenance procedures.
Don’t use spark- or friction-prone tools near combustible materials.
Routinely test fire extinguishers.
Number, Location, and Selection of Portable Fire Extinguishers
Organizations are required by OSHA in 29 CFR 1910.150(c) to have on hand the proper number of
portable fire extinguishers of the right type and in the right locations. For example, OSHA has the
following requirements concerning the number and locations of portable fire extinguishers: (1) A fire
extinguisher rated no less than 2A is required for each 3,000 square feet of building areas to be
protected or any major fraction of that area; (2) No fire extinguisher may be located more than 100 feet
from any point in the protected area; (3) One or more fire extinguishers rated no less than 2A shall be
located on each floor of a multi-story building; (4) In multi-story buildings at least one fire extinguisher
must be located adjacent to stairways; (5) A fire extinguisher rated no less than 10A must be located
within 50 feet of any location where five gallons or more of flammable or combustible liquids or five
pounds of flammable gas are stored or used in the workplace; (6) Toxic vaporizing liquid fire
extinguishers are prohibited; (7) Portable fire extinguishers must be maintained and inspected in
accordance with NFPA Number 10A-1970; and (8) Only fire extinguishers that have been approved by a
nationally recognized testing laboratory may be used to meet the requirements of 29 CFR 1910.150(c).
Choosing the right fire extinguishers for the setting in question is important. The determination of which
type of fire extinguisher is appropriate in a given setting is based on the class of fire that is most likely to
occur: Class A, B, C, or D. The following types of fire extinguishers are appropriate for the corresponding
class of fire:
Class A fires. These are wood, paper, and trash fires. Appropriate fire extinguishers for Class A fires are
water, foam, and multipurpose (ABC) extinguishers.
Class B fires. These are flammable liquid, gasoline, paints, and grease fires. Appropriate fire
extinguishers for Class B fires are carbon dioxide, sodium or potassium bicarbonate, or multipurpose
Class C fires. These are electrical fires. Appropriate fire extinguishers for Class C fires are carbon dioxide,
sodium or potassium bicarbonate, or multipurpose (ABC) extinguishers.
Class D fires. These are combustible metal fires. Class D fires require special extinguishing agents that
have been approved by nationally recognized testing organizations.
In larger or isolated industrial facilities, an employee fire brigade may be created. (See OSHA
requirements in next section.) Standpipe and hose systems provide the hose and pressurized water for
firefighting. Hoses for these systems usually vary from one inch to 2.5 inches in diameter.2
Automatic sprinkler systems are an example of a fixed extinguishing system because the sprinklers are
fixed in position. Water is the most common fluid released from the sprinklers. Sprinkler supply pipes
may be kept filled with water in heated buildings; in warmer climates, valves are used to fill the pipes
with water when the sprinklers are activated. When a predetermined heat threshold is breached, water
flows to the heads and is released from the sprinklers.
Portable fire extinguishers are classified by the types of fire that they can most effectively reduce. Figure
19–8 describes the four major fire extinguisher classifications. Blocking or shielding the spread of fire
can include covering the fire with an inert foam, inert powder, nonflammable gas, or water with a
thickening agent added. The fire may suffocate under such a covering. Flooding a liquid fuel with
nonflammable liquid can dilute this fire element. Figures 19–9, 19–10, and 19–11 are photographs of
effective fire prevention equipment.
Figure 19–8 Fire extinguisher characteristics.
Figure 19–8 Full Alternative Text
Figure 19–9 Fireproof filing cabinets.
Source: Source: Marynchenko Oleksandr/Shutterstock.
Figure 19–10 Storing chemicals in fire-resistant barrels.
Figure 19–11 Storing biological hazards in fire-resistant barrels.
OSHA’S Regulations for Fire Brigades
Fire brigade regulations are covered in 29 CFR 1910.156 (Subpart L, Appendix A). Relevant requirements
from the regulations are as follows:
Scope. Employers are not required to form a fire brigade. However, if an employer does decide to
organize a fire brigade, the requirements of this section apply.
Prefire planning. Have prefire planning conducted by the local fire department or the workplace fire
brigade so that they may become familiar with the workplace and process hazards. Involvement with
the local fire department or fire prevention bureau is encouraged to facilitate coordination and
cooperation between members of the fire brigade and those who may be called upon for assistance
during a fire emergency.
Organizational statement. The organizational statement should contain the following information: a
description of the duties that the fire brigade members are expected to perform; the line authority of
each fire brigade officer; the number of the fire brigade officers and number of training instructors; and
a list and description of the types of awards or recognition that brigade members may be eligible to
Physical capability. The physical capability requirement applies only to those fire brigade members who
perform interior structural firefighting. Employees who cannot meet the physical capability requirement
may still be members of the fire brigade as long as such employees do not perform interior structural
firefighting. It is suggested that fire brigade members who are unable to perform interior structural
firefighting be assigned less stressful and physically demanding fire brigade duties (e.g., certain types of
training, record keeping, fire prevention inspection and maintenance, and fire pump operations).
“Physically capable” can be defined as being able to perform those duties specified in the training
requirements of Section 1910.156(c). Physical capability can also be determined by physical
performance tests or by a physical examination when the examining physician is aware of the duties
that the fire brigade member is expected to perform.
Training and education. Training and education must be commensurate with those functions that the
fire brigade is expected to perform (i.e., those functions specified in the organizational statement). Such
a performance requirement provides the necessary flexibility to design a training program that meets
the needs of individual fire brigades.
At a minimum, hands-on training is required to be conducted annually for all fire brigade members.
However, for those fire brigade members who are expected to perform interior structural firefighting,
some type of training or education session must be provided at least quarterly.
Firefighting equipment. It is important to remove from service and replace any firefighting equipment
that is damaged or unserviceable. This prevents fire brigade members from using unsafe equipment by
Firefighting equipment, except portable fire extinguishers and respirators, must be inspected at least
annually. Portable fire extinguishers and respirators are required to be inspected at least monthly.
Protective clothing. Paragraph (e) of 1910.156 does not require all fire brigade members to wear
protective clothing. It is not the intention of the standards to require employers to provide a full
ensemble of protective clothing for every fire brigade member without consideration given to the types
of hazardous environments to which the fire brigade member may be exposed. It is the intention of the
standards to require adequate protection for those fire brigade members who may be exposed to fires
in an advanced stage, smoke, toxic gases, and high temperatures. Therefore, the protective clothing
requirements apply only to those fire brigade members who perform interior structural-firefighting
Additionally, the protective clothing requirements do not apply to the protective clothing worn during
outside firefighting operations (brush and forest fires, crash crew operations) or other special
firefighting activities. It is important that the protective clothing to be worn during these types of
firefighting operations reflect the hazards that may be encountered by fire brigade members.
Respiratory protective devices. Respiratory protection is required to be worn by fire brigade members
while working inside buildings or confined spaces where toxic products of combustion or an oxygen
deficiency are likely to be present; respirators are also to be worn during emergency situations involving
toxic substances. When fire brigade members respond to emergency situations, they may be exposed to
unknown contaminants in unknown concentrations. Therefore, it is imperative that fire brigade
members wear proper respiratory protective devices during these situations. Additionally, there are
many instances where toxic products of combustion are still present during mop-up and overhaul
operations. Therefore, fire brigade members should continue to wear respirators during these types of
Training employees may be the most successful lifesaving preparation for a fire disaster. Company fire
brigade members should be trained and tested at least quarterly. Disaster preparation initially requires
management commitment and planning and continued response and recovery practice by the fire
brigade on a regular basis. Also necessary are regular, but less frequent, fire drills for all personnel.
Disaster preparations also include the integration of company planning with community plans.
Community disaster relief agencies such as the police, fire department, Red Cross, and hospitals should
be consulted and informed of company disaster preparation plans.
Preventing Office Fires
The shop floor is not the only part of the plant where fire hazards exist. Offices are also susceptible to
fires. There are approximately 7,000 office fires a year. The following strategies are helpful in preventing
Confine smoking to designated areas that are equipped with nontip ashtrays and fire-resistant
Periodically check electrical circuits and connections. Replace frayed or worn cords immediately.
Make sure that extension cords and other accessories are Underwriters Laboratories (UL)-approved and
used only as recommended.
Make sure there is plenty of air space left around copying machines and other office machines that can
Locate heat-producing appliances away from the wall or anything else that can ignite.
Frequently inspect personal appliances such as hotplates, coffee pots, and cup warmers. Assign
responsibility for turning off such appliances every day to a specific person.
Keep aisles, stairwells, and exits clear of paper, boxes, and other combustible materials.4
Development of Fire Safety Standards
The purpose of modern fire safety standards is the protection of life and the prevention of property
damage. However, the impetus for developing standards has always been and continues to be the
occurrence of major disasters. Typically, standards are developed after a major tragedy occurs in which
property is damaged on a large scale and lives are lost. Public shock turns into an outcry for action. A
flurry of political activity follows, and agencies and organizations that develop standards are called on to
develop new standards.
The trend in fire safety standards is toward performance-based standards and away from the traditional
specification-based approach. An example of each type of standard will help illustrate the difference. A
specification-based standard may require that brick, concrete, or steel material be used in a given type
of building. A performance-based standard may specify that materials used have a one-, two-, or fourhour fire resistance rating.5 Advances in the testing of engineering materials will help overcome most of
the barriers to full development and implementation of performance-based standards.
OSHA Fire Standards
OSHA standards for fire protection appear in 29 CFR 1910.156 (Subpart L). This subpart contains the
standards for fire brigades, fixed fire suppression equipment, and other fire protection systems.
Employers are not required to form fire brigades, but those who choose to do so must meet a number
of specific requirements. There are other fire-related requirements in other subparts. For example, fire
exits, emergency action plans, and means of egress are covered in Subpart E. The standards in Subpart L
are as follows:
1910.155 Scope, application, and definitions
1910.156 Fire brigades
Portable Fire Suppression Equipment
1910.157 Portable fire extinguishers
1910.158 Standpipe and hose systems
Fixed Fire Suppression Equipment
1910.159 Automatic sprinkler systems
1910.160 Fixed extinguishing systems, general
1910.161 Fixed extinguishing systems, dry chemical
1910.162 Fixed extinguishing systems, gaseous agent
1910.163 Fixed extinguishing systems, water spray and foam
Other Fire Protection Systems
1910.164 Fire detection systems
1910.165 Employee alarm systems
Figure 19–12 summarizes fire prevention and suppression strategies.
Figure 19–12 Fire prevention and suppression summary.
OSHA and Fire Prevention Plans
OSHA has both requirements and recommendations relating to the development of fire
prevention plans. The requirements apply only to organizations that use and/or store ethylene oxide (29
CFR 1910.1047), methylenedianiline (29 CFR 1910.1050), or 1, 3 butadiene (29 CFR 1910.1051).
However, OSHA recommends that all employers develop fire prevention plans. Those that have 10 or
fewer employees may communicate the plan to them verbally. Those with more than 10 employees are
to put the plan in writing, kept in the workplace, and made accessible to employees. OSHA’s
requirements/recommendations concerning fire prevention plans are as follows:
Make a list of all fire hazards in the workplace.
Record the proper handling and storage procedures for all hazardous materials in the
List potential ignition sources in the workplace and their means of control.
Record the type(s) of fire protection equipment needed to control all fire hazards in the
Develop and record procedures to control flammable and combustible waste materials.
Develop and record procedures preventing the accidental ignition of combustible material
through regular maintenance of safeguards on heat-producing equipment.
List the names or job titles of all personnel who are responsible for controlling fuel source
List the names or titles of all personnel who are responsible for preventing or controlling sources
of ignition or fires through regular equipment maintenance.
OSHA’s Requirements for Exit Routes
Establishing adequate and proper exit routes is an important part of preventing injuries and
deaths from fires. Because having adequate exit routes is so important, OSHA has specific requirements
for their provision. However, before considering OSHA’s requirements for exit routes, it is important for
safety and health professionals and other personnel to understand exit-related terminology. Key
concepts relating to exits and exit routes are as follows:
Exit routes. A continuous unobstructed path that leads from any location in the workplace to a
place of safety. Exist routes have three components: exit access, exit, and exit discharge.
Exit access. Any portion of an exit route that leads to an exit.
Exit. Any part of the exit route that provides a means of access to the exit discharge.
Exit discharge. Any part of the exit route that leads directly outside of the building or to an open
space that has access to the outside. An exit discharge may lead to a stairway, street, sidewalk, public
way, or designated refuge area, but it must lead outside the building.
With these terms understood, OSHA’s requirements for exit routes may now be summarized
under four generic headings: required number of exit routes, design considerations, operational issues,
and specific exit requirements:
Required number of exit routes. Under normal conditions, two exit routes are required.
However, more are required if the number of employees, size of the building, or arrangement of the
workspace will not allow employees to exit safely with just two exit routes. Only one exit route is
sufficient by exception if it can be demonstrated that these same factors are such that all employees
may safely exit with just one.
Examples of design requirements. Exit routes must be permanent parts of the building and must
support the maximum permitted occupancy load for each floor, ceilings of exit routes must be no less
than 7’—6” in height, and doors must be unlocked from the inside.
Examples of operational requirements. Exit routes must be kept free of explosive or highly
flammable furnishings and unobstructed by materials, equipment, locked doors, or dead-end corridors.
They must also be properly lighted for people of normal vision and equipped with “EXIT” signs in plainly
Examples of exit requirements. Exits are to be separated by fire-resistant materials and should
have only those openings that are necessary to allow access to the exit from occupied areas or to the
What is provided in this section is a representative sample of OSHA’s requirements for exit
routes. To view all of the requirements, go to OSHA’s Web site (www.osha.gov) and download 29 CFR
1910.33 through 1910.39: Exit Routes, Emergency Action Plans, and Fire Prevention Plans.
Life safety involves protecting the vehicles, vessels, and lives of people in buildings and
structures from fire. The primary reference source for life safety is the Life Safety Code, published by the
NFPA. The code applies to new and existing buildings. It addresses the construction, protection, and
occupancy features necessary to minimize the hazards of fire, smoke, fumes, and panic. A major part of
the code is devoted to the minimum requirements for design of egress necessary to ensure that
occupants can quickly evacuate a building or structure.
In this section, the term structure refers to a structure or building:
Every structure, new and existing, that is to be occupied by people must have a means of egress
and other fire protection safeguards that (1) ensure that occupants can promptly evacuate or be
adequately protected without evacuating and (2) provide sufficient backup safeguards to ensure that
human life is not endangered if one system fails.
Every structure must be constructed or renovated, maintained, and operated in such a way that
occupants are (1) protected from fire, smoke, or fumes; (2) protected from fire-related panic; (3)
protected long enough to allow a reasonable amount of time for evacuation; and (4) protected long
enough to defend themselves without evacuating.
In providing structures with means of egress and other fire protection safeguards, the following
factors must be considered: (1) character of the occupancy; (2) capabilities of occupants; (3) number of
occupants; (4) available fire protection; (5) height of the structure; (6) type of construction; and (7) any
other applicable concerns.
No lock or other device may be allowed to obstruct egress in any part of a structure at any time
that it is occupied. The only exceptions to this requirement are mental health detention and correctional
facilities. In these, the following criteria are required: (1) responsible personnel must be available to act
in the case of fire or a similar emergency and (2) procedures must be in place to ensure that occupants
are evacuated in the event of an emergency.
All exits in structures must satisfy the following criteria: (1) be clearly visible or marked in such a
way that an unimpaired individual can readily discern the route of escape; (2) all routes to a place of
safety must be arranged or clearly marked; (3) any doorway and passageway that may be mistaken as a
route to safety must be arranged or clearly marked in such a way as to prevent confusion in an
emergency; and (4) all appropriate steps must be taken to ensure that occupants do not mistakenly
enter a dead-end passageway, Figure 19–13.
Figure 19–13 Fire exits must be clearly marked.
Egress routes and facilities must be included in the lighting design wherever artificial
illumination is required in a structure.
Fire alarm systems must be provided in any facility that is large enough or so arranged that a fire
itself may not adequately warn occupants of the danger. Fire alarms should alert occupants to initiate
appropriate emergency procedures.
In any structure or portion of a structure in which a single means of egress may be blocked or
overcrowded in an emergency situation, at least two means of egress must be provided. The two means
of egress must be arranged in such a way as to minimize the possibility of both becoming impassable in
the same emergency situation.
All stairs, ramps, and other means of moving from floor to floor must be enclosed (or otherwise
protected) to afford occupants protection when used as a means of egress in an emergency situation.
These means of vertical movement should also serve to inhibit the spread of fire, fumes, and smoke
from floor to floor.
Compliance with the requirements summarized herein does not eliminate or reduce the need to
take other precautions to protect occupants from fire hazards, nor does it permit the acceptance of any
condition that could be hazardous under normal occupancy conditions.6
The information in this section is a summary of the broad fundamental requirements of the Life
Safety Code of the NFPA. More specific requirements relating to means of egress and features of fire
protection are explained in the following sections.
Fire Ratings for Doors, Walls, and Floors
A three-hour fire wall will provide protection for three hours. Right? Not necessarily. In fact, any
relationship between a fire rating and the reality of fire resistance may be little more than coincidental.
The problem is that the factors used to determine fire ratings are outdated. They are based on materials
that were in use many years ago and no longer have any relevance. The materials used for constructing
and furnishing buildings today are radically different from those upon which fire ratings are based.
Consider fire ratings overvalued, and plan for less time than they allow.
Means of Egress
This section explains some of the more important issues in the Life Safety Code relating to
means of egress. Students and practitioners, who need more detailed information, are encouraged to
refer to the Life Safety Code.
Doors. Doors that serve as exits must be designed, constructed, and maintained in such a way
that the means of egress is direct and obvious. Windows that could be mistaken for doors in an
emergency situation must be made inaccessible to occupants.
Capacity of means of egress. The means of egress must have a capacity sufficient to
accommodate the occupant load of the structure calculated in accordance with the requirements of the
Life Safety Code.
Number of means of egress. Any component of a structure must have a minimum of two means
of egress (with exceptions as set forth in the code). The minimum number of means of egress from any
story or any part of a story is three for occupancy loads of 500 to 1,000 and four for occupancy loads of
more than 1,000.
Arrangement of means of egress. All exits must be easily accessible at all times in terms of both
location and arrangement.
Measurement of travel distance to exits. The travel distance to at least one exit must be
measured on the walking surface along a natural path of travel beginning at the most remote occupied
space and ending at the center of the exit. Distances must comply with the code.
Discharge from exits. All exits from a structure must terminate at a public way or at yards,
courts, or open spaces that lead to the exterior of the structure.
Illumination of means of egress. All means of egress shall be illuminated continuously during
times when the structure is occupied. Artificial lighting must be used as required to maintain the
necessary level of illumination. Illumination must be arranged in such a way that no area is left in
darkness by a single lighting failure.
Emergency lighting. Emergency lighting for all means of egress must be provided in accordance
with the code. In cases where maintaining the required illumination depends on changing from one
source of power to another, there shall be no appreciable interruption of lighting.
Marking of means of egress. Exits must be marked by readily visible, approved signs in all cases
where the means of egress is not obviously apparent to occupants. No point in the exit access corridor
shall be more than 100 feet from the nearest sign, Figure 19–14.
Figure 19–14 Exits must be clearly marked.
Source: Igor Stevanovic/Shutterstock
Special provisions for high-hazard areas. If an area contains contents that are classified as highly
hazardous, occupants must be able to exit by traveling no more than 75 feet. At least two means of
egress must be provided, and there shall be no dead-end corridors.7
Exit sign requirements. All exit signs must contain the word “Exit” in plainly legible letters that
are no less than six inches high and 0.75 inches wide (in the main stroke of the letter).
Exit sign lighting requirements. Light sources for exit signs may be external or internal.
Regardless of whether the light source is external or internal, the face of the sign must be continually
illuminated while the building is occupied from a reliable source as determined by the Authority Having
The requirements summarized in this section relate to the fundamental specifications of the Life
Safety Code relating to means of egress. For more detailed information concerning general
requirements, means of egress, and other factors such as fire protection and fire protection equipment,
refer to the actual code.
For employees who work in jobs in which flames or electric arcs may occur, wearing flameresistant clothing can be a lifesaver.8 Electric arcs are the result of electricity passing through ionized air.
Although electric arcs last for only a few seconds, during that time they can produce extremely high
levels of heat and flash flame.
OSHA’s standards relating to flame-resistant clothing are found in CFR 1910.269, Paragraph 1.
Key elements of Paragraph 1 explain the employer’s responsibilities regarding personal protective
equipment and flame-resistant clothing.
CFR 1910.269, Paragraph 1(6) reads as follows:
When work is performed within reaching distance of exposed energized parts of equipment, the
employer shall ensure that each employee removes or renders nonconductive all exposed conductive
articles, such as key or watch chains, rings, or wrist watches or bands, unless such articles do not
increase the hazards associated with contact with the energized parts.
The employer shall train each employee who is exposed to the hazards or flames or electric arcs
in the hazards involved.
The employer shall ensure that each employee who is exposed to the hazards of flames or
electric arcs does not wear clothing that, when exposed to flames or electric arcs, could increase the
extent of injury that would be sustained by the employee.
Note: Clothing made from the following types of fabrics, either alone or in blends, is prohibited
by this paragraph, unless the employer can demonstrate that the fabric has been treated to withstand
the conditions that may be encountered or that the clothing is worn in such a manner as to eliminate
the hazard involved: acetate, nylon, polyester, and rayon, Figure 19–15.
Figure 19–15 The proper PPE is critical.
Source: Tyler Olson/Shutterstock
Fuse Handling. When fuses must be installed or removed with one or both terminals energized
at more than 300 volts or with exposed parts energized at more than 50 volts, the employer shall ensure
that tools or gloves rated for the voltage are used. When expulsion-type fuses are installed with one or
both terminals energized at more than 300 volts, the employer shall ensure that each employee wears
eye protection meeting the requirements of Subpart I of this Part, uses a tool rated for the voltage, and
is clear of the exhaust path of the fuse barrel.9
Fire Safety Programs
Organizations that are interested in protecting their employees from fire hazards should
remember the Boy Scouts’ motto: Be prepared. The best way to be prepared is to establish a
comprehensive fire safety program that encompasses all the functional activities required for being
prepared.10 A comprehensive fire safety program should have at least the following components:
assessment, planning, awareness/prevention, and response.
An effective way to develop, implement, and maintain a comprehensive fire safety program is to
establish a cross-functional fire safety committee. “Cross-functional” means that it should have
members from the organization’s various functional units. It should also have at least one executivelevel manager to ensure and demonstrate that level of support. This approach has several advantages
including the following: (1) it focuses the eyes and ears of a broad cross section of the workforce on fire
safety; (2) it ensures a broad base of input; and (3) it ensures executive-level commitment. This
committee should be staffed and chaired by the organization’s highest ranking safety and health
Assessment of the workplace for fire hazards should be continuous and ongoing. Although the
organization’s safety and health professional will have primary responsibility for this, committee
members also need to be involved and involve the departments that they represent. Members of the
safety committee should be trained in the fundamentals of fire hazard assessment by the safety and
health professional. They should then pass on this knowledge to employees in their departments, units,
and teams. In this way, all employees are involved in continually looking for fire hazards and
communicating their concerns to the safety committee.
OSHA requires that an organization’s emergency fire safety plan have at least the following
Emergency escape procedures and routes
Critical “shutdown” procedures
Employee headcount procedures
Rescue and medical procedures
Procedures for reporting fires and emergencies
Important contact personnel for additional information
Once the plan is in place, it should be reviewed at least annually and updated as necessary.
Figure 19–16 Have an emergency evacuation plan in place.
Awareness and Prevention
After the fire safety committee has completed the emergency plan and upper management has
approved it, employees must become acquainted with it. All employees should receive awareness
training so that they understand their role in carrying out the emergency plan. The fire safety committee
should evaluate the training program periodically, using guidelines such as the following:
Do all employees know the role they play in implementing the emergency plan?
How are employees with disabilities provided for?
Do all employees understand the escape plans? Do they understand the evacuation procedures?
Do all new and temporary employees receive training?
Are all employees informed when the plan is revised?
Is a comprehensive drill undertaken at least once each year?
Are all employees familiar with the sound of the alarm system?
Is the alarm system checked periodically?
Are sufficient fire detection devices in place? Are they tested periodically?
Do all employees know the most likely causes of fires?
Response and Fire Drills
Accidents can happen in even the safest organizations. Therefore, it is very important that
employees understand the emergency plan and periodically practice responding. Just knowing what the
plan says is not sufficient. People do not always think clearly in an emergency situation. They will,
however, do what they have learned to do through practice. Consequently, one of the fire safety
committee’s most important responsibilities is to arrange periodic drills so that employees automatically
There is a tendency among people to take fire drills lightly or to simply ignore them. To
overcome this tendency, apply the following strategies:
Have unannounced fire drills periodically and treat them like the real thing in every way. People
behave differently when they know it’s just a drill.
Do not allow personnel to simply ignore fire drills.
Make sure that personnel responsible for shutting down operations in the event of a fire are
properly trained to: (1) know how to do their shutdown jobs and still get out safely and (2) make a
rational decision concerning when to evacuate even if shut-down procedures have not been
Complete procedures for accounting for all personnel. Do not ignore this critical aspect of an
evacuation just because it is a drill.
Periodically use outside third-parties to evaluate your evacuation procedures and act
immediately on any discrepancies noted.
Many chemical and toxic substances used in modern organizations are flammable or
combustible. Consequently, under certain conditions, they can explode. Working in these conditions
involves hazards that require special precautions for handling, storing, transporting, and using such
Safety relating to explosive materials is a highly specialized field. This section discusses terms
and concepts used in this field with which modern safety and health professionals should be familiar:
A flammable substance is any substance with a flash point below 37.8°C (100.04°F) and a vapor
pressure of less than 40 psi at that temperature. Such liquids are also known as Class I liquids. They tend
to be compositions of hydrogen and carbon such as crude oil and its numerous by-products.
A combustible substance is any substance with a flash point of 37.8°C (100.04°F) or higher. Such
liquids are known as Class II liquids. They also tend to be compositions of hydrogen and carbon such as
crude oil and its numerous by-products.
The flash point is the lowest temperature at which a substance gives off sufficient vapors to
combine with air to form an ignitable mixture. Ignition can be precipitated by a spark.
The auto-ignition temperature is the lowest temperature at which a vapor-producing substance
or a flammable gas ignites even without the presence of a spark or a flame. This is sometimes known as
In most cases, a certain amount of oxygen must be present in a vapor-air mixture for an
explosion to occur. The amount that must be present for a given substance is the oxygen limit for that
Volatility is the evaporation (vaporization) capability of a given substance. The greater the
tendency of a substance to vaporize, the more volatile it is.11
Common Uses of Flammable and Combustible Substances
Flammable and combustible substances are widely used in modern organizations. Therefore, the
hazards associated with them are not limited to the industries producing such materials and substances.
The NSC lists the following as common uses of flammable and combustible substances in modern
industry and specific related precautions that should be taken with each:
Dip tanks. Dipping operations involving flammable or combustible substances should take place
in a stand-alone, one-story building constructed of noncombustible materials. The building should be (1)
well ventilated; (2) clearly marked as a hazardous area; (3) free of ignition sources; and (4) large. The dip
tank itself should be covered and should contain an automatic fire-extinguishing system.
Japanning and drying ovens. Ovens used to evaporate varnish, Japan enamel, and any other
combustible substance should be (1) well ventilated; (2) equipped with an automatic fire protection
system; and (3) have a shutdown system that activates automatically in the event of a fire or explosion.
Oil burners. Selecting the proper type of fuel for use in an oil burner is the best precaution to
prevent the accumulation and potential ignition of soot. The safest fuel to use in an oil burner is one
that meets the following criteria: (1) flash point higher than 37.8°C (100.04°F); (2) hydrocarbon-based;
and (3) acid- and grit-free. In addition, the supply tank should be located outside the building housing
the oil burner and should be underground. The top of the storage tank should be lower than all pipes
entering it. Finally, the oil burner should have an automatic system for preventing the discharge of
unburned oil into a hot firebox.
Cleaning solvents. Many of the solvents used to clean metal parts are combustible. The primary
precaution when cleaning metal parts is selecting substances that are not easily ignited. Additional
precautions include ventilation and the selection of a cleaning area that is free of ignition sources.
Internal combustion engines. Internal combustion engines are widely used in modern industry
for powering such equipment as forklifts and lift trucks. Because they are typically fueled with gasoline
or diesel fuel, there are fire and explosive hazards associated with this operation. Precautions include (1)
proper maintenance; (2) good housekeeping; (3) shutdown of engines and cooling of exhaust pipes
before filling fuel tanks, and (4) a well-ventilated area for filling fuel tanks.
Spray-painting booths. The hazard associated with spray-painting booths is that an explosive
mixture of paint vapor and air can occur. To prevent such occurrences, proper ventilation is critical.
Regular cleaning of the booth to remove accumulated spray deposits is also important. Paint booths
should be equipped with automatic fire protection systems.12
The preceding section lists only some of the many ways in which potentially explosive materials
are used in modern organizations.
Other Health Hazards of Explosive Materials
The health hazards associated with explosions and fires are well known. The potential for
serious injury or death from the force of a blast or from burns is very high. However, there are other
hazards associated with explosive and combustible materials. These include skin irritation, intoxication,
Irritation can occur when the skin comes in contact with hazardous substances. The degree of
irritation can range from minor to severe, depending on the type of substance, its concentration, and
the duration of contact. Intoxication can occur when an employee breathes the vapors of combustible
substances. This can cause impaired judgment, performance, and reaction time, which can, in turn,
result in an accident. Finally, the vapors from combustible materials can accumulate in confined spaces.
When this happens, the air becomes contaminated and is both toxic and explosive. In such cases, the
hazard of suffocation must be added to those associated with explosives.13
OSHA’s Firefighting Options
Even with the best fire prevention program, and even with the best engineering controls in
place, it may still be necessary to manually fight fires at some point. Some companies prefer to have
their employees evacuate the premises in the event of a fire. However, for some companies the
potential for fires is so much a part of daily operations that they prefer to equip their employees to fight
fires. Companies that either allow or expect employees to help fight fires should follow the guidelines
set forth by OSHA for manual firefighting.14
There are three options available to companies that wish to have their employees participate in
All employees are involved.
Only designated employees are involved.
Only employees who are part of an established fire brigade are involved.
Each of these options has its own set of requirements.
Option 1: All Employees Fight Fires
With this option, all employees are allowed to fight fires. However, first they are required to:
Have and understand an emergency action plan provided by the company
Have and understand a fire prevention plan provided by the company
Complete annual training and refresher training concerning their duties in fighting fires and in
the proper use of fire extinguishers
Option 2: Designated Employees Fight Fires
With this option, only selected employees are allowed to fight fires. First they are required to:
Have and understand an emergency action plan provided by the company
Have and understand a fire prevention plan provided by the company
Complete annual training and refresher training concerning their duties fighting fires and in how
to properly use fire extinguishers
Option 3: Fire Brigades Fight Fires
With this option, only those employees who are part of an established fire brigade are allowed
to fight fires. Fire brigades are divided into two types—incipient and interior structural. An incipient fire
brigade is used to control only small fires. It requires no special protective clothing or equipment. An
interior structural fire brigade may fight any type of fire provided it has been issued the appropriate
protective clothing and equipment, Figure 19–17.
Figure 19–17 Fire brigades must be properly trained and equipped.
The requirements for each type of fire brigade are different. Employees who are part of an
incipient fire brigade are required to:
Have and understand an emergency action plan provided by the company
Have and understand a fire protection plan provided by the company
Have and understand an organizational statement that establishes the scope, organizational
structure, training, equipment, and functions of the fire brigade
Have and understand standard operating procedures for the fire brigade to follow during
Complete annual training and refresher training that is hands-on in nature
The requirements of an interior structural fire brigade are the same as those for an incipient fire
brigade through the standard operating procedures. However, there are also additional requirements,
Satisfactory completion of medical examinations that verify their fitness to participate
Special protective clothing and equipment of the type used by local fire departments, including
self-contained breathing equipment
Quarterly, as opposed to annual, training and retraining that is hands-on in nature
Self-Assessment in Fire Protection
Safety and health personnel cannot be everywhere at the same time. Consequently, it is wise to
enlist the assistance of supervisors and employees in fire protection. An excellent way to do this is to
provide them with a self-assessment checklist that will guide them in scanning their areas of
responsibility for fire hazards. Such checklists should contain at least the following questions:
Are portable fire extinguishers properly mounted, readily accessible, and available in adequate
number and type?
Are fire extinguishers inspected monthly for both operability and general condition with
appropriate notation made on their respective tags?
Are fire extinguishers recharged regularly and are the dates noted on their tags?
Are interior standpipes and valves inspected regularly?
Is the fire alarm system tested regularly?
Are employees trained in the proper use of fire extinguishers?
Are employees trained concerning under what conditions they should help fight fires and under
what conditions they should evacuate?
Are the nearest fire hydrants flushed annually?
Are the nearest fire hydrants maintained regularly?
Are avenues and ingress and egress clearly marked?
Are all avenues of ingress and egress kept free of clutter and other types of obstructions?
Are fire doors and shutters in good working condition?
Are fusible links in place and readily accessible?
Is the local fire department familiar with the facility and any specific hazards?
Is the automatic sprinkler system in good working order, maintained on a regular basis, given
the proper overhead clearance, and protected from inadvertent contact damage?15
Hot Work Program
It is important for industrial firms that do hot work to have a comprehensive hot work program.
OSHA defines hot work as work that involves welding, cutting, chipping, and the use of tools that cause
sparks. Even before getting into the specifics of developing a comprehensive hot work program, safety
professionals personnel understand the following foundational precautionary measure: “Flammable,
combustible, or ignitable materials should be kept a minimum of 20 to 35 feet away from the hot work,
or those materials should be covered with a flame-retardant covering for protection.”16
Components of the Hot Work Program17
Safety professionals should take the lead in developing a comprehensive hot work program.
Components of the program include safety equipment, work practices, contractor requirements, fire
watch, and permits. The details of each of these components should be put in writing and training
should be provided so that all stakeholders understand their roles and responsibilities in preventing fires
that might be caused by hot work.
Fire Safety Equipment
Does the facility have the proper fire safety equipment in place? The program should require
that the following fire safety equipment be in place, operable, and properly maintained over time: (1)
fire sprinklers; (2) fire extinguishers of the proper type located throughout the work area; (3) back-up
fire extinguishers for extra protection during hot work projects; and (4) fire-retardant tarps or thin
sheets of metal for covering combustible and ignitable materials in the hot work area.
Precautionary Work Practices
The program should require at least the following precautionary work practices: (1) a minimum
of 35 feet of separation between the hot work and combustible and ignitable material; (2) use of a
flammable gas meter to detect gas vapors in the hot work area (hot work should not be allowed if the
meter reads anything but zero); (3) do not allow hot work when the sprinkler system is inoperable; (4)
keep floors cleanly swept of combustible and ignitable materials in the hot work area; (5) combustible
floors should be dampened or covered with an appropriate protective material; (6) when performing
hot work on walls, ceilings, or open-rack flooring openings should be covered and fire-resistive
tarpaulins should be suspended beneath the work; (7) use metal sheeting or damp cloths or both when
hot work is performed within three feet of a sprinkler; (8) remove all flammable gases and liquids from
the hot work area; and (9) use lockout/tagout procedures and other standard procedures when
performing hot work in a confined space.
Contractors that perform hot work in your facility should have their own hot work program that
your organization approves or they should be required to follow yours. All of the contractor’s employees
must know their duties and responsibilities relating to the plan and complete the same type of training
required of your employees.
Fire Watch Requirements
During hot work, an individual should be posed in the area with only one responsibility:
watching for and responding immediately to fires. This individual should carry with him a properly rated
fire extinguisher and a means of communicating with emergency personnel.
An in-house permit should be developed so that safety personnel and other stakeholders can
assure themselves that all proper steps in the plan have been taken and approved before hot work
begins. There are examples of hot work permits on the Internet, but make sure to tailor the permit
chosen specifically for your organization. It should ensure that everything required in the plan has been
accomplished before hot work begins.
Chemical Burn Injuries
Chemical burn injuries are covered only briefly in this chapter. Readers are referred to Chapter
16 for a more in-depth coverage of this kind of injury. Chemical burn injuries are a special category with
which prospective and practicing safety professionals should be familiar. The greatest incidence of
chemical burns (approximately one-third) occurs in manufacturing. Other high-incidence industries are
services, trade, and construction.
The chemicals that most frequently cause chemical burn injuries include acids and alkalies;
soaps, detergents, and cleaning compounds; solvents and degreasers; calcium hydroxide (a chemical
used in cement and plaster); potassium hydroxide (an ingredient in drain cleaners and other cleaning
solutions); and sulfuric acid (battery acid). Almost 46 percent of all chemical burn injuries occur while
workers are cleaning equipment, tools, and vehicles.
What is particularly disturbing about chemical burn injuries is that a high percentage of them
occur in spite of the use of personal protective equipment, the provision of safety instruction, and the
availability of treatment facilities. In some cases, the personal protective equipment is faulty or
inadequate. In others, it is not properly used in spite of instructions.
Preventing chemical burn injuries presents a special challenge to safety and health
professionals. The following strategies are recommended:
Familiarize yourself, the workers, and their supervisors with the chemicals that will be used and
their inherent dangers.
Secure the proper personal protection equipment for each type of chemical that will be used.
Provide instruction on the proper use of personal protection equipment and then make sure
that supervisors confirm that the equipment is used properly every time.
Monitor that workers are wearing personal protection equipment and replace it when it begins
to show wear.
Heat Burn Injuries
Heat burn injuries present a special challenge to safety and health professionals in the modern
workplace. Almost 40 percent of all such injuries occur in manufacturing every year. The most frequent
causes are flame (this includes smoke inhalation injuries), molten metal, petroleum asphalts, steam, and
water. The most common activities associated with heat burn injuries are welding, cutting with a torch,
and handling tar or asphalt.
Following are several factors that contribute to heat burn injuries in the workplace. Safety and
health professionals who understand these factors will be in a better position to prevent heat burn
Employer has no health and safety policy regarding heat hazards.
Employer fails to enforce safety procedures and practices.
Employees are not familiar with the employer’s safety policy and procedures concerning heat
Employees fail to use or improperly use personal protection equipment.
Employees have inadequate or worn personal protection equipment.
Employees work in a limited space.
Employees attempt to work too fast.
Employees are careless.
Employees have poorly maintained tools and equipment.
These factors should be considered carefully by safety and health professionals when
developing accident prevention programs. Employees should be familiar with the hazards, should know
the appropriate safety precautions, and should have and use the proper personal protection equipment.
Safety professionals should monitor to ensure that safety rules are being followed, that personal
protection equipment is being used correctly, and that it is in good condition.
Fire hazards are conditions that favor fire development or growth.
The elements required to start and sustain a fire in the smoldering mode are oxygen, fuel, and
The elements required to start and sustain a fire in the flaming mode are heat, an oxidizing
agent, a reducing agent, and a chemical chain reactive.
The product of combustion is energy in the form of heat.
By-products of combustion include light and smoke.
For a fire to start, there must be either a source of ignition or a sufficiently high temperature for
Fire is an exothermic chemical reaction. Exothermic reactions generate heat. Endothermic
reactions consume more heat than they generate.
Chemical reactions in a fire break down materials into basic elements.
Loose atoms bond with each other to create substances that were not originally present.
Cooling is one of the principal ways to control a fire or extinguish it.
Carbon is found in almost every flammable substance.
In a fire, released carbon atoms combine with oxygen to form either carbon dioxide or carbon
Carbon dioxide can deplete oxygen concentrations in the air near the fire.
Carbon monoxide is a colorless, odorless, deadly gas.
Hydrogen, found in most fuels, combines with oxygen to form water.
Synthetic polymers in plastics and vinyls often form deadly toxic fumes when they are
consumed, melted, or disintegrated in the presence of fire or high heat.
Liquid and solid fuels are first converted to a vapor before they burn.
The trend with regard to safety standards is away from the traditional specifications-based
approach to a performance-based approach.
Removing the fuel, starving the fire of oxygen, or cooling it below the combustion point may
extinguish a fire.
An explosion is a very rapid, contained fire.
Heat always travels from a higher temperature to a lower one.
Excess heat is transferred to other objects by conduction, radiation, or convection.
Conduction is direct thermal energy heat transfer, molecule to molecule, through solids and
Radiation is electromagnetic wave heat transfer through air in a straight line to surrounding
Convection is heat transfer through the movement of hot gases.
Spontaneous combustion is rare, but not impossible.
Almost everything in the industrial environment can burn.
Fires are classified according to their properties, which relate to the fuels.
Class A fires involve solid fuels.
Class B fires involve flammable liquids and gases.
Class C fires involve live electricity.
Class D fires involve combustible metals.
Special categories include extremely active oxidizers and flammables containing oxygen.
All common packing materials burn easily.
Fire walls are defined by their ability to slow the spread of fire.
Wood and textiles can be treated to reduce their flammability.
The flash point is the lowest temperature at which vapors are produced in sufficient
concentration to burn, given a source of ignition.
The fire point is the lowest temperature at which vapors will continue to burn, given a source of
The auto-ignition temperature is the lowest point at which the vapors of a liquid or solid selfignites without a source of ignition.
Flammable liquids have a flash point below 37.8°C (100.04°F).
Combustible liquids have a flash point at or above 37.8°C (100.04°F).
Flammable and combustible liquids are each divided into three classifications.
Most flammable liquids are lighter than water; therefore, water cannot be used to put out these
Most gases are lighter than air.
Many of the gases present in smoke and at a fire site are toxic to humans.
Most fatalities from fire result from breathing toxic gases and smoke, or from suffocating
because of a lack of oxygen.
A red, blue, yellow, and white diamond label is used to identify hazards present when a
Natural and generated electricity play a major role in causing fires.
Heat, in the form of hot surfaces, can be a source of ignition.
Automatic fire detection systems employ different means of detecting a fire.
The best way to reduce fires is to prevent their occurrence.
OSHA’s regulations for fire brigades include requirements for prefire planning, an organizational
statement, physical capability, training and education, firefighting equipment, protective clothing, and
respiratory protective devices.
A comprehensive fire safety program should have at least the following elements: assessment,
planning, awareness and prevention, and response.
OSHA provides specific requirements for manual firefighting in three optional approaches: all
employees, designated employees, and fire brigades.