Fixed Extinguishing Systems
Fixed fire extinguishing/suppression systems are commonly
used to protect areas containing valuable or critical
equipment such as data processing rooms, telecommunication
switches, and process control rooms. Their main function
is to quickly extinguish a developing fire and alert occupants
before extensive damage occurs by filling the protected
area with a gas or chemical extinguishing agent.
In this section we will review the employer's responsibilities
for operating, testing, and maintaining fixed extinguishing
systems that are installed to meet a particular OSHA standard,
29 CFR 1910.160(a)(1),
or where its extinguishing agent may expose employees
to possible injury, death, or adverse health effects [29 CFR 1910.160(a)(2)].
This section does not apply to automatic sprinkler systems
(see
29 CFR 1910.159)
or to systems installed to protect areas where there is
no potential for employee exposure.
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This section will help you understand your requirements
under the fixed extinguishing system standard by addressing
the following issues:
See the
Fixed Extinguishing Systems Checklist [69 KB
PDF,
1 page]. For further
assistance, consult the following National Fire
Protection (NFPA) standards:
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NFPA 12, Standard
on Carbon Dioxide Extinguishing Systems
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NFPA 12A, Standard on Halon 1301 Fire
Extinguishing Systems
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NFPA 17, Standard for Dry Chemical Extinguishing
Systems
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NFPA 17A, Standard for Wet Chemical Extinguishing
Systems
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NFPA 750, Standard on Water Mist Fire Protection
Systems
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NFPA 2001, Standard on Clean Agent Fire
Extinguishing Systems
Accessibility Assistance: Contact the OSHA Directorate of
Science, Technology and Medicine at 202-693-2300 for
assistance accessing OSHA PDF materials. |
Does
the "Fixed Extinguishing System" standard apply
to me? |
OSHA's fixed
extinguishing systems, general standard applies to all employers
who have a fixed extinguishing system installed
to meet a particular OSHA standard, with the exception
of automatic sprinkler systems that are covered
by
29 CFR 1910.159.
29 CFR 1910.160
contains specific provisions for any fixed system,
regardless of why it was installed, that may expose
employees to possible injury, death, or adverse
health consequences caused by the extinguishing
agent. These systems are only subject to the
requirements of
29 CFR 1910.160(b)(4)
through
29 CFR 1910.160(b)(7)
and
(c)
of this standard.
OSHA's "Fire Extinguishing System" Standard
includes a general standard applicable all fixed
extinguishing systems, and three specific standards,
applicable to the type of extinguishing agent used:
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Note: Systems
installed to protect areas where there is no potential
for employee exposure to the extinguishing agent are exempted
from the requirements of this standard.
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System
design and application |
A fire extinguishing
systems is an engineered set of components that
work together to quickly detect a fire, alert
occupants, and extinguish the fire before extensive
damage can occur. All system components must be:
- Designed and approved for use on the
specific fire hazards they are expected to
control or extinguish [29 CFR 1910.160(b)(1)].
- Protected against corrosion or either made
or coated with a non-corrosive material if it
may be exposed to a corrosive environment [29 CFR 1910.160(b)(12)].
- Designed for the climate and temperature
extremes to which they will be exposed
[29 CFR 1910.160(b)(14)].
Typical elements and components
include: |
Note: Use
your mouse to explore the picture above. Click
on any number to go to that component's requirements.
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Text Version
System Components
[In the image above, there is an cutaway 3-D image of a room with an
entrance door and an exit door on the opposite wall, with two discharge
nozzles, one on the wall between the doors, and one above the exit door
(marked with an arrow and a number 1). Piping (marked with an arrow and a number 2) extends across the
top of the room to the opposite wall with a set of four agent containers on
the outer side of the wall attached to a control panel (marked with an arrow
and a number
3). Outside the room at the entrance door is a control panel (marked with an
arrow and a
number 4) and on the door, there is a hazard warning sign (marked with an
arrow and a number 5). Above the exit door inside the room, there is a fire
detector mounted adjacent to the exit sign (marked with an arrow and a
number 6). To the right of the exit door is a manual discharge station
(marked with an arrow and a number 7). Outside the room, on the outer wall
are the four agent storage containers connected to the piping (marked with
an arrow and a number 8).
When your mouse moves over each marked number, the relevant OSHA standard
will be displayed to the right of the image:
1. Discharge Nozzle [Rollover image includes image of discharge nozzle]
Discharge nozzles are used to disperse the extinguishing agent into the
protected area.
2. Piping [Rollover image includes image of piping with arrows] The
piping system is used to transport the extinguishing agent (carbon dioxide,
halon, argon, etc) from its storage container to the discharge nozzle.
3. Control Panel [Rollover image includes image of control panel] The
control panel integrates all devices and displays their operational status
and condition.
4. Warning Alarm [Rollover image includes image of fire alarm] Electronic
devices that provide an audible or visual alarm when detected.
5. Warning and Caution Signs [Rollover image includes image of Caution
sign and Halon Dump sign with text "Alarm will sound"] Hazard warning signs
must be posted at the entrance to, and inside, areas protected by fixed
extinguishing systems.
6. Fire Detectors [Rollover image includes image of fire detector] A
device that detects fire and causes an alarm signal to be generated.
7. Pull Station [Rollover image includes image of pull station with pull pin
and text "Pull pin then pull handle hard" and "Will release extinguishing
agent"] A device that provides a way to manually discharge the fire
extinguishing system.
8. Agent Storage Containers [Rollover image
includes image of five agent containers] The storage system discharges agent into the piping and through the discharge nozzles when activated by a manual or automatic device.
For more information, see each of the components below.
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Discharge
Nozzles
A
discharge nozzle is a device designed to release
the extinguishing agent at a specific rate and
pattern to quickly extinguish a fire. Discharge
nozzles must be suitable for the fire it is
intended to extinguish [29 CFR 1910.160(b)(1)].
The nozzle pictured is designed for total flooding
applications. Its bell shape and multiple small
discharge openings will create a widely dispersed
and diffused discharge pattern to quickly flood
an enclosed area with an extinguishing agent.
This type of nozzle is common in paint spray booths,
flammable liquid storage rooms or other similar
areas.
Nozzles designed for local application usually
consist of a cylindrical body with a straight
unobstructed center opening. This type of nozzle
produces a small discharge pattern that directs
the agent toward a local application such as paint
dip tanks, quench tanks or areas where a flammable
liquid spill may occur. |
Discharge Nozzles. Discharge nozzles are used to dispense the
extinguishing agents into the protected area. |
Piping
The piping network is designed to properly distribute
the extinguishing agent to the protected areas.
All fire protection systems must have pipes and
fittings that are suitable for the expected temperature
extremes with good corrosion resistance properties.
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Piping. The piping system is used to transport the
extinguishing agent (carbon dioxide, halon, argon,
etc.) from its storage container to the discharge
nozzles. |
Control
Panel The
control panel monitors and integrates all components
together and controls the audible and visual alarms
and discharge functions. When an automatic or
manual device is activated it sends a signal to
the control panel where, depending on the type
of system and hazards, can be programmed to:
- Activate a pre-discharge alarm
- Initiate agent release
- Shutdown ventilation systems
- Shutdown machinery or equipment
- Activate visual and audible fire alarms
- Notify emergency response personnel
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Control Panel. The control panel integrates all
devices and displays their operational status and
condition. |
Discharge
Alarm or Signaling Devices Each
area protected by a fixed extinguishing system
must have a distinctive alarm or signal which
complies with
29 CFR 1910.165
to alert occupants that the system is discharging.
These alarms must be able to be heard or seen
above ambient noise or light levels, unless the
discharge is immediately recognizable [29 CFR 1910.160(b)(3)].
If the alarm or signaling device is used on a
total flooding system, it must also:
- Alarm before the system discharges, to
give employees sufficient time to safely exit
the space [29 CFR 1910.160(c)(3)].
- Be connected to an approved fire detection
device that automatically activates the
pre-discharge alarm prior to the system
discharge [29 CFR 1910.160(c)(4)].
- Be addressed in an emergency action plan
in accordance with
29 CFR 1910.38
for each area that is protected.
Note: Areas protected
by a total flooding system where employees
cannot enter during or after the system's
operation are exempt from the requirements
of
29 CFR 1910.160(c) of this section [29 CFR 1910.160(c)(2)].
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Warning Alarm.
Electronic devices that provide an audible or
visual alarm when fire is detected. |
Warning
Signs and Safeguards
Warning signs must be posted to warn employees in
advance about the hazards associated with the
extinguishing agent. Hazard warning or caution
signs must be posted at the entrance to and inside
of areas protected by fixed extinguishing systems
which use agents in concentrations known to be
hazardous to employee safety and health [29 CFR 1910.160(b)(5)].
Recommended guidelines for posting:
- To avoid confusion, keep hazard warning
signs consistent by using standardized patterns,
phrases, colors, shapes and pictures.
- Wording on signs should be concise, easy
to read, and contain sufficient information
that is easily understood.
- Warning signs must be in English and should
also be posted in the native language spoken
by the employees.
In addition to warning
signs, the employer must also provide effective
safeguards to warn employees when the atmosphere
of a protected area remains hazardous to their
safety or health as a result of a system
discharged [29 CFR 1910.160(b)(4)].
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Warning and Caution
Signs. Hazard warning signs must be posted at the
entrance to, and inside, areas protected by fixed
extinguishing systems. |
Automatic
Fire Detectors Automatic
detection devices sense the smoke, heat, or flames
from a fire and initiate an alarm. All automatic
detection equipment must be approved, installed
and maintained in accordance with
29 CFR 1910.164.
Automatic detection devices used on a total flooding
system must:
- Automatically activate the pre-discharge
alarm before the system discharges to give
employees time to safely exit from the
protected area [29 CFR 1910.160(c)(4)].
Note: Areas
protected by a total flooding system where
employees cannot enter during or after the
system's operation are exempt from the
requirements of
29 CFR 1910.160(c) of this section [29 CFR 1910.160(c)(2)].
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Fire Detectors. A
device that detects fire and causes an alarm
signal to be generated. |
Manual
Discharge Station
A manual discharge station is a device usually
mounted on a wall near the emergency exit(s)
which will automatically sound an alarm and
release the extinguishing agent. If your workplace
is equipped with a fixed suppressant system, there
must be at least one manual station for each
protected area [29 CFR 1910.160(b)(15)].
Pull Station Guidelines:
- Properly mark and/or label pull stations
and other activation devices to indicate their
function and the potential hazard to personnel
[29 CFR 1910.160(b)(16)].
- Pull stations must be clearly visible (not
blocked or covered) and located near exits
or escape routes.
- Post operating instructions
at each station.
- Train employees to know when,
where, and how to use pull stations.
- Determine, if possible, if someone is in
the area and get them out before using a manual
discharge station.
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Pull Station. A
device that provides a way to manually discharge
the fire extinguishing system. |
Extinguishing
Agent Storage Containers Storage
containers hold the extinguishing agent until
it is needed and can be high or low pressure cylinders
or tanks. These containers can be used to hold
specialized fire suppression agents like carbon
dioxide or halon to protect special work areas,
such as computer rooms, chemical storage, or similar
areas.
Storage Container Requirements:
- Check the weight and pressure of refillable
containers at least
semi-annually. Maintain the the container if
it shows a loss in net content or weight of
more than 5 percent, or a loss in pressure of
more than 10 percent [29 CFR 1910.160(b)(7)].
- Weigh factory charged non-refillable containers
that have no means of pressure indication at least semiannually.
Replace the
container if it shows a loss in net content or
weight of more than 5 percent [29 CFR 1910.160(b)(8)].
- Record inspection and maintenance dates on
the container, on a tag attached to the
container or in a central location. Maintain a
record of the last semi-annual check until the container is checked
again or for the life of the container, whichever
is less
[29 CFR 1910.160(b)(9)].
- Do not use chlorobromomethane or carbon
tetrachloride as an extinguishing agent in an
area where
employees may be exposed [29 CFR 1910.160(b)(11)].
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Agent Storage
Containers. The storage system discharges agent
into piping and through the discharge nozzles when
activated by a manual or automatic device. |
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Operation, maintenance, and testing |
Automatic fire suppression systems,
particularly the total flooding variety, must be operated
properly and regularly maintained and tested to guarantee
worker safety and system effectiveness. To ensure your
fire extinguishing system will perform as expected in
the event of a fire, you are required to:
- Inspect each system annually, and operate and
maintain them in a working condition, making sure they
are always turned on, except during repairs or
maintenance [29 CFR 1910.160(b)(6)].
- Notify employees and establish measures to guarantee
their safety if a fixed extinguishing system becomes
inoperable. Fix any defects or impairments
by trained personnel. [29 CFR 1910.160(b)(2)].
- Check the weight and pressure of refillable
containers at least semiannually. If the
container shows a loss in net content, weight, or
pressure, it must be subjected to maintenance [29 CFR 1910.160(b)(7)].
- Assure that factory charged non-refillable
containers that have no means of pressure indication
are weighed at least semiannually. Replace the container if it shows a loss in net weight [29 CFR 1910.160(b)(8)].
- Assure that inspection and maintenance dates are
recorded and kept until the container is checked again
or for the life of the container, whichever is less [29 CFR 1910.160(b)(9)].
- Train employees designated to inspect, maintain,
operate, or repair fixed extinguishing systems. Review
their training annually to keep them up-to-date [29 CFR 1910.160(b)(10)].
- Train all employees with respect to the type of
systems installed in the workplace, the hazards involved,
proper activation in case of emergency, and the correct
response to audible and visual pre-discharge alarms.
Provide training for non-English speaking employees
in languages understood by the affected employees
and other individuals that may be exposed to the hazard.
- Provide and assure the use of personal protective
equipment (PPE) for rescuing employees trapped in
areas that have become hazardous due to an agent
discharge [29 CFR 1910.160(b)(17)].
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Total flooding applications |
Total Flooding Applications consist
of protecting an enclosed space by flooding it with a
gas, such as carbon dioxide or halon. This method is
used to protect electrical equipment and other types of
deep-seated smoldering fires that may re-ignite after
the flame has been extinguished. Because these systems
can create an oxygen deficit or toxic atmosphere they
deserve special attention.
The following special provisions apply to all fixed suppression
systems used for total flooding applications:
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Assure that
employees are not exposed to toxic levels of gaseous
agent or its decomposition products [29 CFR 1910.162(b)(3)].
The requirements of
29 CFR 1910.162(b)(2) and
29 CFR 1910.162(b)(4) through
29 CFR 1910.162(b)(6) apply only to total flooding
applications.
- Maintain the designed concentration of gaseous
agents until the fire has been extinguished or is
under control except during overhaul [29 CFR 1910.162(b)(2)].
- Assure that the designed extinguishing
concentration is reached within 30 seconds of initial
discharge except for Halon systems which must achieve
design concentration within 10 seconds [29 CFR 1910.162(b)(4)].
- Provide a distinctive pre-discharge employee alarm
capable of being perceived above ambient light or
noise levels when agent design concentrations exceed
the maximum safe level for employee exposure.
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Provide a pre-discharge employee
alarm for alerting employees before system discharge
on Halon 1211 and carbon dioxide systems with a design
concentration of 4 percent or greater and
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Provide a pre-discharge employee
alarm for Halon 1301 systems with a design
concentration of 10 percent or greater.
The pre-discharge employee alarm shall provide
employees time to safely exit the discharge area prior
to system discharge.
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Do not use Halon 1301 in
concentrations greater than 7 percent where egress
from an area cannot be accomplished within one minute
[29 CFR 1910.162(b)(6)(i)].
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Do not use Halon 1301 in
concentrations greater than 10 percent where egress
from an area cannot be takes greater than 30 seconds
but less than one minute [29 CFR 1910.162(b)(6)(ii)].
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Use Halon 1301 concentrations
greater than 10 percent only in areas not occupied by
employees provided that any employee in the area can
escape within 30 seconds. Assure that no unprotected
employees enter the area during agent discharge.
- Provide an emergency action plan in accordance
with
29 CFR 1910.38
to provide for the safe evacuation of employees from
within each area protected by a total flooding system
which provides agent concentrations exceeding the
maximum safe levels set forth in
29 CFR 1910.162(b)(5) and
29 CFR 1910.162(b)(6)
[29 CFR 1910.160(c)(1)].
- Systems installed in areas where employees cannot
enter during or after the system's operation are
exempt from the requirements of this section [29 CFR 1910.160(c)(2)].
- Equip each area protected with a pre-discharge
alarm that complies with
29 CFR 1910.165
that is capable of being perceived above light or
noise levels, and which gives employees time to safely
exit the area before discharge [29 CFR 1910.160(c)(3)].
- Install and connect fire detection devices to
a control system which sounds a pre-discharge alarm
and automatically
activates total flooding systems [29 CFR 1910.160(c)(4)].
- Post signs in and at the entrance to areas
protected by total flooding fire suppression systems
which use agents that are a serious health hazard,
such as carbon dioxide, Halon 1211, etc.
- Have personal protective equipment (such as
5-minute "escape packs") available and ready for
rescuing employees trapped in areas that may become
hazardous due to an agent discharge [29 CFR 1910.160(b)(17)].
Safety and Health Hazards
The Material Safety Data Sheet
for each extinguishing agent should be available in the
workplace. It is important that employees know the potential
hazards of the extinguishing agents they may be exposed
to and how to protect themselves. Additionally, employees
who are likely to enter such areas should receive a basic
level of instruction into the operating principles of
the system to include alarms and related hazards, as well
as evacuation procedures. The two most common extinguishing
agents used for total flooding applications are carbon
dioxide and halon.
Carbon Dioxide Carbon dioxide,
under normal conditions, is a colorless, odorless, electrically
nonconductive gas that is approximately 1.5 times heavier
than air. It will not disturb live electrical components,
is non-corrosive, and leaves no residue to clean up.
- Agents used for initial supply and replenishment
shall be of the type approved for the system's
application. Carbon dioxide obtained by dry ice
conversion to liquid is not acceptable unless it is
processed to remove excess water and oil [29 CFR 1910.162(b)(1)].
Specific hazards include:
- Asphyxiation - Exposure to high concentrations of
CO2 gas may create an oxygen-deficient atmosphere.
- Cold Temperature - Direct contact with the vaporizing
liquid during discharge can cause frostbite burns
to the skin.
- For further assistance, consult
NFPA 12, Standard
on Carbon Dioxide Extinguishing Systems.
Halon Systems
Halon is a bromo freon that works
by replacing oxygen, thus creating an oxygen-deficient
atmosphere. This can be very dangerous to employees. The
reaction products of halon on hot surfaces may result
in the release of toxic substances and carcinogens. These
areas should be clearly labeled as follows:
Specific halon hazards
include:
- Asphyxiation - Exposure to high concentrations of
halon can create an oxygen-deficient atmosphere.
- Cold Temperature - Direct contact with the vaporizing
liquid during discharge can cause frostbite burns
to the skin.
- Central Nervous System (CNS) - Inhaling high concentrations
of halon gas can cause dizziness, tingling in extremities
and, in severe cases, unconsciousness.
- Cardiovascular Effect - In some people, exposure
to halon can cause an increased sensitivity of the
heart to adrenaline resulting in irregular heartbeats
and, in severe cases, heart attack.
- When halon is exposed to temperatures above 900
degrees F. it could break down and create high concentrations
of toxic gases.
- For further assistance, consult
NFPA 12A, Standard on Halon 1301 Fire
Extinguishing Systems.
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