Most handheld portable fire extinguishers

in buildings are rechargeable, stored-pressure dry chemical extinguishers.

These extinguishers require annual external maintenance examinations.

An internal maintenance examination

is only required at the 6-year

maintenance interval and the 12-year

hydrostatic test interval. The cycle of

external maintenance, internal maintenance,

and hydrostatic testing is repeated

for the service life of the extinguisher

to ensure the safety of the user

and the reliability of the device.

Annual external maintenance of these

extinguishers is necessary so that a

number of critical components can be

examined and repaired (if necessary) in

order to make the fire extinguisher ready

for use during a fire emergency. Where

repairs are not appropriate, the extinguisher is replaced. When the external maintenance is performed correctly and completely on an annual basis and internal maintenance and hydrostatic testing are conducted on schedule, the maximum level of assurance that the extinguisher will work (as designed) to suppress or extinguish an unwanted fire is provided.

The responsibility for establishing a

contract for portable fire extinguisher

maintenance falls on the building owner,

the owner’s designated agent or the tenant

of the building where fire extinguishers

are located. Once the contract

is established, performing maintenance

correctly and at the right intervals normally

is the responsibility of the fire

equipment distributor. The actual task

of extinguisher maintenance is assigned

to a technician that understands how to

examine the extinguishers and to take

any necessary corrective action.

The technician performing the maintenance

relies on the extinguisher manufacturer's

service manual for specific

information on external examinations.

The manuals also contain cautions and

warnings so that the technician performs

the tasks safely. Generally, the

same external examination procedures

are followed for all rechargeable, stored pressure dry chemical extinguishers.

The practice has been standardized and

the complete list of items to be examined

has been added to the 2010 edition

The extinguisher is removed from the

hanger or cabinet and checked for damage. A broken or deformed verification of service collar indicates a suspect extinguisher that must be taken out of service for full maintenance, which includes internal examination. The hanger

must be the one designed for the extinguisher. If it is identified as the wrong

hanger or is damaged, the hanger is replaced. Extinguisher height and hanger

mounting hardware are also examined.

Incorrectly installed or loose hangers are

removed. The hanger must then be properly located and securely re-attached at the correct height. Cabinets are checked for damage and proper operation. Auxiliary components such as “break glass devices” must be checked to make sure they are the proper ones for the cabinet and readily available for use.

The operating instructions label on

the extinguisher is examined to confirm

that it is the right one and it is securely

attached to the extinguisher. The label

must not be faded and must be in a condition in which it is clearly legible and

will not come off easily. Also, the location

of the label is evaluated to make sure

the instructions will be facing outward

when the extinguisher is returned to its

hanger or cabinet. Problematic operating

instructions labels are replaced.

Any extinguishers that are subject

to recall or have become obsolete due

to safety concerns are removed from

service. Extinguishers that are considered

obsolete are listed in Section 4.4 of

NFPA 10.

The service technician reviews the

maintenance and hydrostatic test records.

Any extinguishers due for the 6-year

teardown or hydrostatic testing are removed so that the work can be done. Any fire extinguisher that is removed from a

building for repair, internal maintenance,

or hydrostatic testing must be replaced

by a fire extinguisher that is appropriate

and rated for the hazard.

A thorough examination of the condition

of the extinguisher cylinder is conducted

to check for corrosion, dents,

gouges, and repairs. If corrosion, dents,

or gouges are identified, an evaluation

is made to determine whether the problem

areas are within tolerable ranges

or whether the extinguisher needs

to be replaced. Tolerances for corrosion,

dents, and gouges are provided in

NFPA 10. Any extinguisher that shows

signs of being repaired such as welding

is replaced.

An evaluation is conducted as the

pull pin is being removed. A pin that

does not slide out easily is replaced.

Additionally, the pin and the slot are

examined. A bent or corroded pin is

replaced. With the pin out, the valve

stem is examined to make sure that it

protrudes out the top of the valve and

is correctly extended. The valve stem is

also checked for corrosion and damage.

A valve stem problem typically necessitates

the teardown of the extinguisher

and the replacement of the valve stem.

The handle and the actuation lever

are examined. Bent or corroded handles

or levers and rivets that cause the lever

to stick are reasons for extinguisher removal for repair. A new tamper seal

is installed when the pull pin is inserted

in the extinguisher lever. The new tamper seal is not only required, but it gives the building owner or a fire inspector a visual indication that the pull pin, valve stem, handle, and lever evaluations were most likely conducted during maintenance.

The pressure gauge is checked to

make sure the needle is in the operable

range. The pressure gauge is examined

to ensure it is not damaged or bent, or

the face plate cracked. The technician

also confirms that the pressure gauge

matches the agent type and the nameplate’s operating pressure and verifies the gauge threads are compatible with the valve body material. An extinguisher with a problematic gauge is removed for replacement of the gauge.

The extinguisher hose is removed and

examined for cracks or deformation.

The technician verifies that the hose

is the correct one for the extinguisher

model and that the hose assembly has

no obstructions. Additionally, the condition of the hose assembly threads

and couplings is assessed. While the

hose is off, the valve port surfaces

are examined for signs of leakage or

corrosion that indicates the need for

a teardown to correct these problems.

Any improper, cracked, clogged or otherwise problematic hoses are replaced.

The extinguisher must have a hose in

good condition installed with one end

fastened securely to the valve and the

other end in the hose retention band

that is securely and properly adjusted

before it is returned to service.

The extinguisher is weighed to verify

the weight corresponds to the nameplate

weight. A lower weight indicates

a problem that necessitates recharging

of the extinguisher. After the proper

weight has been verified, the extinguisher

is wiped clean of any dirt and

contaminants. The maintenance is recorded on a new extinguisher tag or label, and the extinguisher is replaced on

the hanger or returned to the cabinet.

Once the external maintenance is

complete, the extinguisher is ready

for use during a fire emergency. When

periodic maintenance and hydrostatic

testing are conducted correctly during

the required regular intervals, the probability that the extinguisher will work

as designed to suppress or extinguish

an unwanted fire is maximized.

The above article is the opinion of the author and

does not necessarily represent the position of a

NFPA technical committee or the NFPA and may

not be considered to be or relied upon as such.

Mark Conroy is an engineer with Brooks Equipment

Company and a principal member of the

NFPA Technical Committee on Portable Fire Extinguishers.

Copyright 2010, all rights reserved.