Portable fire extinguishers are the first line of defense against a small fire at a live event — the tool that can prevent an incipient fire from becoming a life-threatening incident. But they only work if they are the correct type, located where they can be found quickly, maintained in working condition, and operated correctly by someone who has been trained to use them. A dry chemical extinguisher rated for Class A fires placed near a commercial fryer, a CO2 extinguisher not usable on a Class A fire, or an extinguisher mounted behind a stack of flight cases are all effectively useless.

Understanding what fire extinguishers are required, where they must be placed, how to read their ratings, and how to use them correctly is a practical competency that every event safety officer and senior event staff member should have.

The Governing Standard: NFPA 10

Portable fire extinguishers at all locations other than single-family residences must be installed, inspected, maintained, and tested in accordance with NFPA 10, Standard for Portable Fire Extinguishers. OSHA’s standard 29 CFR 1910.157 imposes similar requirements for workplaces where fire extinguishers are provided for employee use and also requires that employees who may be expected to use extinguishers be trained in their use annually (Occupational Safety and Health Administration [OSHA], 2016; National Fire Protection Association [NFPA], 2022a).

NFPA 10 governs the selection, distribution, installation, inspection, maintenance, recharging, and testing of portable fire extinguishers. Event organizers should verify that every extinguisher in their venue or event site has been inspected and serviced by a qualified fire protection service company within the past year — a fact confirmed by the inspection tag attached to each unit (NFPA, 2022a).

Extinguisher Ratings Explained

Fire extinguisher ratings indicate both the classes of fire the extinguisher is effective against and the quantity of fire it can suppress. Ratings are established by testing under ANSI/UL 711, Rating and Fire Testing of Fire Extinguishers, and consist of a number-letter combination. Understanding what these numbers mean helps in selecting the correct extinguisher for each location (Underwriters Laboratories, 2018).

Consider an extinguisher rated 4-A:80-B:C:

• The A rating (4-A) indicates Class A fire capability. The number multiplied by 1.25 gives the equivalent extinguishing capacity in gallons of water. A 4-A rating is equivalent to 5 gallons of water on a Class A fire. Higher numbers indicate greater extinguishing capability.
• The B rating (80-B) indicates the area in square feet of a Class B fire that a trained user should be able to extinguish. An 80-B extinguisher can suppress an 80-square-foot flammable liquid fire.
• The C designation indicates only that the extinguishing agent will not conduct electricity — it does not provide a numerical fire suppression rating for electrical fires.
• There is no numerical D or K rating in the combination format. Class D extinguishers are rated by specific metal types. Class K extinguishers are rated for commercial cooking equipment separately.

Types of Extinguishers and Their Applications

The most common extinguisher types found in live event environments and their appropriate applications are:

ABC Dry Chemical

The multipurpose ABC dry chemical extinguisher is the most versatile and most commonly deployed extinguisher in event venues. It is effective on Class A, B, and C fires. The dry chemical agent — typically monoammonium phosphate — works by interrupting the chemical chain reaction and coating the fuel. Dry chemical extinguishers produce a visible cloud of powder that can reduce visibility and cause respiratory irritation if used in a crowd or confined space. The powder can also damage sensitive electronic equipment (NFPA, 2022a).

Carbon Dioxide (CO2)

CO2 extinguishers discharge a gaseous agent that displaces oxygen. They are effective on Class B and C fires and leave no residue — an important advantage in areas with sensitive audio or video equipment. CO2 extinguishers are not effective on Class A fires (the gas dissipates without cooling the fuel sufficiently) and are not suitable for outdoor use in windy conditions where the gas disperses before reaching the fire. CO2 can displace breathing-quality air in confined spaces, posing an asphyxiation hazard to the user if the space is not well ventilated. CO2 extinguishers are identified by their characteristic flared horn at the discharge end (NFPA, 2022a).

Wet Chemical

Wet chemical extinguishers are specifically designed for Class K fires involving cooking oils and fats. The potassium acetate-based agent reacts with hot cooking oil to form a soapy foam layer (saponification) that seals the surface, cools the oil, and prevents re-ignition. Wet chemical extinguishers must be positioned within 30 feet (9.1 m) of all commercial cooking equipment. A standard ABC extinguisher at a food vendor location does not satisfy the Class K requirement (NFPA, 2022a).

Water and Water Mist

Water extinguishers are rated for Class A fires only and cool the fuel by absorbing heat. They must never be used on Class B, C, or D fires. Water mist extinguishers use ultra-fine water droplets and are safer than solid stream water extinguishers near electrical equipment — they create less of a conductive path — but are not rated for Class C fires (NFPA, 2022a).

Class D Dry Powder

Class D extinguishers contain metal-specific dry powder agents that work by smothering the burning metal and interrupting the chemical reaction. They must be matched to the specific metal involved — sodium chloride-based agents for sodium fires, copper-based for lithium fires, and so on. They are applied gently using a low-velocity nozzle to avoid disrupting finely divided burning metal particles (NFPA, 2022a).

Placement Requirements

NFPA 10 and the International Fire Code establish maximum travel distances from any point in the building or site to the nearest extinguisher (International Code Council [ICC], 2021a; NFPA, 2022a):

• Class A hazards: maximum travel distance of 75 feet (22.9 m) to the nearest extinguisher
• Class B hazards: maximum travel distance of 50 feet (15.2 m) to the nearest extinguisher
• Class K hazards: maximum travel distance of 30 feet (9.1 m) for all commercial cooking equipment

Extinguishers must be mounted on manufacturer-provided or approved brackets securely anchored to a wall or surface, with the handle no more than 3.5 feet (1.07 m) above the floor for units over 40 pounds and no more than 5 feet (1.52 m) above the floor for lighter units. They must be located along normal paths of travel, not concealed, not obscured, and not blocked by stored equipment or materials (NFPA, 2022a).

At live events, required placement locations include:

• All tents and membrane structures
• Within 30 feet (9.1 m) of commercial cooking equipment (Class K extinguisher required)
• Near portable generators and fuel storage areas (minimum 2-A:20-B:C rating)
• In electrical intake rooms and near major distribution equipment
• In dressing rooms and performers’ areas
• Where scenery, staging materials, or combustible production materials are stored
• In occupied truss positions, at catwalk intersections, and at followspot platforms (NFPA, 2022a; ICC, 2021a)

Extinguishers installed at heights above grade — such as those mounted in occupied trusses — should be secured with a safety cable to prevent them from falling onto people below in the event of a structural movement.

The PASS Technique

All staff who may be expected to use a fire extinguisher must be trained in its operation before the event. OSHA requires that employers who provide fire extinguishers for employee use train those employees in the general principles of fire extinguisher use and the hazards involved in incipient stage firefighting at the time of initial employment and annually thereafter (OSHA, 2016).

The standard operating procedure for a portable fire extinguisher is described by the acronym PASS:

• P — Pull the safety pin from the handle
• A — Aim the nozzle or horn at the base of the fire, from a safe distance of approximately 6 to 8 feet (2 to 2.5 m)
• S — Squeeze the handle to discharge the agent
• S — Sweep the nozzle from side to side while keeping it aimed at the base of the fire

Training should also address when not to use an extinguisher — specifically, when the fire is past its incipient stage. If the fire has reached the ceiling, if the user’s escape route is threatened, if the correct extinguisher type is not available, or if the first extinguisher discharge does not achieve clear progress toward suppression, the proper action is to evacuate, direct others to evacuate, and call the fire department. A portable extinguisher is not a substitute for the fire department — it is a tool for controlling small fires while people escape and before professional firefighters arrive (NFPA, 2022a).

Inspection, Maintenance, and Documentation

Every extinguisher must be inspected monthly to verify that it is in its designated location, visible, accessible, and has not been discharged or tampered with. Annual maintenance — including a full inspection by a qualified service technician — is required by NFPA 10. Every six or twelve years (depending on agent type), extinguishers must undergo hydrostatic testing of the pressure vessel (NFPA, 2022a).

Each extinguisher should have a service tag attached indicating the date of the most recent annual inspection and the name of the servicing company. Event organizers can verify compliance by checking that all extinguishers at the venue have been serviced within the past 12 months. Extinguishers without current inspection tags — or with tags that indicate discharge or damage — must be replaced before the event opens (NFPA, 2022a).

Stages: A Special Requirement

Under NFPA 101 and the IFC, stages greater than 1,000 square feet (93 m2) require a Class III wet standpipe system with 1.5-inch and 2.5-inch hose connections on each side of the stage area. Where stages exceed 1,000 square feet and are more than 50 feet in height with combustible hangings, automatic sprinklers may also be required. Consult the local AHJ for specific requirements applicable to the stage configuration being used (NFPA, 2021; ICC, 2021a).

References

International Code Council. (2021a). International fire code. ICC.

National Fire Protection Association. (2021). NFPA 101: Life safety code. NFPA.

National Fire Protection Association. (2022a). NFPA 10: Standard for portable fire extinguishers. NFPA.

Occupational Safety and Health Administration. (2016). 29 CFR 1910.157: Portable fire extinguishers. U.S. Department of Labor.

Underwriters Laboratories. (2018). ANSI/UL 711: Rating and fire testing of fire extinguishers. UL Standards & Engagement.