A portable extinguisher is the cheapest and most widespread way to tackle a fire in its first minutes. It is also the most underestimated: an extinguisher filled with the wrong agent, hung in the wrong place or that nobody knows how to use is simply wall decoration. FM Global DS 4-5 Portable Extinguishers covers selection by hazard, distribution and maintenance, and positions the extinguisher clearly as a first-aid tool.
Scope and Fire Classes
The data sheet covers hand-held and wheeled extinguishers, agent selection, placement, staff training and the inspection and maintenance regime. Selection starts with the fire class, and the American and European systems name them differently:
| Fuel | NFPA 10 class | EN 2 class | Suitable agent (typical) |
|---|---|---|---|
| Ordinary combustibles (wood, paper, textiles) | A | A | Water, foam, ABC dry powder |
| Flammable liquids | B | B | Foam, BC or ABC dry powder, CO2 |
| Flammable gases | (within B) | C | Isolate the gas first; dry powder |
| Energised electrical equipment | C | Not a separate class | CO2, clean agent, non-conductive agents |
| Combustible metals | D | D | Metal-specific Class D powder |
| Cooking oils | K | F | Wet chemical |
Key Loss-Prevention Principles
Extinguishers do not replace sprinklers
In the FM approach the portable extinguisher complements automatic protection. Its value shows when the fire is small and the user has a safe escape route. A discharge lasting a matter of seconds cannot put out a developed fire, so adding extinguishers does not make up for a deficient sprinkler system.
Match the agent to the hazard
For each area, the agent is chosen for the worst credible fire. Examples:
- Ignitable liquid dispensing and process areas: consider wheeled units for longer reach and more agent.
- Electronic equipment and control rooms: ABC powder can leave serious contamination and corrosion; CO2 or clean agent units are preferred.
- Commercial kitchens: water-based and general-purpose powders can be ineffective or dangerous on cooking oil; a wet chemical extinguisher is provided in addition to the hood suppression system.
- Combustible metals: with magnesium, aluminium powder or titanium the wrong agent can intensify the fire; only a Class D agent suited to that metal is used.
Placement and access
Extinguishers should be visible, accessible and on normal routes of travel, preferably near exits and escape routes, so the user approaches the fire with a safe exit behind them. An extinguisher blocked by racking, pallets or machinery is one of the most common site defects. Outdoor units are protected from freezing and weather.
Training
Someone using an extinguisher for the first time during a real fire usually wastes most of the agent. FM expects hands-on training for staff and an emergency plan that makes clear who fights the fire and who evacuates. The core message should be "raise the alarm first, then attack; if the fire is growing, withdraw".
Inspection and maintenance
Pressure gauge, seal, hose and body are checked visually at regular intervals, and a competent service provider carries out periodic maintenance and pressure testing. A used or discharged extinguisher is replaced at once.
Planning the Inventory
A practical method is to divide the site into risk zones and keep a one-line decision record for each: zone name, likely fire class, chosen agent, extinguisher type (hand-held or wheeled), quantity and position. The record is reviewed whenever the process changes or new machinery arrives. If part of a warehouse becomes a charging area and another part an oil store, for example, the adequacy of general-purpose extinguishers must be reassessed. The same record also serves as a ready document at insurance surveys.
How It Differs from NFPA 10 and EN 3
NFPA 10 rates extinguishers by UL test ratings (for example 2-A:10-B:C) and sets distribution by rating and travel distance; the commonly cited maximum travel distance for Class A hazards is 22.9 m (75 ft). The inspection rhythm is a monthly visual check and annual maintenance, with hydrostatic test intervals depending on the agent. In Europe the EN 3 series defines extinguisher performance against test fires (for example 13A, 89B), while how many units go where is set by national rules. In Turkey the national fire regulation (BYKHY) governs numbers and placement.
FM does not contradict these rules, but the emphasis differs: an extinguisher is not protection unless it combines the right agent, an accessible position and a trained user. FM also expects extinguishers to be approved (FM Approved or listed by a recognised body).
Common mistake: hanging an ABC powder extinguisher next to switchboards because it "works on everything". The switchboard fire goes out, but the powder contaminates contacts and electronics and can cause a larger loss than the fire itself. CO2 or clean agent is the better choice beside sensitive equipment.
Practical Checklist
- The likely fire class for each area is identified and the agent chosen accordingly.
- Non-contaminating agents are used in electronic and control rooms.
- Kitchens have wet chemical units; metalworking areas have the correct Class D agent.
- The need for wheeled units in ignitable liquid areas has been assessed.
- Extinguishers are visible, signed, unobstructed and near exits.
- Staff have hands-on training and response roles are set out in the emergency plan.
- Periodic visual checks, annual maintenance and pressure tests are recorded.
- Used extinguishers are recharged or replaced immediately.
Frequently Asked Questions
Does a sprinklered building need extinguishers?
Yes. Regulations require them and FM sees them as first-aid firefighting tools. They do not, however, reduce or replace sprinkler protection.
Why is ABC powder not suitable everywhere?
Powder can contaminate and corrode electronic equipment, and it is inadequate or dangerous on cooking oil and combustible metal fires. The agent should suit the actual hazard in the area.
Which class covers electrical fires in Europe?
Under EN 2 electricity is not a separate fire class. Whether an extinguisher is suitable for use on energised equipment is stated separately on its label and test results.
When are wheeled extinguishers needed?
Where the agent quantity and reach of a small unit will not be enough, such as ignitable liquid dispensing areas, refuelling points and large process equipment.
How often should extinguishers be checked?
The general practice is regular visual checks plus competent servicing at least once a year. Pressure test intervals depend on the agent and body type; confirm against the current standard and local regulations.
SprinkCalc — Fire Sprinkler Design Across Three Standards
SprinkCalc covers hazard classification, design density and area, K-factor selection, water demand and hydraulic calculations for NFPA 13, FM Global and BS EN 12845 in a single iOS app, and exports a professional PDF report.
Download SprinkCalc on the App Store
MEP Calc — 86+ Engineering Calculators
MEP Calc bundles 86+ engineering modules in one iOS app: 21 fire calculations plus heating, cooling, HVAC, plumbing, steam and natural gas.
Download MEP Calc on the App StoreFM Global Property Loss Prevention Data Sheet 4-5, Portable Extinguishers; NFPA 10, Standard for Portable Fire Extinguishers; EN 2 (classification of fires); EN 3 series. This page is a summary in our own words, not the data sheet text. Download and design to the current revision from fmglobal.com.