Fire Extinguisher Discharge

A document summarizing the discharge principles, methods, and latest technological trends for suppressing fires using fire extinguishers.

Fire Extinguisher Discharge

Overview

Fire extinguisher discharge (소화기 분사) is the act of extinguishing a fire during its initial stage by discharging the extinguishing agent compressed in a fire extinguisher, thereby removing one or more of the three elements of combustion (fuel, oxygen, heat). The applicable fire types vary depending on the discharge method and the type of agent, and most of the success rate of initial suppression depends on correct discharge within 3 minutes. Recently, special discharge technologies and smart fire extinguishers for responding to new hazards such as lithium-ion battery fires are drawing attention.

Main Content

Principle of Fire Extinguisher Discharge

A fire extinguisher has a structure that pushes out the extinguishing agent using internal pressure (stored-pressure type) or a separate gas cartridge (cartridge-operated type). When the handle is pressed, the valve opens, and the agent is discharged through the nozzle by the pressure difference. The discharged agent acts directly on the flame and blocks the combustion reaction through cooling (water/water-based), smothering (carbon dioxide/foam), and negative catalysis/chemical inhibition (dry chemical/halon replacement agents).

Application by Fire Class

Class A (ordinary combustibles): water/water-based, ABC dry chemical, foam extinguishers
Class B (flammable liquids/gases): foam, carbon dioxide, ABC dry chemical
Class C (electrical): carbon dioxide, clean agents (halon replacements), dry chemical
Class D (metals): dedicated metal fire dry chemical
Class K (cooking oils): wet chemical/loaded-stream extinguishers

Correct Discharge Method (PASS Technique)

1. P (Pull): Pull the safety pin.

2. A (Aim): Aim the nozzle at the base of the fire (the burning material, not the flames).

3. S (Squeeze): Squeeze the handle firmly to discharge.

4. S (Sweep): Sweep side to side and discharge evenly.

Precautions During Discharge

Keep your back to the wind, maintain a low posture at a distance of 2–3 m, and note that most extinguishers cannot be reused once discharged. Using a carbon dioxide extinguisher in a closed space can cause suffocation, so ventilate and evacuate immediately after discharge. Also, spraying water on an electrical fire risks electric shock, so an appropriate agent must be selected.

Discharge Time and Effective Range

A typical household ABC dry chemical extinguisher (3.3 kg) has an effective discharge time of about 10–15 seconds and a discharge distance of about 3–5 m. Carbon dioxide extinguishers have a short discharge time of around 10 seconds but leave no residue, making them advantageous for electronic equipment fires. Therefore, fire extinguishers should be used within 1–2 minutes of the initial fire, and if suppression is judged difficult, evacuate immediately and report to 119.

Inspection and Maintenance

Regularly check that the needle of the pressure gauge is in the green zone and that the safety pin and nozzle are normal. Dry chemical extinguishers should be shaken upside down once a month because the agent may harden.

Latest Trends

In 2024–2025, as lithium-ion battery fires surge, special fire suppression technologies for electric vehicles and energy storage systems (ESS) are emerging. Existing dry chemical and CO₂ extinguishers have difficulty preventing battery thermal runaway, so aerosol discharge types, fluorine-based penetrating agents, and nitrogen injection types are being developed. In addition, automatic discharge fire suppression devices are increasingly being built into electric vehicle battery packs and household electrical outlets, and smart fire extinguishers that detect fires in connection with IoT sensors, automatically discharge, and send notifications to managers are spreading. Since 2024, the National Fire Agency has been pursuing measures to strengthen installation standards for residential fire safety facilities and include fire extinguisher usage training in the regular curriculum and workplace safety education. In addition, VR/AR-based virtual fire extinguisher discharge training content is spreading, making it possible to improve response capabilities without actual discharge experience.