Having fire extinguishers installed across your premises is an excellent first step toward workplace safety. However, if a fire breaks out, knowing which extinguisher to use is critical. Using the wrong type of extinguisher on a specific class of fire can be incredibly dangerous and can actually cause the fire to spread rapidly.
Here is a simple breakdown of the most common fire extinguisher types found in New Zealand workplaces and how to identify them.
The Classes of Fire
To understand extinguishers, you first need to understand what is burning. Fires are classified into distinct categories:
Class A: Wood, paper, textiles, and plastics.
Class B: Flammable liquids like petrol, oil, and paint.
Class C: Flammable gases (LPG, natural gas).
Class E: Electrically energized equipment (computers, switchboards).
Class F: Cooking oils and fats (commercial kitchen fryers).
1. Dry Powder Extinguishers (Red with a White Band)
Often referred to as “ABE” extinguishers, dry powder units are the most versatile and common type found in offices, retail spaces, and vehicles.
Best for: Class A, B, C, and E fires. They safely smother fires involving wood, paper, flammable liquids, and live electrical equipment.
What to watch out for: The powder creates a dense cloud that can severely reduce visibility and is messy to clean up, meaning it can damage sensitive electronics even if it puts the fire out.
2. Carbon Dioxide (CO2) Extinguishers (Red with a Black Band)
CO2 extinguishers are the ideal choice for server rooms, office spaces with heavy computer setups, and electrical switchboards.
Best for: Class E (Electrical) fires. Because CO2 is a clean gas, it leaves absolutely no residue behind, protecting your expensive electronic infrastructure.
What to watch out for: They have limited effectiveness on Class A wood or paper fires. Because the gas dissipates quickly, the fire can easily re-ignite if the source remains hot.
3. Water Extinguishers (All Red or Red with a White Band)
Water extinguishers are traditional units designed purely for basic combustible materials.
Best for: Class A fires (wood, cardboard, paper, fabrics).
CRITICAL WARNING: Never use a water extinguisher on an electrical fire (water conducts electricity and will shock the operator) or a cooking oil fire (it will cause an explosive fireball).
4. Wet Chemical Extinguishers (Red with an Oatmeal/Beige Band)
If your business involves a commercial kitchen, restaurant, or staff lunchroom with a deep fryer, a Wet Chemical extinguisher is a legal necessity.
Best for: Class F (Cooking oils and fats) and Class A fires. The chemical gently reacts with the hot oil to create a thick, soapy layer that cuts off the oxygen supply and cools the fat.
What to watch out for: Like water units, they are generally not safe for use on high-voltage electrical equipment unless explicitly rated.
Is Your Workplace Prepared?
Knowing the theory is helpful, but nothing replaces hands-on experience. Regular equipment inspections ensure the gauges are pressurized and the hoses are clear, while professional fire extinguisher training gives your team the confidence to react calmly, pull the safety pin, and protect your workplace when seconds count.