Fire Extinguisher Types & Emergency Procedures — AS 2444

Fire safety on construction sites is critical. Flammable materials, electrical equipment, hot work, and temporary power supplies all create fire risks. Australian Standard AS 2444 (Portable fire extinguishers and fire blankets) sets out requirements for the selection, installation, and maintenance of firefighting equipment in workplaces. Understanding fire classes, extinguisher types, and emergency procedures is essential for your White Card test and for protecting yourself and others on site.

Understanding Fire Classes

Fires are classified by the fuel that sustains them. Using the wrong extinguisher can make a fire worse or cause serious injury.

Class A fires involve ordinary combustibles such as wood, paper, cardboard, fabric, and plastics. These are common on construction sites in formwork, scaffolding timber, and packaging materials.

Class B fires involve flammable liquids including petrol, diesel, oil, solvents, and paint thinners. These fuels are often present in site storage areas and workshops.

Class C fires involve flammable gases such as LPG, acetylene, and natural gas. Welding and cutting operations use these gases, creating ignition risks if equipment is faulty or used incorrectly.

Class D fires involve combustible metals such as magnesium, aluminium shavings, titanium, and sodium. These are less common but can occur in metalworking and fabrication.

Class E fires involve electrical equipment. Once the power is isolated, the fire is reclassified (typically as Class A or B). Never use water or conductive extinguishing agents on energised electrical fires.

Class F fires involve cooking oils and fats. These typically occur in site canteens or lunchroom kitchens.

5 Fire Extinguisher Types

Australian fire extinguishers are identified by coloured bands or labels. Each type is suited to specific fire classes.

1. Water (Red Label)

Water extinguishers are identified by a red body or red band. They are designed for Class A fires only. Water cools and soaks ordinary combustibles, extinguishing the fire. Never use water on electrical or flammable liquid fires. Water conducts electricity and can cause electrocution. On flammable liquid fires, water can spread the burning liquid and worsen the blaze. On construction sites, water extinguishers are suitable for fires in timber, paper, and similar materials.

2. Dry Chemical Powder (White Label)

Dry chemical powder extinguishers have a white band or label. They are effective on Class A, B, and E fires and are the most versatile type for general use. The powder interrupts the chemical reaction of the fire and smothers flames. They leave a residue that requires cleanup and can cause visibility and breathing issues in enclosed spaces. Dry chemical extinguishers are commonly found on construction sites because they can handle multiple fire types including electrical equipment and flammable liquids.

3. Foam (Blue Label)

Foam extinguishers have a blue band or label. They are suitable for Class A and B fires. Foam creates a blanket that smothers flames and prevents reignition by separating the fuel from oxygen. They are particularly effective on flammable liquid spills. Foam should not be used on electrical fires while the equipment is energised, as the foam may conduct electricity. On construction sites, foam extinguishers protect against fires in fuel storage areas and where oils or solvents are used.

4. CO2 (Black Label)

Carbon dioxide extinguishers have a black band or label. They are suitable for Class B and E fires. CO2 displaces oxygen, starving the fire, and leaves no residue—making them ideal for electrical equipment and sensitive machinery. The discharge is extremely cold; never hold the horn when operating, as it can cause frostbite. CO2 extinguishers are often placed near switchboards, offices, and electrical plant. They are not suitable for Class A fires in open areas, as the gas dissipates quickly and the fire may reignite.

5. Wet Chemical (Oatmeal or Beige Label)

Wet chemical extinguishers have an oatmeal or beige band. They are designed for Class A and F fires—especially kitchen and cooking oil fires. The wet chemical agent cools the oil and creates a soap-like layer that prevents reignition. They are the correct choice for deep-fryer and commercial kitchen fires. Wet chemical extinguishers are typically installed in site canteens, lunchrooms, and anywhere cooking oils are used.

Emergency Evacuation Procedures

When a fire occurs, evacuating safely is the priority. Know the procedures before an emergency.

Raise the alarm—activate the nearest fire alarm or alert others by shouting. Do not assume someone else has done it.

Evacuate immediately—leave by the nearest safe exit. Do not stop to collect belongings. Close doors behind you to slow the spread of fire.

Proceed to the assembly point—every site must have designated assembly points. Go there and stay until you are accounted for. Do not leave the assembly point without authorisation.

Follow warden instructions—fire wardens (identified by their role) direct evacuation and coordinate with emergency services. Cooperate fully with their instructions.

Do not re-enter—never go back inside until the site has been declared safe by the appropriate authority. Many fatalities occur when people re-enter burning buildings.

Familiarise yourself with evacuation routes and assembly points as soon as you start on a new site. Participate in fire drills when they are conducted.

RCD Safety Switches

Residual Current Devices (RCDs), also known as safety switches, are critical for electrical safety on construction sites. They detect an imbalance in electrical current—such as current leaking through a person to earth—and trip the circuit within milliseconds, potentially preventing electrocution.

RCDs are required on all portable electrical equipment and extension leads used on construction sites. They must trip at or below 30 mA within 30 milliseconds when an earth fault is detected. This threshold is designed to protect against fatal electric shock while allowing normal equipment operation. RCDs must be tested regularly (typically by pressing the test button) to ensure they are functioning. Never bypass or disable an RCD. Construction sites present increased electrical risk due to wet conditions, damage to cables, and use of power tools—RCDs are a legal requirement and a key defence against injury.

Under the WHS Regulations and AS 2444, fire safety equipment and electrical safety devices work together to protect workers. Knowing how to use extinguishers correctly and understanding evacuation and RCD requirements will help you pass your White Card test and stay safe on site.