• Classes of Fire

• Types of Extinguishers

• Use of Extinguishers 

• Halon

• Inspections & Surveys - Hand Operated Fire-fighting Equipment

A fire extinguisher is an active fire protection device used to extinguish or control a fire, often in emergency situations. Typically, a fire extinguisher consists of a handheld cylindrical pressure vessel containing an agent which can be discharged to extinguish a fire.  

Usage

The typical steps for operating a fire extinguisher (described by the acronym "PASS") are the following:

P - Pull the safety pin.

A - Aim the nozzle at the base of the fire, from a safe distance.

S - Squeeze the handles.

S - Sweep the extinguisher from side to side while aiming at the base of the fire

There are various types of extinguishers, which are used for different types of fires; using the wrong type can increase the fire hazard and be hazardous, but using the right one can better the situation.

Note: Only attack the fire if you are trained and it is safe to do so.

History

The modern fire extinguisher was invented by British Captain George William Manby in 1818.  It consisted of a copper vessel of 3 gallons (13.6 litres) of pearl ash (potassium carbonate) solution contained within compressed air.

The soda-acid extinguisher was invented in the 19th century, which contained a cylinder of 1 or 2 gallons of water with sodium bicarbonate mixed into it. A vial was suspended in the cylinder containing concentrated sulphuric acid. Depending on the type of extinguisher, the vial of acid could be broken in one of two ways. One used a plunger to break the acid vial, while the second released a lead bung that held the vial closed. Once the acid was mixed with the bicarbonate solution, carbon dioxide gas was expelled and thereby pressurizes the water. The pressurized water was forced from the canister through a nozzle or short length of hose.

Around 1912 Pyrene invented the carbon tetrachloride or CTC extinguisher, which expelled the liquid from a brass or chrome container by a hand pump; it was usually of 1 imperial quart (1.1 L) or 1 imperial pint (0.6 L) capacity but was also available in up to 2 imperial gallon (9 L) sizes. The CTC vapourised and extinguished the flames by chemical reaction. The extinguisher was suitable for liquid and electrical fires, and was popular in motor vehicles for the next 60 years. The vapour and combustion by-products were highly toxic, and could cause death in confined spaces.

Chemistries

A fire extinguisher may emit a solid, liquid, or gaseous chemical.

Installation

Notes: Installation of fire extinguishers in vehicles & pleasure craft must be in accordance with NZS 4503 Page 34 3.10 and Page 35 Table 3.4.

Fire extinguishers are typically fitted in buildings at an easily-accessible location, such as against a wall in a high-traffic area. They are also often fitted to motor vehicles, water and aircraft - this is required by law in many jurisdictions, for identified classes of vehicles. Under NFPA 10 all commercial vehicles must carry at least one fire extinguisher (size/UL rating depending on type of vehicle and cargo (i.e. fuel tanker typically must have a 20lb. when most others can carry a 5lb.).

A fire extinguisher fitted to the passenger seat of a car.

Maintenance

  An empty fire extinguisher which was not replaced for years.

Most countries in the world require regular fire extinguisher maintenance by a competent person; this will allow fire equipment to” operate safely and effectively, as part of the requirements under NZS 4503.  Lack of maintenance can lead to an extinguisher not discharging when required, or rupturing when pressurized. Deaths have occurred, even in recent times, from corroded extinguishers exploding. 

Fire Extinguishers are maintained in accordance with NZS 4503 section 6. All Inspection and maintenance of hand held operating equipment with the exception of monthly checks must be carried out by a competent person.  

• Basic Service: All types of extinguisher require a basic inspection annually to check operational condition as required by NZS54503 (page 52 table 6.2 item 6.2.1).
• Extended Service: Wet Chemical & Foam Type Fire Extinguishers require a 3 yearly service. This includes a more detailed examination including a test discharge of the extinguisher & recharging if satisfactory.
• 5 yearly Pressure Testing: All Fire Extinguishers are subject to pressure vessel safety legislation and must be hydraulically pressure tested & date stamped or labeled every 5 years.

Fire hose reels are located to provide a reasonably accessible and controlled supply of water to combat a potential fire risk. The length of a fully extended fire hose is between 18 and 36 meters with a diameter of 13 or 19mm Internal Diameter. These appliances are designed to deliver, as a minimum, 0.33ltrs of water per second. A control nozzle attached to the end of the hose enables the operator to control the direction and flow of water to the fire. All fire hose reels come with a unique ball or gate valve shut off device, a plastic or solid brass hose reel nozzle, and mounting bracket.

Note: Fire Hose reels are manufactured to comply with AS/NZS 1221 and are maintained in accordance with NZS 4503. Frequencies of Inspections are on a monthly and yearly basis.

Fire hose reels located in buildings are to be used by building occupants to fight fire, especially when they are trapped and cannot escape to an emergency EXIT.

The fire hoses are connected to the mains water supply, or Fire Systems Feeds, and extend up to 36 metres.  Some fire hose reels are located in cabinets whilst others are visible on the wall in fire cells.  They require appropriate signage indicating their location and fuel risk suitability.

Operation

Fire hose reels are all very similar in operation. This is the generic procedure:

1. Ensure the nozzle or jet is in the closed position
2. Turn on the main valve (some will not let the nozzle out until this is done)
3. Pull the hose off the drum, towards the fire
4. Open the nozzle or valve and direct the stream of water at the fire
5. Only use on Class A fuels.

Canvas Fire Hoses

Canvas fire hoses attached to or adjacent to fire hydrant points are installed only for use by the Fire Brigade, or an Emergency Response Team.  They must not be used by untrained personnel as injury or excessive property damage may result.

Maintenance of Hose Reels

For the maintenance of hose reels, monthly checks may be carried out by the building owner. It is mandatory under NZS 4503 that annual checks are carried out by a competent person. 

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