Every fire needs 3 things to keep burning: Heat, Oxygen, and Fuel.

So any method used to stop a fire must take away at least one of these three. Water is used to reduce heat in many fires, but other times, a compound, gas, or liquid is needed to cut off the flow of oxygen to the fire. sprinklers and fire extinguishers use these methods in multiple ways to put out fires.

So how do they work?


Sprinklers can extinguish small fires in 90 seconds using a tenth of the water it would take a hose to do the same job. At their most basic, sprinklers involve a network of pipes with holes allowing pressurized water to flow onto a fire. Of course, most of the time we don’t want that water to flow, so the holes remains blocked by plugs. These plugs generally come in 2 types, both of which are designed to react to the heat of a fire:

1. GLASS BULB: a small bulb filled with a glycerin-based liquid will expand quickly when exposed to heat causing the glass to shatter and allowing water to flow.
2. ALLOY: a special mixture called “Wood’s Metal” made of bismuth, lead, tin, and cadmium which melts at 70°C (160°F) holds together 2 spring-loaded arms. Once the alloy melts, the arms spring open allowing water to flow.

It’s important to note that each sprinkler head functions independently of all the others – each reacts on its own to the fire rather than all of them being triggered at once. This prevents unnecessary water damage in areas where there’s no fire.

Additionally, the piping has two general types:

WET-PIPE: These have water resting throughout the piping ready to flow immediately when needed.

DRY- PIPE: These have pipes filled with compressed air which, once released, create low pressure areas into which the water rushes, then flows out. They are used in cases where extreme cold could cause water to freeze were it sitting in the pipes constantly.


You know they’re around, but it’s vital to familiarize yourself with exactly where they’re located and what type they are – just in case you ever need to spring into action.

Although there are a few different kinds, each fire extinguisher is essentially a canister with pressurized contents and a spray nozzle. The user pulls out a safety pin, points the nozzle at the base of the fire, then depresses the lever. This does 2 things simultaneously:

  • it presses down a sharp rod which pierces the internal canister releasing a pressurized gas
  • it opens a valve which allows the fire-suppressing contents to escape the canister via the nozzle

The contents of the canister come in 5 general types – Water, Foam, Dry Powder, CO2, and Wet Chemical. And although there is overlap, each has a different purpose; there is no type of fire extinguisher that is suitable for all types of fires!

1. WATER – These combat fires fueled by paper and wood and do so by cooling the fuel. They must NOT be used on electrical fires as they could cause electrocution.

2. FOAM – These are for organic materials like fabrics, wood, coal, paint, and petrol, and they cool the fuel while creating a barrier between flame and fuel.

3. DRY POWDER – Used for organic materials as well as flammable gasses and electrical equipment, they also form a barrier between flame and fuel.

4. CO2 – Predominately used for electrical fires, they are commonly kept in server rooms. The CO2 gas displaces the oxygen thus causing the fire to extinguish.

5. WET CHEMICAL – These are specialized for cooking oils and fats and work by creating a layer of foam on the surface of the fuel preventing oxygen from reaching it.

Both sprinklers and fire extinguishers are vital part of fire preparedness. Of course, always contact a fire protection expert to insure you’re choosing the appropriate types for your situation.