Selecting a building’s essential safety measures requires a fair amount of strategic planning, both from building managers as well as fire safety specialists. It’s imperative to conduct a fire risk assessment and collate an assessment report that clearly outlines all the identified fire hazards within a worksite or building. The findings of this fire risk assessment can then provide more guidance alongside Australian Standards on the selection of effective ESMs for that particular environment.
The reason why a fire risk or safety assessment is required prior to finalising ESMs is simply that not all types of ESMs are designed to suppress all fire types. There are different ESMs for grease fires or cooking fires as opposed to paper or wood fires. On this same note, you wouldn’t put out an electrical fire with a fire hose, as adding water can not only ruin electrical equipment but also potentially result in an electric shock.
This raises the question of understanding which fire suppression systems are a good fit for your building? Our fire safety technicians at Alexon will be answering that question today by providing an overview of the most common types of fire suppression systems and giving examples as to where these systems would be most effective.
As its name suggests, a fire suppression system is a system that’s designed to extinguish or suppress fires and uncontrolled flames within a building. Some fire suppression systems are even designed to prevent fires from occurring altogether.
The most common types of fire suppression systems that you’re likely to see include water-based fire sprinkler systems that are typically heat-activated and release water from its sprinkler heads. But there are a few more fire suppression systems that you may be less familiar with.
The following are the fire suppression system types that we’ll be exploring today:
1. Water-based fire sprinkler systems
2. Water mist sprinkler systems
3. Foam deluge fire suppression systems
4. Dry chemical fire suppression systems
5. Gaseous fire suppression systems
As we mentioned, water-based sprinkler systems are amongst the most commonly utilised fire suppression systems today. These systems work by using pipes installed building-wide to direct a flow of water straight to an area that has triggered a sprinkler due to extreme heat.
The extreme heat activation mechanism usually involves the breaking of a glass bulb or ampule that covers a sprinkler head. This glass ampule is filled with a glycerin-based liquid that naturally expands when exposed to heat. The expansion then prompts the glass to break, which then opens the sprinkler head and allows for the flow of water.
Water sprinkler systems can be wet-pipe or dry-pipe (also known as pre-action valve) systems. The difference between these two system configurations is essentially that dry-pipe systems have a pre-action valve located between the water tank and system pipes. This valve must also be activated via a detector in order to open and allow water to flow from the tank and into the opened sprinkler heads.
Water sprinkler systems usually require buildings to have a dedicated water tank installed. The water pressure of your sprinkler system must also be tested annually as per Australian Fire Safety Standard AS2118.
This next one is fairly similar to your traditional water sprinkler systems, except for the fact that it utilises a water mist rather than a water spray, or a heavier stream of water. Water mist systems can be used as humidification systems in greenhouses, food stores, and other environments. They can also be effective alternatives to water spray sprinkler systems, catering particularly for work environments that house mechanical or electrical equipment that may become damaged when exposed to high levels of moisture.
Water mist systems come with a fair few advantages of their own, including reduced water consumption and the fact that they can work with smaller, lighter pipes, making installation of these systems fairly easy to complete. As water mist systems expel less water, they are usually also safe to use in fighting Class A & B fires, which are solid combustible materials and liquid chemical fires respectively.
High-pressure water mist systems may also be used in kitchen environments and even environments with machinery, although there are still some risks with using water mist for electrical fires. Be sure to consult with your fire safety specialist to determine if a water mist system is the right fire suppression system for your building.
Instead of using water, foam deluge fire suppression systems utilise a chemical suppressant and water-based foam mixture to combat fires. The foam in question is designed to have a lower density than oil, gasoline, or water, allowing it to easily coat or blanket fires, with the foam’s moisture and air pockets effectively smothering open flames. It’s often referred to as ‘firefighting foam’.
Foam deluge fire suppression systems can be used for Classes A, B, and F fires, these being fires originating from solid combustible materials, liquid materials, and cooking fats or oils. Foam deluge systems are, however, not effective for combating Class C, D, and E fires, these being fires originating from flammable gases, flammable metals, and electrical equipment respectively.
As foam deluge systems are reliant on retaining a balance between the chemical suppressant and water molecules in the foam mixture, servicing this fire equipment in accordance with AS1851 is absolutely critical for ensuring the effectiveness of these systems.
Unlike foam deluge systems that utilise a moisture-rich chemical mixture, dry chemical fire suppression systems use a chemical powder to extinguish fires. Dry chemical fire suppression systems usually use the same chemical powders found in powder fire extinguishers. Monoammonium phosphate is the most commonly used chemical powder in dry chemical fire suppression systems in Australia.
Dry chemical fire suppression systems can be used to combat Class B and C fires, these being fires originating from flammable liquids like paint or petroleum, and fires originating from flammable gases like methane. So dry chemical suppression systems may also be useful for combating Class A solid combustible material fires, but this is dependent on the chemical powders that are used for your dry chemical system.
If you’ve been thinking about the fact that none of the fire suppression systems outlined above actually work for electrical fires, then we thank you for staying with us this far. Pressurised gas fire suppression systems are the answer to the novel problem that is fighting electrical fires without causing further damage to plant and equipment, as well as to a building and its occupants.
As you may have guessed, gaseous fire suppression systems work in a similar fashion to water-based systems, except instead of raining down water, they disperse gas as a means of reducing the oxygen supply in the affected areas. Carbon dioxide or CO2 gas is what’s most typically used in these fire suppression systems, however other inert gases like nitrogen and argon have also been used in recent years.
Rest assured that these composite gas suppressants are breathable, so reducing the oxygen availability in an affected area won’t cause any immediate adverse effects for occupants of that space. That being said, it’s best to proceed with the emergency evacuation protocol in your fire safety plan in the event that your gaseous fire suppression system is activated.
With a clearer understanding of these fire suppression systems, building managers should find it easier to engage with their building’s ESMs and develop an effective fire safety plan as well as tailored maintenance procedures for all your installed fire systems.
Want to inquire about securing an ideal fire suppression system for your building? Or are you looking for expert fire safety technicians to provide equipment testing, maintenance, or fire safety reporting services? Then simply contact the team at Alexon today. Our dedicated specialists are here to offer their assistance with all things fire safety.
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