By Karel Roodt, director and engineer at The Fire Engineer
WET FIRE SPRINKLER SYSTEMS
The wet-pipe system employs automatic sprinklers attached to a piping system connected to a water supply. The water discharges immediately from sprinklers opened by a fire. Only those sprinklers which have been operated by heat over the fire will discharge water. This remains the most effective fire suppressor – though not for complex fires. It is important to note that wet fire sprinkler systems require regular maintenance and inspection to ensure that they are functioning properly. This includes checking for leaks, rust, corrosion and other damage, as well as ensuring that the water supply is adequate.
DRY PIPE FIRE SUPPRESSION SYSTEM
A dry pipe fire suppression system is a type of fire sprinkler system that uses compressed air or nitrogen to keep the water in the pipes pressurised. The system only releases water when a sprinkler head opens, triggered by a heat detector sensing a fire.
Dry pipe systems are typically used in unheated areas or areas where the temperature may drop below freezing, such as a warehouse, garage or a parking structure. The compressed air or nitrogen maintains the pressure on the water, preventing freezing. Once a fire is detected, the heat activates a valve that releases the compressed air and allows the water to flow through the open sprinkler head, extinguishing the fire. Dry pipe systems have several advantages over wet pipe systems. They are typically more efficient in preventing freezing and can be used in areas where freezing is a concern. They also can provide an additional layer of protection by requiring a separate fire detection system to confirm the presence of fire before the sprinklers activate.
SPECIAL HAZARD FIRE PROTECTION SYSTEMS
Special hazard fire protection systems are a type of active fire protection system that is specifically designed to protect unique or specialised environments, such as data centers, cleanrooms or industrial processes. These systems are typically used in environments where traditional water- based fire suppression systems would not be suitable or would cause damage. There are several types of special hazard fire protection systems, including:
- Inert gas systems: These systems use gases such as argon, nitrogen or carbon dioxide to extinguish fires by removing the oxygen necessary for combustion to occur.
- Clean agent systems: These systems use halocarbon or halon compounds as a fire suppression agent, which can effectively extinguish a fire while leaving no residue.
- Water mist systems: These systems use fine water droplets to extinguish fires, they are typically used in areas where traditional water-based systems would cause damage, such as in electronic or data centers.
- Foam systems: These systems use foam to extinguish fires, typically used in industrial processes or where flammable liquids are present.
Special hazard fire protection systems have several advantages over traditional water-based systems. They are effective in extinguishing fires in specialised environments, and they are also relatively clean and leave no residue, which makes them ideal for sensitive equipment and environments.
DRY CHEMICAL FIRE SUPPRESSION
Dry chemical fire suppression systems are a type of active fire protection system that use dry chemical powders to extinguish or control fires. They are typically used in environments where flammable liquids such as oil or gasoline, or flammable gases are present and where traditional water-based fire suppression systems would not be effective. Dry chemical fire suppression systems work by releasing a dry chemical powder into the environment, which smothers the fire by cutting off its oxygen supply. The powder also creates a barrier between the fuel and the oxygen, preventing re-ignition. There are several types of dry chemical fire suppression systems, including:
- Regular Dry Chemical: This type of system uses a sodium bicarbonate- based powder that is effective in extinguishing fires in Class B (flammable liquids and gases) and Class C (electrical equipment) fires.
- Purple-K Dry Chemical: This type of system uses a potassium bicarbonate-based powder that is more effective in extinguishing Class B fires and less effective on Class A (ordinary combustibles) fires.
- Monoammonium Phosphate: This type of system uses a monoammonium-based powder that is effective in extinguishing Class A, B and C fires.
Dry chemical fire suppression systems have several advantages over other types of fire suppression systems. They are effective in extinguishing fires in flammable liquids and gases, they are also relatively low in toxicity and can be used in occupied spaces.
GASEOUS FIRE SUPPRESSION SYSTEMS
Gaseous fire suppression systems are a type of fire protection system that uses a gaseous agent, such as carbon dioxide (CO2), argon or nitrogen, to extinguish fires. These systems are typically used in environments where traditional fire suppression methods, such as water or foam, are not feasible or would cause damage.
Gaseous fire suppression systems work by releasing the gaseous agent into the protected area. The agent displaces the oxygen in the space, which is necessary for combustion to occur. Without oxygen, the fire cannot continue to burn. Gaseous fire suppression systems have several advantages over other types of fire suppression systems. They are clean and leave no residue, which makes them ideal for sensitive equipment and environments. They are also effective in extinguishing fires in the early stages, before they have a chance to spread.
FOAM FIRE SUPPRESSION SYSTEMS
Foam fire suppression systems are a type of active fire protection system that use foam to extinguish or control fires. They are typically used in environments where flammable liquids, such as oil or gasoline, are present and where traditional water- based fire suppression systems would not be effective. Foam fire suppression systems work by creating a foam solution that is applied to the surface of the burning liquid, which smothers the fire by cutting off its oxygen supply. The foam also cools the liquid and the surrounding area, reducing the risk of re-ignition.
Foam fire suppression systems have several advantages over other types of fire suppression systems. They are effective in extinguishing fires in flammable liquid, they are also relatively low in toxicity and biodegradable, which makes them a good choice for sensitive environments.