Fire sprinklers are essential components of any modern fire suppression system. Designed to detect and control fires automatically, these devices activate when ambient heat reaches a set temperature, releasing water directly over the source. Fire sprinklers help save lives, minimise property damage, and are mandatory in many commercial and residential buildings.
What are Fire Sprinklers?
Fire sprinklers are automatic devices that detect heat and discharge water to suppress fires. Each sprinkler head activates individually when a specific temperature is reached, targeting the fire at its source. This system prevents the spread of flames and protects lives and property efficiently.
How Fire Sprinklers Work
A fire sprinkler system works by using individual sprinkler heads that activate independently when exposed to high heat. Each head contains a heat-sensitive element—either a glass bulb or fusible link—that breaks or melts at a set temperature. This action releases water directly over the fire’s origin, limiting its spread and reducing damage.
Independent Activation of Sprinkler Heads
A key operating principle of these systems is that each closed-head sprinkler activates independently when the ambient temperature immediately surrounding it reaches its specific design activation temperature. This localised operation maximises the available water pressure over the point of origin of the fire, minimising water damage, which stands in stark contrast to the common depiction in films where the entire system activates simultaneously.
Core Components of a Sprinkler Head
Nearly all fire sprinklers share the same fundamental components, which include a frame, a sealing assembly or “plug” designed to prevent water from escaping, a deflector used to distribute water effectively, and a heat-sensitive element that dictates when water is allowed to flow.
The heat-sensitive element is typically either a frangible glass bulb or a fusible link. When a glass bulb is used, it contains a glycerin-based liquid. If the air around the sprinkler reaches a specific activation temperature, commonly 68°C or 93°C, the liquid expands, causing the glass to fracture. This action releases the water that was held back by the bulb, allowing it to flow toward the deflector, which subsequently disperses the water throughout the area.
Types of Sprinkler Systems
Sprinkler systems are generally categorised into four main types, depending on the environment and the specific fire hazard they are intended to protect against.
Wet Pipe System
The wet pipe system is the most traditional and common fire sprinkler installation across commercial and residential buildings. In this setup, the pipes are continuously charged and filled with pressurised water. When a fire begins, the heat activates the nearest sprinkler head independently, immediately releasing the stored water. These systems are simple, reliable, inexpensive, and typically require low maintenance, making them appropriate for standard commercial properties, offices, and schools.
Dry Pipe System
In contrast to wet systems, dry pipe systems do not store water within the pipes. Instead, the pipes are filled with pressurised air or nitrogen, which is held back by a valve. If a fire activates a sprinkler head, the air or nitrogen is released, causing the pressure in the system to drop.
This reduction in pressure opens the valve, allowing water to fill the pipes and subsequently discharge over the fire or smoke. Although this system is more costly and complex to install and maintain, it is the most appropriate option for cold climates and exposed areas, such as parking garages or outdoor balconies, where there is a high risk that pipes may freeze, which would otherwise halt an emergency fire response.
It is important to note that these systems have a slightly slower response time due to the necessary delay between activation and the eventual discharge of water.
Pre-Action System
The pre-action system is a form of dry pipe sprinkler that necessitates a two-step activation process to operate. Initially, smoke or heat must be detected by a separate external sensor, which triggers the opening of the pre-action valve, allowing water to enter the pipes.
Following this, the individual sprinkler heads must be activated by heat before they release water over the fire. This two-step mechanism is valuable because it allows facility personnel to shut off the system in the event of a false alarm, thereby protecting critical assets from water damage.
Consequently, pre-action systems are highly recommended for places where accidental water discharge could cause irreparable harm, such as data centres, museums, and libraries.
Deluge System
The deluge system is another variation of a dry pipe system, distinguished by the fact that all of its sprinkler heads are always open and do not feature an internal heat-sensing element. Activation relies entirely on an external smoke or heat sensor.
Once a sensor detects heat, water rapidly fills the pipes and is released simultaneously through every open sprinkler head, effectively flooding the entire protected area.
This method is primarily used in industrial settings that handle flammable liquids that have a high potential to spread rapidly.
Types of Sprinkler Heads
Sprinkler heads are generally categorised based on their installation orientation and the pattern in which they spray water.
- Pendent Sprinkler Heads: These hang down from the ceiling and direct water downward in a circular pattern to achieve maximum coverage. They are ideally suited for environments such as offices, hotels, and factories.
- Concealed Pendent Heads: These are mounted within the ceiling and concealed by a cover plate, offering a solution where aesthetics are a concern. They operate similarly to standard pendent heads after the cover plate falls off upon reaching a temperature 6°C lower than the sprinkler’s activation temperature.
- Upright Sprinkler Heads: These stand upright and spray water upward in a hemispherical pattern. They are useful in structures with exposed ceilings, such as mechanical rooms, or difficult-to-reach locations like ducts and beams.
- Side Wall Sprinkler Heads: Mounted on the side of a wall, these heads feature only half of a deflector and spray water in a crescent or half-circle shape. They are highly effective for hallways, small rooms, and areas where sprinkler pipes are routed along walls.
Sprinklers are also classified based on their speed of response. Quick response sprinklers are defined as having an RTI of 50 (meter-seconds)1/2 or less, indicating a high level of thermal responsiveness. Specialised fast response sprinklers are used in residential occupancies specifically for life safety; these systems feature a higher discharge pattern than standard spray sprinklers and are designed to direct water higher onto walls to maintain lower ceiling gas temperatures.
Regulations, Standards, and System Design
Fire sprinkler systems are subject to stringent regulation, and their design, installation, and application are guided by standards, most notably those issued by the National Fire Protection Association (NFPA). Standards such as NFPA 13 govern the installation of these systems, while NFPA 25 addresses their maintenance, testing, and inspection. These standards establish the necessary framework for proper installation and maintenance.
During system design, all factors, including the type of flow, the coverage area, the size of the sprinkler heads, and their location, must be determined by a qualified engineer. Any change in a building’s occupancy—for instance, converting a commercial space to include a larger kitchen—requires a complete review and redesign of the system. This ensures that the appropriate temperature rating of the sprinkler head is used, as an improperly rated head can accidentally activate due to the heat generated by the new occupancy. For commercial or residential spaces, the bulbs are typically colour-coded orange or red, indicating a lower temperature rating, whereas areas with higher ambient heat, such as restaurant kitchens, require green or blue bulbs, which correspond to higher activation temperatures.
Contact Malaysia’s Leading Fire Sprinkler Supplier
Fire sprinklers are vital for safety, but choosing a reliable supplier with proven expertise is just as critical. A trusted partner like Unitrade helps ensure system performance and long-term project success.
Unitrade is a leading Malaysian supplier of construction materials, specialising in pipes, fittings, valves, structural steel, cement, and solar PV systems. With 40+ years of experience and landmark projects like KLIA and KLCC, it serves as a trusted one-stop provider for major developments.
Contact us now for a free quotation and expert advice tailored to your project’s specific needs.