— Activation Process

How Are Fire Sprinklers Activated?

Fire sprinklers are activated based on the type of sprinkler system installed. The two common types of release mechanisms are glass bulbs and fusible links.

1 Glass Bulb Sprinklers:

   – The glass bulb is filled with a heat-sensitive liquid, typically glycerine-based.

   – When exposed to fire, the temperature rise causes the liquid to expand.

   – At a predetermined temperature (usually 68°C), the liquid expansion shatters the glass bulb.

   – This action releases a valve, allowing pressurized water to flow through the sprinkler head onto the fire.

2 Fusible Link Sprinklers:

   – These use a fusible link made of a low-melting alloy to hold back pressurized water.

   – In a fire, the heat causes the alloy to melt, releasing water through the sprinkler head onto the fire.

Each sprinkler head operates independently, meaning only the sprinklers directly affected by the fire will activate, thus minimizing water damage to other areas.

— Running Time

How Long Do Fire Sprinklers Stay On?

Sprinklers remain active until the fire is extinguished or the water supply is manually shut off or exhausted. The duration depends on the occupancy risk:

   – Light Hazard: 30 minutes

   – Ordinary Hazard: 60 minutes

   – High Hazard: 90 minutes

Statistics from the US show that 94% of all fires in buildings with sprinkler systems are extinguished with four or fewer sprinklers. The fire and rescue service will manually stop the system once they confirm the fire is under control or extinguished.

— Depends on Location

How Sensitive are Fire Sprinklers?

The sensitivity of sprinkler heads varies based on their location. In residential and office settings, sprinklers typically activate at around 68°C.

In industrial settings or near heat-producing equipment, sprinklers may have higher operating temperatures (79°C to 141°C or more) to prevent false activations from non-fire-related heat sources, such as cooking or exhaust systems.

— Smoke Detection

Do Fire Sprinklers Detect Smoke?

No, fire sprinklers do not detect smoke; they are designed to respond only to heat. However, they are often used alongside smoke detection systems to enhance fire safety.

Smoke detectors trigger alarms to alert occupants and enable safe evacuation, while sprinklers control and prevent the fire’s spread.

— Accidental Activation

Can Fire Sprinklers GO OFF Accidentally?

Although accidental discharges are rare, they can happen due to:

   – Mechanical or physical damage to the sprinkler head

   – Exposure to non-fire-related temperature extremes

   – Vandalism

   – Manufacturing defects

   – Chemical corrosion

   – Improper service and maintenance