Fusible Links are Critical in Restaurant Systems

By Mark Conroy

The fusible link is one of the simplest forms of heat detection devices. When links are used in a restaurant system, their purpose is to cause the system to function and extinguish the fire. Fusible links used in this manner are actually releasing devices that are heat actuated. They cause the system to automatically operate at a predetermined “fixed” temperature.

Location is Critical
Fusible links must be located in the path of the exhaust air from the appliances. This is done so that the links will be exposed to the heat from a fire, should one occur. At least one fusible link or similar heat detection device is required to be provided above each protected cooking appliance. Additionally, one is required to be installed within each exhaust duct opening.

How They Work in Restaurant Systems
Links are employed to restrain the operation of the system until a fire occurs. Each link is connected by a cable to the restaurant system releasing mechanism. When a high temperature is reached, the two halves of the link separate. When the cable tension is released by the separation of the link, the system operates and wet chemical flows out the discharge nozzles into the fire area.

Periodic Replacement
Excessive buildup of grease or deterioration of a fusible link could cause the system to inadvertently actuate or not function properly in the event of a fire. NFPA 96, Ventilation Control and Fire Protection of Commercial Cooking Operations requires the following:

• System maintenance shall be conducted every 6 months
• Fusible links shall be replaced every 6 months
• Installation date and year the link was manufactured shall be recorded on a service tag
• Service tag shall be signed or initialed by the service technician
• All fusible links shall be destroyed upon removal

Where mandated locally, NFPA 96 also requires a maintenance certificate to be sent to the authority having jurisdiction. Replacing fusible links every six months will help ensure the system will operate when there's a fire.