What is a Fire-Safety Valve with a Fusible Link and How Does It Work?

A fire-safety shut-off valve, also known by thermal shut-off valve or simply a fusible link valve, is a safety device designed to provide automatic valve shut-off in the event of a fire. Fire-safety valves of this type are designed for facilities that utilize flammable or toxic gases and chemicals in their production or for fuel systems of all types.

The fusible link is an FM and/or UL approved two-part linkage held together by a specialized heat-sensitive solder. These link(s) hold the fire safety valve open by keeping tension on a spring pack through a trigger assembly.

How Does a Fire-Safe Valve Work with a Fusible Link?

A fire safety shut-off valve is comprised of five main components – API 607 fire-safe valve, spring pack, mounting hardware, trigger assembly, and fusible link. The last four of these components work in unison to close the API 607 valve should a fire be detected within a facility.

The fusible link portion is the linchpin of the assembly and keeps the fire safety valve open by keeping tension on a spring pack through the trigger assembly. When a fire breaks out, the link separates when its rated temperature is met, releasing the spring pack and allowing it to close the valve.

The API 607 standard is a specification for the fire testing of quarter-turn valves. For fire-safety valve with fusible links, this means that the valves have a primary drop-tight seat, typically made of TFE, along with a secondary seat made of metal for isolation in a fire. The secondary seat is coupled with graphite seals for further protection. This means the top works of the shut-off valve can be paired with any quarter-turn API 607 fire safe valve – ball valve, butterfly valve, or plug valve.

Where are Fusible Links Used?

Fusible link fire-safety valves are used in a variety of industries within an organization’s overall fire safety system for widespread fire protection. Most modern facilities have at diesel generators and day tanks that that requires this type of safety valve at a minimum. Other locations where flammable or toxic media are part of the production process,  this valve type is placed at strategic locations throughout facilities including storage tanks, pumps, entryways into a building, and at key piping junctions. Entryways into buildings are especially key so that have employees, customers, and patients have as much time for notification and evacuation as possible.

Applications that use Fire-Safety Shut-off Valves include:

• Backup generator systems
• Chemical plants
• Refineries
• Storage or day tanks
• Solvent or paint lines
• Biofuel plants
• Fuel systems (diesel or natural gas)
• Hospitals

Choose BI-TORQ Valve Automation

A fire safety valve should be used as a safety precaution on any system that utilizes flammable or hazardous media. Designed to save lives and enable quick resumption of operations after a fire has been handled, fusible link assemblies are necessary for the safe daily operations of many commercial operations, plants, and manufacturing facilities. Many of these operations will find that insurance for their business is not available without a fire safety valve with fusible link.

BI-TORQ has been designing this type of assembly for over two decades. Let’s have a conversation about your fire safety needs and how our products can provide safety for your workers and operation. Contact us for more information on fire safety valves with fusible links, or to discuss any of our wide range of valve solutions.