John Evans’ Sons has specialized in spring innovation and manufacturing since the days of horse-drawn buggies, producing reliable, powerful springs and spring-based assemblies for industries as varied as medical devices, aerospace, robotics, and window manufacturing. Our extensive in-house capabilities include the production of numerous types of springs as well as customized solutions to meet our customers’ diverse needs. 

With this extensive background in spring manufacturing, our product lines include multiple types of springs for installation or part replacement in fire dampers. Fire dampers are a passive fire safety feature in locations where walls, floors, and ceilings contain openings for ducts, vents, and other air transfer components, designed to close during a fire to prevent its spread.

What Is a Fire Damper? 

Ductwork and vents are critical to maintaining people’s health, comfort, and safety by enabling adequate airflow and temperature control. These passages also help to create appropriate environmental conditions for manufacturing operations, material and merchandise storage, and countless other purposes. Unfortunately, they are also readymade conduits for smoke and flame to travel quickly and access additional oxygen and fuel in the event of a fire. Fire dampers help to stop the spread of fire and smoke. They are essentially valves designed to automatically or manually close, typically with a spring-based mechanism, upon detecting the heat of a fire, halting its advance through a structure. 

Types of Fire Dampers

Spring-loaded fire dampers can be installed in numerous types of ducts and conduits to provide fire protection. Three of the most common types of fire damper installations are:

  • Duct Fire Dampers: These fire dampers are installed in duct penetrations, and can be manual or dynamic, closing and opening with a spring mechanism. 
  • HVAC Fire Dampers: Spring-actuated fire dampers for HVAC systems generally work by closing when they detect the absence of air pressure in the system. 
  • Automatic Fire Dampers: Automatic dampers are triggered to close when environmental conditions reach a set temperature threshold. 

At John Evans’ Sons, we have the capability to produce springs for each of the above-mentioned fire spring dampers.

The Role of Springs in Fire Dampers

Springs play a critical role in making sure fire dampers work properly by providing the torque needed to operate the blades or panels inside fire dampers. Such springs provide:

  • Simple operation by closing to block flame and smoke when temperature thresholds are reached or alarms trigger their closure
  • Automatic or manual damper reopening for regular airflow if and when it is safe to do so.

Installing or replacing springs with top-quality, appropriate spring sizes and styles for individual fire damper models can help to ensure their performance meets or exceeds regulatory and safety requirements. 

Springs Most Commonly Used in Fire Dampers

While traditional helical or round wire springs can be used in fire dampers, constant force springs, spiral torsion springs, and wire forms are the most common choices.  

Constant Force Springs

Supplying a steady, consistent, uniform force along the full spring length, constant force springs are well-suited to curtain opening and closing actions needed in fire damper applications. These springs are commonly used in applications where parts need to spring open or closed, such as door closers, appliances, cable retractors, and other situations where their extended, dependable performance is required. Typically made of stainless steel, their benefits include the following:

  • Stable, consistent force
  • Providing high power under tight space constraints
  • Smooth, reliable extension and retraction
  • Versatile mounting capabilities with customizable end designs
  • Multiple installation configurations to meet varying load requirements

The diameter and thickness of the spring’s material determine its duty cycle.

Spiral Torsion Springs

Spiral torsion springs are used when smooth extension and retraction actions are needed, such as in clocks and watches, windup toys, and, importantly, in fire dampers. Created from a coiled strip of metal with evenly-spaced coils, typically from steel for fire damper applications, they can exert a high degree of rotational torque from even very small rotations. This smooth, powerful action makes them ideal for the reliable, powerful, prompt responses required from fire damper systems. 

John Evans’ Sons Fire Damper Spring Design

Fire dampers can save lives and protect valuable property. Durable, dependable springs are a critical component in these safety devices. By operating fire dampers effectively in situations where smoke and fire can create exponentially more dangerous situations in moments, our springs can help save lives. With spring solutions for duct, HVAC, and automatic fire dampers, we offer the quality and precision these important installations deserve. Contact us to learn more about our full capabilities or to request a quote for your fire damper or other spring-related applications.