July 1, 2002 is the deadline for manufacturers of UL Classified fire, smoke and combination fire/smoke dampers to comply with the new more stringent UL test requirements. Both UL555 (Fire Dampers) and UL555S (Smoke Dampers) test standards have been revised in order to assure end users that the labeled products will perform their intended function in a reliable and safe manner.

The most significant changes to the UL standards are highlighted here:

  • "Heated" Airflow Dynamic Closure Test
    • This provides more realistic field conditions during fire
    • Changed minimum velocity from 0 fpm to 2,000 fpm
    • A built in 400 fpm safety factor (i.e. must pass 2,400 for 2,000 rating)
  • Actuator/Damper Cycle Requirement Changed from 5,000 to 20,000
    • This ensures the operation of the damper assembly
    • Ruskin’s Internal Cycle Requirement is 100,000

For more detailed information consult our Changes to UL Test Standards Engineering Report located in our online product catalog. In addition, please contact your local representative or Ruskin directly for further information.

If you are interested in procuring the UL test standards or other documents produced by UL click here www.comm-2000.com.