Fire doors are required to be closed and latched if/when a fire occurs. A closed fire door helps to deter the spread of smoke and flames, and the latch prevents the door from being opened by the pressure created during a fire.
In some locations, hardware that latches the door each time it is closed may not be convenient, so NFPA 80 allows “latching arrangements that do not provide positive latching in the normal mode” as long as the door becomes latched automatically upon fire detection. Electric latch retraction fire exit hardware is often used in this application, but electric strikes are another option. In either case, the hardware must be connected to the fire alarm system so the door will be latched during a fire.
An electric strike used on a fire door assembly must be fail secure, so that if power to the strike fails, the door will be securely latched. Fail safe electric strikes are not listed for use on fire door assemblies, because the spring-loaded keeper could allow the door to be pushed open during a fire, allowing smoke and flames to pass through the opening.
To learn more about these applications, read the following articles:
- Q&A – Electric Latch Retraction on Fire Doors
- Decoded: Electric Strikes on Fire Doors
- More on Electric Strikes on Fire Door Assemblies
Then proceed to the review questions below.
1. Electric strikes used on fire door assemblies must be which function?
- Fail safe
- Fail secure
- Either fail safe or fail secure is acceptable as long as the strike is activated by the fire alarm.
2. When power is cut to electric latch retraction fire exit hardware, which of the following describes the resulting condition?
- Door is locked and does not allow access or egress
- Door is locked on the egress side but allows access
- Door is latched but allows free egress
- None of the above
3. Which of the following applications, actuated by the fire alarm system, would NOT be acceptable on a fire door assembly?
- A stairwell door that requires reentry, equipped with an electric strike
- A cross-corridor pair with automatic operators and electric latch retraction fire exit hardware
- A boiler room with a fail secure electric strike and storeroom function lockset
- All of the above are acceptable
- None of the above are acceptable
Answers: 1 – B, 2 – C, 3 – A