Sizing Up Fire Doors and Rated Hardware

It's the responsibility of locksmiths to understand all components of steel fire doors. All hardware mounted to fire doors must be properly rated.


The Relationship Of Walls And Doors

Doors are classified and rated by the amount of fire protection they provide.

The fire rating of the door is dependent on the rating of the wall on which the door and frame are mounted. The fire rating of the wall is determined by its location and how it serves the building.

Walls that separate buildings or divide large buildings into segmented and separate fire areas are rated at four hours and fire doors mounted on these walls are rated at three hours.

Walls that protect stairwells, refuges, or vertical enclosures in a building are rated for two hours and doors mounted to these walls are rated for 1-1/2 hours of fire protection.

The walls to boiler rooms and exterior walls where fire exposure is high are rated for two hours. The doors mounted to these types of walls are rated for 1-1/2 hours.

Walls between rooms are usually rated for one hour and so are the doors mounted to them.

Corridor and room partitions must have walls rated for one hour and doors rate at 45 minutes (3/4 hour).

Where fire exposure to an exterior wall is moderate, the wall rating can be one hour and the doors rating 45 minutes.

Openings between living quarters and corridors fire exposure are moderate where smoke and draft control is the primary concern. Codes generally require walls rated for one hour and doors rated for 20 minutes (1/3 hour).

Figure 2 provides a general idea of how the fire opening should be rated. It should not be used to determine ratings rather to spot when a lesser rated door was installed or improper hardware is installed on a fire door.

An example of this is when the locksmith is called out by the customer to replace or repair an exit device. The locksmith recognizes that the exit device is rated for life-safety but not for fire doors.

The locksmith in this circumstance cannot replace it with an exact equivalent. An exit device that is matched with the fire-rating of the door must be retrofitted.

Fire Door Assembly

All components of the door -- frames; locks; hinges; closers; latches; gaskets; lites; glazing materials; and other hardware items -- constitute the fire assembly. For the assembly to be effective, all items must be labeled accordingly.

The locksmith must pay attention when substituting non-rated components as the result will be a loss of fire protection rating in its entirety.

An example of this might occur when retrofitting an exit device to an electric latch-retracting exit equivalent. The existing exit device as well as the electric equivalent might be equally labeled, but a change of hinge could corrupt the entire rating of the assembly.

Many concealed electric hinges are UL rated for applications where low-voltage current is to be carried through the hinge but may not be necessarily be rated for use on fire rated opening.

As components to the fire door assembly, all hinges must be fire-rated. The retrofit of one non-rate (electric) hinge voids the fire-protection rating.

A locksmith might be called out to replace a non-rated electric hinge with a rated concealed electric power transfer (EPT) recommended by the manufacturer of the existing exit device. This creates another problem as cutting out the frame for the EPT will most likely void the fire protection of the frame.

In this case the proper retrofit requires the frame be changed and a frame specified for the rating of the door and EPT cut out.

Another alternative is to carry the voltage across the door and frame by using a surface-mounted power transfer. These devices are not as aesthetic as a concealed transfer but they do not degrade the integrity of fire protection. Remember: Before making any modification to a fire rated opening, contact the authority having jurisdiction.

Fire-Rated Hardware Locations

The location of fire-rated hardware on the door is strictly controlled. All manufacturers of steel fire doors follow the standards of the Steel Door Institute (SDI). This is an organization that reconciles and keeps track of all statutes and standards and is provided as an aid to architects and manufacturers regarding steel doors. The manufacturers of fire-rated hardware also adhere to SDI guidelines.

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