Fire dampers - some important notes part 1

Quite often for AC duct penetrating walls which have a fire rating of 2 hr and above we use fire dampers. But what does the code say about how to choose the rating of these Fire dampers?

As per IBC-18, section 717.3.2 and NFPA 90A-15, section 5.4.1 & 5.4.2 below conclusions can be arrived at:

1. Fire dampers used for the protection of openings in walls, partitions, or floors with fire resistance ratings of less than 3 hours shall have a 1 1?2-hour fire protection rating.
2. Fire dampers used for the protection of openings in walls, partitions, or floors having a fire resistance rating of 3 hours or more shall have a 3-hour fire protection rating

Fire dampers are tested in accordance to UL555.

Hence most of the commercially available fire dampers are available as either 1 1?2-hour fire rating or 3-hour fire rating.

Another important note: ensure that fire damper are installed in areas that are easily accessible with properly sized access door.

AMCA has put out a useful document on commissioning and periodic performance testing of life safety dampers (Link to document)