Fire Dampers vs Fire/Smoke Dampers

[John_187]

Can someone elaborate what situations require on fire dampers and what situations require combination fire/smoke dampers? I thought it may have something to do with rating of the walls they are installed in, whether it's just a fire rated wall or a smoke rated wall as well. I am just not aware of all of the code considerations involved in what is required. Thanks for any help

 

[GT-EGR]

To determine when a fire damper is required vs a smoke damper vs a fire and smoke damper, it really is directly dependent on the construction of the barrier the duct is passing through, and then on a lesser note the size of penetration, material of duct penetrating, and a few other items that might get you an exception.

The building code will dictate what type of separations are required between different parts of a building. This will depend on the occupancy type, size of building, chemicals stored, and probably a lot more items that an architect would answer much better. But from that information, the architect determines what type of "separation" is required of different assemblies in the building. Sometimes it is a floor the duct penetrates, sometimes it's a fire partition, sometimes a fire barrier, sometimes it's a shaft, and so on. It really all depends on how that wall is constructed and rated, which isn't really an engineering decision. Once you know the answer to that question, in the building code there is a section (usually chapter 7) that specifically addresses each individual construction type, and how a duct must be protected when it passes through - aka a fire damper, or a fire and smoke damper, or a fire rated through penetration assembly, or some exception that allows for no damper at all.