Testing Fire and Smoke Dampers

Jim Porter, PE Principal

HVAC systems for hospitals are complex. Designers are tasked with designing a system that can be built, meets all the required codes and operates in the manner that is expected. One area that can cause an owner nightmares is the testing and access to fire and smoke dampers. Hospitals are required to test these dampers periodically to ensure proper operation, and with a large building, this requires significant cost and time. If dampers are poorly placed, those costs can increase exponentially. There are two locations dampers are commonly used in hospitals: at chase penetrations and in smoke barriers.

A hospital of any size will have smoke compartments. When a duct passes from one to another, there needs to be a smoke damper and sometimes even a fire damper. There are exceptions listed in the codes, which I recommend using to the fullest. Usually, smoke compartments are not well planned and are put in at the end of projects with little, if any, concern for duct layout. The dampers at these locations are often very difficult to get to, as they were included as an afterthought – plus, they add pressure drop to the system that the designer may not have accounted for.

Chase penetrations are generally easier to access than the dampers that penetrate smoke barriers, but these can often happen at corridor walls where lots of our utilities pass in front. As mechanical engineers, we tend to coordinate with our equipment better than others, such as electrical, telecom or even fire sprinkler piping that is not show on plans during the design. Watch out for cable tray going under these penetrations and access doors. Coordinate with the electrical so they understand where they can run conduit. At the bottom level of a chase, you can penetrate the bottom of the chase or the side. Sometimes putting the damper in the slab and putting the access on the floor above helps; this keeps people from getting on ladders and above ceilings. The chase on the level above will need an access door in it, but it helps a lot. In Ohio, there is an exception that allows for removal of the smoke damper portion. There are other methods on exhaust you can use as well. Familiarize yourself with these exceptions, and if you plan to use them, talk it through with the architect and owner so everyone is aware.

Another component to be aware of is the distance of these dampers from the ceiling. Any damper located in duct installed four feet above the ceiling is almost inaccessible. Getting to these locations requires special lifts, removing ceiling tiles and grid, and clear paths up to these dampers.

In conclusion, be proactive with damper locations, reduce damper quantities when allowed, and always discuss damper maintenance with the owner to ensure everyone is on the same page. If you need guidance on your next HVAC project, reach out to our team of experts.

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