Fire and Smoke Dampers: Best Practice Design Tips
Based On An AMCA International White Paper.
When seconds matter, fire and smoke dampers are the silent protectors in your HVAC system. They slow fire spread, contain smoke, and give suppression systems the time and conditions they need to work. Most importantly, they safeguard lives and property. This guide breaks down why these components are non-negotiable in a comprehensive fire protection strategy—and offers practical design tips to help engineers reduce risk, control cost, and deliver code-compliant performance.
DESIGN TIP #1: SPECIFY DYNAMIC RATED FIRE DAMPERS
Relying on static-rated dampers means waiting for a fan to cycle off—sometimes up to 20 minutes—before airflow stops. Dynamic-rated dampers are tested to close under active airflow and elevated temperatures, ensuring reliable performance during an alarm. The cost difference is minimal compared to the protection they provide.
DESIGN TIP #2: SELECT THE APPROPRIATE FIRE DAMPER CONSTRUCTION TYPE
Two main designs exist: Curtain-type dampers, which use a fusible link to release interlocking blades, are ideal for low-resistance applications or where sleeve transitions create a 100% free area opening. Multi-blade dampers, with triple-vee or airfoil blades, handle higher velocities and larger openings better but introduce slightly more airflow restriction. Choosing correctly means balancing performance, airflow, and space.
DESIGN TIP #3: SPECIFY BALANCING TYPE COMBINATION FIRE/SMOKE DAMPERS
Variable Air Volume (VAV) systems depend on balanced ducts for stable air volume and pressure. A balancing-type combination damper can replace a manual balancing damper, a smoke damper, and a fire damper—streamlining installation, reducing maintenance costs, and providing dual fire-smoke protection without sacrificing airflow control.
DESIGN TIP #4: REDUCE TESTING COSTS WITH POSITION-INDICATING SWITCHES
Periodic testing is mandatory, but accessing ceiling spaces can be disruptive and expensive. Dampers equipped with position-indicating switches allow remote testing via building automation or indicator lights. Benefits include:
Lower labor and maintenance costs
More frequent testing due to easier access
In healthcare settings, no ceiling penetrations—minimizing infection risk and permitting needs
DESIGN TIP #5: SPECIFY FACTORY FABRICATED SLEEVES/TRANSITIONS
Factory-supplied sleeves are custom-built for each damper, following UL-approved installation requirements. They:
Ship directly to the job site, cutting lead times and handling
Reduce installation and material costs
Deliver more consistent, reliable performance than field-built sleeves
DESIGN TIP #6: SPECIFY CLASS I LEAKAGE RATED FIRE AND SMOKE DAMPERS
Maintaining airtight compartments is key during a smoke control cycle. Class I dampers—the lowest leakage rating UL approves—limit smoke migration and support pressure differentials. With costs nearly identical to Class II options (which leak 2.5× more), Class I dampers offer superior protection without inflating budgets.
The Bottom Line
In fire events, the right damper decisions can mean the difference between containment and catastrophe. By specifying dynamic-rated units, matching damper types to airflow needs, leveraging combination dampers, and insisting on Class I leakage ratings and factory sleeves, engineers can improve safety, reduce long-term costs, and keep projects on schedule. At Stan Weaver, we’re here to help you design smarter, safer systems—because when it comes to life safety, every detail matters.
Reference: https://content.greenheck.com/public/DAMProd/Original/10009/AMCAWhitePaper_FireandSmokeDampers.pdf
