Fire dampers are a critical component of passive fire protection (PFP) in any building where HVAC ductwork passes through fire-rated walls or floors. Their purpose is simple and essential: prevent flames and smoke from using ductwork as a pathway between fire compartments.
What Is a Fire Damper?
A fire damper is a mechanical device installed within air ducts. Under normal conditions the blades remain open, allowing airflow. When exposed to elevated temperatures (typically around 72 °C), a fusible link or thermal actuator activates, causing the blades to close and restore the fire-resisting capability of the barrier.
Fire dampers are tested to AS 1530.4 to verify their required Fire Resistance Level (FRL).
How Fire Dampers Work
Most fire dampers use a fusible link or thermally responsive actuator. Under normal conditions, the damper blades remain open, allowing air to flow freely. When the fusible link reaches its melting temperature—often around 72°C—it releases, causing the blades to spring shut. This blocks the passage of hot gases and flames.
Types of Fire Dampers
- Curtain Dampers – folded blades drop into place when released
- Multi-Blade Dampers – rotating blades close when actuated
- Dynamic Dampers – designed to close against airflow in pressurised systems
- Combination Fire/Smoke Dampers – provide both fire resistance and smoke control
Installation Requirements
Under AS 1682.2 and AS 4072.1, fire dampers must be installed exactly as tested, including:
- Penetration size and substrate type
- Fixing methods and frame construction
- Use of tested firestop/sealant systems around the frame
Any deviation from the tested configuration can void compliance.
Common Issues Leading to Non-Compliance
- Gaps between damper frames and wall/floor not properly sealed.
- Use of untested sealants or materials.
- Damper blades obstructed by debris or mechanical damage.
- Incorrect orientation or installation depth.
Maintenance – AS 1851
Fire dampers require routine inspection to ensure they remain functional:
- Check fusible link integrity
- Operate blades to verify full closure
- Remove obstructions
- Confirm seals are intact
Ceasefire PFP’s Role
Ceasefire ensures that every damper installation:
- Uses tested and approved products
- Aligns with the HVAC design and PFP standards
- Is fully documented with photographs and batch numbers
- Receives scheduled maintenance throughout the building lifecycle
Fire dampers are often overlooked—but absolutely essential in preventing fire spread through HVAC systems. With Ceasefire PFP’s precision installation and documentation, building owners can be confident that every damper will perform when it matters most.
