Ductwork runs through almost every wall and floor in a commercial or residential building. Without protection, those ducts would give fire and smoke an easy path from one part of the building to another. Fire dampers close that path.
How a fire damper works
A fire damper sits inside the ductwork where it passes through a fire-rated wall or floor. In normal operation it stays open so air can flow. When a fire is detected, it closes and seals the opening, keeping the fire-rated barrier intact.
Most dampers close in one of two ways: a heat-sensitive link that melts and releases the blades, or a signal from the building's fire system that triggers them to close. Smoke dampers work in a similar way but are designed to stop smoke spreading, and are usually part of a wider smoke control system.
Why dampers fail
Dampers can sit untouched for years, so problems often go unnoticed until they're tested. Common issues include:
- Dust and debris stopping the blades from closing fully
- Corrosion or seized springs
- Links painted over or tampered with
- Ductwork or ceilings altered during fit-outs, leaving dampers damaged or inaccessible
- Access panels missing or blocked, so the damper can't be inspected at all
What testing involves
AS 1851 sets out how fire and smoke dampers are inspected and tested. In practice, a technician will:
- Locate each damper and confirm it can be accessed
- Inspect its condition, including the blades, springs and seals
- Test that it closes properly (often called a drop test), then reset it
- Record the result and report any damper that fails or can't be reached
A good contractor will keep a register of every damper in your building so nothing gets missed from one visit to the next.
Why it matters
A damper that doesn't close can let fire and smoke into stairs, corridors and other units. For building owners and strata managers, dampers are also part of your essential fire safety measures, so they need to be maintained and reported on each year.
If you're not sure when your dampers were last tested, or whether you have a register at all, that's a good place to start.
