Can I use fire dampers where ductwork passes through an escape route such as a protected stairway or corridor?
A. Fire dampers (including intumescent) are not suitable for use on protected escape routes because they do not protect the escape route from smoke. In this instance there are two solutions:- Option 1 Ductwork protected Ductwork passing through the protected route be enclosed with fire resisting construction/the ductwork itself be fire resisting (known as method 2 and 3 respectively) in both cases tested to BS 476: Part 24 or EN1366-1 (with fire exposure from the inside) and not serve the protected route. See Figure 1 Method 2 is illustrated. Option 2 – ES leakage rated fire dampers ES classified leakage rated fire dampers would be suitable. Such dampers should achieve an ES classification to BS EN 13501-3 when tested to BS EN 1366-2. See Figure 2. It is important the ES dampers are installed in accordance with the fire damper manufacturer’s tested details, as the opening into which the damper is fixed is also a leakage path for smoke. The ES classification confirms that the fire dampe