Escape route ducts
Escape route ducts are any duct crossing an escape corridor. In accordance with BS9999:2008, clause 33.4.2, escape route ducts must be fire rated.
In the diagram
The pressurised air supply duct (shown ) from the fire rated plant room above crosses the cleaner’s room and the escape corridor to provide air to the escape lobby. Any type of fire rated duct that crosses the escape corridor requires stability, integrity and insulation (shown ) for the same period of time as the compartment through which it passes.
Both the normal ventilation supply duct and extract duct follow a route from the riser shaft through the office using the dampers and galvanised sheet steel duct - method 1 of BS 9999:2008 (shown ). Ducts that cross in the escape corridor (shown ) must be fire rated and will require stability, integrity and insulation for the same period of time as the compartment through which they pass.
The escape route duct will also require at least one fire damper if either side of the escape corridor is constructed with non-fire rated duct.
All fire rated ductwork and penetration seals must be tested to BS 476-24/ISO 6944 or BS EN 1366-1 and classified in accordance with BS EN 13501-3 by a recognised NAMAS/UKAS accredited laboratory.
Note: Final approval must always be obtained by the local building control officer/fire department prior to commencement of construction