SMOKE EXTRACT

Smoke is recognised as the leading cause of death and serious injury during fire outbreaks. It can spread quickly to areas remote from the scene of the original blaze, threatening life, restricting escape, delaying fire fighting and damaging property.

Stairwells and elevator shafts frequently become smoke logged, blocking evacuation routes and preventing firefighters and other rescue teams from doing their critical jobs.

Thor Duct® Smoke Extract ductwork is a key component of a fire strategy, by routing smoke safely out of a building in a controlled manner.

Exhausting smoke across fire compartments creates a potential flashover risk. Flashover, sometimes referred to as rapid fire progress, occurs when the heat and energy being produced by the fire can no longer be absorbed by the materials in the room, and when the temperature reaches its ignition temperature fire breaks out all at once over all the surfaces. Exhausting hot gases creates a potential flashover risk as the heat and energy is removed through the building. As part of the EN tests, insulation will help prevent flashover, and is tested with the ductwork. Section 6.3 of EN1366-8:2004 states “The test shall be made on a test specimen representative of the complete duct assembly, including integral or intended insulation on which information is required”.

Where thermocouples in a type A or B fire test exceeds 140°C average or 180°C single point, the maximum performance of the insulation has been reached. This is stated in minutes and classified(I), 30, 60, 90, 120, 240.

The inclusion of insulation during fire testing means that the system becomes the product. Use of untested combinations of duct and insulation is not permitted without completing a full test program.