Division .1 GeneralF1F2

United Kingdom

1. .1Ventilation ducts, including single and double wall ducts, shall be of steel or an equivalent material, except for flexible bellows of short length not exceeding 600 mm used for connecting fans to the ducting in air-conditioning rooms. Unless expressly provided otherwise in paragraph .1.6, any other material used in the construction of ducts, including insulation, shall also be non-combustible. However, short ducts, not exceeding 2 m in length and with a free cross-sectional area (The term free cross-sectional area means, even in the case of a pre-insulated duct, the area calculated on the basis of the inner dimensions of the duct itself and not the insulation) not exceeding 0,02 m 2 , need not be of steel or equivalent material, subject to the following conditions:
2. .2The following arrangements shall be tested in accordance with the Fire Test Procedures Code:
3. .3Division .3
4. .4Division .4
5. .5Division .5
6. .6Division .6
7. .7Division .7