A basement smoke exhaust system consists of smoke outlets/vents and is designed to provide a route for heat and smoke to escape to the open air.
- Either natural or mechanical method may be used to ventilate smoke/heat from basements.
- The air extract system should give at least 10 air changes per hour.
- If applicable, the fire duct must be constructed to resist water impingement from any sprinkler system.
In the diagram:
Mechanical exhaust may be used provided that the basement levels are fitted
with a sprinkler system above the smoke extract duct, as
illustrated and shown 
. It must be suitable for clearing smoke within the
compartments and normally rated for one hour stability and integrity to
resist hot smoke and fire from inside (Type B). Fire insulation rating is
not required in the first compartment.
Where the basement duct rises through the shop above, shown 
, it must
maintain stability, integrity, and insulation fire rating
for the same period of time as the compartment through which it passes.
This may be required for the remainder of the ductwork route through the
building to the outside.
In some circumstances, insulation requirements may be waived or varied
by the regulatory authority if there are no combustible materials
within 18in of the duct, such as in the plant room, shown 
.
All FLAMEBAR BW11 Fire Rated Ductwork and Penetration Seals have been tested to ISO 6944 (1985) and manufactured and installed as tested or assessed by an International Accreditation Services Accredited Laboratory.
Note: Final approval must always be obtained from the Authority Having Jurisdiction prior to commencement of construction.
