This standard specifies a method for determining the fire resistance of horizontal ventilation ducts under standardized fire conditions. The test examines the behaviour of ventilation ducts exposed to fire from the outside (duct A) and fire inside the duct (duct B). The fire resistance test of vertical ducts may be carried out by making reference to this standard.
This standard is not applicable to:
a) Ducts whose fire resistance depends on the fire resistance performance of a ceiling;
b) Ducts with doors of inspection openings, unless these doors are included in the duct to be tested;
c) Two- or three-sided ducts;
d) Smoke exhaust ducts;
e) The suspending elements connected walls or floors.
