This test method is applicable to fire resisting ducts that have already passed the appropriate period to EN 1366-1 (Ducts A/500 Pa and B).
Whilst the test method has been designed to cover both vertical and horizontal smoke extraction ducts, provided both horizontal and vertical tests have been carried out to BS EN 1366-1 on the specific system, a vertical duct need not be evaluated to this method - provided that it is tested in a horizontal orientation to this method.
The duct is tested with fire on the inside of the duct (Duct C). Valid for vertical and horizontal ducts. It is applicable only to four sided and circular ducts. One, two and three sided ducts are not covered.
A fan is connected to the end of the duct outside the furnace that induces a furnace gas velocity of 2m/s ±15% within the duct, drawn through openings in the sidewall of the duct within the furnace. A perforated plate, appropriate to one of three prescribed differential pressures of –150Pa, -300Pa or –500Pa is incorporated within the duct, 250mm outside the furnace.
PassiveTec® Ductliner has achieved maximum pressure level (Level 3 -1500 Pa ambient temperature and -500 Pa on fire test).
Test results from the EN 1366-1 test are deemed to demonstrate the insulation performance of the duct.
Integrity failure shall also be deemed to have occurred if any of the following are observed as defined in EN 1363-1. When the cotton pad is ignited or when sustained flaming, of duration at least 10s, appears on the unexposed face of the test specimen outside the furnace.
A failure of the smoke leakage criteria, shall be deemed to have occurred if the leakage flow rate through the duct section outside of the furnace, as determined by the Oxygen sensor method exceeds 10m3/m2/hr relative to the internal surface of the complete duct (inside and outside of the furnace) .
The internal dimensions (width and height for a rectangular duct) shall not decrease by more than 10% during the test.
The duct inside the furnace collapses, so that is can be judged as not being able to maintain its smoke extraction or fire resistance function.
7.3.4 Classifications for Multi-compartment smoke control system ducts BS EN 13501-4
“S” indicates a leakage rate of less than 5m³/(h.m²). ‘500’, ‘1000’ or ‘1500’ indicates that when tested at these negative pressures the duct is suitable for use over the range from the tested negative pressure up to a positive pressure of 500 Pa.