En 1366-1 is the standard intended specifically for ventilation ducts (without the aid of dampers). This standard determines the fire resistance of ducts passing through or between compartment. Furthermore the fire test for ducts is designed to evaluate the fire performance of the duct penetration seal through a wall or floor construction as well as the fire performance of the duct system itself including the support systems. Specimen tests are exposed to external fire (Duct A) and internal fire (Duct B). The performance criterion is used for classifying the duct system according to EN 13501-3.
PassiveTec® Ductliner has exceeded all performance criteria applied to fire resistant ductwork. PassiveTec® Ductliner is classified EIs 120 under EN 13501-3.
The test is divided into two fire scenarios; fire from outside the duct and fire from inside of the duct. In addition, each scenario has to be tested in both a vertical and a horizontal direction, therefore a total of four ducts are therefore necessary for a full test.
The duct is subjected to a pressure of 300 Pa and maintained at this pressure throughout the duration of the test. During the test, the leakage due to pressure, the deflection of the duct and the temperature rise on the unexposed surface are all measured. NOTE: Passivetec Duct Liner has also been tested under pressure of 500 Pa.
Inside the furnace the duct is partly opened. A fan is connected to the duct in order to extract hot furnace gas at a velocity of 3 m/s. For five minutes, prior to every 30 minutes of testing, the fan is switched off.
The integrity is the ability of the duct system to prevent the passage of flames and hot gases through the system and to prevent the occurrence of flames on the unexposed side. The duct can no longer satisfy the integrity criteria if:
The duct does not satisfy the Insulation criteria if the temperature rises on the unexposed side exceeds 180º C on any of the thermocouples or 140º C in average.
Failure of this criterion shall have occurred if the flow rate in Duct A during the test exceeds 10m3/m2h at normal temperature and pressure, related to the internal surface area of the duct inside the furnace.
Where ductwork passes through a compartment wall or floor it must be ensured that the fire separation of the wall or floor is maintained. A Penetration seal is fitted between the duct and the wall or floor.
The purpose of the penetration seal system is to seal the gap between the duct walls and the surrounding wall or floor. In a fire situation, an integrity failure of the penetration seal system is often caused by the movement or distortion of the duct. Therefore it is not possible to separate the fire performance of the penetration seal from the construction of the duct.
Suspension devices are the components used for suspending and fixing a duct from a floor; or supporting and fixing a duct from a wall. Suspensions devices of PasiveTec horizontal ducts consist of two threaded rods, steel angle, washer and nut. If the duct suspension devices are supported by a structural element, this element must provide the same fire resistance as the duct system itself.
Maximum stress levels of steel hanger support must not exceed 10 N/mm2 (6 N/mm2 for vertical orientation elements under tensile efforts).