Suitable for a Bitumen roof covering, Ubbink’s OFT/4 flat roof vent/terminal can be used in soil and vent systems, and for natural (passive) or mechanical ventilation installations.The OFT/4 has a special low air resistance cowl - the pressure/airflow resistance is <1.0 Pascal at 225m3/h. The pipework above the roofline is twin walled and incorporates an integral condensation drain. The stack pipe has an integral collar and separate aluminium flange for use with both felt and asphalt. The Ubbink OFT/4 range is available in five different flange types for different roof coverings, Asphalt, EPDM, Bitumen and PVC, to allow termination through a flat roof to ducting up to 166mm. The stack cap is fixed mechanically so that it is more secure when installed in extreme weathers, however this can be removed for servicing purposes. Features & Benefits Suitable for Bitumen roof covering Easy removal for servicing purposes Large free vent area Low Pa resistance Product Specifications Material: Polyethylene/Aluminium/Bitumen Weight: 3.28kg Diameter: 166mm Height Above Roof: 540mm Flange Diameter: 490mm Depth Below Roof: 510mm Free Vent Area: 20,000mm2 Pressure/Airflow Resistance: 1.0Pa