The Manthorpe 5" Core Drill Vent is designed for use when ventilating a room with a gas appliance, but can also be used for general through wall ventilation. The vent can easily be fitted in both refurbishment and new build situations with the use of a 5" (127mm) diameter core drill. The kit includes a cowl vent for exterior use, a louvre grille for inside, a 350mm length of pipe duct and an optional anti-draught baffle. This baffle reduces the airflow and also the feel of a draught through the vent. Without the use of the anti-draught baffle, the free area of the vent is 100cm², enough to supply an appliance with a rated input of 27kW or 92,000 Btu/h (in accordance with BS5440 Pt.2:2000). With the anti-draught baffle installed, the effective free area of the vent is reduced to 70cm² (BRE tested) providing enough ventilation for an appliance with an input rating of 21kW or 71,500 Btu/h. The external cowl minimises uncomfortable draughts, reduces noise and light from outside the property and acts as a barrier against wind driven rain while the louvre fits on the internal wall and, similarly helps to reduce draughts, noise and light penetration.