Archetech Issue 23 2016 | Page 143

Chimney Heat Monitors Heat transfer is generally caused by faulty chimneys, poorly or incorrectly fitted liners and the addition of high flue gas temperatures being generated by these efficient stoves. The thatch is at a much greater risk of the effects of heat transfer if the chimney is not lined. TAS-33 Thatch Alert Chimney Monitor Systems can be installed to monitor the temperature of the chimney brickwork (heat transfer) at the point where it meets the thatch. In the event of high temperatures being recorded, the system will trigger an audible alarm allowing the homeowner to take action. Heat transfer is further increased at the point where the thatch meets the chimney. This is due to the insulating properties of the thatching material. The heat transfer process can cause thatch to smoulder and ignite if temperatures in excess of 200oC are reached. Fire Barriers Physical fire barriers for thatched roofs are designed to create a separation between the thatch and the rest of the building. The principle being, in the event of a fire the thatch is seen as sacrificial. In terms of fire resistance either a fireboard or firewall membrane can be used to achieve the required fire resistance (integrity) and a noncombustible Thatchbatt® for further fire protection as well as acoustic and insulation values. Both TAS100 fireboards and TAS firewall membranes are designed to resist spread of flame and penetration as set out in BS476: Part 3: 2004 & CEN/TS 1187: 2012, test 4. Both products are water resistant and will reduce the potential water damage that can be generated as part of the firefighting process. The TAS100 fireboards are normally used for new builds, extensions or Page 143 - Archetech the brickwork of the chimney to the thatch, this is known as heat transfer.