Other ways of reducing the fireplace opening in order to improve
Modern flue heat transfer manufacturers favor a ratio of one to seven, and there are sizing charts published that give details of current standards. For wood or coal burning fires to burn well, a good supply of air is required along with a chimney to expel the hot exhaust gases and smoke. If a flue is too large, its size can be reduced to improve its efficiency by the fitting of a liner.With the growing trend in restoring to use those fireplaces that have been bricked or boarded up, it is important that these restored fireplaces and chimneys are working efficiently. However, because domestic stoves are relatively inefficient not all of these substances are consumed. When wood and coal are burned, flammable gases, tarry substances, acids and dust are given off.
A soot laden flue is a fire hazard, since the unburned elements of the soot can ignite, causing a chimney fire which can reach high temperatures and damage the chimney. If your fire smokes or won’t burn properly, see if opening a window improves matters. A variety of methods and materials are used, including flue liners made of flexible stainless steel, ceramic, lightweight concrete sections, or concrete cast in situ. It is important to have regularly used chimneys swept at least twice a year, ideally before, during and at the end of the heating season and the local trade directories contain details of fully qualified and suitably insured sweeps. He recommended that the cross-sectional area of the flue should be about a tenth of the size of the opening.
A much more efficient form of ventilation is either a single ducted vent set into the floor in front of the fireplace, or twin ducted vents set into the floor or external walls on each side of the chimney breast.
Other ways of reducing the fireplace opening in order to improve fire efficiency is to raise the level of the hearth or to fit a baffle across the top of the opening. If raising the hearth level or adding a baffle are not practical or unsightly then it may be worth asking a fireplace specialist whether fitting a metal smoke hood or canopy in the opening is the best solution. In his thesis on the principles of fireplace design published in1799, Count Rumford emphasized the importance of the size of the flue compared with the size of the fireplace opening. Instead, they rise up the chimney Heat exchangers suppliers and some of them condense on the inside of the flue. If the chimney or flue is inadequate or the flow of air insufficient, the fire will not function effectively.