Poor ventilation causing smoking fireplaces
Ventilation for open fires
Everyone’s pet hate! The evil necessity that brings cold air into a cosy warm room.
Our advice is to keep the vents at least a metre or more away from the fireplace and they can be anywhere within the room.
There are exceptions to the rule where canopies are fitted into large inglenooks over 2m wide and in these cases advice should be taken.
Fighting for the available air supply
The natural draw of a fire will never be able to overcome mechanical extraction found in both commercial and domestic kitchens and in these cases permanent vents have to be introduced to accommodate both systems.
Similarly two flue systems within the same vicinity can fight for an available air supply usually with the tallest chimney being the victor and causing the weaker flue to spill fumes no matter where it is within the house.
In commercial properties chimney fans can be fitted to the top of chimneys to create a draw to overcome the effects of a small flue or kitchen extraction. They are very successful but require cleaning at least three times during the burning season as the blades have the tendency to clog up and overheat the motor if left too long without maintenance.
Always make provision for an air supply even if you don’t use it.
Everyone’s pet hate! The evil necessity that brings cold air into a cosy warm room.
- The golden rule for a permanent vent for a solid fuel fire (excluding stoves) is 50% of the surface area of the flue although this is not always the case for many old houses especially those with 100mm thick walls, plus draughty doors and windows.
- Incidental air supply from all of the leaking windows etc can be a godsend but if the draughty side of the house faces north east then the prevailing south-westerly’s can produce a low pressure on this side and literally suck air out of the house and pull it down the chimney. Re-positioning air vents on the SW side is the only solution to this combined with some draught exclusion.
- If vents are introduced they can be positioned behind radiators or furniture, high up in the room to mix with warmer air or through the floor from a cellar or suspended floor.
- Never should vents be anywhere near the front of fireplace opening and never inside the fireplace .
Why? Firstly, British Standards state that the vent must not communicate with the fireplace opening. Building Regulations explain further that dust and ash can get blown about by air movement. During our investigations it has become clear that air rushing out of a vent close to the fire often tends to travel up and past the opening counteracting the flow of air being drawn in and keeping the smoke from going up the chimney, sometime actually pulling it out. - The worst position is to place vents inside the opening and this is often seen in larger fireplace and Inglenooks. By placing the vents within the opening the crucial volume and speed of air coming from the room into the fireplace opening is being reduced and smoke spillage can occur.
Don't be confused by the workings of the Baxi style inset fire which had an under floor vent. This is a small secondary air vent used to feed a coal fire with a controlled air supply. The main air supply for function still comes from the room.
Our advice is to keep the vents at least a metre or more away from the fireplace and they can be anywhere within the room.
There are exceptions to the rule where canopies are fitted into large inglenooks over 2m wide and in these cases advice should be taken.
Fighting for the available air supply
The natural draw of a fire will never be able to overcome mechanical extraction found in both commercial and domestic kitchens and in these cases permanent vents have to be introduced to accommodate both systems.
Similarly two flue systems within the same vicinity can fight for an available air supply usually with the tallest chimney being the victor and causing the weaker flue to spill fumes no matter where it is within the house.
In commercial properties chimney fans can be fitted to the top of chimneys to create a draw to overcome the effects of a small flue or kitchen extraction. They are very successful but require cleaning at least three times during the burning season as the blades have the tendency to clog up and overheat the motor if left too long without maintenance.
Always make provision for an air supply even if you don’t use it.
