There are two types of smoke test and there is often confusion as to which one is required and under what circumstances. One is called a ‘Draw Test’ and takes place as part of a sweep and the other is called a ‘Smoke Pressure Test’. This test checks the integrity of the existing brick flue to make sure there are no leaks. More details about the tests can be found in the tabs below, alternatively call us to talk through any questions and concerns on 01273 726 989 or 07742 829 848.
A smoke pressure test is not a 100% guarantee that there are no leaks – the flue passes through areas that you can’t easily check, for example in the void between ceilings and floors, or in an adjopioning property. There is also no guarantee that a leak wont develop at some point in the future. There may be cracks in the flue thaty are covered in soot and sweeping might uncover them. The only way to ensure smoke cannot leak out of a brick flue is to have it lined. There are a number of ways of doing this and the most simple and cost effective is to insert a flexible steel lining into the existing flue. For more information on this, please see out Lining Your Flue page.
You do NOT need a smoke pressure test if you are having a flue lining installed. Once the lining is installed smoke can only escape though it and it no longer passes through the brick flue.
For more information about how chimneys work, please see our How Chimneys Work page.
Smoke Pressure Tests
The purpose of a Smoke Pressure Test is to check the integrity of the chimney, i.e. to make sure smoke passing through the chimney can’t leak through any cracks or damage into other rooms in the same property or adjoining properties. There are many properties in Brighton & Hove that are well over 100 years old and the inside of a chimney is often the only part of a home that is not regularly maintained. Walls, ceilings, floors and roofs are usually well maintained, but the inside of a chimney is not accessible and usually gets no attention. Over time the brickwork inside the chimney can deteriorate and cracks can form. Sometimes chunks of brick and even whole bricks can break away and fall down the flue, either landing in your fireplace or on a shelf inside the chimney. This can create cracks and holes in the flue wall.
A smoke pressure is a two person job, with one on the roof by the chimney pot and one in the room with the fireplace. A smoke bomb is released in the fireplace, this creates a large amount of smoke which travels up the flue. As it gets to the top and emerges from the pot, the person on top blocks off the pot so the smoke can’t escape. The person in the room then blocks off the fireplace so the smoke can’t escape back into the room. The top and bottom should only be blocked when the flue is full as smoke will not move through the flue if it is already blocked.
Theoretically, as the flue fills up with smoke, if there are any cracks it will be forced through them. The person in the room with the fireplace goes from room to room looking for smoke. This may also involve checking rooms in an adjoining properties. If you find smoke, you have a leak.
This is not a 100% guarantee that there are no leaks as there are some areas it is very difficult to check, e.g. the void between floors and ceilings, an adjoining property if you can’t get access.
We can offer a smoke pressure test if there is easy and safe access to the chimney pots, i.e. a flat roof or with scaffolding and there is someone there to go from room to room and check for smoke leaking out.
This is a simple test usually completed once a chimney has been swept. The purpose of the test to to check the ‘draw’ or ‘up-draught’ of the fireplace. This is the movement of emissions generated by the fire, up through the chimney and out of the top. It is important to check this as a poor draw could result in smoke not moving up the chimney and instead drifting back into the room. There are a number of reasons why a draw might be poor, more on this on our Why Does Smoke Come Into My Room? post.