Open Fireplace Chimneys and Flues ~ the main functions of a
chimney and flue are to:-
1. Induce an adequate supply of air for the combustion of the
fuel being used.- Remove the products of combustion.
In fulfilling the above functions a chimney will also encourage a
flow of ventilating air promoting constant air changes within the
room which will assist in the prevention of condensation.
Approved Document J recommends that all flues should be lined
with approved materials so that the minimum size of the flue so
formed will be 200 mm diameter or a square section of equivalent
area. Flues should also be terminated above the roof level as
shown, with a significant increase where combustible roof coverings
such as thatch or wood shingles are used.Open Fireplace and Flues