f) To check the airtightness of the chimney, cover the roof end and introduce
paper with damp straw into the chimney.
g) It is very important for the chimney to stand out by more than one metre from the
highest part of the house. If the draught is to be increased, increase the height of the
chimney.
h) The cowls must not hinder the draught.
Fig.-8
Fig.-9
Fig.-10
28