Intent 1:
To limit the probability that:
- contact with flue gases will lead to corrosive damage
to mortar, or
- flue gas condensate will leak from joints in chimney
liners, which could lead to corrosion or freeze-thaw damage to surrounding
masonry.
This is to limit the probability of:
- the structural failure of the chimney, or
- the ingress of condensed water vapour into the cavity
between the chimney liner and the surrounding masonry, which could
lead to freezing and induced stresses, which could lead to damage
to the masonry, which could lead to the collapse of the chimney.
This is to limit the probability of harm to persons.