Intent 1:
To limit the probability that:
- rainwater will flow across the chimney cap and into
the flue, which could lead to damage to the liner due to freeze-thaw
stresses,
- flue gases will enter the space between the liner and
the chimney, or
- mechanical or freeze-thaw damage to the extended portion
of the liner will lead to blockage of the flue or subsequent freeze-thaw
damage to the upper courses of surrounding masonry.
This is to limit the probability of
the spillage of combustion products, which could lead to the leakage
of carbon monoxide gas into living space, which could lead to the
acute poisoning or asphyxiation of persons.