9.21.4.7.(1)

Intent 1:

To limit the probability that smouldering material will accumulate at the bottom of the chimney, which could lead to:

• an increase in the severity of a chimney fire,
• the ignition of the cleanout frame or door, or
• the spillage of smouldering material onto combustible material.

This is to limit the probability of the ignition of combustible building components, which could lead to harm to persons.