Connection to the same chimney flue of solid-fuel-burning appliances and appliances burning other fuels, where the appliances have a combined total rated heat output of 120 kW or less and rectangular masonry or concrete chimneys are not more than 12 m in height, in buildings to which Part 9 applies [see Sentence 1.3.3.3.(1) of Division A for application of Part 9].

This also applies to the connection to the same chimney flue of solid-fuel-burning appliances and appliances burning other fuels, where the appliances have a combined total rated heat output of 120 kW or less and rectangular masonry or concrete chimneys are not more than 12 m in height, in buildings to which Part 6 applies [see Sentence 1.3.3.2.(1) of Division A for application of Part 6], as stated in Sentence 6.3.1.2.(1).

To limit the probability that the ignition of an oil- or gas-burning appliance will lead to a relatively sudden increase in flue pressure, which could lead to the spillage of combustion products from a solid-fuel-burning appliance, which could lead to the leakage of carbon monoxide gas into living space, which could lead to the acute poisoning or asphyxiation of persons.

To limit the probability that blockage of the flue by creosote from a solid-fuel-burning appliance located at a higher level will lead to the leakage of carbon monoxide gas into living space, which could lead to the acute poisoning or asphyxiation of persons.