Factory-made metal chimney
Approved Document J, Combustion appliances and fuel storage systems, 2010 edition incorporating 2010, 2013 and 2022 amendments, defines factory-made metal chimneys (also known as system chimneys) as: ‘…prefabricated chimneys that are commonly manufactured as sets of components for assembly on site (although they can be supplied as one unit), having the performance appropriate for the intended appliance. They are available in various materials and types ranging from single-walled metal chimneys suitable for some gas appliances to twin-walled chimneys with insulation sandwiched between an inner liner and an outer metal wall which are designed for oil or solid fuel use.’
See also: System chimney.
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