Technical Booklet L Combustion Appliances and Fuel Storage Systems·Page 27·2.23
Construction of flue block chimneys
Flue block chimneys must be constructed from factory-made components suitable for their intended application, installed per manufacturer's instructions, with a minimum performance designation of T400 N2 S D 3 as per BS EN 1443.
A flue block chimney should be constructed of factory-made components suitable for the intended application and installed in accordance with the manufacturer's instructions. The flue blocks should have a minimum performance that corresponds to the designation T400 N2 S D 3, as described in BS EN 1443, such as clay flue blocks of Class FB1 N2 as described in BS EN 1806.
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