Technical Booklet L Combustion Appliances and Fuel Storage Systems·Page 59·4.15
Height of natural draught flues for open-flued appliances
Natural draught flues must be sufficiently high to ensure adequate draught to safely clear combustion products, with height requirements depending on appliance type and manufacturer instructions.
A flue should be high enough to ensure sufficient draught to safely clear the products of combustion. For an appliance that is CE marked as compliant with the Gas Appliances (Safety) Regulations 1995, it should be installed in accordance with the manufacturer's installation instructions.
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