Technical Booklet L Combustion Appliances and Fuel Storage Systems·Page 76·5.22
Lining requirements for flues in chimneys with lower temperature flue gas (≤250°C)
Where flue gas temperature is not expected to exceed 250°C, the liner may use materials specified for higher temperatures or alternatively independently certified flue lining systems appropriate to the appliance type.
Where the flue gas is expected not to be greater than 250ºC the liner should be –
(a) any of the linings described in 5.21 above; or
(b) if the appliance is new and of known type, flue lining systems that have been independently certified as having a performance not less than that corresponding to the designation given in Table 5.2 for the intended appliance type.
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