Technical Booklet L Combustion Appliances and Fuel Storage Systems·Page 66·4.34
Hearths for gas-burning appliances - installation conditions
Gas-fired appliances must be placed on a hearth unless the appliance is installed with all flames or incandescent material at least 225 mm above the floor, or the manufacturer's instructions state a hearth is not required.
A gas-fired appliance should be placed on a hearth unless –
(a) it is installed so that every part of any flame or incandescent material should be not less than 225 mm above the floor; or
(b) the manufacturer's instructions state that a hearth is not required.
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