Castle Farm, Marshfield, Nr Chippenham, Wiltshire, SN14 8HU
01225 891469

Twin Wall Insulated Flue

A prefabricated factory-made twin-wall chimney system incorporating a high-quality insulation.


It is suitable for appliances burning all types of fuel. The standard specification product is constructed entirely from stainless steel, but the system is available with a variety of material options depending upon application. In all cases, the external casing is weather-proof and carries the structural load. The inner lining is resistant to the often corrosive products of combustion and is free to expand or contract as flue gas temperatures change.

The annulus between the inner liner and outer skin is filled with a high temperature resistant
insulation, and the product is designed to provide high thermal resistance, rapid stabilisation of the flue temperature, and a low temperature on the external surface of the pipes and fittings.
This system is designed primarily for gravity flow application and for appliances with flue-gas temperatures up

to 540°C under continuous firing, and 760°C under short firing. The range of available diameters provides for
appliances rated up to 4MW. The system is not designed for use with condensing or pressure applications.
SM W is designed to be used internally and externally. The smooth stainless steel inner lining heats rapidly to produce a strong draught which ensures that waste gases are exhausted and condensation of the harmful products of combustion is minimised.

pdfSelkirk Brochure


please note: all installations must be fitted by a qualified Hetas engineer or with building regulation approval.