Insulated chimney pipes

A domestic insulated chimney pipe section for use with domestic boilers, open fires or the like, said chimney pipe section comprising an inner one-piece tubular refractory liner consisting of vacuum formed inorganically bonded aluminosilicate fibers having a density of between 100 and 600 kg/m.sup.3, and zero effective coefficient of thermal expansion, said inner liner being exposed in use to hot and corrosive gases passing through said pipe, an outer structural metallic wall member spaced from said inner liner, and two end caps one at each end of said inner liner and outer wall member, the said two end caps supporting and maintaining the said inner liner in a spaced relationship to said outer wall member so as to define therebetween an annular insulating dead air space, whereby the said inner liner and outer wall member and two end caps provide a rigid and lightweight insulated chimney pipe section, the outer wall member being protected from the heat and corrosive effects of the said gases by means of the said inner liner and its spaced relationship therefrom.