Abstract: An elongate tubular heat transfer element having a longitudinal tube axis that runs through the hollow interior of the heat transfer element. The heat transfer element includes a wall of monolithic construction having an outer surface and an inner surface. The wall is formed from a composite material including a matrix and rovings embedded in the matrix. The composite material is in contact with the hollow interior such that the inner surface determines a boundary of the hollow interior which extends longitudinally along the axis of the heat transfer element. The matrix is of a fluoropolymer having embedded therein rovings of boron-free chemically resistant glass fibres. The rovings include from about 20% to about 60% by volume based upon the volume of the composite material, rovings that extend longitudinally in a lengthwise direction parallel to the axis of the heat transfer element and rovings that extend spirally around the axis.

Abstract: The invention relates to a capstock polymer composition comprising a blend of a melt extrudable acrylic polymer component; from 10% to 50% by weight of a halogen donor component; a halogen volatilisation component; and a char-inducing component which induces formation of a char upon application of flame to the composition.