This part of ISO 8894 describes the hot-wire methods (“cross-array” and “resistance thermometer”) for the determination of the thermal conductivity of non-carbonaceous, dielectric refractory products and materials.This methods are applicable to dense and insulating refractories (shaped products, refractory castables, plastic refractories, ramming mixes, powdered or granular materials) with thermal conductivity values less than 1,5 W/m×K (“cross-array”) and less than 15 W/m×K (“resistance thermometer”) and thermal diffusivity values less than 5 x 10-6 m2/s.