The document provides specific technical criteria for the assessment of laboratories to undertake steady-state heat transfer property measuremnt on circular pipe insulation. It gives gudiance to the organization and contents of the equipment manual, the calibration and maintenance files and the measurement procedure document. It provides information on mandatory equipment itself and on calculations for the equipment design and error analysis on circular pipe apparatus and on the guarded hot plate apparatus. It provides information on experimental procedures suitable for the assessment of instrument accuracy.