This part 3 of this standard provides specific technical criteria for the assessment of laboratoriesto undertake steady-state heat transfer property measurements by the heat flow meter methodaccording to prEN 12667 and prEN 12664.It complements the common criteria in part 1. Guidance is given on the organization and contentsof the equipment manual, the calibration and maintenance files and the measurement proceduredocument.It provides information on mandatory equipment performance specifications, equipmentdescription and on calculations for the equipment design and error analysis.It provides information on experimental procedures suitable for the assessment of equipmentaccuracy.