This document specifies the reference method for the determination of the concentration of formaldehyde in emissions from stationary sources. Waste gas samples are taken by absorption in water and subsequently analysed by spectrophotometry or HPLC. The method applies to waste gases in which the formaldehyde concentration is 2 mg/m3 to 60 mg/m3, on dry basis, at the reference conditions of 273 K and 101,3 kPa. The specific components and the requirements for the measuring system are described. A number of performance characteristics with associated minimum performance criteria are specified for the measuring system.