ISO 21660-3:2021 specifies a method for the determination of moisture in a general analysis sample by drying the sample in an oven. This method is suitable for use for general analysis samples in accordance with CEN/TS 15414-1^[3][1]. It is applicable to all solid recovered fuels.

If solid recovered fuels contain large amounts of oil-fractions the Karl-Fischer-Method (for example ISO 760) is advisable. Otherwise, a lower temperature is recommended (e.g. 50 °C ° 10 °C) and a longer drying time until constant mass is achieved.

NOTE The term moisture content, when used with recovered materials, can be misleading since solid recovered materials, e. g. biomass, frequently contain varying amounts of volatile compounds (extractives) which can evaporate when determining the moisture content of the general analyses sample by oven drying.

[1] The adoption of the standard series EN 15414 as standard series ISO 21660 is planned. ISO 21660-3 is published in parallel at CEN level as EN 21660-3.