ISO 589:1981

For all hard coals two methods are specified: A) The sample is heated in a flask under reflux conditions with boiling toluene. The moisture from the coal is entrained by the toluene vapour and carried to a condenser fitted with a graduated receiver. The water then separates in the receiver, to from the lower layer, whilst the excess toluene is returned to the destillation flask by means of an overflow. The moisture in the coal is calculated from the volume of water collected. B) The sample is dried in an oven at a temperature of 105 to 110 °C in a current of nitrogen and the moisture calculated from the loss in mass.