Certain materials require drying prior to moulding. After moulding it may be necessary to condition parts. Nylon components with critical dimensions used to be immersed in tanks of hot water after moulding for anything up to 24 hours in order to condition them. However, modern grades of Nylon are more stable so this conditioning process is less common nowadays.
Water absorption is measured by immersing a test sample of specified dimensions in water for a specified time at a specified temperature. Prior to this the specimens are dried and cooled. Results are given either as milligrams of absorbed water or as a percentage increase in weight.
In this instance the two test standards are essentially the same.