This International Standard specifies the equipment and procedures for determining trace quantities of the water soluble chloride, fluoride, silicate and sodium ions in an aqueous extract of the product. It also describes a procedure for the determination of the pH of the aqueous extract. This International Standard is applicable to thermal insulating products. NOTE The determination of these parameters may be relevant for thermal insulating products intended for application to stainless austenitic steel surfaces. The presence of chloride, fluoride, silicate and sodium ions under certain conditions can influence the risk of stress corrosion cracking. See Annex B for further information.