ISO 18757:2003提供了通过根据Brunauer、Emmett和Teller的方法（BET法）测量物理吸附气体的量来测定分散或多孔（孔径大于2 nm）细陶瓷材料的总比表面积和内表面积的指南。本国际标准仅关注与精细陶瓷材料相关的具体细节。还应注意，BET法不能应用于I型等温线（微孔材料或化学吸附行为）或固体吸附测量气体时。

ISO 18757:2003 provides guidelines for the determination of the total specific external and internal surface area of disperse or porous (pore diameter greater than 2 nm) fine ceramic materials by measuring the amount of physically adsorbed gas according to the method of Brunauer, Emmett and Teller (BET method). This International Standard only focuses on specific details relevant to fine ceramic materials. It should further be noted that the BET method cannot be applied to type I isotherms (microporous materials or chemisorption behaviour) or when the solid adsorbs the measuring gas.