Codes & Standards - Purchase
The BET method is applicable only to adsorption isotherms of type II (disperse, nonporous or macroporous solids) and type IV (mesoporous solids, pore diameter between 2 nm and 50 nm). Inaccessible pores are not detected. The BET method cannot reliably be applied to solids which absorb the measuring gas.
A strategy for specific surface area determination of microporous materials (type I isotherms) is described in an annex.