ISO 15901-1:2005 describes a method for the evaluation of the pore size distribution and the specific surface in pores of solids by mercury porosimetry according to the method of Ritter and Drake. ISO 15901-1:2005 describes a comparative test, usually destructive due to mercury contamination, in which the volume of mercury penetrating a pore or void is determined as a function of an applied hydrostatic pressure, which can be related to a pore diameter.

Practical considerations presently limit the maximum applied absolute pressure to about 400 MPa (60 000 psia) corresponding to a minimum equivalent pore diameter of approximately 0,003 m. The maximum diameter is limited for samples having a significant depth due to the difference in hydrostatic head of mercury from the top to the bottom of the sample. For the most purposes, this limit can be regarded as 400 m. ISO 15901-1:2005 applies to inter-particle and intra-particle porosity but cannot distinguish between these porosities where they co-exist.

ISO 15901-1:2005 is suitable for the study of most non-wettable, by mercury, porous materials. Samples that amalgamate with mercury, such as certain metals, e.g. gold, aluminium, reduced copper, reduced nickel and silver, can be unsuitable for this technique or can require a preliminary passivation.