ISO 24095:2009 gives guidelines for the quality assurance of measurements of respirable crystalline silica in air using direct on‑filter or indirect X‑ray diffraction and infrared analysis methods. The scope of ISO 24095:2009 includes the following crystalline silica polymorphs: quartz, cristobalite, and tridymite. These guidelines are also relevant to the analysis of filters obtained from dustiness measurements in accordance with EN 15051.