ASTM D7948-14e1

5.1 Respirable crystalline silica is a hazard to the health of workers in many industries who are at risk through exposure by inhalation. Industrial hygienists and other public health professionals need to determine the effectiveness of measures taken to control workers’ exposure, and this is generally achieved by taking workplace air measurements. This standard has been published in order to make available a method for making valid exposure measurements for crystalline silica exposures in industry. It will be of benefit to: agencies concerned with health and safety at work; industrial hygienists and other public health professionals; analytical laboratories; industrial users of silica-containing products and their workers, etc.

5.2 This standard specifies a generic sampling and analytical method for measurement of the mass concentration of respirable crystalline silica in workplace air using infrared (IR) spectrometric methods. Several different types of sampling apparatus are used to collect respirable dust, according to the occupational hygiene sampling convention. This standard is designed to accommodate a variety of appropriate samplers and sampling materials that are commercially available.

1.1 This standard specifies a test method for collection and analysis of samples of airborne particulate matter for measurement of respirable crystalline silica by infrared (IR) spectrometry.

1.2 This test method is applicable to the analysis of crystalline silica (the polymorphs quartz, cristobalite and tridymite) over a working range of 0.025 to 0.4 mg/m³ for a 400 L air sample or 0.02 to 0.25 mg/m³ for a 1000 L air sample, depending on the analytical method.

1.3 The methodology is applicable to personal sampling of the respirable fraction of airborne particles and to static (area) sampling.

1.4 This test method describes three different procedures for sample preparation and infrared analysis of airborne crystalline silica samples, which are delineated in Annex A1 – Annex A3, respectively: (1) a potassium bromide (KBr) disc IR measurement method, (2) indirect IR analysis after redeposition onto a filter used for measurement, and (3) direct on-filter IR analysis.

1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.