1.1 This test method specifies a 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 (polymorphs of 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 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 Annexes A1, A2, and 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 Units of the International System of Units (SI) are used throughout this guide and should be regarded as 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.
Inhalation of respirable crystalline silica (RCS) is a cause of one of the oldest known occupational diseases, silicosis. Exposure to airborne respirable silica can also cause lung cancer and is possibly linked to a disease known as chronic obstructive pulmunory disease (COPD). Crystalline silica is abundant in the earths crust and is found in many products and materials. The number of workers potentially exposed to RCS is very high. There are efforts to reduce the occupational exposure limits (OELs) for exposure to RCS in several countries, thus, many national institutes, companies, and organizations are concerned about the precision and reliability of respirable silica measurements. Sampling is of crucial importance in this context, while the analytical method used and its sensitivity are dependent on the type of sampling apparatus used. Multinational companies operate globally and, in the absence of international standards, investigators in various countries might not apply harmonized procedures to different processes uniformly. It is essential that the performance criteria for sampling and analytical methods minimize the variability of exposure data, which may affect reliability of the results obtained. The establishment of standards in this area will help improve the understanding and comparability of the differences between analysis procedures. Newly proposed methods for silica measurement by IR are timely in view of the need to improve detection limits as well as the precision and bias of data collected for exposure assessment. This effort addresses the increasing need to compare data from different analytical procedures to improve risk or safety assessments, all of which is driven by new legislation concerning occupational exposures and product safety. The U.S. Occupational Safety and Health Administration (OSHA) is working on updating its permissible exposure limit (PEL) for respirable crystalline silica. Consensus standard methods are desired that will enable measurements of acceptable quality to be obtained. This draft ASTM standard is based on government methods published by occupational health agencies in the United States, United Kingdom, France, Spain, Canada, and other countries.
Keywordsair monitoring; respirable crystalline silica; infrared; sampling and analysis; samplers; tests; workplace atmospheres
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top
Ballot Item Approved as D7948-2014 and Pending Publication