The performance of laboratories analysing alpha-quartz in the Workplace Analysis Scheme for Proficiency (WASP).

The Workplace Analysis Scheme for Proficiency (WASP) is a proficiency testing (PT) scheme for the analysis of occupational hygiene and environmental air samples and is operated in the United Kingdom by the Health and Safety Laboratory (HSL) on behalf of the Health & Safety Executive (HSE). One of the 26 analytes available to laboratories is silica (alpha-quartz) on 25 mm Gelman GLA5000 filters. This paper investigates the performance of laboratories participating in the scheme since the HSL took over the production of the samples in 1998.

Accuracy and repeatability of weighing for occupational hygiene measurements: results from an inter-laboratory comparison.

Gravimetric analysis is a fundamental technique frequently used in occupational hygiene assessments, but few studies have investigated its repeatability and reproducibility. Four inter-laboratory comparisons are discussed in this paper. The first involved 32 laboratories weighing 25 mm diameter glassfibre filters, the second involved 11 laboratories weighing 25 mm diameter PVC filters and the third involved eight laboratories weighing plastic IOM heads with 25 mm diameter glassfibre filters.