Evaluation of air sampling methods for abrasive blasting.
Ceballos-D; Sylvain-D; Kiefer-M
J Occup Environ Hyg 2013 Mar; 10(3):D34-D39
The National Institute for Occupational Safety and Health (NIOSH) investigators compared methods for collecting personal breathing zone (PBZ) air samples for particulates during abrasive blasting at a shipyard. Abrasive blasting is the cleaning or finishing of surfaces by the use of an abrasive carried in a strong current of air. The U.S. government has provided regulatory requirements and guidelines for ventilation, enclosures, and personal protective equipment during abrasive blasting. However, current Occupational Safety and Health Administration (OSHA) sampling and analytical methods can overestimate worker exposures to airborne metals and other particulate contaminants during abrasive blasting. Shielding the 37-mm filter cassette inlet to exclude non-inhalable particles, mounting the PBZ air sampler behind the employee's head to protect the sampler from rebounding abrasive materials, and using the Institute of Medicine inhalable dust sampler, have been proposed as alternatives to assess exposure. All were impractical or ineffective in abrasive blasting environments. Sampling simultaneously inside and outside the employees' abrasive blast hood has shown that the lower air concentrations inside the abrasive blast hood produce less overloading of the 37- mm cassettes; however, sampling inside PPE is not accepted by OSHA for compliance purposes. Aizenberg et al.(6) used a Button Aerosol Sampler (BAS; SKC Inc., Eighty Four, Pa.) with a prototype shield to evaluate PBZ exposures during abrasive blasting operations. The investigators reported that the protective shield prevented non-inhalable particles from overloading the filter and did not interfere with sampling smaller particles; however, the researchers did not determine whether the prototype protective shield altered the collection efficiency of the BAS. Following the Aizenberg study, SKC Inc. designed a snap-on domeshaped stainless steel protective secondary shield (Abrasive Blasting Sampler for Heavy Metals kit, part no. 225-367, SKC Inc.) for use with the BAS when sampling during abrasive blasting. This shield differed in size, shape, and screen opening from the prototype screen tested by Aizenberg et al. Due to uncertainty about possible effects that shielding may have on the performance characteristics of the BAS, the objectives of this evaluation were to: (1) compare the commercially available BAS (with and without the shield) with the conventional 37-mm cassette sampler in an abrasive blasting environment, and (2) evaluate whether the protective shield designed for the BAS prevented inertia-driven particles from entering and possibly overloading the sampler.
Samplers; Sampling; Sampling-methods; Sampling-equipment; Sand-blasting; Respirable-dust; Particulate-sampling-methods; Particulate-dust; Particulates; Dust-samplers; Dust-sampling; Dusts; Air-samplers; Air-sampling; Air-sampling-equipment; Air-sampling-techniques; Shipbuilding-industry; Shipyard-industry;
Author Keywords: Ship Building and Repairing; abrasive blasting; air sampling; button aerosol sampler; abrasive blasting sampler; total particulate; inhalable particulate; HETA 2001-0279-3163
Diana Ceballos, National Institute for Occupational Safety and Health, 4676 Columbia Parkway, MS R-11, Cincinnati, OH 45226
Journal of Occupational and Environmental Hygiene