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The Effects of Bit Wear on Respirable Silica Dust, Noise and Productivity: A Hammer Drill Bench Study.
Ann Work Expo Health. 2017 Jul 01; 61(6):700-710.AW

Abstract

OBJECTIVES

Hammer drills are used extensively in commercial construction for drilling into concrete for tasks including rebar installation for structural upgrades and anchor bolt installation. This drilling task can expose workers to respirable silica dust and noise. The aim of this pilot study was to evaluate the effects of bit wear on respirable silica dust, noise, and drilling productivity.

METHOD

Test bits were worn to three states by drilling consecutive holes to different cumulative drilling depths: 0, 780, and 1560 cm. Each state of bit wear was evaluated by three trials (nine trials total). For each trial, an automated laboratory test bench system drilled 41 holes 1.3 cm diameter, and 10 cm deep into concrete block at a rate of one hole per minute using a commercially available hammer drill and masonry bits. During each trial, dust was continuously captured by two respirable and one inhalable sampling trains and noise was sampled with a noise dosimeter. The room was thoroughly cleaned between trials.

RESULTS

When comparing results for the sharp (0 cm) versus dull bit (1560 cm), the mean respirable silica increased from 0.41 to 0.74 mg m-3 in sampler 1 (P = 0.012) and from 0.41 to 0.89 mg m-3 in sampler 2 (P = 0.024); levels above the NIOSH recommended exposure limit of 0.05 mg m-3. Likewise, mean noise levels increased from 112.8 to 114.4 dBA (P < 0.00001). Drilling productivity declined with increasing wear from 10.16 to 7.76 mm s-1 (P < 0.00001).

DISCUSSION

Increasing bit wear was associated with increasing respirable silica dust and noise and reduced drilling productivity. The levels of dust and noise produced by these experimental conditions would require dust capture, hearing protection, and possibly respiratory protection. The findings support the adoption of a bit replacement program by construction contractors.

Authors+Show Affiliations

School of Public Health, University of California, Berkeley, CA, USA.Department of Bioengineering, University of California, Berkeley, CA, USA.Department of Bioengineering, University of California, Berkeley, CA, USA.Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI, USA.School of Public Health, University of California, Berkeley, CA, USA. Department of Medicine, University of California, San Francisco, CA, USA.School of Public Health, University of California, Berkeley, CA, USA. Department of Bioengineering, University of California, Berkeley, CA, USA. Department of Medicine, University of California, San Francisco, CA, USA.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

28595322

Citation

Carty, Paul, et al. "The Effects of Bit Wear On Respirable Silica Dust, Noise and Productivity: a Hammer Drill Bench Study." Annals of Work Exposures and Health, vol. 61, no. 6, 2017, pp. 700-710.
Carty P, Cooper MR, Barr A, et al. The Effects of Bit Wear on Respirable Silica Dust, Noise and Productivity: A Hammer Drill Bench Study. Ann Work Expo Health. 2017;61(6):700-710.
Carty, P., Cooper, M. R., Barr, A., Neitzel, R. L., Balmes, J., & Rempel, D. (2017). The Effects of Bit Wear on Respirable Silica Dust, Noise and Productivity: A Hammer Drill Bench Study. Annals of Work Exposures and Health, 61(6), 700-710. https://doi.org/10.1093/annweh/wxx041
Carty P, et al. The Effects of Bit Wear On Respirable Silica Dust, Noise and Productivity: a Hammer Drill Bench Study. Ann Work Expo Health. 2017 Jul 1;61(6):700-710. PubMed PMID: 28595322.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The Effects of Bit Wear on Respirable Silica Dust, Noise and Productivity: A Hammer Drill Bench Study. AU - Carty,Paul, AU - Cooper,Michael R, AU - Barr,Alan, AU - Neitzel,Richard L, AU - Balmes,John, AU - Rempel,David, PY - 2017/01/09/received PY - 2017/05/11/accepted PY - 2017/6/9/pubmed PY - 2018/8/8/medline PY - 2017/6/9/entrez KW - concrete drilling KW - dust concentration KW - masonry KW - noise level KW - tool wear SP - 700 EP - 710 JF - Annals of work exposures and health JO - Ann Work Expo Health VL - 61 IS - 6 N2 - OBJECTIVES: Hammer drills are used extensively in commercial construction for drilling into concrete for tasks including rebar installation for structural upgrades and anchor bolt installation. This drilling task can expose workers to respirable silica dust and noise. The aim of this pilot study was to evaluate the effects of bit wear on respirable silica dust, noise, and drilling productivity. METHOD: Test bits were worn to three states by drilling consecutive holes to different cumulative drilling depths: 0, 780, and 1560 cm. Each state of bit wear was evaluated by three trials (nine trials total). For each trial, an automated laboratory test bench system drilled 41 holes 1.3 cm diameter, and 10 cm deep into concrete block at a rate of one hole per minute using a commercially available hammer drill and masonry bits. During each trial, dust was continuously captured by two respirable and one inhalable sampling trains and noise was sampled with a noise dosimeter. The room was thoroughly cleaned between trials. RESULTS: When comparing results for the sharp (0 cm) versus dull bit (1560 cm), the mean respirable silica increased from 0.41 to 0.74 mg m-3 in sampler 1 (P = 0.012) and from 0.41 to 0.89 mg m-3 in sampler 2 (P = 0.024); levels above the NIOSH recommended exposure limit of 0.05 mg m-3. Likewise, mean noise levels increased from 112.8 to 114.4 dBA (P < 0.00001). Drilling productivity declined with increasing wear from 10.16 to 7.76 mm s-1 (P < 0.00001). DISCUSSION: Increasing bit wear was associated with increasing respirable silica dust and noise and reduced drilling productivity. The levels of dust and noise produced by these experimental conditions would require dust capture, hearing protection, and possibly respiratory protection. The findings support the adoption of a bit replacement program by construction contractors. SN - 2398-7316 UR - https://www.unboundmedicine.com/medline/citation/28595322/The_Effects_of_Bit_Wear_on_Respirable_Silica_Dust_Noise_and_Productivity:_A_Hammer_Drill_Bench_Study_ L2 - https://medlineplus.gov/occupationalhealth.html DB - PRIME DP - Unbound Medicine ER -