In-Depth Survey Report: Removing mortar with a powered chisel

Details

• Alternative Title:
  In-Depth Survey Report: Removing Mortar with a Powered Chisel, International Union of Bricklayers and Allied Craftworkers Southern Ohio-Kentucky Regional Training Center, Batavia, Ohio
• Personal Author:
  Echt, Alan S. ; Qi, Chaolong
• Corporate Authors:
  National Institute for Occupational Safety and Health. Division of Applied Research and Technology
• Description:
  Background: Workplace exposure to respirable crystalline silica can cause silicosis, a progressive lung disease marked by scarring and thickening of the lung tissue. Crystalline silica is found in several construction materials, such as brick, block, mortar and concrete. Construction tasks that cut, break, grind, abrade, or drill those materials have been associated with overexposure to dust containing respirable crystalline silica. Tuckpointing (repointing) removes damaged mortar from joints in masonry walls and replaces it with new mortar to restore the wall. The use of grinders to remove mortar results in worker overexposure to respirable crystalline silica. NIOSH scientists are conducting a pilot study to assess the respirable crystalline silica exposures associated with mortar removal when tools other than grinders are used. Assessment: NIOSH staff visited the Bricklayers and Allied Craftworkers Southern Ohio-Kentucky Regional Training Center, Batavia, Ohio on October 29, 2015 and performed industrial hygiene sampling, which measured exposures to respirable dust and respirable crystalline silica while an apprentice bricklayer used a powered chisel to remove type N mortar from a brick wall. The NIOSH scientists also collected weather data and observed the work process in order to understand the conditions that contributed to the measured exposure. Results: Personal breathing zone respirable crystalline silica concentrations measured during 15-minute-long periods of mortar removal ranged from less than the limit of detection (LOD) to 0.13 mg/m3. Personal breathing zone respirable dust concentrations collected on filter samples ranged from 0.21 mg/m3 to 1.0 mg/m3. The lower value in the range was a sample result between the LOD and limit of quantitation (LOQ), which is considered a trace value with limited confidence in its accuracy. Conclusions and Recommendations: The chisel tested here produced respirable crystalline exposures less than those reported when grinders were used with local exhaust ventilation under similar test parameters. If the powered chisel can remove mortar with the speed and quality required by contractors and is acceptable to workers, it represents an alternative to the use of grinders. However, if the chisel was used for a full shift and dust levels remained constant, the highest quartz concentration measured during use of the chisel, 0.13 mg/m3, would be 2.6 times the OSHA PEL and NIOSH REL, requiring the use of a respirator with an assigned protection factor of 10, such as an N-95 filtering facepiece respirator. On the other hand, a quartz exposure of 0.13 mg/m3 would permit a worker to use the chisel under these conditions for more than 3 hours (up to 185 minutes) in an 8-hour shift with no other exposures to quartz without exceeding the REL or PEL. Full-shift sampling on job sites should be conducted to validate these findings. In the meantime, additional research will be conducted to assess the effectiveness of tool-mounted local exhaust ventilation on reducing respirable dust and crystalline silica exposures associated with the use of this powered chisel.
• Subjects:
  Construction Industry Dust Engineering Environmental Monitoring Manufacturing And Industrial Facilities Occupational Exposure Occupational Health Personal Protective Equipment Quartz Respiratory Protective Devices Safety Silicon Dioxide Ventilation

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• Keywords:
  Air Sampling Breathing Zone Brick Bricklayer Bricklayers Cements Chisels Concretes Construction-equipment Construction Workers Control-technology Crystalline Silica Dust-exposure Dust Control Employee-exposure Engineering-controls Equipment Testing Exhaust Ventilation Exposure-assessment Exposure-levels Exposure-limits Industrial Environment Industrial Hygiene Masons Mortar Mortar Removal N95 Filtering Facepiece Respirators OSHA Region 5 PELs Permissible Exposure Limits Power Tools Quartz Quartz-dust Recommended Exposure Limits RELs Respirable-dust Respirable Dust Respirators Respiratory Protection Sampling Silica-dusts Tools

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• Series:
  Engineering and Physical Hazards Survey Reports
• DOI:
  https://doi.org/10.26616/NIOSHEPHB35819a
• Publisher:
  National Institute for Occupational Safety and Health
• Document Type:
  Text
• Name as Subject:
  International Union of Bricklayers and Allied Craftworkers
• Genre:
  Field Study
• Place as Subject:
  Ohio ; Batavia (OH) ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  DART - Division of Applied Research and Technology ; EPHB - Engineering and Physical Hazards Branch
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-17
• NIOSHTIC Number:
  nn:20049948
• Citation:
  Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, EPHB 358-19a, 2017 Apr ; :1-17
• CAS Registry Number:
  Quartz (SiO2) (CAS RN 14808-60-7)
• Federal Fiscal Year:
  2017
• NORA Priority Area:
  Construction ; Manufacturing
• Peer Reviewed:
  False
• NAICS and SIC Codes:
  611513 - Apprenticeship Training - (NAICS)
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:0e25faf64830d622ba8141bcd07ed0a7dc810e9833851dda93b86a9333ddd75fd82a390e7e40aaeb3c6fdc925bb78310f642183a617c3619c7e672f110c5c738
• Download URL:
  https://stacks.cdc.gov/view/cdc/175014/cdc_175014_DS1.pdf
• File Type:
  [PDF - 897.57 KB ]