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

Details

• Alternative Title:
  In-Depth Survey Report: Removing Mortar with a Powered Saw, 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 March 29, 2016 and performed industrial hygiene sampling, which measured exposures to respirable dust and respirable crystalline silica while an apprentice bricklayer used a powered saw with on-tool local exhaust ventilation to remove mortar from a brick wall. The NIOSH scientists also observed the work process in order to understand the conditions that contributed to the measured exposure and collected air flow data. Results: Personal breathing zone respirable crystalline silica concentrations measured during 26 to 28-minute-long periods of mortar removal ranged from 0.056 to 0.15 mg/m3. Personal breathing zone respirable dust concentrations collected on filter samples ranged from 0.30 mg/m3 to 1.0 mg/m3. The lower value in both ranges was a sample result between the limit of detection (LOD) and limit of quantitation (LOQ), which is considered a trace value with limited confidence in its accuracy. Conclusions and Recommendations: The powered saw tested here produced respirable quartz exposures less than those reported when grinders were used with local exhaust ventilation under similar test parameters. If the saw 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 saw was used for a full shift and dust levels remained constant, the highest quartz concentration measured, 0.15 mg/m3, would be 3 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 0.15 mg/m3 would permit a worker to use the saw under these conditions for up to 160 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.
• Subjects:
  Air Movements 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

  More +
• Keywords:
  Air Flow Air Sampling Breathing Zone Brick Bricklayer Bricklayers Cements Concretes Construction-equipment Construction Workers Control-technology Crystalline Silica Cutting Tools Dust-exposure Dust Control Employee-exposure Engineering-controls Equipment Testing Exhaust Ventilation Exposure-assessment Exposure-levels Exposure-limits Filters Industrial Environment Industrial Hygiene Local Exhaust Ventilation Masons Mortar Mortar Removal N95 Filtering Facepiece Respirators On-tool Dust Control 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 Task Performance Tools

  More +
• Series:
  Engineering and Physical Hazards Survey Reports
• DOI:
  https://doi.org/10.26616/NIOSHEPHB35820a
• 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:
  1-20
• NIOSHTIC Number:
  nn:20049949
• 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 358-20a, 2017 Apr ; :1-20
• 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-512:24cb996efd746497981e8a135985592b2fad09dd2dd7f1911cd8236191f3550baf6f43fb5fb62afafd0508a7bd19045c084730b76b867de944b8dbfa4e930caa
• Download URL:
  https://stacks.cdc.gov/view/cdc/175015/cdc_175015_DS1.pdf
• File Type:
  [PDF - 1.52 MB ]