In-Depth Survey Report: Removing mortar with a powered saw and modified on-tool hood

Details

• Alternative Title:
  In-Depth Survey Report: Removing Mortar with a Powered Saw and Modified On-Tool Hood, International Union of Bricklayers and Allied Craftworkers Southern Ohio-Kentucky Regional Training Center, Batavia, Ohio
• Personal Author:
  Echt, Alan S. ; Menchaca, Kevin ; 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. Several construction materials, such as brick, block, mortar and concrete contain crystalline silica. 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 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 31, 2017 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 with a modified shroud 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 25 to 30-minute-long periods of mortar removal ranged from 0.036 to 0.26 mg/m3
  
  the average concentration was 0.12 mg/m3. The lower concentration was a sample result between the limit of detection and limit of quantitation, which is considered a trace value with limited confidence in its accuracy. The results in this evaluation of a modified on-tool local exhaust ventilation shroud were not significantly different (p>0.05) to the unmodified shroud supplied by the saw's manufacturer. Conclusions and Recommendations: The saw with on-tool ventilation and a modified shroud produced personal breathing zone respirable quartz exposures less than those reported when grinders were used with LEV. However, the modified on-tool hood did not significantly reduce those exposures compared to the manufacturer's hood. Additional research could investigate other shroud designs and/or the impact of a higher exhaust ventilation flow rate on respirable crystalline silica dust concentrations.
  
  
• 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

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• Keywords:
  Air Flow Air Sampling Breathing Zone Brick Bricklayers Cements Concretes Construction-equipment Construction Workers Control-technology Craft Union Apprenticeship Training Programs Crystalline Silica Cutting Tools Dust Dust-exposure Dust Control Employee-exposure Engineering-controls Equipment Testing Exhaust Ventilation Exposure-assessment Exposure-levels Exposure-limits Filters Industrial Environment Industrial Hygiene Masons Mortar N95 Filtering Facepiece Respirators OSHA Region 5 Power Tools Quartz-dust Respirable-dust Respirable Crystalline Silica Respirators Respiratory Protection Sampling Silica-dusts Task Performance Tools Tuckpointing Tuck Pointing

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• Series:
  Engineering and Physical Hazards Survey Reports
• DOI:
  https://doi.org/10.26616/NIOSHEPHB38114a
• 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:20057438
• 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 381-14a, 2019 May ; :1-20
• CAS Registry Number:
  Quartz (SiO2) (CAS RN 14808-60-7)
• Federal Fiscal Year:
  2019
• NORA Priority Area:
  Construction
• 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-512:817fe53fe935b50c703daed7b2e1c6ad559388685d1fc38dc448e29a7bd218c4d85c8a697b3851f0963bbcbd795392446d8f9e2194b8e3cf12f111e3db15d359
• Download URL:
  https://stacks.cdc.gov/view/cdc/175041/cdc_175041_DS1.pdf
• File Type:
  [PDF - 1.26 MB ]