In-Depth Survey Report: Concrete Surface Preparation Tools Machines 6

Details

• Personal Author:
  Echt, Alan S. ; Garcia, Alberto ; Marlow, David A. ; Steltz, Austin
• Corporate Authors:
  National Institute for Occupational Safety and Health. Division of Applied Research and Technology
• Description:
  Workplace exposure to respirable crystalline silica can cause silicosis, a progressive lung disease marked by scarring and thickening of the lung tissue. Quartz is the most common form of crystalline silica. 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. Colored, stained, and polished concrete floors are increasingly popular for use in homes, offices, retail establishments, schools, and other commercial and industrial settings. Some businesses specify integrally-colored concrete floors in new stores in place of vinyl composite tile. Polished concrete floors are durable, sanitary, and easy to maintain. NIOSH scientists are conducting a study to develop and evaluate engineering control recommendations for respirable crystalline silica generated from concrete polishing operations. This survey was part of that study. NIOSH staff visited the Vance Outdoors facility in Columbus, Ohio on September 9th and 10th, 2014. During the site visit, personal breathing zone (PBZ) air samples were collected to measure the respirable dust and respirable crystalline silica exposures of the operator while he used a concrete polisher (HTC, HTC Inc., Sweden). Additionally, area samples were collected on top of the machine during the completion of the task. The HTC 800HD Classic floor polisher was outfitted with a local exhaust ventilation (LEV) system consisting of two exhaust ports located on the back of the shroud that encased nine polishing tools. The exhaust from both ports was connected to a vacuum system with a manufacturer-rated exhaust airflow of approximately 10,000 liters per minute (L/min) (353 cubic feet per minute (cfm)). The vacuum was equipped with a pre-separator. Once through the pre-separator, the air stream passed through a High Efficiency Particulate Air (HEPA) filter and then recirculated to the room. The aim of this survey was to collect emissions data from the concrete polisher during the use of different polishing grits while operating the dust collection system provided with the machine. Sample times ranged between 41 and 75 minutes with an average sample time of 60 minutes. A bulk sample was collected from the bag filter of the concrete polisher's vacuum system and was found to contain 21% quartz. No cristobalite or tridymite were detected in the air samples or bulk sample. Therefore, for the purposes of this report, the terms respirable crystalline silica or respirable quartz may be used interchangeably. The evaluated HTC floor polisher was outfitted with an Ermator (Tampa, Florida) dust collection system intended to control and remove dust particles generated during the concrete polishing process. PBZ samples ranged between 24 micrograms per cubic meter (microg/m3) and 61 microg/m3 with an arithmetic mean concentration of 44 microg/m3. Five of the eighteen samples exceeded the NIOSH Recommended Exposure Limit (REL) for respirable quartz of 50 microg/m3 as a time weighted average (6% - 22% over the NIOSH REL). The dust control system, as described in this report, did not adequately control worker exposure to respirable crystalline silica during this site visit. Additional evaluation is recommended to collect repeated samples using the same equipment to quantify the actual air flow of the vacuum system and establish a correlation between the actual and the listed airflow.
• Subjects:
  Air Movements Dust Engineering Environmental Monitoring Epoxy Resins Manufacturing And Industrial Facilities Occupational Health Quartz Safety Silicon Dioxide Ventilation

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• Keywords:
  Abrasive-grinding Air-flow Air-sampling Concrete Polishing Concretes Control-technology Dust-control Dust-control-equipment Dust-particles Dust-suppression Dusts Emission-sources Engineering-controls Engineering Controls Equipment-design Equipment-reliability Exhaust-ventilation Exposure-assessment Exposure-levels Exposure-limits Filters HEPA Filters High-efficiency Particulate Air Filters Local Exhaust Ventilation Machine-operation Machine Operators OSHA Region 5 Performance-capability Quartz-dust Recommendations Recommended Exposure Limits RELs Resins Respirable-dust Sampling Silica Silica-dusts Time-weighted-average-exposure Vacuum-equipment Vacuum Cleaning Systems Ventilation-systems

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• Series:
  Engineering and Physical Hazards Survey Reports
• DOI:
  https://doi.org/10.26616/NIOSHEPHB36815a
• Publisher:
  National Institute for Occupational Safety and Health
• Document Type:
  Text
• Name as Subject:
  Concrete Contracting Solutions ; Vance Outdoors
• Genre:
  Field Study
• Place as Subject:
  Ohio ; Columbus (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:20050783
• NTIS Accession Number:
  PB2018-100574
• 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 368-15a, 2017 Oct ; :1-17
• CAS Registry Number:
  Quartz (SiO2) (CAS RN 14808-60-7)
• Federal Fiscal Year:
  2018
• NORA Priority Area:
  Construction
• Peer Reviewed:
  False
• NAICS and SIC Codes:
  238340 - Tile and Terrazzo Contractors - (NAICS) ; 238110 - Poured Concrete Foundation and Structure Contractors - (NAICS)
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:8878b7817aa44b281d48b5d7847b73c5c91302ef47f66370dcaa91026c22edd7942f71912e5cae062f3c886263f50717a89647e14cab9045ceb836558c917bc7
• Download URL:
  https://stacks.cdc.gov/view/cdc/175026/cdc_175026_DS1.pdf
• File Type:
  [PDF - 311.29 KB ]