Position and size of drywall on the physical demands for drywall installers

Details

• Personal Author:
  Yuan L
• Description:
  The present study utilized an integrated biomechanical modeling approach that was previously developed by the researcher to investigate the effects of position and size of drywall on the physical demands for drywall installers. First, a sensitivity analysis was conducted to examine the impact of some quantitative assumptions that have been made to facilitate the modeling approach. Through setting up null hypothesis for each assumption and changing one parameter at a time, the new model output values were compared to the original ones. Using student t-tests to evaluate the statistical differences of the mean values, the sensitivity analysis was achieved by determining if any assumption or parameter has significant impact on the model. The results indicated that the modeling approach seemed to be the most sensitive to both the distribution of work cycles for a typical 8-hour workday and the distribution and values of Euler angles that are used to determine the "shoulder rhythm." Other assumptions including the distribution of trunk postures did not appear to have significant impact on the model output values. It was concluded that the integrated approach might provide an applicable examination of exposure variability particularly reflected by the non-routine feature of the work. The results from the second part of the study verified the hypotheses on the impact of drywall storage position and size. In particular, the required muscle contraction forces and joint reaction forces at the low back and shoulder reduced approximately 8% (with a range of 3.6% - 12.8%) if the drywall sheets were stored vertically and spiked if the size of drywall sheets increased. These changes were even more notable for the exclusive comparison of the activity 2 (lift), which could be used as guidance to help ASTM (American Society for Testing and Materials) make recommendations about drywall. Specifically, those 4x12 and 4x16 sheets increase the physical burden for drywall installers significantly and could expose them to a higher risk of musculoskeletal injuries and disorders. KEY FINDINGS 1. The application of computer-aided simulation to convert observational work sampling data into continuous variables as inputs for biomechanical modeling permitted a valid estimation of the physical loads on the low back and shoulder during drywall installation. 2. If the drywall sheets were stored vertically instead of flat, it would reduce the required muscle contraction forces and joint reaction forces at the low back and shoulder approximately 8% on average during drywall installation. In particular, the L4/L5 disc compression forces and the absolute values of L4/L5 anterior-posterior shear forces decreased 6.1% and 8.5%, respectively, and at the shoulder during lifting the forces of rotator cuff muscles decreased 9.8%, and the coracohumeral ligament forces decreased 12.8%. The reaction forces at both the GH (glenohumeral) and SC (sternoclavicular) joints went down by 7.2% and 3.6%, respectively. 3. As a drywall stabilizing clip could be used to secure the sheets in a vertical storage position, more research is needed to examine how it is used in practice as well as how the work efficiency and productivity could be affected. 4. The bigger size (e.g., 4x12 and 4x16) of drywall sheets increased the physical burden for drywall installers significantly and could expose them to a higher risk of musculoskeletal injuries and disorders. In some simulations the average low back lateral shear forces increased to 1674.7 N and 2152.2 N, respectively. These forces are significantly above the 1000 N recommended for a single lift. 5. These results indicated that it would be physically too difficult or even impossible for one person alone to lift bigger and heavier drywall sheets. Therefore, sound engineering (e.g., lifting tables) and/or administrative (e.g., two-person team work) solutions to handling oversized drywall sheets are strongly recommended. [Description provided by NIOSH]
• Subjects:
  Biomechanical Phenomena Construction Industry Construction Materials Engineering Ergonomics Manufacturing And Industrial Facilities Musculoskeletal Diseases Musculoskeletal System Occupational Health Safety
• Keywords:
  Biomechanical-modeling Biomechanics Construction Construction-industry Construction-materials Construction-workers Control-technology Engineering-controls Injury-prevention Manual-lifting Manual-materials-handling Materials-handling Models Muscle-function Musculoskeletal-system Skeletal-stress

  More +
• Publisher:
  CPWR-The Center for Construction Research and Training
• Document Type:
  Text
• Funding:
  Cooperative Agreement
• Genre:
  Guidance
• Place as Subject:
  Louisiana ; Maryland ; OSHA Region 3 ; OSHA Region 6
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-16
• NIOSHTIC Number:
  nn:20047223
• Citation:
  Silver Spring, MD: CPWR-The Center for Construction Research and Training, 2013 May; :1-16
• Email:
  Lu.Yuan@selu.edu
• Federal Fiscal Year:
  2013
• NORA Priority Area:
  Construction
• Performing Organization:
  CPWR - The Center for Construction Research and Training, Silver Spring, Maryland
• Peer Reviewed:
  False
• Start Date:
  20090901
• Source Full Name:
  Position and size of drywall on the physical demands for drywall installers
• End Date:
  20240831
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:c6a1166e94ea83a7c456512648a20ff680cef3e5f4789164f05f20de470a5725ee1637e9e06c8301f34edc78a0df5b485b3965fb613568b1af52f79face45e5c
• Download URL:
  https://stacks.cdc.gov/view/cdc/202377/cdc_202377_DS1.pdf
• File Type:
  [PDF - 288.92 KB ]