Masonry Ergonomics Best Practices (Completed – 2004-2009)
Dan Anton, PT, PhD, Eastern Washington University; Jennifer Hess, DC, PhD, MPH, University of Oregon; Ryan Mizner, PhD, Eastern Washington University; Marc Weinstein, PhD, Florida International University.
A masonry worker handling an average of 200 concrete masonry unit (CMU) blocks per day, weighing 38 pounds each, lifts the weight of more than five Ford F-350 pick-up trucks each week, or two and one-half fully loaded Boeing 747-100s each year. So it’s not really surprising that masonry workers have the highest rate of back injuries causing days away from work among all the construction trades. However, research by Drs. Dan Anton, Jennifer Hess and colleagues identified a variety of innovations being used around the country that show promise in reducing the risk of back injuries and other MSDs among masonry workers.
The innovations fall into three categories: materials, such as H-block, lightweight block, and autoclaved aerated concrete (AAC); work practices, such as working in lift teams; and equipment, such as grout delivery systems and adjustable scaffolding. Alternative materials such as H-block and lightweight block reduce stress to the upper extremities and low back. Adjustable height or mast climbing scaffolds can help prevent awkward back postures when used for placing work materials at optimum heights.
In a survey of masonry contractors around the country, the researchers found that the main advantage driving use of an innovation was time savings, followed closely by increased productivity. Improving safety was usually the least important “advantage” noted by contractors from among a list provided in the survey. Increasing safety usually ranked third, except for the use of half-weight cement bags and two-person lift teams with 12-inch block, where safety was the most important advantage. Cost was the greatest disadvantage for equipment such as mast climbing scaffolding and mortar silos, while quality concerns were the greatest disadvantage for H-block and AAC. As the charts show, contractors use various innovations despite their disadvantages. The researchers concluded that masonry contractors are beginning to innovate in the use of new equipment, materials, and work practices, a trend that should help reduce injury risks to masons.
Original Project Abstract:
The specific aims of this project are (1) To catalogue existing tools, materials and work practices in masonry that, if used, could reduce the risk of WMSDs among masons and mason tenders. (2) To identify how decisions are made regarding use of these tools, materials, and work practices. (3) To identify gaps in existing data on specific interventions. (4) To document effectiveness of specific interventions. (5) To disseminate best practices into the masonry industry.
Masons have a particularly high risk of developing low back pain and low back disorders; among working masons, 70% report on-going back pain. Primary risk factors for lower back injury are the weight of bricks or blocks, the frequency of lifting, the height from which the block is picked up, the height at whick the block is placed, the height of the mortar stand, the distance of the block from the worker’s body, and degree and frequency of twisting involved. Research has identified changes in materials, work practices and tools that reduce masons’exposure to back, shoulder and wrist stress; for example studies measuring the compressive load on the lumbar spine show a decrease in mean and peak spinal compression at lower brick/block weights, while others document successful technical solutions to the work posture problems associated with masonry work.
This project will identify barriers to use of best practices, develop a model intervention program, pilot the program in three regions of the US , and refine the interventions based on the pilot. We will then enroll contractors into intervention and control groups and monitor use of best practices with regular audits. The audit will collect information on how effectively the interventions are being used, and that information will be used in a model to determine how much of a change in ergonomic stress has occurred. Final analysis will incorporate the cost and benefits of use of practices.