Last data update: Aug 15, 2025. (Total: 49733 publications since 2009)
| Records 1-5 (of 5 Records) |
| Query Trace: McKenzie EA Jr[original query] |
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| Fall safety in steel construction: a research study
McKenzie EA Jr , Bobick TG , Hause MG . Prof Saf 2025 70 (2) 20-29 Key takeaways: Workers at elevation can be exposed to falls to a lower level when working. A personal fall arrest system is designed to stop workers from experiencing free fall, but even after the system engages, a worker will continue to fall. A NIOSH study compared the end effects of using a proper and improper personal fall arrest lanyard in a 12-ft free fall foot-level tie off. A 12-ft free fall personal fall arrest lanyard should always be used for free fall distances greater than 6 ft. A 6-ft free fall personal fall arrest lanyard should never be used at foot-level tie off. The personal energy absorber reached its maximum effectiveness during pullout and stopped extending. When this occurred, an excessive force spike was measured before the fall was fully arrested. Energy is absorbed in the mannequin's harness, as well as the personal fall arrest lanyard during a fall arrest, resulting in a shorter pullout length of the personal fall arrest lanyard as compared to a drop weight. |
| Identification of contact avoidance zones of robotic devices in human-robot collaborative workspaces
Cheng MH , Liang CJ , McKenzie EA Jr , Dominguez EG . IFAC-PapersOnLine null 56 (3) 577-582 The objective of this study was to establish a framework for producing indoor maps and locating robotic devices in a manufacturing environment. The framework employs computer vision techniques to construct the map and identify the presence of human workers. It defines the contact avoidance zones around human workers and existing obstacles. Once the location of the robot is identified, the map is used to plan paths to ensure safe human-robot collaboration for mobile and collaborative robots in shared workspaces with humans. The incorporation of avoidance zones into the map allows the robotic devices to anticipate the movements of workers and prevent collisions, this decreases the risk of injuries in collaborative environments. This paper illustrates the implementation of robots evading unforeseen contact with pre-defined contact avoidance zones, employing two distinct examples as demonstration. |
| Slide guard effectiveness on steep-sloped roofs
Bobick TG , McKenzie EA Jr , Powers JR Jr . Prof Saf 2021 66 (2) 28-33 Key Takeaways: 1) Roofing contractors should consider using a slide guard as a supplemental means of fall protection when working on roof slopes that are 34 degrees (8 in 12) or less, but a slide guard should never be considered as the sole means to achieve work site fall protection compliance. 2) Using a slide guard on a 45 degree roof slope (12 in 12) would not be an effective fall protection supplement to comply with OSHA's fall protection requirements. 3) Contractors should consider purchasing and using synthetic underlayment materials with higher coefficient-of-friction values. This type of information may be available from the suppliers of underlayment materials that are used on steep-sloped roofs. |
| A demonstration project in New York and Virginia: retrofitting cost-effective roll-over protective structures (CROPS) on tractors
Hard DL , McKenzie EA Jr , Cantis D , May J , Sorensen J , Bayes B , Madden E , Wyckoff S , Stone B , Maass J . J Agric Saf Health 2015 21 (3) 173-185 The NIOSH cost-effective roll-over protective structure (CROPS) demonstration project sought to determine whether three prototype roll-over protective structures (ROPS) designed to be retrofitted on Ford 8N, Ford 3000, Ford 4000, and Massey Ferguson 135 tractors could be installed in the field and whether they would be acceptable by the intended end users (farmers). There were a total of 50 CROPS demonstrators (25 in New York and 25 in Virginia), with 45 observers attending the New York CROPS demonstrations and 36 observers attending the Virginia CROPS demonstrations, for a total of 70 participants in New York and 61 in Virginia. The oldest retrofitted tractors were 77 to 62 years old, while the newest retrofitted tractors were 40 to 37 years old. The most frequently retrofitted tractor in the CROPS demonstration project was a Ford 3000 series tractor (n = 19; 38%), followed by Ford 4000 (n = 11; 22%), Massey Ferguson 135 (n = 11; 22%), and Ford 8N (n = 9; 18%). A major issue of CROPS retrofitting was the rear wheel fenders. The effort involved in disassembling the fenders (removing the old bolts was often faster by cutting them with a torch), modifying the fender mounting brackets, and then reinstalling the fenders with the CROPS generally required the most time. In addition, various other semi-permanent equipment attachments, such as frontend loaders, required additional time and effort to fit with the CROPS. Demonstrators were asked to rank the reasons why they had not retrofitted their tractors with ROPS until they had enrolled in the CROPS demonstration program. ROPS "cost too much" was ranked as the primary reason for participants in both states (80% for New York and 88% for Virginia). The second highest ranked reasons were "ROPS wasn't available" for Virginia (80%) and "hassle to find ROPS" for New York (69%). The third highest ranked reasons were "not enough time to find ROPS" for New York (67%) and "hassle to find ROPS" for Virginia (79%). All demonstrators and observers indicated that they were glad to have participated in the CROPS project. |
| Evaluation of guardrail systems for preventing falls through roof and floor holes
Bobick TG , McKenzie EA Jr , Kau TY . J Safety Res 2010 41 (3) 203-11 INTRODUCTION: Fall-related occupational injuries and fatalities are serious problems in the U.S. construction industry, especially incidents related to unguarded holes. The National Institute for Occupational Safety and Health, Division of Safety Research, Morgantown, WV conducted a project to evaluate the effectiveness of guardrail systems to prevent falls through roof and floor holes. METHODS: Two commercial edge-protection products were evaluated when used as perimeter guarding around a roof hole. Installations of the commercial products were compared to job-built guardrails constructed of 2('')x4('') construction-grade lumber. Occupational Safety and Health Administration (OSHA) regulations require that "a force of at least 200pounds" must be supported by the top rail of a guardrail system "in any outward or downward direction at any point along the top edge." A laboratory testing system was developed to evaluate this requirement. A dynamic 200-lb force was generated against the top rail using a weighted manikin mounted on a hinged steel frame. Nine construction workers, who served as test subjects, each built five different guardrail configurations. RESULTS: All 45 configurations met the 200-lb OSHA requirement. Installation time for one commercial product was 32% quicker than the job-built configuration (25.6min vs. 37.9min). IMPACT ON INDUSTRY: This study: (a) indicates that the two edge-protection products can be used as perimeter guarding; (b) highlights the importance of using proper materials and fasteners to construct guardrails to protect workers from falling into unguarded roof and floor holes; and (c) discusses an overall-strength-testing methodology that can be used by fall-protection researchers. |
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