Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-9 (of 9 Records) |
Query Trace: Powers JR[original query] |
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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. |
Respiratory Protection in a Time of Crisis: NIOSH Testing of International Respiratory Protective Devices for Emergency Use.
Andrews AS , Powers JR Jr , Cichowicz JK , Coffey CC , Fries ML , Yorio PL , D'Alessandro MM . Health Secur 2021 19 (4) 379-385 National Institute for Occupational Safety and Health (NIOSH)-approved respirators are required by the Occupational Safety and Health Administration (OSHA) when personal respiratory protection is used in US occupational settings. During the COVID-19 pandemic, the demand for NIOSH-approved N95 filtering facepiece respirators overwhelmed the available supply. To supplement the national inventory of N95 respirators, contingency and crisis capacity strategies were implemented and incorporated a component that endorsed the use of non-NIOSH-approved respiratory protective devices that conformed to select international standards. The development and execution of this strategy required the collaborative effort of numerous agencies. The Food and Drug Administration temporarily authorized non-NIOSH-approved international respiratory protective devices through an emergency use authorization, OSHA relaxed their enforcement guidance concerning their use in US workplaces, and NIOSH initiated a supplemental performance assessment process to verify the quality of international devices. NIOSH testing revealed that many of the non-NIOSH-approved respiratory protective devices had filtration efficiencies below 95% and substantial inconsistencies in filtration performance. This article reports the results of the NIOSH testing to date and discusses how it has contributed to continuous improvement of the crisis strategy of temporarily permitting the use of non-NIOSH-approved respirators in US occupational settings during the COVID-19 pandemic. |
Factors affecting extension ladder angular positioning
Simeonov P , Hsiao H , Kim IJ , Powers JR , Kau TY . Hum Factors 2012 54 (3) 334-45 OBJECTIVE: The study objectives were to identify factors affecting extension ladders' angular positioning and evaluate the effectiveness of two anthropometric positioning methods. BACKGROUND: A leading cause for extension ladder fall incidents is a slide-out event, usually related to suboptimal ladder inclination. An improved ladder positioning method or procedure could reduce the risk of ladder stability failure and the related fall injury. METHOD: Participants in the study were 20 experienced and 20 inexperienced ladder users. A series of ladder positioning tests was performed in a laboratory environment with 4.88-m (16-ft) and 7.32-m (24-ft) ladders in extended and retracted positions. The setup methods included a no-instruction condition and two anthropometric approaches: the American National Standards Institute A14 and "fireman" methods. Performance measures included positioning angle and time. RESULTS: The results indicated that ladder setup method and ladder effective length, defined by size and extended state, affected ladder positioning angle. On average, both anthropometric methods were effective in improving extension ladder positioning; however, they required 50% more time than did the no-instruction condition and had a 9.5% probability of setting the ladder at a less-than-70 degrees angle. Shorter ladders were consistently positioned at shallower angles. CONCLUSION: Anthropometric methods may lead to safer ladder positioning than does no instruction when accurately and correctly performed. Workers tended to underperform as compared with their theoretical anthropometric estimates. Specific training or use of an assistive device may be needed to improve ladder users' performance. APPLICATION: The results provide practical insights for employers and workers to correctly set up extension ladders. |
Assessment of fall-arrest systems for scissor lift operators: computer modeling and manikin drop testing
Pan CS , Powers JR , Hartsell JJ , Harris JR , Wimer BM , Dong RG , Wu JZ . Hum Factors 2012 54 (3) 358-72 OBJECTIVE: The current study is intended to evaluate the stability of a scissor lift and the performance of various fall-arrest harnesses/lanyards during drop/fall-arrest conditions and to quantify the dynamic loading to the head/ neck caused by fall-arrest forces. BACKGROUND: No data exist that establish the efficacy of fall-arrest systems for use on scissor lifts or the injury potential from the fall incidents using a fall-arrest system. METHOD: The authors developed a multibody dynamic model of the scissor lift and a human lift operator model using ADAMS and LifeMOD Biomechanics Human Modeler. They evaluated lift stability for four fall-arrest system products and quantified biomechanical impacts on operators during drop/fall arrest, using manikin drop tests. Test conditions were constrained to flat surfaces to isolate the effect of manikin-lanyard interaction. RESULTS: The fully extended scissor lift maintained structural and dynamic stability for all manikin drop test conditions. The maximum arrest forces from the harnesses/lanyards were all within the limits of ANSI Z359.1. The dynamic loading in the lower neck during the fall impact reached a level that is typically observed in automobile crash tests, indicating a potential injury risk for vulnerable participants. CONCLUSION: Fall-arrest systems may function as an effective mechanism for fall injury protection for operators of scissor lifts. However, operators may be subjected to significant biomechanical loadings on the lower neck during fall impact. APPLICATION: Results suggest that scissor lifts retain stability under test conditions approximating human falls from predefined distances but injury could occur to vulnerable body structures. |
Evaluating the protective capacity of two-post ROPS for a seat-belted occupant during a farm tractor overturn
Guan J , Hsiao H , Zwiener JV , Current RS , Lutz TJ , Cantis DM , Powers JR Jr , Newbraugh BH , Spahr JS . J Agric Saf Health 2011 17 (1) 15-32 This study evaluated the effectiveness of a commercial rollover protective structure (ROPS) and size-extended ROPS in protecting a 95th percentile male operator during tractor overturns. Six rear upset tests (commercial ROPS) and ten side upset tests (commercial and size-extended ROPS) were conducted. A 95th percentile instrumented male manikin was used in all tests. Head injury criterion (HIC15), 80 g limit on resultant head acceleration, neck injury criterion (Nij), and peak axial force (extension-compression) were employed to evaluate injury potential. In all rear tests, the manikin's head impact with the ground was within the tolerance limits for head/neck injuries. Based on limited trials in the side tests, the study observed a small to moderate chance of neck injuries under the commercial and size-extended ROPS conditions; the injury risk was not statistically significant between these two test conditions. This study identified a risk of non-fatal injuries for large-size operators in side overturns, although the prevention effectiveness of commercial versus size-extended ROPS cannot be determined without further testing. These findings may have implications for future ROPS designs. |
Estimation of the kinetic energy dissipation in fall-arrest system and manikin during fall impact
Wu JZ , Powers JR , Harris JR , Pan CS . Ergonomics 2011 54 (4) 367-379 Fall-arrest systems (FASs) have been widely applied to provide a safe stop during fall incidents for occupational activities. The mechanical interaction and kinetic energy exchange between the human body and the fall-arrest system during fall impact is one of the most important factors in FAS ergonomic design. In the current study, we developed a systematic approach to evaluate the energy dissipated in the energy absorbing lanyard (EAL) and in the harness/manikin during fall impact. The kinematics of the manikin and EAL during the impact were derived using the arrest-force time histories that were measured experimentally. We applied the proposed method to analyse the experimental data of drop tests at heights of 1.83 and 3.35 m. Our preliminary results indicate that approximately 84-92% of the kinetic energy is dissipated in the EAL system and the remainder is dissipated in the harness/manikin during fall impact. The proposed approach would be useful for the ergonomic design and performance evaluation of an FAS. STATEMENT OF RELEVANCE: Mechanical interaction, especially kinetic energy exchange, between the human body and the fall-arrest system during fall impact is one of the most important factors in the ergonomic design of a fall-arrest system. In the current study, we propose an approach to quantify the kinetic energy dissipated in the energy absorbing lanyard and in the harness/body system during fall impact. |
Effectiveness of a worker-worn electric-field sensor to detect power-line proximity and electrical-contact
Zeng S , Powers JR , Newbraugh BH . J Safety Res 2010 41 (3) 229-39 PROBLEM: Construction workers suffer the most electrocutions among all industries. Currently, there are no electrical contact warning devices on the market to protect workers. This paper proposes a worker-worn electric-field sensor. As the worker is in proximity to, or in contact with, a live power-circuit, the sensor sets off an audible/visual warning alarm. The sensor also has the potential to wirelessly trip a wireless-capable circuit breaker, and to trigger a wireless transmitter to notify emergency response of an electrical contact. METHODS: An experiment was conducted to measure electric-field variation on simulated human-wrists (10 defrosted hog-legs) in various proximities and in electrical-contact to a simulated power-circuit. The purpose of these tests was to determine the feasibility of developing a worker-worn electric-field detection sensor for use in protecting workers from contact with energized electrical conductors. RESULTS: This study observed a significant electric-field-magnitude increase as a hog-leg approaches the live-circuit, and the distinct electric-field-magnitude jump as the leg contacts with the live-circuit. The observation indicates that this sensor can be an effective device to warn the workers of electrical hazards. Additionally, the sensor has the potential to wirelessly trip a wireless-capable circuit-breaker and trigger a wireless transmitter (such as a cell phone) to notify an emergency response. The prompt notification prevents the worker from further injury caused by postponed medical-care. IMPACT ON INDUSTRY: Widespread use of this sensor could lower electrocution and electrically related injury rates in the construction industry. |
Fall arrest characteristics of a scissor lift
Harris JR , Powers JR Jr , Pan CS , Boehler B . J Safety Res 2010 41 (3) 213-20 PROBLEM: Census of Fatal Occupational Injuries (CFOI) data indicate 306 aerial lift fatalities between 1992-2003. Seventy-eight of these fatalities specifically involved scissor lifts. Members of standards committees have requested that NIOSH conduct research to determine the effects of safety-control practices related to using fall-protection systems for scissor lifts. METHOD: This research examined the structural and dynamic stability of a scissor lift subjected to fall arrest forces. This was accomplished by conducting drop tests from a scissor lift. Anchorage locations evaluated included manufacturer-supplied anchorage points on the scissor lift platform as well as mid-rail and top-rail locations. RESULTS: Preliminary drop tests determined that a 2400lb maximum arrest force (MAF) could be generated by dropping 169lb through a fall height of 36" using Nystron(R) rope as a lanyard. The scissor lift maintained structural and dynamic stability for all drop tests when fully extended and on an incline. DISCUSSION: Anchoring a fall arrest system to either the mid-rail or top-rail is not a recommended practice by the scissor lift manufacturer. Anchor points are provided on the platform floor of the scissor lift for this purpose. However, our results demonstrate that the mid-rail and top-rail absorb substantial energy from an arrested fall and may have potential as appropriate anchorage points. IMPACT TO INDUSTRY: Employers and workers should consider implementing fall arrest systems when using scissor lifts as part of their overall risk mitigation plan for fall injury prevention. |
Machine safety: developing an operator presence system
Powers Jr JR , Ammons DE , Brand I . Prof Saf 2009 54 (11) 28-31 Most hydraulic stump cutters do not have an operator presence system, which could help prevent injuries that can occur when an operator approaches the cutter wheel with the clutch still engaged. NIOSH and Vermeer Corp. partnered to develop a technology to detect the operator at the machine's controls. The development of this safety system provides an example of how a research to practice partnership can benefit all. |
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- Page last updated:May 06, 2024
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