FALL INJURIES PREVENTION IN THE WORKPLACE

Fall-related Research Projects

Assessment Technology and Interventions for Package Drivers

This project will build upon prior NIOSH research on sensor development and digital human modeling and will respond to industry-wide demands for effective assessment methods and interventions to control exposures to musculoskeletal disorders (MSDs) and slips, trips, and falls (STFs) for package-delivery truck drivers who are exposed to unique, multiple biomechanical and vibration hazards. The primary outcomes of this project will be new technologies to conduct evaluations and integrated assessment methods leading to effective interventions and real-time monitoring of MSDs and STFs. Newly developed exposure assessment and control devices and intellectual property will be transferred to stakeholders via commercialization agreements with selected package delivery companies, and a comprehensive injury reduction/control program will be recommended and disseminated to stakeholders.

Project contact: Chris Pan, Ph.D.
Protective Technology Branch
(304) 285-5978 CPan@cdc.gov
Project period: 2011-2014

Evaluation of Slip, Trip, and Fall Prevention Practices in Food Services

The purpose of this research project is to evaluate the efficacy of slip, trip, and fall (STF) prevention practices in the food services industry. A randomized controlled trial is being conducted to evaluate the effectiveness of slip-resistant shoes in reducing slips and falls injuries. The study involves the participation of approximately 4,000 employees wearing slip-resistant shoes and will continue through 2014. One of the largest food service companies in the US is collaborating in this NIOSH-led research by providing access to its workforce. It is anticipated that this research would impact worker safety by providing scientific evidence and business case support for a comprehensive STF prevention program to effectively reduce STF injuries among food service workers. By demonstrating the effectiveness of STF prevention measures, it is anticipated that food service companies initially hesitant to expend time and money on prevention programs with unknown effectiveness could use these research findings to help justify implementing prevention strategies.

Project contact: Jennifer L. Bell, Ph.D.
Division of Safety Research, Analysis and Field Evaluations Branch
(304) 285-5802; JBell@cdc.gov
Project period: 2010-2014

Injury Assessment for Emerging Mast Elevated Work Platform Technology

This study applies advanced engineering technologies to identify the mechanisms of fall injuries and fatalities for selected mast elevated work platforms (MEWP). The project also studies fall protection systems; the physical reactive forces and motions upon the platforms and fall-control systems; the interactions among workers, platforms, environments, and fall protection systems; and the sequence of events following the imposition of a sudden load on a worker or a platform. The outputs of this project will provide information associated with fall protection systems to MEWP and fall-protection-system standards committees and manufacturers.  

Project contact: Chris Pan, Ph.D.
Protective Technology Branch
(304) 285-5978 CPan@cdc.gov
Project period: 2010-2013

Effectiveness Evaluation of the NIOSH Roof Bracket Assembly

A direct result of the carpenter study was the development of a new, NIOSH-developed, patented design (U.S. Patent No. 7,509,702) of an adjustable roof bracket and safety rail system. This follow-on research study was initially focused on evaluating the new design with a series of laboratory tests. The study has been expanded to include an assessment of the system performance in a field evaluation study. The initial design was focused on preventing falls from roof edges, or through roof holes and skylights. The adjustable design permits guardrail system on flat commercial and industrial roofs, and on residential roofs with seven different slopes (designated as rise over run), ranging from 6:12 (27°) to 24:12 (63°, or A-frame) Along with the initial roof design, a total of 5 other system designs have been developed – two additional for roofs and three for interior work. The field evaluation studies, scheduled for summer and fall 2011, will be conducted with the West Virginia University Safety & Health Extension Office and two construction contractors from the north-central West Virginia area to assess the system performance.

Project contact: Thomas Bobick, Ph.D., P.E., CSP
Protective Technology Branch
(304) 285-5986; TBobick@cdc.gov
Project period: 2009-2011

Effectiveness of Extension-Ladder Safety Innovations

The purpose of this research is to develop and comparatively evaluate, in controlled laboratory settings, extension-ladder safety innovations, e.g., a multimodal inclination indicator, multifunctional convertible top ladder stabilizer, an electro adhesion safety device, and a walkthrough device. A surround-screen virtual reality system is used to simulate ladder transitioning tasks at elevation. Ladder users’ performances is being quantified by motion systems and force platforms, and their perceptions is being collected using computerized questionnaires. A graphic-oriented practical guide on ladder use, maintenance, and inspection will be developed and evaluated by focus groups and trainers at partner sites. The project results will be transferred to manufacturing partners for product adaptation and advancement, to improve the safety of extension ladders and reduce the risk of fall injury for millions of ladder users across many industries.

Project contact: Peter Simeonov, Ph.D. and Hongwei Hsiao, Ph.D.
Protective Technology Branch
(304) 285-5910; PSimeonov@cdc.gov   HHsaio@cdc.gov
Project period: 2007-2011

Fall Injury Controls and Interventions for Aerial Lifts

The objective of this study is to identify fall protection strategies and recommend effective intervention programs to workers who are at risk of injury from work at elevation on aerial lifts. This project has three study components: (1) biomechanical and mechanical assessment of harness/lanyard uses on aerial lift operators; (2) establishment of lift stability margins and their impact on operators; and (3) evaluation of fall hazards and relevant intervention effectiveness. This project addresses strategic priorities for prevention of traumatic injuries for two out of the four leading causes (i.e., falls and machines) of fatal injury, and one of the priority industries (i.e., construction). The outcomes of this project will provide information associated with fall protection systems to aerial-lift standards committees, industries, and interested parties.

Project contact: Chris Pan, Ph.D.
Protective Technology Branch
(304) 285-5978 CPan@cdc.gov
Project period: 2007-2011

Laboratory Evaluation of Guardrail Systems

This laboratory study used local carpenters to construct job-built guardrail systems around a roof hole, and then compared with two commercial products for strength and installation times.  A total of 45 different guardrail configurations were constructed with typical construction supplies or the two commercial products.  All of the guardrail configurations met the OSHA requirement of having to support a 200-lb dynamic load on the top rail of the guardrail system.  Guardrail systems built with all-purpose screw fasteners (3″ length) were significantly stronger than guardrails constructed with standard 16-penny framing nails (3½″ length).  Constructing guardrails with screw fasteners occurred slightly, but not significantly, quicker than building them with framing nails.

Project contact: Thomas Bobick, Ph.D., P.E., CSP
Protective Technology Branch
(304) 285-5986; TBobick@cdc.gov
Project period: 2004-2008

Harness Design and Sizing Effectiveness

Fall-arrest harnesses provide the last line of defense to 6.3 million construction workers in areas where fall-from-height hazards cannot be completely eliminated. This project provides updated harness sizing and cut-length information for harness design to reduce the risk of worker injury that results from poor fit or improper size selection. The research results are currently used by leading harness manufacturers to develop the next-generation harnesses and to update current sizing systems which relied on body measurements of military personnel taken during 1970s and 1980s. The major impacts of the project to occupational safety and health include (1) the development of a computer-graphics procedure to quantify national human torso-shape variations, (2) the formulation of improved harness sizing systems that accommodate diverse populations in the current workforce, and (3) the determination of harness strap lengths for manufacturing production runs.

Project contact: Hongwei Hsiao, Ph.D.
Protective Technology Branch
(304) 285-5910; HHsiao@cdc.gov
Project period: 2002-2008

Sensory-Enhanced Balance Control at Elevated Workplaces

The risk of falls from height on a construction site increases under conditions which degrade workers’ postural control. At elevation, workers depend heavily on sensory information from their feet to maintain balance. This study tested two hypotheses: “sensory enhancement” – sub-sensory (undetectable) random mechanical vibrations at the plantar surface of the feet can improve worker’s balance at elevation; and “sensory suppression” – supra-sensory (detectable) random mechanical vibrations can have a degrading effect on balance in the same experimental settings. The study findings suggest that sensory suppression associated with elevated vibration levels on a construction site may increase the danger of losing balance. Construction workers at elevation, e.g., on a beam or narrow plank might be at increased risk of fall if they can detect vibrations under their feet. To reduce the possibility of losing balance, mechanical vibration to supporting structures used as walking/working surfaces should be minimized when performing construction tasks at elevation.

Project contact: Peter Simeonov, Ph.D.
Protective Technology Branch
(304) 285-6268; PSimeonov@cdc.gov
Project period: 2003-2008

Drywall Installation Safety

This study was undertaken to quantify stresses and changes in gait biomechanics associated with stilts. Falls and overexertion are the leading causes of traumatic injuries in the construction industry and are largely attributable to the nature of construction work, which continually requires workers to maintain awkward postures and perform tasks at elevations. Stilts are elevated tools that are frequently used by construction workers to raise workers 18 to 40 inches above the ground. Three methods were carried out for this project. Results were analyzed and validated along with findings from the two previously mentioned laboratory methods with human subject tests. To reduce the potential for loss of balance and overexertion, workers should avoid or limit prolonged use of stilts, especially when stilts are elevated at high levels. Also, placing the feet parallel and directly beneath the body, with the feet positioned either 1 to 1½ shoulder width apart, caused less postural instability and joint loadings than at half shoulder width.

Project contact: Chris Pan. Ph.D.
Protective Technology Branch
(304)285-5968; CPan@cdc.gov
Project period: 2003-2007

Influence of Visual Cues and Restricted Space on Workers at Elevation

Falls from elevation continue to be the most serious hazard for the workers in construction. Simple and cost effective technical approaches to improve workers’ balance on sloped roofs and deformable/unstable platforms have the potential to reduce the risk of falls. This project evaluated the effectiveness of simple vertical structures as visual references for balance improvement. Results indicate that the roof-environment characteristics, height, and sloped-support surface synergistically increased workers’ standing postural instability, while simple proximal structures (e.g., narrow vertical bars) can serve as visual cues and assist workers’ balance. The results further demonstrate that workers’ balance improves linearly with cue proximity within the tested distance range both on sloped and deformable surfaces. At a moment of instability, workers can redirect their attention to a proximal structure, available in the line of sight, to assist their balance control. These findings may be useful in modifying elevated work environments and construction procedures to improve workers’ postural balance during various construction phases.

Project contact: Peter Simeonov, Ph.D.
Protective Technology Branch
(304) 285-6268 PSimeonov@cdc.gov
Project period: 2003-2007

Evaluation of Scaffolding Tasks

This study determined the most favorable strategy for carrying scaffold end frames while minimizing the risk of injuries from being struck by an object, falling, and overexertion. Scaffold erectors are at risk of high exposure to the aforementioned hazards associated with the dynamic human-scaffolding interface and work environments. Identifying an optimal work strategy can help reduce risk of injuries to the worker. Three carrying methods, four types of work surfaces, two weights of scaffold frames, and three directions of stepping movement were tested in a laboratory with 18 construction workers. The effects of carrying method on postural instability and task difficulty rating were significant for handling the 22-kg end frame. Response time, postural instability, and perceived task difficulty rating were significantly reduced when the 9-kg end frame was used as compared with the 22-kg flame. The symmetric side-carrying method was the best option for handling 22-kg scaffold end frames. A 9-kg end frame (e.g., made of reinforced light weight materials) has the potential to reduce injury risk among scaffold handlers during their scaffold erection and dismantling jobs. Scaffold erectors may want to adopt the symmetric side-carrying method as the primary technique for handling the 22-kg scaffold end frame, which is currently the one most used in the industry.

Project contact: Hongwei Hsiao, Ph.D.
Protective Technology Branch
(304)285-6354; HHsiao@cdc.gov
Project period: 2003-2007