Application of Annealed Cable for Vehicle Arresting Barriers

Transportation and traffic managers have had to deal with increased liability issues regarding containing vehicles during impact with protective barriers. Today’s security environment has a heightened need for means of stopping vehicles in controlled manner for security and liability purposes. Using strain energy absorption via annealed steel cables has proven to be a commercial success. Gated vehicle barrier applications using this mechanism range from safely stopping runaway vehicles at railroad crossing in compliance with National Cooperative Highway Research Program (NCHRP) Report 350 to stopping a potential attacker at an industrial plant in compliance with Nuclear Regulation (NUREG) CR-6190. This paper will examine different applications of this mechanism for controlling vehicle impact, analyze the nonlinear interactions at work, and develop operating parameters for using annealed steel wire rope for these applications.

Forklift Mounted Self Dumping Hoppers

A safety device is proposed that will enable the operator of a sit-down rider forklift to discharge a self-dumping hopper while seated at the control station. Dumping proceeds without ground personnel which removes them from traffic flow and protects them from impacting loads that overspill the hopper, roll, bounce, or are accidentally discharged from the hopper. Just the right amount of rearward mast tilt is normally required to overcome the latching resistance of heavily loaded forward biased hoppers without becoming relatched when the trip lever is released. The associated trial and error balancing procedure is eliminated together with any need for muscling the latch rod. Unlatching poles are no longer used for elevated dumping.

Stochastic Theory of Human Slipping

The conventional approach to human slipping is essentially deterministic; it states that no slipping will occur when the average friction coefficient is greater than some critical friction criterion. Under this condition, pedestrians will not slip when they encounter the average friction coefficient. On the other hand, to successfully negotiate a walk of n-steps they must not slip when they encounter the smallest of the n friction coefficients. Consequently, a new slip theory has been formulated as a problem in extreme value statistics. An elegant relationship is obtained among the probability of slipping, the critical friction criterion, the number of steps taken by the walker, and the central measure, scatter, and asymmetry of the distribution of friction coefficients. The new theory reveals the structure of human slipping in a startling way that introduces completely new concepts: the go/no go nature of classical slip predictions is replaced by a probability of slipping; low friction floor/footwear couples may lead to fewer slips than high friction ones; slipping can occur in any case where conventional theory predicts “no slip”; and the number of slips depends on the distance traveled by a pedestrian. Finally, this paper develops the idea that the slipperiness of a real floor must be evaluated for a duty-cycle. Duty-cycles can be represented as frequency histograms when a floor is homogeneous and isotropic.

NIOSH AutoROPS Latch and Release Mechanism: Second Generation

Approximately 132 agricultural tractor overturn fatalities occur per year (Myers and Snyder, 1993). The use of rollover protective structures on farm tractors (ROPS), along with operator seat belt use, is the best known method for preventing these fatalities. One impediment to universal ROPS use, however, is low clearance situations, such as orchards and animal confinement buildings. To address the need for ROPS that are easily adapted to low clearance situations, the Division of Safety Research (DSR), National Institute for Occupational Safety and Health (NIOSH), developed a prototype automatically deploying, telescoping ROPS (AutoROPS). The NIOSH AutoROPS consists of two subsystems. The first is a retractable ROPS that is normally mounted to the tractor axle and latched in its lowered position for day-to-day use. The second subsystem is a sensor that monitors the operating angle and rate of roll on two axes of the tractor. If an overturn condition is detected by the sensor, the retracted ROPS will deploy and lock in the full upright position before ground contact. This paper discusses the second generation design of the latch and release mechanism (LRM) for the NIOSH AutoROPS and recommends key areas for future surveillance and design research to best facilitate reduction in farm rollover fatalities.

A Comparison of European and North American Safety Requirements for Industrial Machinery

This paper provides an introduction to various safety requirements for the design, manufacture and use of industrial machinery systems. To be successful, manufacturers must be aware of the different safety requirements that exist in North America and Europe with respect to electrical, mechanical and electromagnetic compatibility. With this knowledge, manufacturers can reduce the overall time to market and curb potential lawsuits. Users will also benefit from the safer equipment with a reduction of work-related accidents, injuries and down-time.

Use of Failure Modes Effects and Criticality Analysis to Improve Patient Safety

The Joint Commission for Accreditation of Healthcare Organizations recently approved revisions to their accreditation standards that are intended to support improvements in patient safety and reduce medical errors. Key among these is the requirement to perform a Failure Modes, Effects, and Criticality Analysis (FMECA) on one high-risk process each year and propose measures to address the most critical failures. Because FMECA was developed for other industries such as nuclear, aerospace, and chemical, some adaptation of its form and use is needed. The FMECA process is normally performed by analyzing each element of an engineered system as represented on a process flow diagram. Medical processes, in contrast, are usually defined procedurally. The key elements of a medical process are more likely to be actions than equipment and components. A community project was put together to develop and test the FMECA adaptation and had good results. This collaboration consisted of safety analysts at Pacific Northwest National Laboratory in Richland, Washington and the Quality and Performance Improvement managers of the three local hospitals. This paper describes this adaptation.

Standard Infant Crib Testing Enhanced With Live Children Shaking

An infant asphyxiated when a machine screw detached from a crib, the headboard separated from the crib rod, and the infant’s head stuck in the opening. The evaluation of infant cribs by inanimate standard test protocols is enhanced by live child crib shake testing. This live testing provides data for quantifying the horizontal push and pull forces that children actually apply to the sides of a crib. Comparisons are made between the live child shake test results and the inanimate test requirements contained in crib safety standards. Although the inanimate standard test protocols are inconsistent, the machine screw did not fail from normal use because the inanimate test requirements far exceed the maximum live results.

The Application of Probabilistic Risk Assessment to Habitable Payloads: Utilization of Risk-Based and Traditional Rule-Based Methodologies: A “First” for NASA

The safety of the public, the astronaut crew, Agency assets, other payloads, and the environment are NASA’s priorities when assessing the adequacy of space flight designs. While Probabilistic Risk Assessment (PRA) has been successfully applied to Space Shuttle and Space Station vehicle risk decision-making, the mandated use of a non-probabilistic rule-based approach is unique to the safety certification of NASA’s habitable payloads. A 1997 survey of historical safety policies with NASA’s Payload Safety Review Panel (PSRP) revealed that the non-probabilistic approach for habitable payloads was not arbitrary but founded on informed risk decisions from 20 years ago by then NASA Headquarters policy makers. Based on a sound payload safety track record, there has been no compelling reason, until recently, to consider expanding from the present NSTS 1700.7B rule-based approach to include risk-based PRA as a viable alternative. However, with the Agency’s increased focus on structured risk management, the establishment of a Risk Assessment Program at NASA Headquarters, and refined PRA guidelines and techniques, PRA is now formally recognized as an essential method for evaluating complex and high risk systems. The PSRP recognizes a growing need and an opportunity for evaluating the efficacy of risk-based PRA methods for application to increasingly complex next generation payload technologies. Therefore, it is timely to revisit the potential application of PRA to habitable payloads. This paper discusses PRA as a risk-based method that, when properly implemented, will result in equivalent or improed safety compared with the rule-based failure tolerance requirements for achieving the Agency’s “Safety First” core value. The benefits and cautions associated with infusing PRA methodology into the PSRP safety certification process are also discussed, as well as a proposed deployment strategy of how PRA might be prudently tailored and applied to habitable payloads. The use of PRA for assessing payload reliability is unrestricted at NASA but this is beyond the scope of the present discussion of payload safety applications.

Commercial Tree Chipper: The Leg Pull-In Hypothesis

This paper addresses a commercial mobile tree chipper with a mechanical infeed system that is manually fed. The purpose of this paper is to show that tree branches and brush presented to a disc chipper through the infeed hopper will not pull an erectly standing operator’s leg off the ground and into the feed wheels given the conditions set forth in this test program. In order for an erectly standing operator’s leg to contact the feed wheels, it is necessary for the leg to be pulled off the ground and over the bottom leading edge of the infeed hopper. Experiments demonstrate that the operator’s leg is pulled up against the lower leading edge of the infeed hopper and lodges there during pull-in scenarios using a winch, cable, and rope attached to the operator’s ankle. Two safety devices, an infeed extension pan and a safety control bar are explored in this paper.

Critique: Drain Cover Standard ASME/ANSI - A112.19.8M-1987 (1996) Case Study — Steering Wheel

The current ASME/ANSI standard for pool/spa drain covers is relied upon as an effective guideline for drain system safety by pool industry practitioners, state building code commissions, the Consumer Product Safety Commission, the National Spa and Pool Institute, and a myriad of pool safety sophisticates. In fact, it is a license to kill. To demonstrate its shortcomings in the dawn of its next revision, an ordinary steering wheel is shown to satisfy the current standard while exposing bathers to every known fatal drain cover scenario. The paper raises a new issue: ASME, ANSI and pool professionals may all be in legal jeopardy.