The failure of an elastomeric resistance band used in performing physical exercises can often result in human injury. This paper investigates the cause(s) of failure and attempts to identify designs, materials, and manufacturing methods that can prevent failures in elastomeric resistance bands. This paper discusses three separate failure analysis case studies involving elastomeric resistance bands to identify failure modes. It also provides evaluation of six different elastomeric resistance bands to identify design, manufacturing, and material characteristics that are important in prevention of elastomeric resistance band failures.

Accident reconstruction involving consumer products and industrial equipment often requires biomechanical and/or human factors analyses to help determine the root cause of an accident scenario. A systematic method has been established which incorporates numerous components of the sciences of biomechanics and human factors and uses the scientific method as the framework for evaluating competing theories. Using this method, available data are gathered pertaining to the accident or incident and organized in a modified Haddon matrix, with categories for Man [person(s) involved in the accident], Product/Machine, and Environment. Information about the person(s) is separated further into injury and human factors components. The injuries are viewed as physical evidence, where each injury occurred as a result of being exposed to a specific combination of energy, force, motion/deflection, acceleration, etc. The injuries are evaluated with known injury research and categorized with a specific type, location, mechanism, and injury threshold. This injury evidence is then reconciled with the other physical evidence developed from the accident environment and product/machine categories. Human factors evaluations of body size, posture, capabilities, sensory perception, reaction time, and movements create similar information that is also reconciled with the rest of the evidence from an accidental circumstance. At the core of this method is developing scientific data or information that can be used to support or refute accident reconstruction conclusions. An accurate and complete accident reconstruction using the available data must be consistent with the laws of physics, and the physics of interaction between the man, product/machine, and environment.

Child drownings continue to be problematic in aboveground and portable pools. Attempts to address the hazard posed by child access to aboveground pools through on-product warnings and instruction manuals have not been effective in stemming the incidence of drowning. Utilizing the safety hierarchy to implement other higher-level risk reduction methods (such as making pool ladders child-resistant) has the potential to greatly reduce this risk. Preliminary research studied child subjects to determine their ability to access a pool using various aboveground pool ladder designs, each of which contained varying levels of child resistance and active versus passive safety devices. This effort has significant implications for the incorporation of child resistance principles into the design of consumer products intended for children under supervision.

A safety engineering accident investigation was conducted to analyze the circumstances surrounding an unwitnessed household child fatality allegedly associated with a cookingrange tipover. An accident reconstruction utilizing child dummies was performed to address various cooking-range tipover scenarios. Unlike previous research, the present test program uses a novel approach with an actual cooking range to evaluate child interaction during a tipover scenario. Results of the accident reconstruction case study indicate that the child's death is inconsistent with a cooking-range tipover event. The results presented in this paper make a significant contribution to the technical literature concerning the safety analysis of cooking-range tipover events involving children through the utilization of child dummies. Caution should be used to generalize the results presented in this case study to the entire population, because any similar future situation must be analyzed on a case-by-case basis.

Human Factors and Ergonomics (HF/E) research, projects, expert witness cases, and product designs that target children and their caretakers require a unique set of knowledge and skills. Panelists will describe some of their professional child-focused practices and explain how their education and experiential backgrounds prepared them for this work. In cases where traditional HF/E training was not sufficient, panelists will describe how they met this challenge. The discussion between panelists and attendees will focus on suggestions for preparing HF/E professionals for working with this target market.

This paper addresses the ability of a human worker to activate safety devices to stop and reverse the mechanical infeed system inside a commercial tree chipper infeed hopper. Studies were performed using a tray equipped commercial tree chipper incorporating a safety control bar and safety cables to stop and reverse the mechanical infeed system. The test results indicate that the human test subject was able to successfully activate the safety control bar and the safety cables from a variety of body positions around and within the tree chipper infeed hopper.

The present study describes the failure analysis and accident reconstruction of a brush chipper, whereby an initial impact from the rotating disk with the chipper's hinged hood precipitated a chain of events that culminated with the ejection of the hood from the chipper. This analysis specifically addresses whether or not the welds and/or four additional (aftermarket) retaining bolts would have been sufficient to contain the energy from the disk strike, thus prohibiting the hood from departing the machine and striking the operator.

A 23 month old child sustained a severe head injury when a crib tent inverted and collapsed, lodging the child’s head against the top rail of the crib. A testing program was conducted using anthropomorphic child dummies to analyze the inversion danger during a crib tent collapse event. The primary goal of this investigation is to make crib tent designers, retailers, and users more aware of the inversion danger and to identify a design alternative to help reduce the number of these types of injuries.

A three year old boy fell through a third floor apartment window resulting in fatality. An accident reconstruction was performed using live surrogate children under static and dynamic loading conditions. The failure modes and physical characteristics of tested window screens are presented. Accident prevention strategies are explored.

This paper addresses the eye impact hazard associated with a jacket elastic drawstring toggle which temporarily catches on an object and then releases. Approaches utilized in this safety analysis include an accident statistics survey, literature review, risk-utility analysis, and evaluation of alternative jacket drawstring technology. A variety of drawstring design alternatives are explored for accident prevention while achieving jacket function and aesthetic goals.

This paper addresses the safe use of lifting slings and tie down straps in the field. From time to time, web straps used as lift slings or tie down devices fail in service. The appearance of the failed portion of the web provides insight into the cause of the strap failure and provides physical evidence of the pre-failure condition of the strap. The safety analysis consists of a technical literature review, research of applicable safety standards and guidelines, results of testing of slings and straps to failure in a variety of initial conditions, and evaluation of the appearance of the straps after testing. The paper presents an evaluation of the effect on breaking strength of the web or sling of various intentionally-applied cuts to the material, and an appraisal of the post-test appearance as it relates to the pre-test condition. Furthermore, comparisons using macroscopic and microscopic techniques are made of the failed surfaces of the tested slings and straps to products that are known to have failed during field applications. The results presented in this paper make a significant contribution to the technical literature concerning the safety and failure prevention of industrial sling and strap products.

A three year old boy died when a dining room chair he was sitting on fell backward, triggering bleeding along his spinal cord. Approaches utilized in the danger analysis include: accident reconstruction, safety literature review, safety standards research and testing, accident statistics survey, and evaluation of alternative dinette chair designs. The primary goal of this investigation is to make dinette chair designers, retailers, and users more aware of the tip over danger and to identify design alternatives to help reduce the number of these types of injuries.

An 18 month old boy died when he became entrapped in a gap formed between the bottom of a trampoline net safety enclosure and the top of the trampoline structure. Accident statistics survey, safety literature review, standards research, and alternative trampoline safety enclosure design evaluation are approaches utilized in the safety engineering analysis. The primary goal of this investigation is to make trampoline enclosure designers, retailers, customer service providers, and users more aware of the entrapment and strangulation dangers and to identify design alternatives to prevent similar injuries from occurring.

A tragic accident occurred when a seven year old child was struck in the eye with a metal barb tip on an elastic lanyard which released from a plastic name badge worn around the child's neck. The safety hierarchy would suggest that attempting to eliminate the elastic lanyard impact danger through design is the first priority. Non-elastic lanyards and safety breakaway lanyards are explored as design alternatives for accident prevention.

A tragic accident occurred in a day care center when a 5 year old child fell face down with a plastic toy asparagus spear in his mouth, puncturing the soft palate and dissecting the internal carotid artery. Approaches utilized in the risk analysis include: literature review, safety standards research, accident statistics survey, biomechanical testing, and evaluation of alternative toy asparagus designs. The goal of this investigation is to make toy designers and users more aware of the puncture/impaling hazard and to identify design alternatives to prevent similar injuries from occurring.

A 10 month old boy sustained burn injuries from contact with the inside of a hot consumer gas range lower broiler door. A unique human factors test program was conducted with live children to determine if they could open alternative lower broiler door designs. Safety and functional analyses of alternative broiler door designs are also performed. Finally, techniques for supervising young children around ovens are explored in this paper.

The suffocation of infants caused by crib sheet entanglement appears to be a nonproblem which has nevertheless resulted in a brouhaha that has incited remediation activities by the Good Housekeeping Institute (GHI), American Society for Testing and Materials (ASTM), Consumer Product Safety Commission (CPSC), Juvenile Products Manufacturers Association (JPMA), crib sheet manufacturers, and product liability support professionals of different stripes. To show that the removal of crib sheets by infants is not a safety issue, one may establish that the problem is not reasonably foreseeable. Three approaches for doing this are described in this paper: anecdotal, simulation, and reliability. The reliability of a crib sheet is the probability that it will remain in situ when exposed to the community of infants. Application of the classical “load minus strength” analysis required new information on the pull strength of infants.

Ancient Egyptians allegedly moved large stone blocks by placing cylindrical rollers beneath them and manually urging them along. This rolling procedure required that the rollers emerging from the rear of the stone be manually lifted and replaced in front. This roller replacement protocol has been automated in commercially available roller units that allow continuous movement of heavy machinery under the action of pry bars, come-a-longs, winches, or manual push efforts. Unfortunately, when slopes or asperities are encountered these heavy loads may accelerate uncontrollably or steer themselves in unsafe directions when the roller units become reoriented. This paper describes two inventions that cause the locomotion of the machinery to proceed in inchmeal fashion by intermittently braking the system while the roller units are manually reset.

Most of the technical works of humankind are designed without the guidance of safety codes and standards. Specific safety standards are generally developed when contrivances give rise to numerous accidents and liability actions. The salient features of such standards are briefly outlined in this article.