Extension Ladder Research Articles

Effects of extension ladder fly configuration on climbing safety

Fall injuries often occur on extension ladders. The extendable fly section of an extension ladder is typically closer to the user than the base section, though this design is minimally justified. This study investigates the effects of reversing the fly on foot placement, frictional requirements, adverse stepping events (repositioning the foot or kicking the rung), and user preferences. Participant foot placement was farther posterior (rung contacted nearer to toes) in the traditional ladder compared to the reversed fly condition during descent, with farther anterior foot placements during ascent. The reversed configuration had similar friction requirements during early/mid stance and significantly lower frictional requirements during late stance. Increased friction requirements during late stance were associated with farther anterior foot placement and further plantar flexed foot orientation. The reversed fly had 5 adverse stepping events versus 22 that occurred in the traditional configuration. Users typically preferred the reversed fly. These results suggest that a reversed extension ladder configuration offers potential benefits in reducing fall-related injuries that should motivate future research and development work.

Design and production of a tiltable extension ladder on a trolley for engineering workshop and warehouse

There are always needs to carry loads of many forms in workshops and warehouses in industries to different heights. which makes conventional ladder not suitable. A tiltable extension ladder on a trolley satisfies this requirement and above all possess the compactness of its kind. The tiltable extension ladder on a trolley was designed using the principle of a beam fixed at both ends with a point load acting at the centre of the beam, The system has two major parts, the trolley and tiltable extension ladder. The designed load was 150kg. The machine was produced and put to use with acceptable machine performance.

Расчётная оценка достаточности сил и средств для спасения людей при пожаре

PURPOSE. The process of rescuing people in case of a fire from buildings is hampered by the fact that the only escape routes are staircases, where the chance to run the risk of exposure to fire hazardous factors increases every second. Evacuation from high-rise buildings is limited by the insufficient number of elevators available, which, as the experience of fires in various countries shows, soon after the fire fail. Moreover, firefighters face additional challenges in the form of various adjacent buildings, the presence of vehicles in the parking lot for fire appliances, a lot of electrical equipment and wires near buildings. The authors analyzed the requirements of fire safety, methods and techniques for saving people in case of a fire in a building and revealed problem areas: 1) requirements for saving people do not take into account derived estimates; 2) derived estimates do not take into consideration technical characteristics of turntable ladders (TL) and extension ladders (EL), that affect the time of rescuing people. Considering the fact that the use of derived estimates on requirements effectiveness and organization of fire departments management on rescuing people in case of a fire in a building is impossible in the operational mode, information support was developed to assess rescuing people in case of a fire in a building, taking into account the technical characteristics of TL and EL. METHODS. To solve the set tasks the expert method, system analysis method, control theory and decision-making were used. FINDINGS. The presented information and analytical support will make it possible to assess sufficiency of fire departments means and forces to rescue people from a building using TL, EL. RESEARCH APPLICATION FIELD. Specialists of State Fire Service can apply the derived estimates of rescuing people from a building in case of a fire using TL and EL; heads of enterprises, organizations, as well as persons who legally own, manage or use real estate, property. The latter, including tenants responsible for compliance with the fire regime in premises, buildings rented by them for a certain period according to agreements. CONCLUSIONS. For assessing operational and safe rescuing people in case of a fire in a building, the method for using technical means to rescue people from a building using TL and EL.

Our Proud Past Is Prologue

Our Proud Past Is Prologue

Modeling and Simulation of Heavy-Lift Tethered Multicopter Considering Mechanical Properties of Electric Power Cable

In case of a fire at a high-rise building which is densely populated, an extension ladder is used to rescue people who have yet to evacuate to a safe place away from the fire, whereas those who are stranded at a height that is unreachable with the ladder should be promptly saved with different rescue methods. In this case, an application of the tethered flight system capable of receiving power over a power cable from the ground to a multicopter may guarantee effective execution of the rescue plan at the scene where fire is raging without any restrictions of the flight time. This article identified restrictions that should be considered in the design of a multicopter capable of tethered flight aimed to rescue stranded people at an inaccessible location with an extension ladder at a fire-ravaged high-rise building and assessed its feasibility. A power cable capable of providing dozens of kilowatts of electricity should be installed to enable the implementation of the rescue mission using the tethered multicopter. A flexible multi-body dynamics modeling and simulation with viscoelastic characteristics and heavy weight of power cable were carried out to evaluate the effects of such cable of the tethered flight system on the dynamic characteristics of the multicopter. The results indicate that as for a heavy-lift tethered multicopter designed to be utilized for rescue operations, the properties of the power cable, such as weight, rigidity and length, have a major impact on the position and attitude control performance.

Technical safety measures when performing works at heights on the stairs

Works at heights are a hazardous activity. The most common in industrial and economic activities works at heights are carried out on the stairs. Injury statistics in the Russian Federation indicate that when performing work at heights, the proportion of injuries is about 25 percent of their total number. A large number of injuries are recorded in everyday life from falling when performing work at heights from the stairs. Falling down the stairs is the second leading cause of industrial accidents in the US construction industry. A significant part of these incidents occurs at the construction sites and during operation when using extension ladders. Injuries from falling down the height, including down a ladder, are usually severe. About 70% of injuries are with serious consequences. When working with portable ladders, the most common cause of falls and injuries is the stairs’ sliding. The article presents the engineering solutions aimed at eliminating the sliding of the upper part of the stairs during works on the support. An assessment of these engineering solutions for various options for their application volumes has been performed.

Structure and Mechanical Properties of Aluminium Alloy Sampled from a Firefighter Ladder

Firefighter ladders are manufactured of aluminium alloy AA 6063. These ladders are a widely used technical tool for firefighting, for intervening and for rescued persons. The quality of the ladders is checked by so-called user which is a non-destructive deflection test defined by CSN EN 1147. Unfortunately, this test is not sufficiently conclusive in terms of safety. Therefore, the project called Safety improvement of extension ladders for firefighters (VI20162020021) is focused on the complex assessment of the existing firefighter ladders through mathematical modelling, material analysis and real testing. In the present work structure and mechanical properties of samples (aluminium alloy AA 6063) taken from different areas of a firefighter ladder are presented. The obtained result confirm excellent mechanical properties of selected samples, such as tensile yield strength and ultimate tensile strength, at laboratory temperature but a huge decrease in these properties after exposure to temperatures above 200 °C for even short times. This results in the necessity to control temperatures in the proximity of the ladder, especially in the case when the ladder is located near a flame.

Evaluation of a “walk-through” ladder top design during ladder-roof transitioning tasks

This study evaluated the effect of an extension ladder “walk-through” top design on kinetic and kinematic behaviors and the outward destabilizing forces induced on the ladder during transitioning at elevation. Thirty-two male participants performed stepping tasks between a ladder top and a roof at simulated elevation in a surround-screen virtual-reality system. The experimental conditions included a “walk-through” and a standard ladder top section supported on flat and sloped roof surfaces. Three force platforms were placed under the ladder section and in the roof to measure propulsion forces during transitions. A motion measurement system was used to record trunk kinematics. The frictional demand at the virtual ladder base was also calculated. The results indicate that under optimal ladder setup (angle 75.5 °), the frictional demand at the ladder base remains relatively small for all experimental conditions. Also, the “walk through” ladder top eased the ladder-to-roof transitions but not the roof-to-ladder transitions.

The Angle of Inclination of Extension Ladders

For extension ladders and other non-self supporting ladders, setting the angle of inclination of the ladder is a critical step in the set up process. The angle of the ladder influences: 1) the potential for a ladder to slide out at the base, 2) the overall strength of the system, and 3) the biomechanics of the climber/user on the ladder. A field study was conducted where over 120 real world ladder installations were documented, including angle of inclination, site conditions, and use. The average angle of inclination in the field study was 67.7 ± 4.9 degrees. Research was further conducted to assess the effectiveness of existing ladder labels for setting the ladder at the instructed 75.5 degree angle of inclination. 45 participants set up extension ladders following the “anthropometric” label (appendices of current ANSI A14 ladder safety standards), and/or the backward “L” label (historic ANSI A14 label). The average set up angle for the “anthropometric” label was 74.1 ± 3.2 degrees. This is consistent with calculations of the expected angle of inclination using anthropometric data. The calculated angles ranged from 74.9 to 75.2 degrees. The average angle of inclination for the backward “L” label was 72.7 ± 2.7 degrees. These results indicate that the current “anthropometric” label resulted in a set up angle consistent with anthropometric calculations and significantly higher than documented in real world ladder use.

The effect of instructions on potential slide-out failures during portable extension ladder angular positioning

Accidents involving portable ladders are a common cause of serious occupational and non-occupational injuries throughout the industrialized world. Many of these injuries could be prevented with better instruction on the proper usage of portable ladders. Research is reported that focused on both the human factors and engineering aspects of portable extension ladder usage based on common ladder setup procedures. Results of the human factors experiment revealed evidence of unsafe acts that could lead to catastrophic ladder slide-out accidents in real-life situations. Six different ladder setup methods were evaluated for safety and stability based on placement angles: the basic, 75 degree, stand–reach, L sticker, 4:1, and bubble level methods. Ideally, ladder users would set the ladder up at 75.5 degrees to achieve the consensus industry standard safest angle. Setup methods varied in complexity and nature of instruction. The level method produced the most accurate and the least variable results. The engineering analysis determined the coefficient of friction of a variety of clean and contaminated surfaces commonly used with ladders. This analysis determined the total number of slide-out failures that would likely have occurred in the data obtained in each of the ladder setup methods tested in the human factors experiment. Based on test participants’ setup angles, the average calculated ladder slide-out failure rate was 8.7 percent for ladders positioned on a surface with the lowest measured coefficient of friction. When broken down by ladder setup method, the 4:1 method had a failure rate of 18.8 percent, the 75 degree method had a failure rate of 15.2 percent, and the basic method had a failure rate of 9.8 percent. The stand–reach and L sticker methods had identical failure rates at 3.3 percent and the level method was best at 1.1 percent. The level method provided the lowest error, least variability, and setup closest to the target angle of 75.5 degrees. Analysis of the overall results revealed the need for additional user training and clearer instructions affixed to ladders. This research is unique in that it combines an analysis and comparison of human factors and engineering in the same study.

Research to improve extension ladder angular positioning

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. The objective of the study was to comparatively evaluate the effectiveness of a multimodal angle indicator with other existing methods for extension ladder angular positioning.Twenty experienced and 20 inexperienced ladder users participated in the study. Four ladder positioning methods were tested in a controlled laboratory environment with 4.88 m (16 ft) and 7.32 m (24 ft) ladders in extended and retracted positions. The positioning methods included a no-instruction method, the current standard anthropometric method, and two instrumental methods – a bubble level indicator, and a multimodal indicator providing direct feedback with visual and sound signals. Performance measures included positioning angle and time.The results indicated that the anthropometric method was effective in improving the extension ladder positioning angle (p < 0.001); however, it was associated with considerable variability and required 50% more time than no-instruction. The bubble level indicator was an accurate positioning method (with very low variability), but required more than double the time of the no-instruction method (p < 0.001). The multimodal indicator improved the ladder angle setting as compared to the no-instruction and anthropometry methods (p < 0.001) and required the least time for ladder positioning among the tested methods (p < 0.001).An indicator with direct multimodal feedback is a viable approach for quick and accurate ladder positioning. The main advantage of the new multimodal method is that it provides continuous feedback on the angle of the device and hence does not require repositioning of the ladder. Furthermore, this indicator can be a valuable tool for training ladder users to correctly apply the current ANSI A14 standard anthropometric method in ladder angular positioning.The multimodal indicator concept has been further developed to become a hand-held tool in the form of a smart phone application.

Bailey at the Museum (review)

Reviewed by: Bailey at the Museum Elizabeth Bush Bliss, Harry . Bailey at the Museum; written and illus. by Harry Bliss. Scholastic, 2012. [32p]. ISBN 978-0-545-23345-3 $16.99 Reviewed from galleys R 3-7 yrs. Bailey, the confident pooch whose grade-school matriculation was chronicled in Bailey, now joins his class on a field trip to the natural history museum. After ditching his designated buddy to splash in the fountain at the main door, Bailey quickly recovers his school manners and rejoins the group as they're greeted by the stodgy docent. Some displays are a little disappointing, but the T. rex bones are everything a dog could desire, and Bailey is up the display in a shot, gnawing on a tailbone. The guard who retrieves Bailey takes a shine to the pooch, and soon guard and dog are sharing lunch and even getting briefly lost together. While the youngest listeners can easily follow Bailey's Curious George-style exploits via the narration line that runs along the top of most spreads, older children and adults recruited for readaloud duty will appreciate the goofy little gems hidden in plain sight: the "Do not dance" caution label on the extension ladder; the author's name "Author" on all reading matter, the "Almost Organic Soy Stuff " on the milk carton; the Greek urn decorated with the stylized dog chasing a squirrel. Less cerebral, perhaps, than his similarly thick-snouted, flop-eared literary cousin Snoopy, Bailey boasts the same pettable charm and the same tendency to share only his thoughts, never his words. Bailey and his long-suffering cartoon classmates will have firmly secured a fan base with this outing. Copyright © 2012 The Board of Trustees of the University of Illinois

Factors Affecting Extension Ladder Angular Positioning

The study objectives were to identify factors affecting extension ladders' angular positioning and evaluate the effectiveness of two anthropometric positioning methods. 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. 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. 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. 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. The results provide practical insights for employers and workers to correctly set up extension ladders.

Ultrafast, efficient separations of large‐sized dsDNA in a blended polymer matrix by microfluidic chip electrophoresis: A design of experiments approach

Double-stranded (ds) DNA fragments over a wide size range were successfully separated in blended polymer matrices by microfluidic chip electrophoresis. Novel blended polymer matrices composed of two types of polymers with three different molar masses were developed to provide improved separations of large dsDNA without negatively impacting the separation of small dsDNA. Hydroxyethyl celluloses with average molar masses of ∼27 kDa and ∼1 MDa were blended with a second class of polymer, high-molar mass (∼7 MDa) linear polyacrylamide. Fast and highly efficient separations of commercially available DNA ladders were achieved on a borosilicate glass microchip. A distinct separation of a 1-kb DNA extension ladder (200-40,000 bp) was completed in 2 min. An orthogonal design of experiments was used to optimize experimental parameters for DNA separations over a wide size range. We find that the two dominant factors are the applied electric field strength and the inclusion of a high concentration of low-molar mass polymer in the matrix solution. These two factors exerted different effects on the separations of small dsDNA fragments below 1 kbp, medium dsDNA fragments between 1 and 10 kbp, and large dsDNA fragments above 10 kbp.

Work-related falls from ladders – a follow-back study of US emergency department cases

Ladder falls comprise 16% of all US workplace fall-related fatalities, and ladder use may be particularly hazardous among older workers. This follow-back study of injured workers from a nationally representative sample of US emergency departments (ED) focused on factors related to ladder falls in three domains of the work environment: work equipment, work practices, and worker-related factors. Risk factors for fractures, the most frequent and severe outcome, were also evaluated. Workers injured from a ladder fall, treated in one of the 65 participating ED in the occupational National Electronic Injury Surveillance System (NEISS) were asked to participate. The questionnaire included worker demographics, injury, ladder and work equipment and environment characteristics, work tasks, and activities. Multivariate logistic regression models estimated odds ratios and 95% confidence intervals of a work-related fracture. Three-hundred and six workers experiencing an injury from an--on average--7.5-foot-fall from a step, extension, or straight ladder were interviewed primarily from construction, installation, maintenance, and repair professions. Injuries were most frequently to the arm, elbow or shoulder; head, neck, or face with diagnoses were primarily fracture, strain, sprain, contusion or abrasion. Workers were most frequently standing or sitting on the ladder while installing, hanging an item, or performing a repair when they fell. Ladder movement was the mechanism in 40% of falls. Environmental conditions played a role in <10% of cases. There was a significant association between fracture risk and fall height while working on the ladder that was also influenced by older work age. This study advances knowledge of falls from ladders to support those who specify means and methods, select equipment, and plan, supervise, or manage the performance of employees working at heights.

Functionalized Templates for the Convergent Assembly of Polyethers: Synthesis of the HIJK Rings of Gymnocin A

Extension ladder: The successful application of epoxide-opening strategies towards the synthesis of ladder-type polyethers is contingent upon further elaboration of the product. By employing two different functionalized templates, a fragment of gymnocin A that bears four sites for subsequent fragment coupling has been prepared (see scheme; Bn = benzyl).

Portable ladder assessment tool development and validation – Quantifying best practices in the field

Many causes for falls from ladders in construction are related to the user’s activities; however, the extent to which users comply with ladder use best practices is unknown and has not been well quantified before. We developed and tested an audit tool that assesses compliance with best practices guidelines for portable-ladder-use designed for applications in the construction industry. Implemented on a hand-held computer, the assessment tool consisted of a series of check-lists categorized in four groups; ladder condition, setup, moving on a ladder, and completing tasks from a ladder. For these four observational categories, the resulting tool contained 31 and 33 questions for step and extension ladders, respectively. Three individuals trained to use the tool scored a set of photographs and videos depicting 25 ladder conditions, 20 ladder setups, 10 users moving on ladders, and 13 users completing tasks from a ladder for a total of 78 observations. The assessment tool had good agreement across and within raters. For the three raters, agreement ranged from 79% to 97% across the questions. Within one subject, kappa coefficients for the intra-rater reliability ranged from 0.67 to 0.91. The tool offers a practical method to quantify best practices associated with ladder use that can ultimately inform targeted intervention efforts.

Extension-ladder safety: Solutions and knowledge gaps

Abstract Falls from ladders are the second leading cause for work-related fatalities in the US construction industry. A significant portion of these incidents occurs at building-construction-and-maintenance worksites during the use of extension ladders. This paper presents the results of a critical literature review related to: (1) risk factors associated with falls from extension ladders, (2) practical engineering solutions that may reduce fall-from-extension-ladder incidents, and (3) questions pertaining to ladder safety that remain unanswered. The review results show that the underlying causes of falls involving extension ladders include the ladder-base slipping out, ladders tipping, workers slipping while on ladders or transitioning from a ladder to a surface at height, and mechanical failures. Some engineering control measures are available in the literature; yet, significant knowledge gaps remain. The knowledge-gap analysis identified four actions needed to advance ladder-safety practice: (1) research on visual indicators to assist in setting up ladders at the correct angle, (2) developing and evaluating measures to ease the transition from a ladder to a surface at heights, (3) integrating ladder accessories into a convertible design to ease the carrying, assembling, and storing of multiple accessories, and thus to encourage safe practices, and (4) developing a graphic-oriented practical guide for safe ladder use, maintenance, and mechanical-flaw detection. Relevance to industry This paper identified knowledge gaps associated with extension-ladder use for advancing ladder-safety interventions. The development and evaluation of ladder-safety innovations will provide the necessary feedback to ladder manufacturers and ladder-standard-setting bodies for design enhancement and will provide workers practical solutions to reduce injury risks associated with extension-ladder use.

The Role of Public Education in Reducing Ladder-Related Morbidity and Mortality

4 he article in this issue of the American Journal of Preventive Medicine by D’Souza et al.1 addressing ladder-related injuries treated in U.S. emerency departments sheds light on a leading cause of all-related morbidity and mortality. Data from the U.S. onsumer Product Safety Commission’s National Elecronic Injury Surveillance System (NEISS) are seldom ined as thoroughly as these authors have managed. mong the key findings of this manuscript are that opulations at disproportionate risk to ladder-related njuries are male and early middle-aged. The most ommon type of injury is a fracture, and the legs and eet are the most common body parts injured. The ospital admission rate of ladder-related falls is twice hat of consumer product–related injuries overall. Given the prevalence and high severity of ladderelated injuries, more public education campaigns are arranted to advise ladder users as to the proper lacement, use, type, and behaviors. Yet relatively little s known about the circumstances of ladder-related falls nd users’ knowledge, attitudes, and behaviors conerning ladder safety. To help reduce the 180,000 adder injuries and 150 deaths that are reported on verage each year,2 the Home Safety Council (HSC), erner Ladder, and WestCo conducted public opinion esearch to help target their public education efforts. Adults fear falling from tall ladders. According to an mnibus Internet study of 1000 adults, climbing 25 feet igh on an extension ladder causes more anxiety than utting with a sharp knife, using a chainsaw, working ith electricity, public speaking, asking for a raise, alking to children about human sexuality, or getting ulled over by the police.3 One in three adults admits o having fallen or lost their balance on an extension adder. Perhaps home improvement stores might conider hosting ladder safety seminars to allow consumers o practice climbing up and down their extension adders.

Workload of window cleaners using ladders differing in rung separation

The objective of the present study was to compare energetic workload, perceived exertion, perceived discomfort, safety, and mechanical load at lower limb joints among window cleaners during usage of extension ladders with 30 and 35 cm rung separation. Eleven healthy male professional window cleaners of short and tall stature participated in this study. No significant differences between 30 and 35 cm rung separation were observed for the energetic workload. Results concerning the perceived exertion, discomfort, and safety indicate that 35 cm rung separation is preferred. Based on the mechanical load at the hip, knee, and ankle during ascending and descending the ladder, 30 cm rung separation is preferable to 35 cm rung separation. It is advised to climb ladders with the knees inside the side rails of the ladder, but this seems only possible with 35 cm rung separation. Findings of the presents study suggest that overall, a 35 cm rung separation is marginally favourable while using extension ladders.