Locking of Retractable Type Fall Arresters—Test Method and Stand

Retractable type fall arresters are very effective personal equipment protecting against falls from a height. These devices are used under different atmospheric conditions and in the presence of various types of industrial pollution. For this reason appropriate locking after conditioning simulating extreme conditions of a worksite is one of the essential characteristics of retractable type fall arresters. This article presents the requirements for locking of the devices. A previously used locking test method and its disadvantages are discussed. The article suggests an improved test method and test equipment. Measurement of the test mass acceleration is the most important improvement introduced into the test method. The article shows laboratory tests used to verify the method, which turned out to be a valuable source of information concerning the performance of retractable type fall arresters.     

The Influence of Anchor Devices on the Performance of Retractable Type Fall Arresters Protecting Against Falls From a Height

Retractable type fall arresters are part of the equipment used for protecting people against falls from a height. They are an intermediate part between full body harness worn by a man and the structural anchor at the worksite. The most important task of retractable type fall arresters is to arrest people’s falls and to reduce their harmful consequences. Information received from users as well as laboratories testing protective equipment indicates that the performance of such equipment is incorrect under specific conditions. The paper is concerned with an analysis of the conditions in which retractable type fall arresters demonstrate intermittent performance and with an explanation of that phenomenon. The results of tests investigating anchor devices and the performance of retractable type fall arresters are presented. External and internal factors contributing to intermittent performance have been determined and guidelines for safer use of these devices have been developed.     

Locking of retractable type fall arresters--test method and stand.

Retractable type fall arresters are very effective personal equipment protecting against falls from a height. These devices are used under different atmospheric conditions and in the presence of various types of industrial pollution. For this reason appropriate locking after conditioning simulating extreme conditions of a worksite is one of the essential characteristics of retractable type fall arresters. This article presents the requirements for locking of the devices. A previously used locking test method and its disadvantages are discussed. The article suggests an improved test method and test equipment. Measurement of the test mass acceleration is the most important improvement introduced into the test method. The article shows laboratory tests used to verify the method, which turned out to be a valuable source of information concerning the performance of retractable type fall arresters.     

The influence of anchor devices on the performance of retractable type fall arresters protecting against falls from a height.

Retractable type fall arresters are part of the equipment used for protecting people against falls from a height. They are an intermediate part between full body harness worn by a man and the structural anchor at the worksite. The most important task of retractable type fall arresters is to arrest people's falls and to reduce their harmful consequences. Information received from users as well as laboratories testing protective equipment indicates that the performance of such equipment is incorrect under specific conditions. The paper is concerned with an analysis of the conditions in which retractable type fall arresters demonstrate intermittent performance and with an explanation of that phenomenon. The results of tests investigating anchor devices and the performance of retractable type fall arresters are presented. External and internal factors contributing to intermittent performance have been determined and guidelines for safer use of these devices have been developed.     

速差自控器动态性能试验方法的改进

为施工人员选择和配置安全可靠的个人防坠器,每年送到具有相应资质的检测单位进行强制检定,是防止高处坠落事故的重要手段。某型速差自控器在冲击试验中发生了钢丝绳断裂事故,为了查找和分析事故的真正原因,对不同厂家的速差自控器抽样,在相同试验方法和检测条件下进行冲击试验,并根据相关的标准对试验结果进行力学性能对比分析研究,找到了造成钢丝绳断裂事故的主要原因是该类型速差自控器使用的钢丝绳直径偏细以及缺少内部或外部缓冲器,研究中还发现部分国内标准技术要求不够明确,制造、检测和使用方对速差自控器相关标准理解存在偏差,是造成本次事故的间接原因。针对现有的部分速差自控器产品存在的质量问题,并根据现行最新标准和实际工作条件,提出改进了的检测方法和防范措施,从源头上防范坠落事故。     

Influence of weather conditions on the performance of energy absorbers and guided type fall arresters on a flexible anchorage line during fall arresting

Energy absorbers and guided type fall arresters on a flexible anchorage line belong to very popular group of equipment protecting against falls from a height. This equipment is used in different weather conditions (different temperature, humidity, precipitation, etc.), which influence its parameters. Fibre ropes and webbing, made from polyamide fibres, used in energy absorbers and guided type fall arresters, are sensitive to weather conditions. Laboratory tests proved that the changes in temperature, humidity, etc., especially influence dynamic elongation of this equipment and the force acting on anchor point during fall arresting. These phenomena decide directly about the fall arresting process and can influence safety of people working on a height.     

安全带整体静负荷试验机的研制及应用

安全带是有效地预防高处作业人员因意外坠落而受到身体伤害的必要防护装备。本文根据GB6095—2009《安全带》、GB／T6096—2009《安全带测试方法》标准中安全带整体静态负荷试验的要求,对安全带整体静负荷试验机的研制与应用开展一些调研和探讨,希望对从事安全带检验的机构和安全带生产的企业中的科研、检验人员提供一些感性的认知和帮助。     

Dynamic Performance of Horizontal Flexible Anchor Lines During Fall Arrest— A Numerical Method of Simulation

Designing fall arrest systems, which contain horizontal flexible anchor lines is an important technical problem related to the safety of people who work at a height and need horizontal freedom of movement. The article presents a numerical simulation of the dynamic performance of horizontal flexible anchor lines during fall arrest. The model of a 2-component system—a horizontal flexible anchor line and a falling rigid mass, described with a second order non-linear differential equation—is the main element of this method. This method of simulation is realised by a computer program, which allows obtaining the most important data characterising a fall arrest. The article shows laboratory tests used for the verification of this method, which turned out to be a valuable source of information and which can be used for designing fall arrest systems.     

Dynamic Strength Tests for Low Elongation Lanyards

Lanyards are still important and common components of personal systems protecting against falls from a height. Experience with dynamic strength tests of lanyards indicates that test methods based on EN and ISO standards do not make objective assessment possible. This paper presents the results of theoretical and laboratory investigations of the performance of adjustable lanyards during fall arrest. The obtained results indicate that methods of testing and assessment based on those standards demonstrate considerable shortcomings when applied to low elongation lanyards. The assumptions for improved requirements and test methods of lanyards made of e.g., steel wire and aramid ropes are also presented.     

Comparison of risk factors for falls from height between commercial and residential roofers

Introduction

The purpose of this investigation was to compare commercial roofers and residential roofers in terms of their behaviors, beliefs, working conditions, and attitudes toward the use of fall protection devices, which could lead to fall accidents.

Methods

A cross-sectional sample of 252 roofers participated in the survey in the Midwest (Wisconsin, Illinois, Michigan, Indiana, and Iowa).

Results

Residential roofers were more likely to fall (adjusted prevalence ratio = 1.57, 95% CI = 0.86, 2.27) than commercial roofers. Existence of fall protection programs, enforcement of fall protection device use, actual use of fall protection devices, work type, company size, and race/ethnicity were significantly associated with fall accidents.

Impact on industry

This study adds insight into fall accidents from roofs in the construction industry and provides industry-specific cautions against fall accidents that can be reflected in regulatory agency implementation.     

可视化通风机性能测试程序设计

介绍了用通风机性能曲线测定可视化计算机程序的设计。该程序基于Windows环境，采用C Builder5．0开发，可以实现数据的自动保存、处理，及性能曲线、结果报表输出，同时具有可视化的人机界面。应用该程序可以使通风机性能曲线测定试验更加简便易行，还可以使试验结果更加精确。     

Development and validation of a method for evaluating temporary wooden guardrails built and installed on construction sites

Wooden guardrails are usually built and installed on construction sites to protect workers against falls. In this context, it is extremely difficult to verify whether they are safe and comply with existing regulations. The present study describes the development and validation of an evaluation method and a test protocol for verifying whether these wooden guardrails are safe and meet the requirements of the Québec Safety Code for the construction industry (S-2.1, r.6) in order to ensure that workers have adequate fall protection. This study shows that some wooden guardrails do not comply with S-2.1, r.6. The evaluation method and test protocol are reproducible and easily applicable on construction sites and can easily be adapted to international regulations.     

Explosions in closed pipes containing baffles and 90 degree bends

There is a general lack of information on the effects of full-bore obstacles on combustion in the literature, these obstacles are prevalent in many applications and knowledge of their effects on phenomena including burning rate, flame acceleration and DDT is important for the correct placing of explosion safety devices such as flame arresters and venting devices. In this work methane, propane, ethylene and hydrogen–air explosions were investigated in an 18 m long DN150 closed pipe with a 90 degree bend and various baffle obstacles placed at a short distance from the ignition source. After carrying out multiple experiments with the same configuration it was found that a relatively large variance existed in the measured flame speeds and overpressures, this was attributed to a stochastic element in how flames evolved and also how they caused and interacted with turbulence to produce flame acceleration. This led to several experiments being carried out for one configuration in order to obtain a meaningful average. It was shown that a 90 degree bend in a long tube had the ability to enhance flame speeds and overpressures, and shorten the run-up distance to DDT to a varying degree for a number of gases. In terms of the qualitative effects on these parameters they were comparable to baffle type obstacles with a blockage ratios of between 10 and 20%.     

Dynamic strength tests for low elongation lanyards.

Lanyards are still important and common components of personal systems protecting against falls from a height. Experience with dynamic strength tests of lanyards indicates that test methods based on EN and ISO standards do not make objective assessment possible. This paper presents the results of theoretical and laboratory investigations of the performance of adjustable lanyards during fall arrest. The obtained results indicate that methods of testing and assessment based on those standards demonstrate considerable shortcomings when applied to low elongation lanyards. The assumptions for improved requirements and test methods of lanyards made of, e.g., steel wire and aramid ropes are also presented.     

A Study of Annoyance Caused by Low-Frequency Noise During Mental Work

This article presents the results of an analysis of annoyance caused by low-frequency noise (including infrasonic noise) that occurs at work stations located in offices. The tests covered measurements of acoustic parameters specific for this type of noise and a survey conducted in the working environment and in laboratory conditions at a model of a work station.     

A study of annoyance caused by low-frequency noise during mental work.

This article presents the results of an analysis of annoyance caused by low-frequency noise (including infrasonic noise) that occurs at work stations located in offices. The tests covered measurements of acoustic parameters specific for this type of noise and a survey conducted in the working environment and in laboratory conditions at a model of a work station.     

Protecting atmospheric storage tanks against vacuum collapse

Vacuum collapse causes many accidents involving equipment with low pressure ratings such as atmospheric storage tanks and bins. This paper presents methods to establish the appropriate relief capacities and specify pressure relief devices to protect atmospheric storage tanks and other similar equipment against this hazard. Calculations are based on simple heat balance and fluid flow calculations.     

Ensuring Cleanliness in Operating Theatres

High cleanliness of a hospital environment is necessary to ensure safe working conditions for the medical staff, a correct process of hospitalization and to protect hospital visitors, an aspect rarely mentioned. A supply of air cleaned in highly-effective air filters to hospital wards with air conditioning systems and exhaust of infected air will help in maintaining the required standards of cleanliness. This article presents information on recommended classes of air and surface cleanliness, with special focus on operating theatres and suites.     

Health risk assessment of occupational exposure to a magnetic field from magnetic resonance imaging devices.

Health care staff who operate magnetic resonance imaging (MRI) devices are exposed to a static magnetic field of significant spatial heterogenity always produced by MRI magnets during the whole shift. They can also be exposed to pulses of a time-varying magnetic field (gradient field) present only during patients' examinations. The level of the workers' exposure depends both on the type of the magnet and on the ergonomic design of each MRI device. The paper presents methods used for measuring and assessing workers' exposure. It also discusses the results of inspection measurements carried out next to approximately 20 MRI devices of approximately 0.2-2.0 T. The presented characteristic and overview of the variability of workers' exposure to a variety of MRI devices supports the need for data on monitoring occupational exposure to MRI. International exposure assessment standards and guidelines (International Commission on Non-Ionizing Radiation Protection [ICNIRP], Institute of Electrical and Electronics Engineers [IEEE], American Conference of Governmental and Industrial Hygienists [ACGIH], European Commission directive), and those established in Poland are also compared.