Lessons Learned: Solutions for Workplace Safety and Health

Provides case studies of workplace health hazards, regulatory actions taken, and solutions, including product and design alternatives; a synthesis of findings and lessons learned; and federal- and state-level recommendations

The impact of tool selection on back and wrist injury risk in tying steel reinforcement bars: a single case experiment

The paper explores the risk of work-related musculoskeletal injury in tying steel reinforcement bars. Three tools are compared to determine the extent to which ergonomic tools can reduce the risk of injury to the back and wrist in steel-tying. A whole body system of wearable sensors was used to measure biomechanical risk in tying. Three tools were assessed to determine their impact on the risk of work-related musculoskeletal injury when used at different heights. These were: a conventional pincer-cutting tool; a power-driven tying tool, and a long handled stapler tool. No tool was found to work best in all situations. The long handled stapler tool significantly reduced trunk inclination when used from ground to shoulder height, but produced higher trunk extension (backward bending) when used above shoulder height. The power tying tool did not reduce the need to bend when working at lower work heights. The power-tying tool produced significantly lower peak wrist flexion values compared to the conventional pincer-cutter tool at all work heights except overhead. The power tying tool involved significantly lower levels of wrist rotation than the conventional pincer-cutter tool at all work heights above knee level. Many assessments of ergonomic risk factors in construction rely on observational methods. The use of small, lightweight wearable sensors permits the objective measurement of biomechanical risk factors for work-related musculoskeletal injury, as well as providing objective performance data that can be used in the design and selection of task-specific tools. Our analysis of work by height also provides insight into the way in which risk factors and reduction opportunities afforded by different tools vary depending on the height at which work is to be performed

The impact of tool selection on back and wrist injury risk in tying steel reinforcement bars: a single case experiment

The paper explores the risk of work-related musculoskeletal injury in tying steel reinforcement bars. Three tools are compared to determine the extent to which ergonomic tools can reduce the risk of injury to the back and wrist in steel-tying. A whole body system of wearable sensors was used to measure biomechanical risk in tying. Three tools were assessed to determine their impact on the risk of work-related musculoskeletal injury when used at different heights. These were: a conventional pincer-cutting tool; a power-driven tying tool, and a long handled stapler tool. No tool was found to work best in all situations. The long handled stapler tool significantly reduced trunk inclination when used from ground to shoulder height, but produced higher trunk extension (backward bending) when used above shoulder height. The power tying tool did not reduce the need to bend when working at lower work heights. The power-tying tool produced significantly lower peak wrist flexion values compared to the conventional pincer-cutter tool at all work heights except overhead. The power tying tool involved significantly lower levels of wrist rotation than the conventional pincer-cutter tool at all work heights above knee level. Many assessments of ergonomic risk factors in construction rely on observational methods. The use of small, lightweight wearable sensors permits the objective measurement of biomechanical risk factors for work-related musculoskeletal injury, as well as providing objective performance data that can be used in the design and selection of task-specific tools. Our analysis of work by height also provides insight into the way in which risk factors and reduction opportunities afforded by different tools vary depending on the height at which work is to be performed

Design and implementation of ergonomic risk assessment feedback system for improved work posture assessment

Ergonomic risk factors which include force, repetition and awkward postures, can result in Work-Related Musculoskeletal Disorders (WMSDs) among workers. Hence, systems that provide real-time feedback to the worker concerning his current ergonomic behaviours are desirable. This paper presents the design and implementation of a human-machine interface posture assessment feedback system whose conceptual model is developed through a model-driven development perspective using the Unified Modeling Language (UML) and interface flow diagrams. The resulting system provides a shop floor with a simple, cost-effective and automatic tool for real-time display of worker's postures. Testing the system on volunteer participants reveals that it is easy to use, achieves real-time posture assessment and provides easy-to-understand feedback to workers. This system may be useful for reducing the rate of occurrence of awkward postures, one of the contributing factors to risk of WMSDs among workers

Construction Ergonomic Risk and Productivity Assessment Using Mobile Technology and Machine Learning

The construction industry has one of the lowest productivity rates of all industries. To remedy this problem, project managers tend to increase personnel\u27s workload (growing output), or assign more (often insufficiently trained) workers to certain tasks (reducing time). This, however, can expose personnel to work-related musculoskeletal disorders which if sustained over time, lead to health problems and financial loss. This Thesis presents a scientific methodology for collecting time-motion data via smartphone sensors, and analyzing the data for rigorous health and productivity assessment, thus creating new opportunities in research and development within the architecture, engineering, and construction (AEC) domain. In particular, first, a novel hypothesis is proposed for predicting features of a given body posture, followed by an equation for measuring trunk and shoulder flexions. Experimental results demonstrate that for eleven of the thirteen postures, calculated risk levels are identical to true values. Next, a machine learning-based methodology was designed and tested to calculate workers\u27 productivity as well as ergonomic risks due to overexertion. Results show that calculated productivity values are in very close agreement with true values, and all calculated risk levels are identical to actual values. The presented data collection and analysis framework has a great potential to improve existing practices in construction and other domains by overcoming challenges associated with manual observations and direct measurement techniques

National hazard exposure worker surveillance: exposure to biomechanical demands, pain and fatigue symptoms and the provision of controls in Australian workplaces

Biomechanical demands such as repetitive hand or arm movements, lifting heavy loads or working in awkward postures contribute to the development or worsening of inflammatory or degenerative musculoskeletal disorders. However, little is known about patterns of exposure to different biomechanical demands and how they relate to the demographic and employment characteristics of Australian workers. To address this, in 2008 the National Hazard Exposure Worker Surveillance [NHEWS] survey collected information on 4500 Australian workers’ exposure to nine biomechanical demands, pain and fatigue symptoms and the provision of various risk controls. Almost all workers reported some level of exposure to the biomechanical demands surveyed and 22 per cent were deemed to have high overall (composite) biomechanical demand exposure. In particular, young workers, male workers, night workers and lower skilled workers were most likely to report exposure and had the highest overall biomechanical demand exposure. The reporting of pain and fatigue symptoms was highly related to the level of biomechanical demand exposure. Workplace size (number of workers at a site) and the overall level of biomechanical demand exposure were the best predictors of control provision: workers from large workplaces and those with high exposure were most likely to be provided with biomechanical demand controls. This report presents detailed findings of the NHEWS survey and discusses the implications of these findings for work health and safety policy

인간공학적 자세 평가를 위한 비디오 기반의 작업 자세 입력 시스템 개발

학위논문(석사) -- 서울대학교대학원 : 공과대학 산업공학과, 2022. 8. 윤명환.Work-related musculoskeletal disorders are a crucial problem for the worker’s safety and productivity of the workplace. The purpose of this study is to propose and develop a video-based work pose entry system for ergonomic postural assessment methods, Rapid Upper Limb Assessment(RULA) and Rapid Entire Body Assessment(REBA). This study developed a work pose entry system using the YOLOv3 algorithm for human tracking and the SPIN approach for 3D human pose estimation. The work pose entry system takes in a 2D video and scores of few evaluation items as input and outputs a final RULA or REBA score and the corresponding action level. An experiment for validation was conducted to 20 evaluators which were classified into two groups, experienced and novice, based on their level of knowledge or experience on ergonomics and musculoskeletal disorders. Participants were asked to manually evaluate working postures of 20 working videos taken at an automobile assembly plant, recording their scores on an Excel worksheet. Scores were generated by the work pose entry system based on individual items that need to be inputted, and the results of manual evaluation and results from the work pose entry system were compared. Descriptive statistics and Mann-Whitney U test showed that using the proposed work pose entry system decreased the difference and standard deviation between the groups. Also, findings showed that experienced evaluators tend to score higher than novice evaluators. Fisher’s exact test was also conducted on evaluation items that are inputted into the work pose entry system, and results have shown that some items that may seem apparent can be perceived differently between groups as well. The work pose entry system developed in this study can contribute to increasing consistency of ergonomic risk assessment and reducing time and effort of ergonomic practitioners during the process. Directions for future research on developing work pose entry systems for ergonomic posture assessment using computer vision are also suggested in the current study.작업 관련 근골격계 질환은 근로자의 안전과 작업장의 생산성 향상에 중요한 문제다. 본 연구의 목적은 인간공학적 자세 분석에 사용되는 대표적인 방법인 Rapid Upper Limb Assessment(RULA) 및 Rapid Entire Body Assessment(REBA)를 위한 비디오 기반의 작업 자세 입력 시스템을 제안하는 것이다. 본 연구는 영상 내 사람 탐지 및 추적을 위한 YOLOv3 알고리즘과 3차원 사람 자세 추정을 위한 SPIN 접근법을 사용하는 시스템을 개발했다. 해당 작업 자세 입력 시스템은 2차원 영상과 몇 개의 평가 항목 점수를 입력으로 받아 최종 RULA 또는 REBA 점수와 해당 조치수준(Action level)을 출력한다. 본 연구에서 제안하는 작업 자세 입력 시스템이 일관적인 결과를 산출하는지 알아보기 위해 인간공학 및 근골격계 질환에 대한 지식이나 경험을 기준으로 숙련된 평가자와 초보 평가자의 두 그룹으로 분류된 평가자 20명을 대상으로 검증 실험을 진행했다. 참가자들은 국내 자동차 조립 공장에서 찍은 20개의 작업 영상의 작업 자세를 수동으로 평가하여 Excel 워크시트에 점수를 기록하였다. 시스템 사용 시 입력해야 하는 개별 항목을 기준으로 시스템을 통한 점수를 생성하고 기존의 전통적인 방법으로 평가한 결과와 시스템에서 얻은 결과를 비교하였으며, 기술 통계와 Mann-Whitney U test는 제안된 시스템을 사용하면 그룹 간의 차이와 표준편차가 감소한다는 것을 보여주었다. 또한, 경험이 많은 평가자들이 초보 평가자들보다 더 높은 점수를 받는 경향이 있다는 것을 보여주었다. 시스템에 입력되는 평가 항목과 경험 정도와의 관계를 확인하기 위해 Fisher’s exact test를 수행하였으며, 결과는 명백해 보일 수 있는 일부 항목도 그룹 간에 다르게 인식될 수 있음을 보여주었다. 이 도구에서 개발된 작업 자세 입력 시스템은 인간공학적 자세 평가의 일관성을 높이고 평가 과정 중 중에 인간공학적 평가자의 시간과 노력을 줄이는 데 기여할 수 있다. 또한 컴퓨터 비전을 활용한 인간공학적 자세 평가를 위한 작업 자세 입력 시스템 개발에 대한 향후 연구 방향도 이번 연구에서 제시된다.Chapter 1 Introduction 1 1.1 Background 1 1.2 Research Objectives 4 1.3 Organization of the Thesis 5 Chapter 2 Literature Review 6 2.1 Overview 6 2.2 Work-related Musculoskeletal Disorders 6 2.3 Ergonomic Posture Analysis 7 2.3.1 Self-reports 7 2.3.2 Observational Methods 7 2.3.3 Direct Methods 15 2.3.4 Vision-based Methods 17 2.4 3D Human Pose Estimation 19 2.4.1 Model-free Approaches 20 2.4.2 Model-based Approaches 21 Chapter 3 Proposed System Design 23 3.1 Overview 23 3.2 Human Tracking 24 3.3 3D Human Pose Estimation 24 3.4 Score Calculation 26 3.4.1 Posture Score Calculation 26 3.4.2 Output of the Proposed System 31 Chapter 4 Validation Experiment 32 4.1 Hypotheses 32 4.2 Methods 32 4.2.1 Participants 32 4.2.2 Apparatus 33 4.2.3 Procedure 33 4.2.4 Data Analysis 37 4.3 Results 38 4.3.1 RULA 38 4.3.2 REBA 46 4.3.3 Evaluation Items for Manual Input 54 Chapter 5 Discussion 56 5.1 Group Difference 56 5.1.1 RULA 57 5.1.2 REBA 57 5.2 Evaluation Items for Manual Input 58 5.3 Proposed Work Pose Entry System 59 Chapter 6 Conclusion 62 6.1 Conclusion 62 6.2 Limitation, Contribution, and Future Direction 62 Bibliography 65 국문초록 77석

Usability Study of Integrated RULA-KinectTM System for Work Posture Assessment

A good work posture is one of vital contributors to occupational health and to increase the efficiency of industrial workers. Recently, numerous research works have developed an Integrated RULA- KinectTM system for work posture assessment; however, usability of the developed system remains unknown. The objective of this study was to develop a prototype of Integrated RULA-KinectTM system. Additionally, this study performed usability testing on the Integrated RULA- KinectTM system and RULA Employee Assessment Worksheet to determine feedbacks and reactions from the potential users. A focus group session was conducted among eight potential users, which divided into 2 groups (novice and expert). The results of the focus group session revealed that both novice and expert users agreed that the Integrated RULA-KinectTM system is easy to use compared to RULA Employee Assessment Worksheet. This study concluded that the Integrated RULA-KinectTM system is able to counter some limitations of the RULA Employee Assessment Worksheet