THE ROLE OF ERGONOMICS IN WELDING

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Rituraj Bose

Quality Management Consultant

Hony. Secretary General, The Indian Institute of Welding

Introduction

One of the concerns for Occupational health & safety is the Ergonomics, which is the main cause of Musculoskeletal Disorders, but less discussed may be due to some unavoidable bindings in welding.

Human factors and ergonomics are the application of psychological and physiological principles to the engineering and design of products, processes, and systems. The goal of human factors is to reduce human error, increase productivity, and enhance safety and comfort with a specific focus on the interaction between the human and the thing of interest.

What is Ergonomics?

Ergonomics is an applied science concerned with designing and arranging things people use so that the people and things interact most efficiently and safely. (Merriam-Webster)

Ergonomics can roughly be defined as the study of people in their working environment. More specifically, an ergonomist designs or modifies the work to fit the worker, not the other way around. The goal is to eliminate discomfort and risk of injury due to work. (The University of North Carolina at Chapel Hill)

Ergonomics in Welding 

Welding is a precise task that requires the welder to maintain static postures for relatively long periods of time. In almost all cases welding in the field requires the welder to adapt to the workplace, rather than adapting the workplace to the welder. This is because metal is heavy, and it is easier to have the welder assume an awkward posture. Also, the position of welding is always forcing a welder to adapt the posture.

Common Postures Adopted in Welding

Objectives of Ergonomics

  • To reduce injuries and disorders
  • To ensure worker Safety
  • To ensure worker Health
  • To reduce Absenteeism
  • To ensure worker Productivity 

Problems from poor Ergonomics

  • Musculoskeletal Disorders (MSD)
  • Repetitive Motion Injury
  • Worker Dissatisfaction
  • Increased Absenteeism
  • Increased Turnover rates

Causes related to the Problems

  • Reaching
  • Bending
  • Heavy Lifting
  • Using continuous Force
  • Working with Vibrating Equipment
  • Repetitive Motions
  • Awkward Postures 
  • Temperature

Musculoskeletal Disorders

Musculoskeletal Disorders or MSDs are injuries and disorders that affect the human body’s movement or musculoskeletal system (i.e., muscles, tendons, ligaments, nerves, discs, blood vessels etc.).

Many injuries can develop when there is a mismatch between the capabilities of the workforce and the demands of the task. These injuries are generally called Work Related Musculoskeletal Disorders or WMSDs.

Symptoms of Musculoskeletal Disorders

  • Less Gripping strength
  • Less Range of Motion
  • Loss of Muscle function
  • Painful Joints
  • Pain, Numbness in body Limbs
  • Shooting or Stabbing Pains
  • Swelling or Inflammation
  • Stiffness or Burning sensation

Main Causes for Work Related MSDs

  • Demographic Structure of Workforce:
  • Genetic Factors
  • Anthropometric Characteristics
  • Individual Factors
  • Physical and Psychological Work Environment: 
  • Equipment or Device used
  • Works and Tasks
  • Internal Loads
  • External Loads
  • Duration of Work
  • Organizational Factors
  • Social Support
  • Psychological Response
  • Design of Workstation

Overcoming the Problem

  • Positioning of the job:
  • Height of the working table to be adjusted, so that unnecessary bending can be avoided.
  • Tables may be wheeled to avoid unnecessary stretching to reach the job. This will also help to shift the material within the reach of a welder.
  • Manipulator can be used to fix the welding position within comfortable working zone of the welder.
  • Pre-fabrication is a good suggestion to restrict number of difficult welding joint positions. 
  • Stools may be used for better comfort.
  • Heavy Lifting:
  • Modern light weight welding equipment may be used.
  • Manipulator, hoist, lifting & turning tables may be used to avoid heavy lifting.
  • Wheelbarrow may be used for shifting medium to heavy loads.
  • Team lifting is also a good suggestion for shifting loads.

  • Automation in Welding:
  • Automation of the system is a very good solution. Automated job table, manipulator, positioner / turn table, column & boom / rotators, welding travel carriage etc. may be used.
  • Automatic or Semi-automatic welding processes may be used.
  • Another solution is Robotic Automation. This is a feasible solution for highly repetitive motion of arms. It will also reduce the exposure to fumes.

Conclusion

Since the human factors must be kept in mind, organisations have to understand the comfort zone of its workforce and therefore the implementation of ergonomic solution is must. The solution is Evaluate, Identify, Analyse, Develop and Implement. In turn, this will help to growth of the organisation as a whole.  However, due to the positional manual welding requirements, it may not be possible to overcome the Ergonomic problems completely.

References and Acknowledgements

  • ‘Welding Safety’ by Samir Kumar Gupta; The Indian Institute of Welding Monograph TM-07
  • ‘An Introduction to Human Factors Engineering’, by Christopher D. Wickens, Sallie E. Gordon & Yili Liu; Addison Wesley Longman
  • ‘Work Related Musculoskeletal Disorders’ by Orhan Korhan & Asad Ahmed Memon; Intechopen.com
  • ‘Ergonomics in Welding’ by Washington State Department of Labor & Industries
  • Occupational Health and Safety Administration (OSHA)
  • Google images