Common ergonomic practices for Sri Lanka

Ergonomics is defined in wikipedia.org as the study of "designing equipment and devices that fit the human body, its movements, and its cognitive abilities." Research in this field is largely focused on increasing productivity and enhancing occupational health and safety in the workplace.

In the global context, all industries and operations have become very competitive. One of the key words is productivity. There is much emphasis placed in improving productivity. In this context Human Factors or Ergonomics will play a pivotal role. Application of this science assists to ensure the working situations to be in harmony with the activities of the worker.

Prior to the 1980s, ergonomics was hardly known in Sri Lanka. The rapid development process seen in Sri Lanka in early 1980s has been hampered by the political and ethnic unrest. It is widely known that the science of Ergonomics (human factors sciences) contribute immensely to the technology development and can boost the industrialization process in Industrially Developing Countries (IDCS). Two Swedish experts [including myself] visited Sri Lanka in 1996 to spread the awareness to ergonomics. They carried out ergonomic surveys which revealed that significant mismatches existed between the workers and their work tools as well as work systems. These deficiencies affected adversely the productivity and worker comfort. Deficiencies in occupational health and safety and enormous waste in production are other significant negative factors observed by the experts. lights of an approaching car will be affected by disability glare and his vision will be severely affected.

Visitors to a Managing Director’s room complained that a black curtain that was hung inside the room was causing them stress and a negative feeling. The black curtain was later removed and replaced by a blue curtain which made a remarkable difference in the attitude of the staff. sons of modesty the girls wearing miniskirts bent their legs and kept their trunks straight when lifting something from the floor or lifting a weight from the floor level.

Some precautions should be taken when lifting or carrying weights to prevent any damage to the spine. For example heavy weights should not be manually lifted or carried. A weight should be lifted with the trunk straight, bent knees and keeping the weight as close as possible to the body.i was invited to visit a wall tile factory in Sri Lanka to make a presentation about ergonomics to the senior executives. A quick walk through and survey of the workplace was carried out prior to the talk. It was observed during the survey that a team of 10 workers inspected for flaws and cracks in the wall tiles sent along a conveyor belt. The workers stood along the belt which was situated higher than the elbow level of the workers. The workers rejected with their hands the tiles that were defective. Observing the fatigue felt by the workers as they worked standing throughout the day in an uncomfortable posture with their operating level being uncomfortable as they worked raising their elbows, I casually informed the management as follows: Provide 10 tall chairs to the workers to bring their operating level to that of the elbow level and provide foot-rests in the tall chairs. Three months later I received a telephone call from the management that although my advice was given casually, the management provided the workers with the tall chairs and foot-rests. The manager said that the productivity of the workers increased significantly and when calculated for one year the cost benefit was sizable. The workers complaints were also significantly reduced too by this change. A simple and a cheap change giving a big profit to the company.

Work Physiology and Muscular Work

A steady supply of oxygen is needed to do muscular work. A waste product e.g. Carbon Dioxide formed during metabolism is carried by the red blood cells and excreted via lungs. In the absence of oxygen a waste product called lactic acid remains in the muscle which causes muscular pain.

A man was asked to hold a weight of one kg on his palm with the hand outstretched for five minutes. Another man was asked to turn a wheel holding the handle on the wheel. Both jobs had similar energy expenditure. The first man holding the weight complained of a pain in the arm after three minutes and it became unbearable after five minutes. But the man turning the wheel continued to turn the wheel without any complaint. The first man was actually doing static work without any movement and the blood vessels to the muscles were compressed and blocked. In other words the supply of oxygen to the muscles was blocked and could not wash away the waste products causing accumulation of lactic acid which caused the pain. The second man turning the wheel did dynamic work. There was a steady supply of oxygen to the muscles which washed away the waste products. Hence he could continue the work without any pain or fatigue.

Human Factors (Psychological Aspects of Work)

There is wider implications and influence to design from psychological characteristics of man. Some important psychological characteristics are: the capacity and limitations of perception and processing of information, decision making, the mental work load and overload, performance of vigilant tasks, boredom and psychological aspects of control and display design. Modern work is carried out more by machines than by man, more automotive than manual, use more artificial intelligence than man’s intelligence, more sedentary than moving.

Information Processing: Information enters through the senses as a result of physical stimulus impinging on the sense organs. Perception is the identification of the stimulus and influenced by individual factors such as personality, mood, expectation, level of training and its retention. Perception is achieved by the use of memory. With the use of long term memory, working memory, attention, decision and response selection are made. The response execution (in the form of physical activity) in the information processing model will result in a feedback.

What must be avoided in the information processing model are perceptual load (too much of information), mental load (stressful decision making) and physical load (heavy physical activity).

The other important aspects in psychology are:

- The concept of vigilance (human observers state of alertness to tasks demanding efficient detection and processing of signals)

- Design of Displays and Controls