Some of the most essential causes of under productivity among workers are as follows:
Factor # 1. Fatigue:
It is that state of the worker by which power to work is decreased and pleasure taken in work is reduced. There are so many factors which promote fatigue. Some of them are: repetition of the same work again and again, velocity of fly wheels, whirling of hammers, high speeds at which machines and tools are moving, different types of sounds and vibrations.
At the same time, price-rate and financial incentive schemes encourage the worker to work at a faster rate. In such conditions of work, tension is increased and these factors (namely tension, speed, repetition and more strain, etc.) promote fatigue.
Thus, the fatigue is responsible to reduce the power to work with the passing of time. In addition to reduction in the production, continued fatigue also affects adversely the psychology of the worker. When he is tired he cannot think clearly, he readily imagines injustice, he becomes angry very quickly and an angry men can do anything without hesitation, which he would have not done in the good state of mind.
It also affects the personal life of the worker because a physically exhausted and completely tired man cannot perform adequately the functions of the head of the family. Thus fatigue not only affects the production but also psychological state of mind, temperament and his personal life.
Today many employees are subjected to extended workdays. They work extensive overtime hours either out of need or due to a desire to advance. This results in a fatigue, which causes a decline in safety, alertness and sleep disorder. It is an accepted fact that people need between 6 and 8 hours of continuous sleep each day.
When a person does not get enough rest and appropriate sleep, not only fatigue set in, but the cumulative effect can result in serious sleep deprivation, which can cause the body to call upon its energy reserves and leads to a “sleep debt,” and results in a loss of concentration, forgetfulness, inattentiveness, reduced cognitive ability, increased reaction time and diminished alertness.
When an individual’s level of alertness decreases, the individual is no longer as capable of making good decisions, performing tasks or responding quickly to emergency situations.
Contributors to fatigue include stress, worry, sleep apnea, insomnia, lack of exercise, and insufficient sleep.
Generally accepted symptoms of fatigue are:
v. Reduced cognitive ability
vi. Reduction in alertness
vii. Memory and concentration lapses
ix. Loss of appetite
x. Digestive problems
xi. Decreased resistance to illness.
Necessary and Unnecessary Fatigue:
The purpose of ‘Fatigue Study’ is to reduce its influence in decreasing production and unpleasant feelings. For this purpose, fatigues have been characterised as necessary and unnecessary fatigues. As all the works involve fatigue therefore total elimination is impossible, only it can be reduced. Thus when work is carried out, fatigue will essentially be there.
The fatigue caused by unfavourable working methods and conditions of work is known as “Unnecessary Fatigue”. This requires a useless discharge of energy hence capacity of work decreased unnecessarily. This type of fatigue can be avoided to a large extent.
Here some of the considerations in this respect are given as under:
(i) Influence of Hours of Work:
Experiments have shown that average hourly output varies with length of the working day. If the length of working hours in a day is reduced (though upto certain limit) then the average hourly output increases. So many experiments have been conducted by varying the working hours, which shows that hourly output reaches maximum value at about seven hours a day or 40 hours a week.
(ii) Influence of Rest Pauses:
Production and fatigue are influenced considerably by the opportunity provided to the worker for rest during the course of work. Experiments have shown that when number of rest pauses is increased then production is also increased-sometimes upto 20%.
While setting up the duration and number of rest pauses, it should be considered that most favourable rest pause is that which will conserve all the benefits of incitement or warming and at the same time eliminate fatigue as much as possible.
Thus, too long rest pauses are disadvantageous because loss of warming will occur when worker remains away from work for a long time. Research in this regard has shown that 5 minutes rest pause after every 80 minutes work is most desirable.
(iii) Influence of Illumination:
Insufficient illumination causes heavy strain on the eyes of workers and thus resulting unnecessary fatigue. Experiments have shown that illumination of 215 lumens/m2 is most satisfactory.
(iv) Influence of Atmospheric conditions:
Atmospheric conditions have very important role in determining the efficiency and well-being of the worker. An Industrial worker spends most of his time in an environment where heat, moisture, fumes, smokes etc. are constantly evolved in the manufacturing processes.
This factor affects the health and comfort of the worker and hence the quality and quantity of production in general efficiency of the worker. Efficiency of the worker is also affected by the temperature, humidity and air circulation.
(v) Influence of Unnecessary Efforts:
Inefficient working methods, bad arrangement of machines and tools are responsible for a waste of human efforts and thus dissatisfaction in work, reduced output and quality.
When methods are selected based on Time and Motion Study and machines arranged systematically then efforts and time of the worker can be saved to a large extent. Work should be carried out at a place and in position of most comfort.
(vi) Influence of Speed:
Speed of the belt, flywheel, gears, coupling etc. may affect the efficiency of workers. These speeds affect the work adversely by increasing the fatigue and discomfort.
(vii) Effect of Noise:
Observations have suggested that excessive noise may adversely affect output and increases fatigue. In the atmosphere of noise and vibrations, workers feel discomfort.
Variation in humidity plays an important role in the productivity of industries. It has been noticed that wet heat, and dry cold are more uncomfortable. Therefore to provide relief from severe dry cold, it is necessary to raise humidity in low temperature. Similarly at higher temperatures, it is necessary to reduce humidity upto certain extent.
(ix) Monotony and Boredom:
The monotony and boredom are the undesirable effects of repetitive work, as the repetitive work destroys such human values as pride in workmanship and individuality.
Monotony is described as a desire to have a change due to repetitive work and is estate of mind caused by performance of such tasks. While boredom is a mental fatigue due to routine tasks. Attitude and personality are related with boredom or lack of interest in the job.
Thus while fatigue is associated with psychological depletion, decreases capacity for work, and is a conscious in work, and is a feeling of incapacity. Fatigue is due to the work task being temporarily beyond the capacity of a worker, and the worker desires for rest, whereas boredom is due to the consciousness of the uniformity of the work task, the absence of work challenges, and it expresses desire for change.
Factor # 2. Lighting:
Poor illumination reduces the speed of work and results in strain on eyes and thereby causes more accidents. Light should come from correct direction without producing shadow and should produce the illumination sufficient enough for the work being performed.
In artificial light, glare is most common defect, it is harmful to the eyes. It also produces strain and headache, spoilage of work also increases due to glare.
In order to have sufficient light for all the times, both the natural and artificial lights should be planned, and maintained both in the work areas as well as in passages.
All the glazed window panels and skylights should be kept clean on both the inner and outer surfaces. Electrical fittings should also be regularly cleaned so that full light is transmitted from them.
Some of the basic principles of lighting are:
1. Lighting should be so designed that the employee works in comfort with minimum eye strain and physical fatigue.
2. Natural light and artificial light should be integrated to provide good light.
3. Light should be diffused and glare free.
4. There should be adequate contrast between the immediate surroundings and the specific task being performed i.e. the working areas should be illuminated more than their surroundings.
5. Lighting should be designed to allow safe movement of employees from one area to another.
6. Windows and sky lights must be kept clean and shaded to protect workers from direct sunlight and glares.
Factor # 3. Ventilation and Temperature:
Proper ventilation provides circulation of fresh air in the work area, which is necessary for comfortable working condition for the workers.
Ventilation is the process of displacement of stale air of the factory building by fresh air in order to reduce the presence of bad smell, concentration of carbon dioxide, humidity and temperature. Ventilation is essential not only for physical well-being but also to minimize danger of infections. A good ventilation system provides fresh air and gets rid of odours and smoke.
The common methods of ventilation are by providing (i) windows and ventilators on opposite walls, and (ii) exhaust fans. For good ventilation, exhaust fans should be installed at highest possible points.
When the human body is subjected to unusually high temperatures, large amount of perspiration evaporates from the skin. Too high heat dissipation by evaporation causes heat stroke, heat exhaustion, body salt loss and fluid loss which affects efficiency and power to concentrate with accompanying reduction in production and more number of errors.
On the other side, in extreme cold conditions, the body reacts drastically to reduce the blood supply to the skin. The heat generated in the body by metabolism is thus conserved for maintaining the correct body temperature. If the metabolism heat is insufficient to maintain the body temperature, shivering begins. This results in reducing the efficiency of the worker.
If the humidity is high in addition to heat, the evaporation of the sweat is impeded which results in feeling of stuffiness. And if the humidity is too low, too much body temperature is dissipated which results in dryness of mouth, throat and nose. Humidity, as a general rule, should be kept between 30 percent to 70 percent.
Walls and roofs of the work place should be of such material and so designed that the temperature may not exceed to create uncomfortable working conditions. Effective arrangement should be made to protect the workers from processes producing excessively high temperature. Hot parts of the machinery should be insulated.
Minimizing the Effect of Heat:
Sometimes it is not possible to provide thermal comfort in the working area, either because it would be too expensive or because a high or low temperature is essential for process.
In these circumstances the effect of heat or cold can be minimized by taking following measures:
1. Shielding/isolating heat source.
2. The worker may wear properly designed protective clothing to insulate the body.
3. Insulating adequate local ventilation systems.
4. Rotating personnel in extreme heat areas.
5. Permitting rest pauses in cool place for short intervals between work shifts.
6. Making adequate arrangement of supply of cool water to enable frequent drinking of water.
7. Raising salt content in worker’s food to make-up for the salt loss.
Factor # 4. Noise and Vibration:
Noise may be defined as the unwanted and unpleasant sound. Studies have shown that exposure to high noise level over 90 dB for an extended period causes harmful effects like hearing loss.
Adverse effects of noise can be summarized as under:
1. Both loud and monotonous noises are conducive to workers fatigue.
2. Unexpected and infrequent noise also results in loss of temper and difficulty in doing precision work.
3. Constant noise can cause deafness, emotional and mental strain, palpitation, digestive upset, stress and irritability leading to hypertension, loss of mental and physical balance.
4. If the sound level is too low (i.e. pin drop silence), then even a normal sound becomes annoying.
Since noise is harmful to worker’s productivity, efficiency and well-being, all attempts should be made to bring the noise level to minimum, and where it is not possible, workmen should not be exposed too long to such noises.
Too much noise and vibrations also produce mental fatigue and reduce the efficiency of the worker. Although noise cannot be stopped totally for a running machinery but can be reduced by enclosing the source of noise, use of baffles and sound proof materials in construction etc.
Its reduction is very necessary because it is very difficult to concentrate on the work in too much noise. Sometimes too much noise also adversely affects the hearing capacity of the workers. Noise and vibrations can also be controlled to some extent by proper maintenance, checking, lubrication and proper functions etc.
Following are the few examples of noise reduction:
(i) Keep noise source away from all reflecting surfaces.
(ii) Motors, pumps etc. should be mounted on heavy bases to avoid noise transmission.
(iii) All structure born noise can be significantly reduced by mounting vibration source on flexible supports like springs, corks, foam, rubber etc.
(iv) Use conveyers rather than allowing material to fall from a height.
(v) Repair and redesign the machine and repair or redesign the noise producing elements such as bearing, gears, belts etc.
(vi) Replace worn out parts in time.
(vii) Substitute noise producing elements/ processes with quieter elements/alternative processes.
(viii) Isolating excessively noisy operations by enclosures so that the amount of noise transmitted beyond the enclosures is reduced.
(ix) By proper machine lubrication, maintenance etc.
When human body is subjected to vibrations, the tensions and deformations so produce cause localized pain, headache, general discomfort and anxiety. Early symptoms of vibration fatigue are loss of appetite, loss of interest and headache.
Common causes of vibration in machines are in balance, misalignment, bearing wear or its damage, mechanical looseness, coupling problem, gear problems etc. The solution to these problems is regular inspection, timely removal of defects, and proper maintenance.