ENVIRONMENTAL FACTORS IN PLANT OPERATIONS
In this article we are considering various environmental factors on shop floors which may be detrimental to efficient working of shop floor personnel. We have also suggested suitable remedies to control these adverse factors and also given the tolerable limits for each.
Temperature and Humidity:
High temperatures adversely affect the productivity of workers. They also increase the resting time of workers. Research studies shows an increase in accidents both with decreases and increase of temperature from an optimum of 650F, the increase with cold being somewhat the greater. Older people are adversely affected by higher temperature. Therefore comfortable environment must be provided to the workers for optimum efficiency.
For human body, there are gains as well as losses of heat; gain by convection C, radiation R, and basal metabolism (M) and loss by evaporation (E), convection C, and radiation R.
The balance expression is given by
M +/- R +/- E = 0
Evaporation Rate depends on perspiration mechanism and the relative humidity or water pressure of the environment.
If the bodyâ€™s gains exceed the losses by evaporation there is a maximum body temperature rise of about 10C (20F) . If this does not happen, there is severe heat stress, leading to heat stroke. Over a period of time, however, human bodyâ€™s tolerance to heat increases.
Heat affects us adversely under two conditions:
1. Warmâ€“moist Heat is radiated. Work becomes difficult because of high humidity which reduces perspiration.
Remedy: Proper ventilation and AC. If heat is radiated, workmen should be removed for some time to cool off.
2. Hot-dry Warm-dry conditions do not pose a problem
The sources of vibration at the time of work are varied. The effects of vibration could lead to motion sickness, physical discomfort or physical damage. The tolerable limit of vibration between the amplitude (A) and frequency (F) of a vibration is
AF3 = 2 for low frequency vibration = 1-6 cycles /second.
AF2 = 1 /3 for medium frequency vibration = 6-60 cycles/second
AF= 1/60 for high frequency vibration = Over 60 cycles /second.
Tolerable limits of vibrations cause no physical damage; though they may affect efficiency and may result in fatigue. Excessive vibration causes pulmonary damage, hematuria, rectal bleeding and constipation. Hand-held vibrating tools like drills may lead to â€˜white fingers,â€™ dead hand, and Raymondâ€™s phenomenon.
Despite the above, we cannot lay down the specific design recommendation regarding vibrations lessening its effect. The operators feel they are compensated adequately to tolerate vibration discomfort. They accept it so long as it does not affect them physically.
Noise is unwanted sound, and is irritating and fatigue-causing. Sound frequencies between 2400-4800 cycles / sec may cause damage to the ear. As we advance in age, impairment of hearing increases. Individuals exposed to high sound also experience a hearing loss. Intermittent noise is considered a potential hazard. In many countries compensation is payable if deafness has occurred due to noise. Cotton wool in the external ear might protect might protect the ears. Noise above 90 decibels makes us error-prone. Irritation also affects the work efficiency. High-pitched voices are more annoying than low-pitched voices.
Noise can also be meaningfully employed to break the barrier of quietness existing between workers in no- sound work situations. Music is soothing, though it might not be liked by some. High volume music also becomes irritating. Noise affects the oral communication. Raising the voice above the din, we can communicate but it is strenuous. In such situations, visual signs should be considered.
Noise can be reduced at the level of the source itself. Noise can be localized by supporting structure around the source. Resonating parts should be given suitable damping devices. Damping material can be attached to cover surface of the sheet metal. In certain situations, acoustic absorption will have to be tried. Tree plantations around the factories reduce noise pollution for the residents in the neighborhood.
Our inference is the above mentioned adverse factors must be taken care of at the pre-planning stage of plant construction and after that due consideration has to be given on the adverse potential factors during layout planning. If these are not done then it may be too late or costly for making necessary changes. It is not an exaggeration to say the firm may end up in losses or has high attrition rate with no skilled workmen joining the firm (plant) if environmental factors are not taken care of.