Working conditions and the working environment

Background

• The interdependence between the working conditions and productivity is increasingly recognized .

• Studies reveal that productivity can be improved merely by improving the conditions under which people work .

• Following factors contribute to the productivity decrease :

• Hazardous working environment – resulting in occupational accidents and diseases

• Workers dissatisfaction with working conditions.

Occupational safety and health organization

• The most effective method of obtaining good results in the prevention of occupational hazards includes the following :

• To recognize the importance of the employer’s responsibilities for ensuring that the workplace is safe and without risk to worker’s health .

• To adopt an occupational safety and health policy for establishment of a good occupational safety and health organization with the enterprise .

• To encourage strong participation of workers in safety and health activities at the workplace , including safety committees , inspection and accident investigation and the appointment of specialists.

Safety criteria

• Studies of occupational hazards in modern industry have revealed the extremely complex nature of the possible causes of occupational accidents or diseases .

Safety criteria

Prevention of work related accidents

Work related diseases Occupational accidents

Other major hazards and control Fire prevention and protection

Occupational accidents

• The accidents which occur while performing a task at the workplace .

• The accidents which occur at the workplace .

• The causes of occupational accidents are never simple , even in an apparently commonplace accident.

• Statistics show that the most common causes of accidents are not the most dangerous machines nor the most dangerous substances , but rather quite ordinary actions like stumbling , falling , faulty handling of the goods or use of hand tools or being struck by a falling object .

• In modern industry there are a variety of both visible and invisible hazards at the workplace .

• Visible hazards include opening in the floor , , dripping or leaking chemicals .

• Invisible hazards include inert gases , welding fumes , noise , vibration etc.

• Technical progress has created new heath hazards while at the same time making the prevention of occupational accidents achievable in practice .

• An accident is often the result of a combination of technical , physiological and psychological factors ; it depends on both the machine and the environment ( lighting , noise , vibration , vaporizing substances , oxygen deficiency ) , as well as the worker’s posture and work induced fatigue .; it is also conditioned by commuting circumstances and other activities outside the plant and by ill temper , feelings of frustration , youthful exuberance and other specific physical or mental states .

Methods of controlling occupational hazards

Hazard

Individual Hazard

Individual Hazard

Individual Hazard

Individual Elimination of hazard

Removal of the individual from exposure

Isolation of the hazard

Protection of the individual

• Some 30% of all accidents occur in manual handling ; work study can contribute to reducing the incidence of these accidents quite simply by reducing the number of handling operations and the distance involved in transporting goods .

• A significant percentage of other accidents could be prevented by eliminating dangerous operations through prior work study , process analysis and flow process charts . And in general by critical examination of work organization with a view to accident prevention .

Work related diseases

• As discussed under ergonomics

The prevention of industrial accidents

• Fire prevention and protection • Principles :• Design buildings , processes and

storage facilities in such a way as to limit the possible combination of oxygen , fuel and an increase in temperature .

• Eliminate or reduce sources of heat or ignition , thus limiting the rise in temperature.

Preparing for fire emergencies .. • Every workplace should have an

emergency plan with information detailing the role of every worker in case of a fire or other emergency .

• There should be atleast two clear , properly marked , unobstructed exits leading to areas of safety .

• There must be ways of notifying personnel of a need to evacuate , such as an alarm system . In some applications , where there is a high level of noise , visual signals such as flashing or revolving lights are also frequently used .

• The right type of fire extinguisher should always be provided in adequate numbers for the given risk and placed accordingly . Different types of fire extinguisher exits for different fire risks and there are national codes for different types of risk. Each extinguisher should be labelled with easy to read instructions and an indication of which fire extinguisher to use for which risk .

• Every worker should have hands-on training concerning the proper use of the extinguisher , including both when and when not to use it.

• The provision of automatic fire protection such as sprinklers has proved to be very effective in protecting escape routes for workers , as well as in rapidly controlling fire.

Other major hazard control

• The potential for major industrial accidents has become more significant as the production , storage and use of hazardous substances has increased .

• Major fires , explosions or dispersion of toxic chemicals can cause death and injuries to workers and the public .

• Because of the complexity of the industrial activities concerned , the control of major accidents needs to be based on a systematic approach .

Components of major hazard control systems :

• Identifying major hazard installations Government authorities and management should set up , on a priority basis , a system to identify plants where major hazards exist . This may be done by means of a list of hazardous chemicals or categories of chemicals and associated threshold quantities .

• Information about the plant • Once the plants concerned have been

identified , additional information needs to be collected about their design and operation . This information, which is often presented in the form of a safety report should be gathered and arranged, systematically and should be accessible to everyone concerned within the industry , such as govt bodies which may require it for licensing inspection purposes .

• Action inside the plant • Management has the primary responsibility

for operating and maintaining a safe plant . A sound safety policy is therefore required. Technical inspection , maintenance , plant modification and training and selection of suitable personnel must be carried out according to sound procedures. Accidents should be investigated and reports submitted to the authorities .

• Emergency planning • All previous elements focus on the

prevention of the occurrence of major accidents . Emergency planning aims at mitigating the consequences of major accidents . Emergency planning aims at mitigating the consequences of major accidents ,and assumes that absolute safety cannot be guaranteed .

Working premises

• In developing a layout , emphasis should be placed on the principle of isolating any operation which is hazardous or constitutes a nuisance . Wherever possible , work premises should be above the ground level and equipped with windows having surface area of not less than 17% of the floor area .

• Minimum ceiling height should not be less than 3 mtrs and each worker should have atleast 10 cubic meters of air .

• For the purpose of accident prevention , it is important to ensure that each worker has an adequate minimum free floor area which should not be less than 2 square meters per person .

Good housekeeping

• Good housekeeping which when used with reference to factory or workplace is a general term embracing tidiness and general state of repair .

• It not only contributes to accident prevention but is also a factor in productivity .

• Unnecessary items should be disposed of . • Tools and equipment should be arranged in

a way that allows easy access and return to their designated place . Eg: Board on which handtools are kept .

• Gangways and passages should be kept clear and the floor painted with lines of atleast 5 cms wide to distinguish them as such . Depots and storage areas should be similarly marked . Toxic matter should be painted in different colour to identify it as such .

• The work area should be kept clean. Dust may be harmful to certain operations , oil and grease can cause accidents and deposits of toxic material or chemicals left attended are a source of occupational diseases .

• Working clothes should also be kept clean in order to reduce the skin absorption hazard of certain toxic substances . And the problem of skin sensitization and chronic or acute irritation .

• Workers employed on dirty jobs or exposed to dangerous or toxic substances should have wash rooms with a tap for every 3-4 workers .

Lighting

• 80% of the information required in doing a job is perceived visually .

• Good visibility of the equipment , the product and the data involved in the work process is an essential factor in accelerating production , reducing the number of defective products , cutting down waste and preventing visual fatigue and headache among the workers .

• Both inadequate visibility and glare are frequently causes of accidents .

Factors affecting the visibility

• Size and color of the workpiece .• Its distance from the eyes .• The persistence of the image • The lighting intensity • Contrast of color and lighting level

with the back ground .

• In principle , lighting should be adapted to the type of work . However , the level of illumination , measured in lux , should be increased not only in relation to the degree of precision or miniaturization of the work , but also in relation to the worker’s age .

• The accumulation of the dust and wear of the light sources cut down the level of illumination by 10-50% of the original level .

• In general , the lights should be uniformly diffused . Slight shadows help distinguish objects , but shadows that are too pronounced should be avoided .

• Excessive contrast in lighting levels between the worker’s task and the general surrounding should be avoided .

• The use of natural light should be encouraged .

Recommended minimum values of illumination for various

classes of visual task

Use of colors

• Experience shows that careful choice of color schemes makes a valuable contribution to good lighting .

Control of lighting

• For uniform light distribution , install an independent switch for the row of lighting fixtures close to the windows .

• To prevent glare , avoid using highly shiny , glossy work surfaces .

• Use localized lighting in order to achieve the desired level for a particular fine job .

• Clean light fixtures regularly and follow a maintenance schedule so as to prevent flickering of old bulbs and electrical hazards due to worn out cables .

• Avoid direct eye contact with the light sources .

• For VDUs • The general lighting level should be relatively low ,

not to exceed 500 lux .• Avoid glare by suitable positioning of the VDU or

other means . • Ensure that there are no reflected light sources

seen by the user on the screen .• The luminance and contrast of the screen must be

adjustable and the characters must remain sharp . • If additional lighting is needed , it must be

adjustable and positioned in such a way as to avoid glare .

Noise and vibration

• High levels of mechanization , increased machine speeds , density of machinery at the workplace and the lack until recently of the hazards and nuisance factor of noise have resulted in many plants workers being exposed to noise levels which are nowadays considered excessive .

• Noise– means any disagreeable or undesired sound .

• Sound level meters are used to measure the pressure variations producing audible sound.

• Unit of measuring noise is decibel ( dB)

• Human ear responds in different ways to sounds of different frequencies .

• The unit of frequency is hertz ( HZ) and the ear responds over the approximate range of 20 to 20,000 Hz .

• The loudness of sound as judged by the human ear, depends on frequency as well as level . The ear is less sensitive to low and very high frequencies than to the middle range of frequencies from 1,000 to 8,000 Hz.

• Instrument used for measuring the sound – sound level meter – it has electronic network of standardized characteristics built into it to stimulate this charateristics of the average ear .

Problems due to noise

It impedes sound communication First by the acoustical masking effect which

every sound has on other sound of the same frequency or immediately higher frequencies and which reduces the intelligibility of speech that is not more than 10dB louder than the background noise .

Second by temporarily raising the acoustic threshold in the event of exposure to a noise exceeding 78 – 80 Db , if anybody is to conduct a conversation at a normal distance .

Noise may cause sensori – motor , neuro- vegetative and metabolic disorders .

It is one of the causes of industrial fatigue , irritation , reduced productivity and occupational accidents .

• Numerous investigations have revealed that a reduction in the background noise is accompanied by a marked decrease in the number of errors and significant improvement in production .

• Prolonged exposure to noise above a certain level causes permanent damage to hearing and results in occupational deafness .

• It is considered that exposure to continuous noise levels of 90 Db or above are dangerous to hearing .

• Special care should be taken in case of impulse noise , i.e. a sound with a rise time of not more than 35 milliseconds to peak intensity and a duration of not more than a second to the time when the level is 20 db below the peak . Each time the sound level increases by 6 db , the sound pressure doubles and the acoustic enery is quadrupled . , thus it is considered that for an increase of 3 to 5 db in the sound level , the duration of exposure must be halved if the biological effect is to remain unchanged .

Methods to control noise

• Reduce the noise at source • Replace noisy machines or equipments by less

noisy ones .• Particular attention should be given to ventilation

equipment .• Prevent or reduce noise transmission by the

installation of noise absorbent barriers between the noise source and the worker .

• Provide workers with ear plugs made of material such as glass fiber or foam plastic .

• Workers who are systematically exposed to noise levels above danger level should receive periodic audiometric examination .

Vibration

• Although only a limited number of workers are exposed to vibrations which constitute a health hazard , the necessary protective measures should not be neglectted .

Ways to reduce vibration levels Dynamic balancing of rotating parts .Use of vibration absorbing mountings Provide heavy foundations

• Ways to reduce the effect of vibration :

Use of vibration damping handles for hand held machines .

Period of exposure should be controlled .

Persons exposed to vibrations should be subjected to periodic medical examinations .

Climatic conditions

• The human body functions in such a way as to keep the central nervous system and the internal organs at a constant temperature . It maintains the necessary thermal balance by continuous heat exchange with the environment . The extent of this exchange depends on air temperature, ventilation , humidity and radiant heat and on body metabolism .

• During physical activity , metabolic values may go up to 10 times as much as those encountered at rest .

• It is essential to avoid excessive heat or cold and wherever possible to keep the climatic conditions optimal so that the body can maintain a thermal balance .

Working in hot environment

Hot and humid Hot and dry ( desert like )• It is necessary to consider thermal

burden in relation to the energy expenditure required by work . The more burdensome the climatic conditions , the longer the work breaks should be .

Working in a cold environment

• Exposure to cold can produce serious effects especially when workers are exposed to temperatures below 10 degree Celsius .

Work periods in cold environments should where necessary be alternated with work periods in normal temperature.

Workers in cold climates and refrigerated premises should be well protected against cold by wearing suitable clothes , including footwear , gloves and hat .

Ventilation

• For a given number of workers , the smaller the work premises the more intense should be the ventilation .

Advantages :• Disperses heat generated by machines

and people at work . • Dilutes atmospheric contamination .• Maintains the feeling of air freshness .

Exposure to toxic substances

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Working time

• Hours of work • Overtime • Breaks and rest pauses • Daily and weekly rest • Night work • Flexible working time arrangements

Work related welfare facilities

• Drinking water • Sanitary facilities • First aid and medical facilities • Rest facilities • Feeding facilities • Child care facilities • Recreational facilities