(introduction...)

Physical working conditions differ from one enterprise to another. They are closely related to the work process, and depend on the various arrangements of the work premises. It is essential to keep a safe, healthy and comfortable environment as it contributes to work efficiency and the well-being of workers.

If the physical working environment is not safeguarded, there may be many ill-effects on the enterprise and its workers. Accidents due to a poor working environment are unfortunately very common, especially in developing countries. As a result, there is often a loss of life and great suffering on the part of the workers and many man-days lost on the part of the enterprise. Poor lighting has given rise to many health problems, such as eyestrain, and predisposed workers to accidents and reduced productivity or quality of work. Excessive temperature and humidity have resulted in serious discomfort and poor morale of workers. High noise levels have caused deafness in thousands of workers. Improper handling or storage of hazardous materials has led to poisoning.

In many cases, there are overriding dangers or problems that require careful technical solutions. For example, the degree of toxicity of hazardous substances is not easily known to the employer or workers. The effects of noise can eventually lead to deafness, but the hearing loss may not be observed for many years. It is too late when we find symptom of poisoning from chemicals or deafness due to noise. There are therefore regulatory measures covered by laws and regulations which must be followed. At times, technical advice is indispensable to identify effective solutions, and exchange of information between enterprises with similar operations can be helpful.

However, there are a number of measures that can be undertaken by the employer himself as part of his daily responsibilities. A workplace which is adequately designed with good lighting and ventilation, isolation of noisy machines, separate handling of hazardous substances and ample space for workers, contributes greatly to a proper physical environment.

The solutions to environmental problems are often simple and inexpensive. It is often true that prevention is better than cure. Commonsense and foresight may be all that is necessary, sometimes with a small amount of care and money. At other times, problems may have already occurred. The management may realise that a problem exists because of complaints by workers or because of careful assessment of existing hazards. There may also be high labour turnover or absence rates or other indicators of poor morale or low productivity among workers.

At other times, consultations between workers and supervisors or management have led to fruitful results. Often ideas for solutions develop because someone in an enterprise had seen or read about improvements in similar cases. Thus it could be very useful to make it a habit to visit other enterprises in the neighbourhood, especially those in the same line of business.

A note of caution should be made concerning environmental problems. It is always wise to seek advice when dealing with specific hazards. An effective strategy for the control of these specific hazards, as in mechanical hazards or dealing with harmful substances, should make use of all the experience and skills available. The various experts dealing with the different aspects of the physical working environment should be consulted when and where necessary. There is no hard and fast rule on this. A reasonable level of awareness and basic knowledge of the subject would go a long way towards making the right decisions in this matter.

1. Lighting

Lighting has a significant effect on work efficiency, comfort and safety. Although our eyes can adjust to a wide range of brightness, efficiency and safety will deteriorate unless workers can clearly see what they are doing.

No one will challenge the need for proper lighting. Nevertheless, there are great variations from one factory to another in the lighting levels during similar operations. There are many workshops where better lighting can improve productivity and reduce accidents.

Proper lighting varies according to the tasks that need to be performed. Fine work requires stronger lighting than other kinds of work. Lighting which is adequate for simple loading or heavy manual work will not be satisfactory for machine or office work. Fine finishing or painting, assembling or inspecting of small parts, drawing offices, and manipulation of dark objects require much higher standards of lighting. On the other hand, glare from too bright light sources should also be avoided, as it could lead to eyestrain. Strong reflections can also hamper work. Sudden shifts in illumination, as in the case of moving from areas of strong daylight to poorly lit areas, can result in accidents. It is particularly important that older people have plenty of proper lighting.

Proper lighting needs a good combination of daylight conditions and artificial lights. There are many means of improving lighting at low cost. Installation of skylights or wider window openings can greatly help. Relocation of worksites in relation to windows or light sources is sometimes helpful. The adjustment of the height or re-positioning of light fixtures can often make a great deal of difference to lighting. Using light colours for walls and fixtures should be considered. Provision of local lighting or spot lights, especially for operations which require higher lighting levels than others, can often be done at relatively low cost. Simple measures such as regular cleaning of windows, lamp-shades or lamp-covers and replacing old lamps or flickering fluorescent light tubes are also important.

Prevention of direct or reflected glare can be achieved by a change in the light direction towards the worker or by the use of adequate shades for the light sources.

Many examples of low-cost improvements in lighting can be found in developing countries. One advantage is that the enterprise, once aware of the need, can carry out improvements in lighting relatively easily. The cost of such improvements per worksite is usually low. The examples in this section also show that improvements in lighting can lead to a noticeable improvement in work efficiency and the quality of products.

Case 36: Installing skylights

In a furniture-making factory in the Philippines, workers complained about the inadequate lighting facilities. The manager also noticed that work was hampered by the poor lighting. The management installed a number of skylight roofing sheets made of clear polyvinyl chloride among the galvanised roofing sheets. There was a marked improvement in the quality of finished products. There was a noticeable reduction in the re-work rate in the factory. There were no more complaints about the lighting from the workers.

The cost incurred was about US$ 150 which was mainly used for the materials. The skylight sheets were installed by the workers. The work was completed in a week by two workers (average wage, US$ 4 per eight-hour day).

Figure 63: Skylights installed in a furniture factory.

In another tile-manufacturing company Which employed about 20 workers in the Philippines, the workplace was enclosed with concrete walls with few openings. It had been designed that way to prevent sawdust from spreading to the neighbouring residential houses. The manager and his son discussed a plan on how to provide adequate lighting. They had two options to choose from. One was to add ten fluorescent lamps to illuminate the whole area sufficiently. The other was to install six skylights on plastic transparent roofings to enable the natural sunlight to enter the work area.

They eventually decided to install six skylights instead of lamps to save their electricity bills. The six Skylights were installed on two sloping sides of the factory roof. As a result, there was a considerable increase in lighting. About 15 of the total 20 workers benefited from the improvement. The cost for plastic roofings was US$ 35 with the cost of installation at about US$ 11. Considering the electricity and maintenance costs of fluorescent lamps, the installation of skylights proved to be more economical.

Case 37: Fibre-glass skylight sheets

In a big workshop in Calcutta, lamps were placed near the ceiling so as to make enough space for the operation of an overhead crane. As the illumination in the workshop was poor even in the daytime, some skylights were installed. Corrugated fibre-glass transparent sheets were fitted into the roof at four different places directly above the areas requiring more illumination. As a result, the workers had fewer complaints of eyestrain, and safety also improved.

The approximate cost of the fibre-glass sheets was US $55 for 20 square feet and the fitting charge was US$ 5. The costs saved cannot be assessed but the savings in electricity bills amounted to US$ 10 per month. As the electrical lights required less use, there was also a 30 per cent reduction in the costs of replacement of the bulbs.

These two examples show the remarkable improvement in lighting which would result simply by making better use of daylight. Skylights cannot provide enough lighting at all times of day but can contribute to increased illumination levels and savings in electricity bills.

Case 38: Painting the walls white

In a pump-manufacturing factory in Madras, lighting inside the workrooms was found insufficient for work. The reason was not clear to the manager. Sufficient tube lights hanging from the roof had been provided. There were corrugated plastic sheets over the roof at intervals to let in daylight. On careful examination, however, it was noticed that the hanging tube lights were covered with accumulated dirt. The clear plastic sheets were also covered with dirt and sacks. The workers thought the sacks was necessary because of sunlight glare during the summer. It was also noticed that the ceilings and walls were dirty and therefore proper reflection of light was hindered.

It was decided to remove the dirt and the sacks, and to paint the ceilings and walls white after thorough cleaning. All the tube light fittings were cleaned and the underside of the reflectors was also painted white. The ceiling and walls were given two coats of white paint. When this was completed, the factory looked entirely new and there was adequate light for the workrooms.

The white paint for the ceilings and walls cost nearly US$ 220. The cost was small in view of the large benefit in increased production. The workers were happy as eyestrain and discomfort at work were notably reduced.

Figure 64: Both ceilings and walls painted white.

In another small workshop producing electronic equipment parts in Madras, general lighting was also poor. The windows and doors and their north-facing glass should have been sufficient for general lighting in the daytime, but the walls, windows and doors were all dirty. Hence it was decided to clean all the walls and windows and to give the walls a coat of primer and two coats of white paint. As a result, the general lighting conditions improved remarkably. Productivity increased slightly with less complaints of fatigue from workers. The total cleaning and painting cost was US$ 350. The cleaning charges per month were estimated to be US$ 10.

Figure 65: Skylights and windows cleaned and ceilings and walls white painted.

Case 39: Lowering lights

The sewing and knitting sections of a garment firm in the Philippines, with about 65 workers, were affected by poor lighting. Women workers at the sewing and knitting sections on the second floor, and male workers at the knitting section on the ground floor complained of low levels of lighting. The rather high rate of rejected knitted and sewn products seemed in part to be related to the poor lighting. When a foreman talked with the workers, they pointed out the very high positions of fluorescent lamps. There were six pairs of fluorescent lamps on the ceiling of the knitting section, but they were too high and not adequately located in relation to the workers' positions. Using sixty metres of wire, the fluorescent lamps at the two sections were lowered and relocated at more appropriate positions.

The cost incurred was only as US$ 15 for 60 metres of wire. It was no longer necessary to install more lamps. There were no more complaints about eyestrain due to poor lighting. Productivity increased by five to ten per cent.

Figure 66: Fluorescent lights arranged for each workstation in a knitting section.

Figure 67: Lights lowered to an appropriate position to give more light on knitting operations.

Case 40: Repositioning lights with new reflectors

In a fitters' workshop of an engineering factory in Burma, bad illumination was considered to be a factor in causing some accidents and also bad workmanship. The workers complained of visual discomfort. The production manager who surveyed the illumination with a photometer found that the low level of illumination was due to the distance between the existing four overhead lights and the workbench. These four-foot fluorescent lights were without reflectors and fitted on a single overhead hanger.

Figure 68: A 40 W fluorescent light in the fitters' shop.

The positions of the lights were lowered by about 30 cm so that they were about 130 cm above the workbench. This height was found to be optimal as the lights were kept beyond the visual angles of the workers. The lights were fitted on two parallel overhead hangers in a zig-zag pattern. All were fitted with proper reflectors. Approximately US$ 150 was spent on refitting the lights with reflectors. Electricians among the factory staff fitted the lights on the newly arranged overhead hangers.

The illumination measured prior to modification was 130 lux at the workbench height. The improvement resulted in raising the illumination level to 280 lux. The management and the workers agreed that the improvement was satisfactory and reduced risks of injury.

Figure 69: Modified positions of fluorescent lights provided with proper reflectors.

Figure 70: A worker working under the repositioned light with an illumination level of 280 lux.

Case 41: Improving lighting fixtures

The owner of a shoe-making factory in the Philippines, which employed 80 workers, discovered that there was a need for more adequate lighting in its production area of approximately 350 square metres. The workers were asked to specify how lighting in their individual workstations could be improved or modified. Several lamps were found to be either broken or flickering. Some workers complained of fatigue, headache and eyestrain due to inadequate lighting.

With the help of an electrician, the owner made a plan for modifying the lighting arrangements taking into account feedback from the workers. About 20 new fluorescent lamps were installed in place of incandescent bulbs and broken or flickering fluorescent ones.

Reflectors were then fitted into the fluorescent lamps using available materials such as hard cartons and aluminium foil. The light fixtures were lowered to a level appropriate for production work. In most cases, this level was about 30 cm lower than the original height. Instructions were given to the workers to keep the lighting units clean.

After these improvements, the production increased by about 10 per cent on average. The repetitions required decreased by about 25 per cent. Over 90 per cent of the firm's workers considered that the additional fluorescent lamps and other changes undoubtedly reduced their discomfort.

The cost of the twenty units of fluorescent lamps, three rolls of aluminium foil and wood attachments and the labour cost of an electrician and carpenter amounted to approximately US$ 65.

Similar improvements of fluorescent lamp fixtures were made in a small pinewood furniture manufacturing company with 27 workers, also in the Philippines. With the assistance of a stock clerk, the owner-manager consulted the workers about better lighting. They agreed to install reflectors for each of the 25 fluorescent lamps. These reflectors were made of plywood, aluminium foil, tapes and wires. The cost incurred was minimal, approximately US$ 30. The workers felt more comfortable and the increase in their efficiency was estimated to be approximately 10 per cent.

Case 42: Better lighting for an assembly plant

An assembly plant making electronic products in Singapore with 240 people working in two shifts undertook a better lighting scheme in a section of about 180 square metres. This was because several workers of the section had complained of visual discomfort and the rejection rate of assembled sets was quite high.

After a survey of illumination levels and glare and shadow problems, the lights were modified in the following three ways. First, the light covers were cleaned, which led to a significant improvement. Second, the overhead lights were lowered to an optimal height to give good illumination, no glare and no interference with bodily movements. Third, defective lights were replaced with new ones. As a result, an average increase of 20 per cent was noted in the number of assembled sets for every shift, and there was average decrease of 15 per cent in the number of rejected sets per shift. The workers agreed that eyestrain was reduced and comfort increased.

The costs incurred were approximately US$ 500, including lights and labour costs. Since the lights were installed during the weekends when there was no production work, there was no interruption of work during the modifications. Savings from increased productivity far outweighed the costs.

Figure 71: Typewriter assembly operations which require good lighting.

Figure 72: Overhead lights lowered to an optimal height over assembly lines.

This example underlines an important point. Lighting can be improved considerably by modifications in the position and maintenance of lights, and production work, such as assembling small parts, can benefit a great deal from these inexpensive modifications. For similar reasons, lights should be maintained on a regular basis.

Case 43: Glare and lack of contrast

In an electrical assembly plant in Sri Lanka, the lighting from fluorescent light tubes was quite adequate. The work tables were varnished and polished and covered with thick white paper. The walls were light yellow. The components assembled were white or pale yellow. The problem here was glare and lack of contrast of colours. The management covered the table surface with black paper and repainted the walls pale blue. The results were encouraging. The rejection of assembled parts fell by 15 per cent and production increased by 10 per cent. The cost of the improvements came to US$ 120.

Case 44: Reducing injury risks by adding lights

In the section of an engineering factory in Burma where a grinding machine was located, six cases of a foreign body in the eye were reported within a period of three months. The existing general illumination level was found to be only 60 lux, with the light coming from a transparent roofing sheet somewhat distant from the machine. With this low illumination level, the workers did not use the protective eye-glasses provided which were dirty and scratched.

The situation was improved by fitting two additional sets of 40 W fluorescent lights over the machine. The illumination level was raised to 260 lux. New protective eye-glasses were provided. It was also found that the workers who used the machine did not know how to close properly the shutter at the top of the hood guard. The workers were instructed on the use of the shutter which helped prevent dust from escaping. The management agreed to install in the future a standard exhaust system for removing dust.

The two new sets of fluorescent lights cost US$ 140. There were no more complaints of visual discomfort. When the safety committee checked the work station three months after the modifications, the workers were keeping the shutter closed and wearing safety glasses at work. No cases of a foreign body in the eye were reported after the improvement.

Figure 73: An operator working without protective glasses and with the shutter at the top of the hood guard in an open position.

Figure 74: Work at the grinding machine with a newly fitted light. The operator is wearing protective glasses and the shutter is in the closed position.

2. Heat and noise

Most of the developing countries lie in the tropical or sub-tropical regions of the world. A hot and humid climate is therefore common in such countries and may lead to heat and ventilation problems. In addition, manufacturing equipment and processes are probably equally common as causes of heat problems. Examples of heat-producing equipment and processes include furnaces for smelting, heating and other activities, welding, boilers, glass-making and generators. Hard physical work increases heat production within the body and thus adds to the heat problem in hot workplaces. Often heat problems result from the combination of the weather, manufacturing processes and poor ventilation.

Excessive heat affects the comfort and productivity of workers. They may become restless, lose their powers of concentration or feel dizzy. Sometimes workers may develop body aches and muscle cramps. These cramps are due to excessive loss of water and salt from the body through perspiration. Occasionally, the heat may be so severe as to affect the brain. The workers may then suddenly lose consciousness. In such severe cases, death may occur.

Noise is also a widespread problem in enterprises. Machines for stamping, pressing, rivetting or punching metal parts are often very noisy. Weaving looms, bottling apparatus and generators can also produce a lot of noise. In construction, piling machines and many other pieces of equipment can create noise problems. There are also many other sources of high noise levels in small as well as large enterprises.

There is a simple way to determine whether the noise level is dangerous to hearing or not. When a person has to shout to enable another person with normal hearing to hear his words one or two metres away, this usually means the noise level is about 85 dB. There are more elaborate ways of measuring and analysing noise by sound level metres, and these are usually needed for precise monitoring.

There are many low-cost ways of reducing heat or noise problems. Isolation of the sources of heat or noise can be universally applied. Workplaces should be spacious and, especially to reduce heat effects, have adequate windows or doors to allow for good air flow. Walls and roofs should not be made of materials which reflect noise or which are good conductors of solar heat. In other situations, we could use enclosure or insulation of heated machines or pipes or noisy machines. If heat radiation is great, for example from furnaces, workers can be shielded from it by a barrier or screen.

The heat or noise may sometimes still be excessive in spite of available measures. In this case, consideration should be given to drastic technical solutions, such as purchasing cooler or quieter machines or air-conditioning, or, as a last resort, providing protective clothing or ear muffs or plugs.

The following examples illustrate how enterprises have coped with severe heat or noise problems by making simple improvements in the environment. They show that such improvements in the physical environment need not always be expensive.

Case 45: Wider windows and ventilators

In a laundry section of a hotel in Bali, Indonesia, about 15 workers were working in hot and humid conditions. The lack of air movement was obviously aggravating the effects of heat. It was therefore decided to have new openings and windows and to install a few ventilators.

US$ 150 was spent on constructing new windows and openings as shown in figures 75 and 76, Another US$ 60 were spent on ventilators. The air movement improved greatly and the laundry room became cooler. This had a positive impact on the productivity of the workers. The lighting conditions of the room also improved.

Figure 75: High windows and a ventilator in a hotel laundry section.

Figure 76: Ventilation openings in a hotel laundry section.

In a factory producing bangles made of glass in Bangladesh, there were 18 workers in the finishing section. A small heater was used to temper bangles. The workers complained of excessive heat and burns occasionally caused due to handling the iron handles of the heater. The frequent turnover of workers in this section seemed related to the work strain.

A small electric fan was installed on the workroom wall. A wooden handle was fitted to the iron handle of the heater. It was also arranged to increase ventilation in the room by keeping windows and doors open. The improvements were done at low cost. The electrical fan cost US$ 43, the wooden handle US$ 1, and arrangements for cross ventilation about US$ 4. Though no records were available about the production or rejection of products, the management noted a significant reduction in rejected products.

Installation of a ventilator in a varnishing section of a furniture factory with 10 workers in the Philippines also proved useful for the reduction of the heat load of the workers at low cost. Although there were wide windows, the whole building was surrounded by high and thick walls which prevented the air from entering. The manager, after discussing the matter with a supervisor and the workers, installed a ventilator at an appropriate place. This cost US$ 140. Its life span was considered to be ten years or more. With the improved ventilation, the room became cooler. A worker could now varnish ten chairs a day, while before he could hardly varnish eight. The frequency of repeating the finishing touches on the furniture also was reduced.

Case 46: Barriers for thermal radiation

Thermal radiation from furnaces, molten metal and slag produced adverse effects on the workers of a flash smelting shop in Calcutta, India. Many of the 225 workers employed in the shop were exposed to high thermal radiation. The hot metal splashes and sparks also caused injury and fire hazards. The factory asked for advice about low-cost solutions.

An adjustable thermal radiation barrier and hinged covers for channels carrying molten slag seemed practical solutions. As polished aluminium thermal barriers were costly and required regular cleaning, two oxidised iron sheets of one metre by one metre each in size were used to form a thermal barrier, with a gap of 25 cm between them. The two sheets were fixed with iron rods at the four corners and at the middle. The thermal barrier was placed between the sources of high thermal radiation and the workers. The barrier was put on two low-cost stands with different points of suspension. The lower part of the barrier stand was kept open for the circulation of air between the sheets.

The covers over the channels for molten slag were fixed with hinges so that they could be raised when maintenance or cleaning of the channels was done.

Both the thermal barrier and the covers for the channels protected the workers from high thermal radiation. The sheet on the radiation side of the thermal barrier was very hot, but the sheet on the workers' side was much cooler. The difference between the temperature reading of a globe thermometer with and without the thermal barrier for an exposure period of one hour was about 40°C. The barrier as well as the channel covers acted as guards against splashes of metal, sparks, etc. The risk of accidents was greatly reduced.

The cost of the thermal barrier with the stands was estimated to be about US$ 40 and the cost for each cover for the slag channels was estimated to be US$ 15, including the labour cost. However, scrap materials and the spare time of a permanent employee were used. The maintenance cost was negligible.

Figure 77: Side view of an adjustable thermal barrier for portable use.

Figure 78: Front view of a portable heat barrier.

Figure 79: Covers over channels for molten slag. A globe thermometer measuring the heat radiation is seen.

Case 47: Use of longer tongs to reduce heat stress

A blacksmith shop in an engineering factory in Burma was using a forge hammer machine for production of square rods (dog spikes). The workers engaged in heating rod pieces near the machine complained of discomfort due to heat from the furnace. The production target of 2,000 hammered dog spikes per eight-hour shift could not be met.

Out of the five workers engaged in the process, only three were found to be close to the heat source. One of them had to put the rods into the furnace, while another picked the hot rods out of the furnace. This second worker was found to be suffering the most from the heat. The third worker who retrieved the dog spikes from the hammering machine to drop them into water for cooling was exposed in a limited manner. The radiant heat in the proximity of the furnace was 46°C. The tongs used by the two workers at the furnace were found to be 55 cm long. Work was interrupted repeatedly by demands for rest.

Figure 80: Furnace workers using short tongs. Putting a rod into the furnace.

The tongs were replaced by longer ones measuring 80 cm in order to move the worksite as far as possible from the furnace. The weight and the holding force of the tongs were considered carefully so as to avoid new problems. The radiant heat load measured at the work position was found to be 6°C less than in the previous work positions. The longer tongs were produced from ready stock in the factory and did not cost anything.

Parallel to this, a new work regimen was introduced for the heat-exposed work. Two more workers were added to the existing three, and three out of the five workers worked at a time while the other two rested in a cooler area in the shop. This was made possible by approximately US$ 50 per month, the current cost of employing two more persons. This led to an average increase of 60 per cent in the production, and the production target of 2,000 dog spikes per shift was achieved. There was consensus that thermal load was substantially reduced.

Figure 81: Short tongs previously used and long tongs used after the improvement.

Figure 82: A worker using longer tongs to take out a heated rod from the furnace.

Case 48: Insulation slab in front of furnace doors

The smith shop of a railway workshop in India employed 20 workers who were exposed to radiant heat emanating from furnaces. Some adverse effects were noted on the health and efficiency of these workers. At their place of work, the mean difference between readings of a thermometer and a dry bulb thermometer was as high as 46°C. These measurements proved that the workers were put under undue physiological stress due to excessive heat radiation. The workload as evaluated from the pulse rate and the sweating rate of the workers was categorised as “heavy”.

A 90 × 120 cm calcium silicate slab 50 mm thick was placed, as an insulation slab, at a fixed distance of 1.7 metres from the furnace doors. The slab served as a thermal barrier preventing heat radiation from the furnace doors from reaching the workers directly. There was remarkable relief in thermal strain. The pulse rate increase during work reduced by 40 to 70 per cent. The rate of perspiration also reduced by 20 to 30 per cent. The reduction in mean globe thermometer readings was from about 40 to 50 per cent.

The direct cost for fabrication of a set of a calcium silicate slab barriers with a frame was approximately US$ 180.

Case 49: Reducing heat stress by environmental improvements and protective clothing

In a small enterprise in Sri Lanka producing activated carbon, there were 12 workers employed in the kiln section. The process involved the burning of coconut shells and husks. The workers often complained of severe headache, a burning sensation in the eyes, nose and mouth, a hot feeling in the body, body aches and dryness of the skin. The kiln was made of cast iron and fired by diesel oil. There were openings at either end for loading and unloading.

The temperature was found to be often over 41°C, which was very hot, and humidity was also very high. Both ends of the kiln were so hot that the workers could not bear to be there for more than a few minutes at one time.

The problem was solved with a series of simple and inexpensive measures. The whole kiln was painted with white aluminium paint, which reduced the amount of radiant heat. A small wooden cubicle with tinted glass windows was constructed at a short distance from the kiln. The workers were told to stay in the cubicle except during the brief moments when they tended the kiln. In this way they avoided unnecessary heat exposure. When the workers tended the kiln, they wore aprons lined with aluminium foil on the outside and cotton on the inside. They also used tinted glass goggles. This insulated them from much of the heat. Drinking water containing some common salt was provided in the cubicle and the workers were encouraged to drink this frequently. This ensured that the workers had enough water and salt to replace that lost through perspiration. In addition, wire mesh was installed in the windows of the building in which the kiln was located. The windows could now be kept wide open the whole time, whereas previously they were kept closed for security reasons. This meant that general ventilation was improved.

All the above-mentioned environmental improvements led to a drop in the usual temperature around the kiln from over 41°C to about 36°C. The humidity was also reduced. The workers also complained less frequently of discomfort. By staying in the cubicle most of the time and using protective clothes when tending the kiln, they significantly eliminated the health hazard.

The direct cost of the improvements amounted to about US $400. The indirect costs, including the workers' time painting the kiln and building the cubicle, amounted to about US$ 80.

Case 50: Use of insulation material to dampen noise

In a small jewellery factory in Thailand, the noise produced by gem polishing machinery, which operated both day and night, was irritating and caused loss of sleep both for the workers who slept in a dormitory on the premises and for the residents living around the factory.

The gem polishing machinery consisted of a tumbler driven by an electric motor in which rough stones were placed with an abrasive mixture.

Casings for the tumblers were constructed from foam insulation material about 3 cm thick intended for refrigeration purposes and held in place by wire. Each casing cost about US$ 4. The cost of the time spent was minimal. Several trials had to be conducted to determine the thickness of foam required.

As a result, the noise level reduced substantially. The workers who slept in the dormitory reported that the noise was now tolerable. Although an increase in productivity was not measured, it could be surmised that workers were in a better state to work as they slept better.

While the improvement was inexpensive and easy to carry out, patience was needed, as the optimum thickness of insulation was found out only after several trials.

Case 51: Reducing noise by distance

In Sri Lanka, it was found that five power presses in a manufacturing enterprise produced noise levels of 102-104 dB(A). Even when only one or two presses were functioning, noise levels of up to 98 dB(A) were produced. This caused irritation to the workers and also the danger of noise-induced hearing loss.

To cope with this problem, the power presses were moved to a distance of 20 metres from the place where most of the workers were located. In this way, these workers were exposed to acceptable noise levels of 75-80 dB(A). Workers who operated the power presses were provided with ear muffs and rotated to a quieter section of the factory after a maximum of four hours continuous duty in the power press area.

This is an example of a low-cost solution to reduce noise to a safe and acceptable level simply by moving the noisy machines further away from most of the workers. The minority of workers who looked after those machines used ear protectors.

Case 52: Reducing noise by dampeners

In a factory in Thailand, plastic moulding machines produced excessive noise. In this case, noise dampeners were used to solve the problem. Shaped corks were fitted around escape valves from which most of the noise came (Figure 83). To protect the fragile corks, acrylic plastic caps were placed over them (Figure 84). These measures for each machine cost only a few US dollars but the noise levels reduced from more than 85 dB(A) to less than 60 dB(A).

In a small electronics factory in India, loud noise coming from a grinder was disturbing all the workers in the workroom. It was found that the direct mounting of the grinder on a wooden table made the noise much louder than expected. The grinder was without any cover for its power-transmission belt. Rubber dampeners were placed at the base of the grinder. The moving belt portion was covered with a metal cover which was also fixed using the rubber dampeners. The noise was greatly reduced and the workers could now communicate with ease while the grinder was in operation. The mounting of rubber dampeners, together with the belt cover, cost about US$ 18.

Figure 83: Cork silencers to reduce noise around escape valves.

Figure 84: Silencers with acrylic covers.

Case 53: An acoustic box functioning as a noise muffler

A compression process using an ultra-sonic engine was producing loud and sharp noise in a cassette tape recorder and radio factory in Indonesia. The compression process was necessary to fix glass to the main case plate of the front cover of each radio set. The workers manning this compression process were placed in a separate room so that the noise did not disturb other workers. The noise was as high as 105 to 107 dB(A) and thus a severe occupational hazard to the compression process workers, who carried out this process 500 times per work day.

An acoustic box was made using 16 mm particle board. The box was 96 cm long, 82 cm wide and 137 cm high. The inner part of the box was lined with noise-absorbing materials. Both the left and right sides of the box were furnished with a window and a door. The front part could be opened only when the compression process was finished. The ultra-sonic engine was put into the acoustic box.

Figure 85: An acoustic box encasing a noisy compression process. The inner part is lined with noise-absorbing materials.

The box was made by the company workers. The box materials cost US$ 70 for the particle board and US$ 48 for the acoustic materials.

The noise reduction was remarkable. With the box, the noise level fell to the range of 80 to 90 dB(A). The sound coming out of the box was no longer sharp. Other workers, when necessary, could work in the same room. The workers doing the compression process no longer felt isolated.

3. Handling, use and storage of hazardous substances

When hazardous substances are used in a manufacturing enterprise, they may be handled by a number of workers. The workers may have no idea of the nature of these substances or of the dangers they may present. Appropriate precautions must be taken during handling, use and storage of such substances.

Substances vary in their dangerous properties according to the chemical composition, physical state and the conditions under which they are handled, used or stored. There is no uniform system to take into account all these different conditions. Therefore it is essential that each operation considered hazardous should be conducted strictly in accordance with approved procedures. Only designated equipment should be used. Supervisors should specify operations which are considered hazardous and require monitoring by approved safety or other personnel.

The required procedures for preventing hazards from these substances must be applied on a regular basis. These procedures are not necessarily expensive. It is important to involve all the supervisors and workers concerned. For example, supervisors should ensure that hazardous operations are conducted only in designated areas and monitored for compliance with safety rules. Only essential personnel should be permitted during a specific operation. All designated areas should have suitable warnings. Open flames or unprotected electrical equipment should not be permitted in areas where flammable or explosive materials are present. Furthermore, escape routes, exits and stairways should be clearly marked, and emergency lighting provided.

In addition to the above-mentioned precautions, the use of dangerous materials often requires appropriate protective equipment and the provision of appropriate first-aid equipment. Proper maintenance of the equipment is important. Adequate and regular training of personnel on the use of such equipment and on actions to be taken in time of danger must be organised.

As for storage of hazardous materials, the responsibility should be entrusted to one or a few persons with adequate knowledge and competence. Deposits and withdrawals should be carefully and promptly filled in a register, and signed by the recipients. Whenever possible, hazardous raw materials should be kept locked away. Inventories should be conducted at regular intervals. Flammable or explosive substances should be kept away from open flames or excessive temperatures. In addition, all the materials should be properly labelled, describing their nature, with adequate warning signs. Such labels should be in the language understood by the workers.

Obviously, the more hazardous the substance, the greater the precautions to be taken. The examples which follow illustrate some of the precautions which are feasible for small enterprises. They show how the handling, use and storage of hazardous substances can be made safe and convenient.

Some of these examples show that it is better to enclose a hazardous process than to provide personal protective devices for workers. Personal protective devices, such as goggles, masks, aprons, gloves and boots, are often uncomfortable, especially in a tropical climate. As a result, workers tend not to use them. In addition, personal protective devices must fit everyone well to be effective.

It is important that the workers are carefully trained and the process continuously monitored for safety and efficiency. It is not sufficient to merely introduce an improvement. It must work in the long term and workers have to be thoroughly trained. Finally, most of these examples clearly show that productivity and safety often go together.

Case 54: Prevention of chemicals spillage using container holders

In a toy factory in Singapore, spillage of chemicals was a frequent occurrence. Some of these chemicals were irritating to the skin and eyes. The spillages occurred mainly because the containers were not secured to the tops of the work tables. When the worker got up or sat down, he sometimes knocked against the table, and tipped over the container.

The problem was solved by using a glass container with a magnet at the bottom. The container was placed over a slab of heavy and thick steel. This measure avoided tipping over of the container even if the worktable was shaken.

Each glass bottle and magnet cost less than US$ 5. The metal slabs cost nothing, as they were made from the waste materials in the company itself.

The results were gratifying, as no chemical spillages have occurred since the introduction of this simple innovation.

Figure 86: The bottom of a glass container holder. The magnet in the bottom is placed over a steel slab.

Figure 87: A chemical container placed in a holder.

Case 55: Dust suppression by water sprinkling

In a rock crushing enterprise in Sri Lanka which employed 25 workers, there were frequent complaints of difficulty in breathing and eye irritation from the dust. A piping extension from the main water supply was installed to sprinkle water during the crushing process. Complaints from workers were reduced and morale improved as workers were no longer covered with dust.

It should be noted in this instance that the measure was introduced largely because of the complaints of discomfort by the workers. The usual dust from rock crushing has a high silica content, which can give lead to a severe lung disease called silicosis. The reduction of dust by the sprinkling of water was therefore helpful, both in reducing the discomfort of workers and a serious threat to their health at the same time.

Case 56: Suppression of tapioca dust by using a funnel

In a packing plant in Thailand, tapioca powder is re-packed from large sacks into smaller packets for retail sales. During this process, the workers breathed in large amounts of tapioca dust and experienced congestion of the chest and difficulty in breathing. Face masks were provided but the workers did not like using them in the hot, humid conditions of the factory.

Gunny sacks, which are very commonly used in tropical countries, were stitched together to form a funnel for pouring the powder from the large to the small containers. To maintain the quality of newly-packed tapioca flour, fresh gunny sacks were used for this purpose every day.

Figure 88: A funnel to suppress tapioca dust.

There were no further complaints by the workers, as the amount of dust was greatly reduced by this method. There was virtually no cost, as the gunny sacks were available free of charge. Labour for sewing might cost US$ 1 per day.

Case 57: Improved hoods for coal smoke

Workers in a blacksmith shop of a large engineering factory in Burma were exposed to smoke from furnaces. They complained of discomfort due to breathing the smoke. There was a hood over each of the furnaces, but apparently the shape and position of these hoods were inadequate and allowed much of the smoke to escape.

Figure 89: One of the old hoods leading to a chimney over a small coal furnace.

After examining the design of the existing hoods, the normal work position of the workers and the air flow through the chimneys, it was decided to replace the hoods by a better design with a larger volume. A somewhat better hood at the joint with the chimney was also found to be defective, and allowed the smoke to pass through the breathing space of workers. The height of the lower tip of the new hoods was fixed at 60 cm from the furnace tables which were set at 65 cm from the ground. These heights were found suitable for the type of work done. The furnace table was extended to the front by about 30 cm.

Figure 90: A somewhat improved hood still found defective.

Approximately US$ 13 was spent per hood for the material. The labour cost was not estimated as the factory staff were engaged in producing improved designs. Using the new hoods, the coal smoke did not escape from the canopy under normal circumstances.

Figure 91: The improved hood with larger volume, positioned so that the worker can keep away from the smoke.

Case 58: Prevention of acid burns by enclosure

In a small factory making electrical components in the Philippines, copper materials were dipped in a bath of strong acid. Workers wearing face masks had to dip wire cages filled with copper materials into the bath. The work area of this section was about 20 square metres. It was decided to improve productivity by speeding up the process. At the same time, measures were taken to increase safety during the operation.

Figure 92: A worker dipping the wire cage containing copper components into the open acid bath.

The plant manager engaged a consultancy institute, which constructed an enclosure for the acid bath. This enclosure had glass windows to enable the worker to see the process. The workers were all trained in operating the chamber. For the next three months, the chamber operation was monitored daily for effectiveness and safety.

Figure 93: Enclosed acid bath with operation from behind the glass window.

This new method increased productivity by 53 per cent because the six stations of the chamber allowed six batches of parts to be treated simultaneously instead of one by one, as done previously. Moreover, the workers were no longer exposed to the hazards of acid fumes and burns. Fatigue was reduced as the lifting, dipping and hauling up of the wire cages were all done mechanically and not manually as before. Better industrial relations resulted as the workers appreciated the improvements.

About US$ 350 were spent to construct the steel chamber, including the exhaust fans and other mechanical parts. The design and installation were done by the engineering department of the company while the consultancy service was provided free of charge. The training cost consisted of an hour's pay (US$ 0.80) for each of the workers trained, since one hour was sufficient for the training. The recurrent cost for the upkeep of the chamber was estimated at US$ 100 per year.

Savings were considerable, namely, the cost of medical treatment (including hospital charges) for workers who suffered acid burns from the previous process. The 53 per cent increase in productivity also presented significant savings.

4. Guards and other safety devices

Where there is danger from machinery operations, it is not desirable, nor wise, to rely solely upon safe working practices, essential though these are. Guards and other safety devices are useful as ultimate barriers to prevent injury when other precautions fail. Operation of a machine can only be efficient if there is no inherent danger.

An effective way of preventing injuries caused by machinery is to prevent the worker from coming into direct contact with the dangerous machine components, such as moving parts or high voltage wires. These dangerous parts should be guarded or protected in such a way as to prevent dangerous access at all times.

There are different kinds of guards. Fixed guards are set up around various dangerous parts such as rotating shafts, belts or drums, nips at ingathering rotating parts, projections, other moving parts of machinery, fast running or hot surfaces, etc. If frequent access to the area protected by a guard for changing parts or cleaning is necessary, interlocked guards can be applied. An interlocked guard prevents direct contact with danger as it must be back in position before the machine can be restarted. Automatic guards are also useful. One type of automatic guard pushes or pulls any part of a person away from the danger zone when necessary, for example, when working with cutting machines or presses. Another type of automatic guard uses a light beam which scans the danger area and falls on a photo-electric cell which is connected to a stop switch. When any part of a person comes within the area, the dangerous machine motion is stopped by a switch connected to the cell.

Automatic guards also include an automatically operated sliding screen which provides a temporary barrier between an operator loading a workpiece and the danger area. The screen rises to permit the working hands to enter and then prevents access to the danger area when the dangerous part of the machine is in operation.

Trip guards commonly include a trip bar or screen set to operate at a predetermined pressure which, when exceeded, causes the machines to stop with the assistance of braking devices when necessary. Two-handed controls require an operator to apply both hands to the controls in order to activate them. Such controls, however, should not be used as the sole means of protection when guarding is possible.

Other devices to improve safety include enclosure of dangerous machines or isolating them from workers. Finally, fail-safe arrangements are necessary, since equipment failures will be almost bound to occur. These failures produce a high percentage of accidents. Fail-safe arrangements are used to ensure that the occurrence of a failure will leave the system unaffected or convert it into a state in which no injury or damage can result. As example of fail-safe devices is the circuit-breaker which operates when an electrical system is overloaded. The circuit-breaker stops the system and prevents an electrical short-circuit.

It may be noted that mechanical guards and other safety devices can be extremely complex and expensive. However, simple and inexpensive devices can also be used to improve safety or sometimes productivity as seen in the following examples.

As a note of caution, it should be emphasised that in all cases of doubt, expert opinion should be sought. A faulty safety device is often worse than no device at all. It might merely lead to a false sense of security and thereby increase the risk of accidents.

Case 59: Low-cost machine guards

In Sri Lanka, there were 25 workers in a rice milling plant. Several incidences of crushed limbs occurred, including fatal and severe accidents. The owner was very concerned but unable to afford the standard wiremesh guards.

The Government sent a factory inspector to look into the situation. It was recommended that all the moving parts of the machinery - the electric motor, transmission belt and pulley, and the fan - should be fenced with narrow wooden strips firmly fixed into the floor. It is a basic and fundamental need to protect all moving parts of machines. Care was taken to ensure that the spaces between each wooden strip were narrow enough to prevent the limbs of workers from coming into contact with the moving parts of the machine.

The wooden guards were found to be effective in preventing injuries. The costs of the guards were not given but estimated to be low. The costs saved included the approximate sum of US$ 100 per year for compensation and accident leave before the improvement was made. The indirect benefit from better morale could not be shown in exact figures but it was found that profit increased by 20 per cent.

In this case, the small-scale enterprise Could not afford metal mesh and was satisfied with a much cheaper material, or wood. It must be pointed out that metal mesh is still more dependable and reliable than wood when used for machine guarding. Mesh is much finer and its effective lifetime is longer. More frequent replacements are therefore necessary for wood than wire mesh. It must be stressed that prompt replacement or repair of guards is always necessary to prevent accidents occurring as a consequence of inadequate or faulty guards.

Case 60: A guard for falling objects

In a granite quarry in Thailand, five workers manned the grinding section. The stones were taken by a trolley to an overhead platform where a workman dumped them onto a moving screen which allowed only granite pieces below a certain diameter to pass through. The workers at the second, lower level platform were frequently injured by falling stones which had missed the screen and fallen onto the passage and work-way.

The supervisor arranged for the construction of a metal apron attached to the screen to catch the falling stones. This was constructed by the workshop of the enterprise itself. As a result, there were no more accidents caused by falling stones.

The improvement cost about US$ 215 for material and four man-days, or US$ 24, for labour. The losses before the improvement amounted to about two man-days, or about US$ 10, per month due to injury leave and US$ 3 per month for first aid.

This case is instructive for several reasons. The injuries before the improvement was made were fortunately not severe. However, the situation was rightly assessed to be very dangerous, as serious injuries or severe fatalities could occur if no improvements were made. The solution was thought out and implemented by the enterprise itself. Costs were therefore relatively minor but the effect was gratifying. It should be pointed out that the solution employed was far more effective than the provision of safety helmets alone, although these should also be used as a supplementary measure.

Case 61: Prevention of foot injuries by trolleys

In a manufacturing plant in Singapore, workers suffered injuries when trolleys used for transporting heavy loads rolled over their toes.

After several unsuccessful attempts at solutions, the safety officer of the enterprise devised a guard for the trolley wheels. It was made of metal, rectangular in shape and fixed to the wheel in such a way that the wheels could still move freely. The outside of the guard was padded with rubber. Now the wheels of the trolley would not roll over the workers' toes, and would be pushed away by the padded guard.

Since the installation of the guards, no foot injury has occurred in the factory. The wheel guards were made and installed by the workers themselves and cost only US$ 1.50 each. The exact costs from the injuries, including medical expenses and loss of productivity, were not given but said to have been considerable.

Foot injuries from trolleys are quite common. In many developing countries, workers often go around barefoot or in sandals, which make them even more vulnerable to such foot injuries. In this case, apart from the installation of trolley guards, workers should also be protected by the use of proper footwear. For handling heavy loads, safety shoes or boots are essential to prevent foot injuries.

Figure 94: Guard preventing contact between the wheel and the workers' foot.

Case 62: A shield for face protection

In a radio manufacturing plant in Indonesia, several workers were engaged in cutting off component legs under particle circuit boards. The cutting process was done in a dark box, but the fragments cut off the boards could easily fly out and injure the workers' eyes.

A box furnished with a glass plate and a fluorescent lamp was made using plywood boards. The box was 48 cm high. After some trials, the glass plate was installed parallel to the workers' eyes. All the fragments from the cutting process now fell back into the box. A box was made for each worker doing cutting work. The workers were pleased because their eyes were protected and they could see the process more clearly with the help of the lamp. The provision of the boxes also helped keep the workplace clean.

The materials cost US$ 6.50 per box including plywood boards, a fluorescent lamp and a glass plate.

Figure 95: Cutting off component legs under a particle circuit board.

In the grinding and polishing section of a large jewellery factory in Thailand, bits of metal tended to fly off the grinding wheels, thereby causing a hazard to the face and eyes of the workers. The factory employed 120 workers, 30 of whom were engaged in polishing, buffing and grinding.

A sheet of thick glass was inserted in front of each grinding wheel. It was fixed to the wheel with a hinge so as to facilitate cleaning and adjustment to the grinding wheel. The result was totally effective, as no eye or facial injuries occurred thereafter. The cost of the glass was minimal and the cost of labour nil, as the installation was done by the artisans of the factory.

Figure 96: A protective box with a glass plate and a lamp for cutting work.

Eye or facial injuries from flying objects are frequent and can be serious. Many cases of blindness have occurred as a result. Yet prevention of such injuries is often simple and inexpensive, as shown by these examples. The glass should be cleaned regularly or replaced if necessary. A dirty or excessively scratched glass can hamper visibility and workers may be tempted to remove the guard, thereby endangering themselves. In addition, it should be emphasised that safety screens of ordinary glass are only effective against small flying objects. They should not be used against heavy flying objects or small objects ejected at high velocity. Goggles or other forms of eye protection may also be required in addition to glass screens.

Case 63: A glass window guard against flying particles

Women workers in a polishing section of a wholesale jewellery house in Thailand were at times exposed to particles from small grinding machines flying into their face and eyes. About ten workers were engaged in the section. Goggles did not seem effective as the workers tended to take them away during polishing work. All the grinding machines were positioned as to revolve in the downward direction. It was necessary to set up a permanent face guard to prevent possible injuries.

Two wooden cabinets were built around a series of grinding machines so that the polishing work could be done by looking through a glass window. Each cabinet covered four workstations. Each window was made so that the worker could easily see the items to be polished and the movements of the hands inserted underneath the window were not disturbed. All the windows could be easily opened in the case of maintenance work in the grinding machines.

Figure 97: A wooden cabinet with windows to protect against flying particles from grinders.

The manufacture of the two cabinets was contracted with a small shop. The cost for covering the eight workstations in two lines was US$ 145. The work was done during a weekend break.

After the installations of the cabinets, no facial or eye injuries occurred. This allowed the company to save medical expenses which were estimated to be US$ 75 a year. Though not measurable in monetary terms, costs could also be saved by eliminating lost time due to these injuries or other difficulties such as delay in jewellery delivery or turnover of the workers.

Case 64: Wire mesh and metal sheet guards against metal chips

In an enamelware manufacturing factory in Burma, there was a need to safeguard beading machine operators and others around them. They were endangered by metal chips flying out of the machines. The safety committee looked into the matter. Each beading machine was run by a 1.5 horse power motor and worked on the general principles of a simple lathe. While a workpiece mounted on the head stock revolved, the edge would be cut and the rim rounded simultaneously. When the edges of the pressed metalware were cut off, some chips would fly a distance of up to about 5 metres away from the machine on the opposite side of the operator. On some occasions when the operator handled the slide, chips would even fly towards him.

Figure 98: The beading machine without guards.

There were six such machines, installed in two rows six metres apart. Between the two rows of machines at just about the middle, a wire mesh partition was built. Then a wire mesh shield was erected on the vertical plane just above the machine at a height of 90 cm, with a small opening just above the joint of operation. The top side was also covered by wire mesh. A piece of sheet metal, cut and shaped as half of a square metal container cut diagonally across, was fitted onto the machine just beyond the cutting point and very close to it. These guards proved suitable. The flying chips were caught by the wire mesh partitions.

Figure 99: An operator working on the machine with a mesh guard erected in front.

The square mesh partitions with wooden frames for each machine cost about US$ 48. The labour cost was not added as they were made by the factory staff. The small guard on each machine cost only US$ 10. The wire mesh partition near the wall in front of the machines cost US$ 70.

Figure 100: The operator working with a sheet metal guard on the machine.

Case 65: Prevention of arm laceration

In a small plastic moulding factory in Singapore, five cases of severe laceration on the forearms of workers were reported within a period of a few months. The workers were all engaged in trimming the plastic products with a small knife. Sometimes the knife would slip and wound the workers.

The safety officer in the factory investigated the problem. He contacted a company which made rattan products. He arranged for a supply of rattan meshing which was wrapped around the forearms of workers and kept firmly in place by rubber garters. Several trials were conducted to ascertain the optimum length and breadth of the meshing needed. The meshing was found to be effective in preventing arm lacerations.

Figure 101: Rattan mesh and knife used in trimming plastic products.

The rattan meshing for each worker cost US$ 7.50. Recurrent costs for replacement of worn-out meshing could not be calculated as the period of observation was still too short for this purpose. However, such recurrent costs were estimated to be quite small.

Savings in terms of prevention of injury and medical expenses far exceeded the costs incurred. Moreover, the productivity of the workers was enhanced because they could work faster now that the fear of sustaining lacerations was removed. This case is a good example of a working procedure being made more safe by a low-cost guard improvised by the factory itself and using material readily available locally.

Figure 102: Trimming operation in progress.

Figure 103: The rattan meshing now prevents lacerations to the forearm.

Case 66: Welding partitions

Workers of a metal fabrication factory in the Philippines were often disturbed by glare from several welders at work. There were about 60 workers with at least three welders operating simultaneously. The house-keeping conditions of the factory were poor and the welding took place at different parts of the fabrication area of about 800 square metres depending on the situation. The glare from welding caused distractions and inconvenience to non-welders working in the area.

To reduce the glare caused by welding, the owner decided to designate a particular section of the work area as a welding place and to provide partitions around it. He surveyed his factory for light and portable materials that could be used to shield the glare. Available scrap aluminium braces and leftover plywood were given to two workers to make into partitions. A total of six partitions were made.

The owner provided the welders with these partitions and instructed them to use these to contain glare from welding work. The welders readily preferred to work within the confines of these partitions. In fact, according to the owner, they competed for the use of partitions. The non-welders said that there was no more distraction caused by the direct glare from welding work.

The cost for making six partitions included about US$ 40 for scrap aluminium and plywood and about US $15 for four working days (two workers spending two days each for making the partitions). The approximate cost per partition was about US$ 9. Compared with the cost incurred, the advantage of the use of these partitions was remarkable. Though accurate comparison was not readily available, the owner was expecting enhanced productivity and fewers errors by workers formerly affected by the glare.

Case 67: Two-hand device for a foot-operated power press

In a small metalworking factory in Thailand, there were several hand injuries caused by a power press. The power press was being used by workers of a metal cutting unit. The maintenance staff of the factory studied the possibility of incorporating a safety device into the foot-operated power press. It was decided to introduce a two-hand control system in place of a foot lever. The system would require the worker to put both hands simultaneously on two buttons in order to activate the press. It would prevent any hand from coming into contact with the dangerous part in motion.

A design was drawn up by the maintenance department. A small pneumatic cylinder was put on top of the foot lever of the press, connected to a switch and a compressed air system, and the switch was linked to an electric power line which had a two-hand control switch installed on the front side of the power press. All the work was done by maintenance workers.

The cost of refitting the two-hand control system on the press was approximately US$ 55, not inclusive of labour costs.

All workers were trained on safe press operation. The incidence of hand injuries dropped significantly.

Figure 104: A pneumatic cylinder connected to a two-hand switch to control a power press.

Figure 105: Feeding materials into the power press.

Figure 106: Two-hand control to ensure that the hands are away from the danger zone.

Case 68: Protective handrails near steam vats

In a plywood factory in Burma, round logs were placed into steam vats and steamed for a period of three to five days. While placing logs into the vats and taking them out, the workers faced the risk of getting splashed by hot water at about 90°C and of slipping and falling into the vats. The workers also complained of the narrow foot space on the edges of the tanks.

After studying the work process at the steam vats, portable handrails were manufactured. At the same time, the wooden covers for the vats were replaced. Work at the vats was arranged so that when work was done at a particular vat, the vat adjacent to it would be covered. Instead of working on the edges of the vats, the workers would be stationed by the cover placed over the adjacent vat with a handrail fitted in front for protection. The overhead crane clearance at these workplaces was readjusted to ensure safe clearance for crane movement during work.

Construction of a wooden cover and handrails for a medium-size vat cost approximately US$ 240 including labour costs of US$ 32 for a carpenter. The cost for a cover and handrails for a large-size vat was US$ 470 including labour costs of about US$ 170. Second class teak, brackets and iron-ring fasteners were used.

Figure 107: Workers working at the vats without protective guards.

The work at the hot vats became safe. For a period of two years after these modifications, not a single case of splash burns or falling into the vats occurred.

Figure 108: Working at the vats with protective handrails.

5. Safe working procedures

It is far better to make a work process intrinsically safe by eliminating all potential dangers. But it must also be emphasised that safe working procedures are essential in any situation. Safe procedures should start with equipment selection and plant design. Work methods should be planned so that workers can do their work properly and safely following the prescribed procedures.

Safe working procedures go together with various other measures to create a safe working environment. They should be laid down by each enterprise and regarded as codes of conduct to avoid injury and damage. They should be applied to each work area, work method and each category of worker in the enterprise. Obviously, it is not enough to lay down procedures. They must also be properly applied. New workers should be trained in safe working procedures. This could be done either by the safety officer or line supervisor or preferably both.

There should also be regular retraining in safe working procedures. The frequency and nature of such retraining depends on the circumstances in the particular enterprise.

Whenever possible, safety committees should be established within each enterprise. They should be made up of managers, supervisors and workers, together with the safety officer (if there is one). The committees should initiate and monitor safety promotion programmes and suggest ways of preventing accidents. All new materials and processes should be reported to and assessed by the safety committee concerning potential hazards and safe working procedures.

Equipment and training concerning first aid and fire safety is usually required by law. However, it is often possible to meet or go beyond these legal requirements at low cost.

Often, changes in environmental conditions or work methods can help workers observe the safety procedures more consistently. It sometimes happens that despite repeated instructions, it is difficult for workers to observe these instructions all the time. Modifications such as elimination of certain hazards by slight changes in the workplace environment or making work methods easier to follow can help the workers observe the safety procedures. Together with a well-planned programme of safety education, these small changes can contribute to enhancing safety at work.

The examples below give an idea of how safe working procedures are planned and implemented, often at low cost. It should be kept in mind that safe working procedures vary a great deal from enterprise to enterprise. Each enterprise needs to make its own assessment of what procedures are necessary for its own set of circumstances.

Case 69: Improvement in safety through low-cost mechanisation

In the upholstery section of a furniture-making factory in the Philippines, workers used the conventional method of tucking upholstery materials with a hammer and nails. Hand injuries due to the accidental slipping of the hammer occurred. The fear of such injuries also slowed down the work. The upholstery section employed five workers.

Figure 109: The old method of using a hammer to drive in the nails manually.

To overcome the problem, compressed air guns were installed and substituted for the hammers. The workers were given careful instructions on how to use their air guns. Employees were enthusiastic about the change, as it reduced both their physical effort and increased safety. There was an increase of 30-40 per cent in output.

The air compressor cost about US$ 1,000 and the fittings, hand tools and installation about US$ 500. At the same time, the compressor also served the needs of another section of the factory. Maintenance and electricity costs were estimated at around US$ 5 per month.

The 30-40 per cent increase in productivity was partly used to pay for an increase in wages.

This is an example of how low-cost mechanisation improved both safety and productivity. It must be emphasised that the use of the compressed air gun is not entirely free of danger. The mechanical tool must also be handled with care, but is more convenient to use than the hammer.

Figure 110: The new method using the compressed air gun.

Case 70: Tilting a saw frame for safer use

In a section of a wood furniture factory in Malaysia, about five workers operated radial-arm saws. The rotating saw blade was a constant threat to the safety of these workers. Accidents had occurred in which the operator's hand was severed by the rotating blade. After planks were placed on the feed table, the radial-arm saw was pulled forward by the operator towards himself. While being pulled forward, the saw cut the planks. The saw was left at the forward position when the cutting was over and the operator turned around to collect some more planks.

Many accidents happened when the operator turned around again to place the planks for the next cut, not realising that the saw-head was still in contact with the revolving blade. Although the saw was provided with a counterweight or springs for the automatic return of the worktable, some workers found the counterweight unsatisfactory and heavy and also the tension in the springs too high. Extra force was required to pull the saw forward. Thus, the counterweight or the springs were often removed or rendered inoperative.

Instead of providing the saw with a counterweight or springs, the front legs of the saw table were raised slightly so that the saw frame was tilted backward. This tilting caused the saw to return to its starting position by its own weight and inertia due to the rotating action. Thus, the danger of the rotating saw blade at the front end of the worktable was eliminated.

Figure 111: Tilting the saw frame for automatic return of the saw.

The cost of inclining the saw frame was negligible as only a small amount of concrete was necessary. It helped save the further cost of counterweights or springs. The new arrangement was found to be successful in returning the saw to its original starting position. The operators were satisfied with this simple modification. After the change, there were no reports of accidents involving the operators of the saw.

Case 71: Prevention of finger injuries by mechanised riveting

The riveting section of an electrical component manufacturing company in the Philippines employed four workers. Their work was essentially to join a copper fuse holder to its plastic base. To do this the worker placed the base on a stand and then knocked the fuse holder into place with a hammer. There were instances in which workers hurt their fingers with the hammer.

Figure 112: Knocking fuse holders into a plastic base with a hammer.

The engineering department of the enterprise designed a twin-feed riveting machine. Using this, the operator could set up as many as 20 plastic bases, two at a time, in a stand. He then activated the pneumatic-driven riveting machine which knocked the fuse into its plastic base. At first only one of the four workers used the new system while the other three continued using the hammer.

Figure 113: Use of a riveting machine instead of a hammer.

Output increased by 15 per cent using the riveting machine. Moreover, the worker using the riveting machine did not sustain any injury, whereas the other three workers reported hurting themselves with the hammer at least once a day.

The cost of parts to construct the machine was about US$ 2,000. Training of the workers on the machine required overtime payment estimated at US$ 9. Average maintenance costs were estimated to be US$ 150. The direct savings were about US$ 100 per month overtime pay and the loss of productivity due to work injuries, both resulting from using the manual process.

This is another example of how the mechanisation of a procedure led to greater efficiency and safety. Again, it should be pointed out that a riveting machine is not devoid of danger. However, if the controls are properly designed and located, the risk of accident should be lower than that from a manual method using a hammer.

Case 72: A hazard overcome by safe working procedures

A Singapore factory manufacturing metal components had several power presses. Machine guards activated by electronic sensors were installed. Even then, several finger injuries occurred because the workers found ways to bypass these safety measures by tampering with them to speed up production or for other reasons.

The safety officer launched a carefully-planned programme of safety education. At first, clear safety instructions in both English and Chinese (as every worker knew at least one of the two languages) were put on the machines. All the existing operators were then required to undergo an intensive training of one week on the proper and safe use of the presses. They were only allowed to resume work on the machines if they passed a test conducted either by the section head or the safety officer.

Only workers with several years of experience in the company were selected as new operators for the power presses. New workers would start off in other safer sections of the enterprise first. In this way, most of the power press operators had at least five years of service in the company. This ensured that only workers known for their sense of responsibility and safety consciousness were allowed to work on the power presses, which was an attractive job because of higher emoluments.

Since the implementation of these safe handling procedures some time ago, no accident from power presses has occurred in the factory.

The costs involved were minimal. The costs for the training programme involved mainly the time spent by trainers and trainees. The installation of the safety guards and sensors cost about US$ 50 per press. Maintenance and other costs were minimal.

It is important to install machine guards whenever necessary, but unfortunately almost all kinds of guards can be tampered with, as in this case. It is therefore essential to adopt safe working procedures as well. Not only were the dangers and use of safety measures fully explained to all the workers, an elaborate programme of training in safe working procedures was also carried out. The selection of only experienced workers to man the presses must have also contributed to the improvement of safety. Another point to note is that information and educational programmes may need to be given in more than one language, as in this case.

Case 73: A mechanical interlock to eliminate an electrical hazard

Machines used for the manufacture of barbed wire in an engineering factory in Burma presented a particular risk, because the method used required the operator to come very close to the revolving frame underneath the machine several times in every shift. Though the machines were switched off during such operations, electrical faults or interference with the switch might start the machines and cause severe injuries. A fatal accident occurred on one of the machines in this manner.

Figure 114: Operation often done underneath the barbed wire machine.

Immediately after the fatal accident, the safety committee and the engineers concerned shut down all the seven machines and carried out investigations. As a result, it was suggested that suitable interlocking devices be used. These devices would lock the electrical system when workers were required to work underneath the machines. During normal operations, the revolving part of each machine would be covered by a sheet of metal which was hinged on the lower frame of the machine. This cover was to protect the workers during normal operations and had to be opened when the work was done underneath the machine. This opening of the cover was used for the interlock. A limit switch was fitted on the frame of each machine to cut the electricity supply to the revolving frame when the cover was opened.

Figure 115: The limit switch put to “on” position by an extension strip on the metal cover.

Figure 116: The limit switch in “off” position when the cover is down.

Additional measures were also taken to prevent any possible faults. The wiring of the machine on which the fatal accident occurred was changed. The control buttons of each machine were cleaned and the workers were advised to always keep them clean and to touch them with clean fingers. The newly wired system and the operation of the limit switches were thoroughly tested.

The cost of procuring a limit switch and a short length of electric wire was US$ 15 per machine. There was no cost for labour as the technical staff of the factory carried out the modifications. Thanks to these new interlocking devices, there was little chance of a similar accident.

Case 74: Prevention of an electrical hazard by main switch locking

A plywood production plant in Thailand used several machines run on electricity. Because the machines were acquired secondhand, they required frequent alterations and repairs. The machines were arranged along a long production line. Workers repairing or inspecting individual machines could not always be seen from the place where the main switch was located. Injuries had resulted because the main switch was started when workers were still working on the machines.

It was decided that a way must be found to seal off the main switch while the line was under inspection or repair so that the power could not be accidentally started until all maintenance or repairs had been completed.

The switch for the machines was a common knife switch, in which all the knife blades had to be thrown up to complete the circuit and start the machinery. A bracket was attached below the knife switch. From this bracket a non-conducting chain made of strong plastic was attached around the switch while in the “off” position and locked to the bracket. The bracket was made in such a way as to accommodate a series of padlocks along the length of the chain. Once any of the locks was placed in position on the chain, the switch could not be moved to the “on” position.

Each supervisor or member of the work crew was given a personal lock for the chain. They were instructed not to touch the machine until the master switch was switched off and they had fastened a lock onto the chain. Later on, a large box was constructed over the master switch. This contained six locks which could be used to shut down the electrical power until any maintenance or repair work was completed.

This new arrangement effectively prevented injuries from accidental switching on of machinery during inspections or repairs. The bracket, chain and locks cost less than US$ 10 in total. It was difficult to compute accurately the costs saved in the prevention of injuries, but undoubtedly safety was improved significantly.

Case 75: Improving electrical wiring

In an engineering factory with 40-50 workers in Pakistan, there were frequent incidences of short-circuiting which damaged electrical equipment. In certain cases, workers received an electrical shock. It was found that damage caused by defective electricity installations amounted to about US$ 190, and that about US$ 100 had been spent for the treatment and transportation of injured workers.

A short training session was organised to educate the workers on electrical hazards and protection against such hazards. Then, the workers participated in the replacement of old unsafe wiring, insulation of wires and provision of good quality switches, plugs and sockets.

Figure 117: New wiring arrangement with insulated wires.

The approximate cost for changing the wiring was US$ 156. In addition, US$ 32 were paid to the external instructor who lectured at the training session. An example of the new wiring arrangement is given below.

The change of the wiring systems gave a new look to the workplace, with orderly arranged or insulated wires and safe electrical connections. The change contributed to the reduction of electrical hazards. Damage to the electrical equipment was reduced to a minimum. The manager of the factory noted that the new arrangement helped increase the safety awareness of the workers and had a positive impact on work efficiency.

Case 76: Warning about the movement of a mechanical lift

In the finishing section of a printing plant in the Philippines, materials and products were transported to and from the upper floor by a mechanical lift. The plant employed 150 workers and had three sections, a photo-lithography section, an offset press section and a finishing section. A die-cutting machine which was frequently used was located in the finishing section.

The manager observed the operations in the finishing area and found that the accidental activation of the lift switch on the upper floor might lead to serious injury of a worker on the ground floor who was unaware of the lift movement. When he consulted the workers, the majority confirmed this. After discussions, it was decided to install a signal light and a bell to warn workers on the ground floor as soon as the mechanical lift was activated.

A red signal light and a bell assembly were purchased and installed near the ground floor end of the light. The workers were taught how to use the warning device and given written instructions on the operation of the lift. The warning signal worked quite effectively. The likelihood of accidents was reduced considerably. The workers were able to work and move freely and easily without fear that they might be accidentally hit by the moving lift.

The plant cost incurred was minimal. The red signal light and the bell assembly cost about US$ 20. The cost of labour for installation was US$ 4. In all, the management spent US$ 24 for the improvement.

Figure 118: A red signal light and instructions on how to use the lift.

Figure 119: A bell alarm to warn workers of the movement of the lift.

Case 77: Modifications in the use of a portable stand

In an aluminium extrusion plant in Indonesia, an accident involving a die-polishing worker occurred. His hand was cut by a sharp object on a portable stand where he placed dies. The safety committee immediately studied the problem. It was found that the stand was unstable, neither bolted to the floor nor made to balance the weight of dies, and that the safety guard around the top of the stand was crudely made. This guard actually injured the hand of the worker.

The stand was modified so as to meet safety requirements. It was made stable. The safety guard around the top of the stand was also modified to eliminate sharp edges and obstruction of the movements of the worker's hands. The cost of the modification, including materials and work, was about US$ 25.

Case 78: Provision of first-aid facilities

About 100 workers of an engineering factory in Sri Lanka had to leave the worksite to seek treatment at government clinics or from private medical practitioners even for relatively minor injuries. These medical facilities were located some distance away. Some injured workers did not get their wounds attended to. Consequently, some developed infected wounds which prolonged their period of incapacity. At the worksite itself, there was a first-aid box but no person to treat or dress the wounds.

After consulting the factory inspectorate, the management provided a small room of 4.5 by 3.6 metres. It was cleaned, whitewashed and painted. A wash-basin with running water was installed. The room was furnished with a desk, three chairs, a foot stool and a medical examination couch. Towels, bed sheets, pillows and pillow cases were purchased.

Two workers were selected on the basis of their helpful and friendly disposition and willingness to undergo training in first aid. They were sent at the expense of the company to attend a first-aid course comprising ten lectures and ten practical sessions. After completion of the course, they resumed their normal duties but also rendered first aid whenever injuries occurred.

Accident leave was reduced by 30 per cent during the months after the implementation of the first-aid programme. The workers were also spared considerable inconvenience as they did not need to travel to an outside clinic or to wait to get their dressings done. Moreover, the incidence of infected wounds also fell.

The cost of preparing and equipping the first-aid room came to about US$ 240. The cost of training the two workers in first aid, including travel costs, amounted to US$ 16. The indirect costs, including the time spent in training away from normal duties and that in first-aid duty by the two first aiders were not more than US$ 40 for the whole year. The total costs were therefore about US$ 300.

The management estimated that the 30 per cent reduction in accident leave, savings in productivity, and the evident increase in the morale and extent of co-operation by workers, more than recovered the expenses incurred.

Case 79: Provision of a first-aid room

In a battery factory in Burma, 325 workers were engaged in manufacturing sulphuric acid and batteries. The existing first-aid facilities were found inadequate by the safety and health committee as only a nominal amount of first-aid materials were being kept in a small place adjacent to the time-keeper's office. Only a few workers had been trained as first-aiders. The records showed that in the previous year, there were about 160 cases handled by the first-aiders, of which 15 were referred to a hospital.

The management agreed to provide a room in the factory premises for use as a first-aid room. An amount of approximately US$ 375 was provided for buying and replenishing first-aid materials. Fifteen workers were trained as first-aiders. Five first-aid boxes were placed in major sections of the factory. Plenty of water was made available near the workers working with acid. Arrangements were made with a local health officer who undertook the supervision of the first-aid operations. A trained first-aid nurse was appointed to attend to the first-aid room.

The room was arranged by volunteers at no cost. The recurring cost of approximately US$ 375 per year and the salary of approximately US$ 150 a month for the nurse were borne by the management.

Figure 120: Entrance of the new first-aid room.

Figure 121: An examination table, first-aid materials and a trained nurse.

Figure 122: A first-aid box placed in a workroom.

Case 80: Ready accessibility of first-aid supplies

In an electronic parts factory in Singapore, first-aid supplies were frequently missing from the unlocked boxes in which they were stored. The company arranged for the supplies to be placed in locked boxes with the keys in a sealed container below the boxes. In this way the first-aid boxes could be easily inspected for possible loss of contents by noting whether the seal on the key container was intact or not.

Figure 123: The first-aid supplies box.

These boxes proved useful. The first-aid supplies could be kept in good order at all times. The boxes could be easily located by anybody in the factory. The arrangements helped assure quick treatment in case of emergency.

Case 81: Ready accessibility of fire fighting equipment

In a company making electronic parts in Singapore, fire-fighting equipment was kept in a storeroom where chemicals were also stored. Because of the chemicals, the storeroom was kept locked. The fire-fighting equipment was not easily accessible in the event of fires. The fire equipment was then transferred to a box with a glass window outside the storeroom. The glass could easily be smashed to get at the equipment. With this simple procedure, the equipment became easily accessible when needed.

Figure 124: The fire-fighting equipment box with a glass window.

This example presents a straightforward instance of how emergency equipment could be made more readily available when needed. The first few minutes of an emergency could be vital in putting out a fire or saving a life. Precious time is often wasted trying to locate the custodian of or the key to emergency equipment. All the workers in an enterprise should know the whereabouts of such equipment, have quick access to it and be trained to use it properly.