Lighting and Its Effect on Vision

The advance of industries, the increase in industrial and production units, and the ever-growing need of industries for greater output for suppliers require that more work continue in enclosed environments during the night and day. Therefore, the use of artificial light has gradually developed. Today, the matter of lighting has gained special importance for large industrial workshops. Because a shortage of lighting in the work environment, in addition to causing nervous fatigue, inflicts other harm on the health and eyesight of the worker. In general, the goals of providing adequate and suitable lighting can be expressed as follows: 1/ Maximum protection of employees' eyesight 2/ Reducing the factors causing fatigue and strain from insufficient lighting 3/ Preventing accidents arising from work 4/ Increasing work output 5/ Improving product quality Undoubtedly the most important human sense is sight, and for this reason lighting engineering is vitally important. Satisfactory lighting helps human comfort and ease and raises work output and, by reducing accidents arising from insufficient light, contributes greatly to safety. Light sources: For lighting workshops, two light sources can be used: natural light (sunlight) and artificial light (electric). Natural lighting: The most important natural source of light is sunlight, and daylight is one of the most important sources for supplying luminous energy. Daylight is formed from the diffuse light obtained from a clear sky or a cloudy sky and the reflection of the coverings located on the ground, and an amount of direct sunlight at specified hours of the day. The quantity of daylight changes depending on the geographic location, the season of the year, and meteorological conditions. Daylight, on the condition that it is in sufficient quantity, is superior to artificial light. In order to use daylight better and more correctly, the following points must be observed: If the workshop or workplace is large and its windows are not sufficient to bring light to all parts, glass coverings must be used in parts of the roof. To prevent direct sunlight in the summer, it is better for there to be an awning above the windows. To make more use of sunlight, the ceiling of the workshop and other surfaces that reflect light must be light-colored so that they reflect light better. So that sufficient light reaches the workplace, depending on the type of work, the radiation of light, and the sunniness of the location, the total area of the windows or the glass roof of the workshop must be proportionate to the floor area of the workshop. Artificial lighting: In artificial lighting, electric lamps are used. In designing lighting, the following points must be observed: 1/ The lighting must be distributed uniformly across the work surface. 2/ The location of installing the supplementary light source must be on the left side of the work surface (for left-handed people the reverse) and its height above the work surface must not exceed 60 centimeters. 3/ The amount of lighting must be according to the standard for each job. Because otherwise the person, in order to better discern the details of the work, brings the eye close to the work, and in this way not only assumes an unsuitable body posture but also harms their own eyesight. Today the most widespread source of artificial lighting is the use of energy-saving lamps. Advantages and necessary recommendations regarding the use of energy-saving lamps Following the production and widespread use of energy-saving lamps, numerous opinions have been expressed regarding the possible dangers of using these lamps. In this regard, standard number 11722, from the 2009 publications of the Institute of Standards and Industrial Research of Iran, under the title of the biological radiation safety of lamps, has been cited. According to the definition, energy-saving lamps are classified in the category of harmless lamps, and therefore one can confidently claim that the concerns raised about the harmful effects of the radiation of these lamps on the eyes and skin have no scientific basis or foundation. Advantages of using energy-saving lamps 1/ Reduction of energy consumption 2/ Long lifespan 3/ The possibility of choosing the color of the lamp's light 4/ Light without flicker Recommendations at the time of the end of a lamp's life: The end of the life of energy-saving lamps may be accompanied by changes such as the creation of smoke, the creation of a particular sound, a change in color, or a change in the shape of the base. It is better for consumers, after observing the first signs, to proceed with replacing the lamp. These signs are: flickering, light tending toward orange or red emitted from the lamp, the production of sound, the emission of an unpleasant smell, and a change in the color of the base. When an energy-saving lamp has reached the end of its life, what should be done with it? The best way to dispose of an energy-saving lamp is to deliver it to special waste-recycling locations that also accept electronic waste and energy-saving lamps. If there is no such place in your area of residence, you can place the lamp in two layers of plastic bag, tie its end, and place it in ordinary waste. Note that the lamp must by no means be thrown into fire or a furnace. If an energy-saving lamp breaks, what should be done with it? If an energy-saving lamp breaks for any reason, observing the following points is recommended: 1 / Before cleaning: Move people out of the room and be careful that, when leaving the room, they do not pass through the area where the lamp broke. Leave the room's windows open for at least 15 minutes. If there is a central ventilation system, turn it off. 2 / Steps for cleaning hard surfaces such as stone and ceramic Gather the glass pieces with a piece of paper or cardboard and place them in a lidded glass container or a plastic bag. Use a piece of adhesive tape to pick up the small remaining pieces of glass. Clean the area with a dry paper towel and then throw the paper towel into the glass or plastic container. Do not use a vacuum cleaner to clean hard surfaces. 3 / Steps for cleaning carpet or moquette Carefully pick up the glass pieces and place them in a lidded glass container or plastic bag. Use a piece of adhesive tape to pick up the small remaining pieces of glass and powders. After picking up all the removable pieces, if necessary, clean the area using a vacuum cleaner. Remove the vacuum-cleaner bag (or empty its chamber) and place the bag or the swept-up debris inside a plastic bag and seal it. 4 / Steps for cleaning clothing, bedding, etc. If clothing or bedding has come into direct contact with the broken lamp or the mercury powders inside the lamp, the clothing or bedding must be thrown away. Do not put such clothing into the machine, because the washing machine or its wastewater will become contaminated. 5 / Disposing of cleaning tools Place the items you used for cleaning into the garbage bin outside the home. Wash your hands after contact with the cleaning items. Places where energy-saving lamps are used: Residential lighting: The lighting of residential homes is divided into the following sections: 1 / Rooms: Energy-saving lamps, because of their low consumption, long durability, and adequate color rendering, are the best option for lighting the rooms of the home. 2 / Yard, parking, and open areas: In these areas, energy-saving lamps are usable only if the following recommendations are observed: Installation in an upright position or with the socket facing down Use in a globe-covered lamp As far as possible, using types with an amalgam alloy that are more resistant to temperature changes. 3 / Stairway, toilet, and bathroom: Since in these places the frequency of switching is high relative to the time of being lit, this causes a severe reduction in the lamp's life, and therefore the use of energy-saving lamps is not recommended. Workplace lighting Lighting of educational premises Lighting of commercial premises Criteria for selecting an energy-saving lamp Users of energy-saving lamps, by keeping the following points in mind when selecting a lamp, can select the suitable lamp for their intended application. Selecting a suitable lamp plays a significant role in the lamp's optimal performance. 1/ Lamp power: The first point in selecting a lamp is its power. 2 / Lamp color: Cold and daylight colors are used for reading, and warm and sunlight colors are used for the home environment and ordinary use. 3 / Suitable operating temperature of the lamp: Energy-saving lamps, for suitable performance, must be within a specified temperature range, therefore select a lamp whose operating temperature range covers the intended temperature, and it is stated on its packaging. 4/ The ability to be used with a dimmer: Most energy-saving lamps do not have the ability to be used with a dimmer and lighting-adjustment circuits. Therefore, if you want to use a dimmer or circuits with a sensor and photocell, you must use special energy-saving lamps that are made for these applications. 5/ Having a valid standard: Having a valid standard for energy-saving lamps causes the consumer to choose the lamp with greater peace of mind and to be assured of its suitable quality. Therefore, when selecting a lamp, pay attention to having a valid standard. Important points in providing suitable lighting: The light obtained from lighting sources must, as far as possible, be close to daylight. The ceiling and the upper part of the walls are usually colored a light color in order to increase the efficiency of the lighting coming in from the windows, and the lower part of the walls are colored a dark color to create conditions of comfort. The amount of light obtained from the lighting sources must be constant and in sufficient quantity and be distributed uniformly across all the surfaces of the work environment, so that the creation of shadows and dark corners is prevented. Timely repair and servicing of the lighting sources Regularly cleaning the light fixtures Effects of lighting on the human eye: Complications arising from excess light: 1 / Glare: The most important complication arising from excess light. This condition arises from the direct impact of light on the eye or the reflection of the radiated ray of light from transparent surfaces to the eye. 2 / Symptoms of glare: A feeling of discomfort and pain in the eye, reduction of the sense of sight, fear of light, and the shedding of tears appear. For example, when the light source is placed directly in the worker's field of vision, it causes glare. To prevent this problem from occurring, the lighting sources must be installed at suitable distances from one another. Complications arising from a shortage of light: In workshops where suitable and sufficient light does not exist, especially in the case of fine and precise work, it will cause disorder and a reduction in eyesight. These complications include strain in the eye, headache, dizziness, fatigue, disinclination toward work, and occupational nystagmus. (The disease nystagmus causes the occurrence of abnormal movements in the eye.) Factors that intensify the complications arising from a shortage or excess of light: Mental fatigue, eye fatigue, age