Poor lighting can be a safety hazard – misjudgment of the position, shape or speed of an object can lead to accidents and injury.
Poor lighting can affect the quality of work, specifically in situations where precision is required, but also overall productivity.
Poor lighting can also be a health hazard – too much or too little light strains eyes and may cause eye discomfort (burning, etc.) and headaches.
Workplaces are deceptively difficult places to light both safely and well. Lighting is dependent on the tasks, whether they are outdoors or indoors, day or night. Safety professionals struggle to get the adequate lighting for safety without creating glare in the environment.
Workplace lighting standards address a plethora of concerns associated with the principles of design, placement, installation, energy requirements, and upgrades to light fixtures in various workplaces. Proper illumination is essential for the optimisation of both comfort and productivity in the workplace; workplace lighting dictates quality of perception, mood, and performance of employees. The psychological effect of lighting on people in various workplaces details the importance of adhering to workplace lighting standards.
Guidelines for lighting fixtures are outlined for both indoor and outdoor workplaces, as well as a variety of very specific settings including agricultural facilities, hospitals, educational institutions, museums, and so forth. Safe practices with regards to the availability of emergency lighting, specifically the operation and performance testing of evacuation lighting systems, are extremely important.
Sources of light
Daylight
How much daylight reaches inside a building depends on the architecture of the building (does the building have windows; how big; how are they oriented?), the amount and direction of sunlight, cloud cover, local terrain, and the season. The cleanliness of the windows is important as well. The amount of daylight entering the workplace can be controlled with tinted glass, window blinds, curtains, and awnings. Daylight is desirable in the workplace providing it does not cause glare or make the work area too bright.
Remember, not enough light can also be a problem, so even in workplaces where daylight is available it is essential to have a good electric lighting system.
Electric lighting
The amount of light, the colour of the light itself and the colour that objects appear varies with the type of electric lighting. The lighting must match the workplace and the task. The following are common types of bulbs.
Artificial lighting
There are three basic types of lighting:
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General
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Localised-general
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Local (or task)
General lighting provides a fairly uniform array of lighting. An example would be ceiling fixtures that light up large areas.
Localised-general lighting uses overhead fixtures in addition to ceiling fixtures to increase lighting levels for particular tasks such as quality inspection, small work.
Local (or task) lighting increases light levels over the work and immediate surroundings. Local lighting often allows the user to adjust and control lighting and provides flexibility for each user.
Types of light fixtures
The complete lighting unit, also called the light fixture, controls and distributes the light. Light fixtures are often referred to as “luminaires” in technical publications.
Various types of light fixtures are designed to distribute light in different ways. These fixtures are known as:
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Direct
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Direct-indirect
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Indirect
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Shielded (various types)
No single type of light fixture is appropriate in every situation. The amount and quality of lighting required for a particular workstation or task will determine which light fixture is most suitable.
Direct light fixtures project 90 to 100% of their light downward toward the work area. Direct lighting tends to create shadows, so pay attention to the entire surface.
One area of the workstation may be adequately lit while shadows may fall on other areas.
Direct-indirect light fixtures distribute light equally upward and downward. They reflect light off the ceiling and other room surfaces. Little light is emitted horizontally, meaning direct glare is often reduced. They are usually used in “clean” manufacturing areas.
Indirect light fixtures distribute 90 to 100 percent of the light upward. The ceiling and upper walls must be clean and highly reflective to allow the light to reach the work area. They provide the most even illumination of all the types of fixtures and the least direct glare. Indirect light fixtures are usually used in offices.
Shielded light fixtures use diffusers, lenses and louvers to cover bulbs from direct view; therefore, helping to prevent glare and distribute light. Diffusers are translucent or semi-transparent (seethrough) covers are usually made of glass or plastic. They are used on the bottom or sides of light fixtures to control brightness. Lenses are clear or transparent glass, or plastic covers. The lens design incorporates prisms and flutes to distribute light in specific ways. Louvers are baffles that shield the bulb from view and reflect light. The baffles can be contoured to control light and decrease brightness. Parabolic louvers are specially shaped grids that concentrate and distribute light.
How we see colours
Can electric lighting affect what we “see” as the colours of an object?
Yes. The “colour” of an object actually depends upon the colour composition of the light itself as well as the colours of the light that the object reflects and absorbs.
Natural sunlight is made up of all the colours of the rainbow (spectrum): red, orange, yellow, green, blue, indigo and violet. Most electric lights do not “make” of all these colours even though the lights appear to be emitting “white” or “normal” light. In fact, different lights give different colour rendering characteristics. As a result, the true colour of an object can only be determined when viewed under sunlight or under lighting, such as full spectrum lighting, that has the same spectral composition as sunlight.
For most work situations, colour rendering is not an issue. However, full spectrum lighting may be needed when colour judgement is important; for example, in a fabric manufacturing or sewing environment.
In the United States, the Occupational Safety and Health Administration (OSHA) is responsible for safety lighting in workplaces.
Portable, ATEX and temporary lighting
When adequate illumination is not obtainable by permanent lighting 68 sources, temporary lighting may be used as supplementation.
The employer needs to ensure that neither matches nor open-flame devices are used for lighting.
Temporary lights
The employer needs to ensure that temporary lights meet the following requirements:
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Lights with bulbs that are not completely recessed are equipped with guards to prevent accidental contact with the bulb
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Lights are equipped with electric cords designed with sufficient capacity to safely carry the electric load
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Connections and insulation on electric cords are maintained in a safe condition
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Lights and lighting stringers are not suspended solely by their electric cords unless they are designed by the manufacturer to be suspended in this way
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Lighting stringers do not overload branch circuits
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Branch circuits are equipped with over-current protection with a capacity that does not exceed the rated current carrying capacity of the cord used
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Splices have insulation with a capacity that exceeds that of the original insulation of the cord
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Exposed, non-current-carrying metal parts of lights are grounded. For this the employer needs to ensure that grounding is provided either through a third wire in the cord containing the circuit conductors or through a separate wire that is grounded at the source of the current
To detect insufficient light, try the following:
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Measure the average illumination throughout the workplace and compare this to the recommended levels
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Look for shadows, especially over work areas and on stairways
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Ask workers if they suffer from eye strain or squint to see
Workers should sit in their normal working positions during measurement to give accurate results.
To correct insufficient light:
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Replace bulbs on a regular schedule – old bulbs give less light than new ones, so replace them before they burn out, but be sure to follow manufacturers’ instructions
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Clean light fixtures regularly – dirt on light fixtures reduces the amount of light given off, whereas light fixtures with open tops allow air currents to move dust up through the fixtures so dust and dirt do not accumulate on them
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Add more light fixtures in appropriate places
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Paint walls and ceilings light colours so light can be reflected
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Use more reflected light and local lighting to eliminate shadows – a covered light mounted under a transparent guard on a grinding wheel provides the added light needed to clearly see the task
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Do not position a work station with light fixture directly behind a worker
Portable lights
In any dark area that does not have permanent or temporary lights, where lights are not working, or where lights are not readily accessible, the employer shall provide portable or emergency lights and ensure that employees do not enter those areas without such lights.
Where the only means of illumination on a vessel or vessel section are from lighting sources that are not part of the vessel or vessel section, the employer shall provide portable or emergency lights for the safe movement of each employee. If natural sunlight provides sufficient illumination, portable or emergency lights are not required.
Explosion-proof, self-contained lights
The employer shall provide and ensure that each employee uses only explosionproof, self-contained temporary and portable lights, approved for hazardous conditions by a nationally recognised testing laboratory (NRTL), in any area that the atmosphere is determined to contain a concentration of flammable vapours that are at or above 10 percent of the lower explosive limit (LEL) as specified in 29 CFR part 1915, subparts B and C.
Emergency lighting standards
Emergency lighting standards seek to provide visual conditions which make safe and timely evacuation possible while simultaneously curtailing panic.
Safeguards for emergency management are vital in areas to which either the public or workers have access. Recommendations for specific luminaires such as exit signs and other sources of guidance, as well as the installation, operation, and testing of these, are outlined. These standards also address design principles that account for optimal placement, energy use, and possibility of electrical supply failure during emergencies.
Summary
Well balanced illumination is essential for the establishment of a safe and productive work environment; optimising illumination in the industrial workplace requires a number of considerations including type of equipment, environmental considerations, financial needs, goals, and type of work, etc. Generally, factors that affect the effectiveness of illumination are quantity and quality of light, amount of flicker, amount of glare, contrast and shadows. Each factor must be adjusted differently to optimise illumination in emergency, safety, operations, and security situations. Industrial lighting standards serve to address these concerns, in addition to the plethora of other concerns associated with the design, placement, installation, and energy requirements of illumination in industrial workplaces.
Proper illumination is essential for the optimisation of safety, comfort and productivity in the workplace; workplace lighting also dictates quality of perception, mood, and performance levels of employees.
Safe practices with regards to availability of emergency lighting, specifically the operation and performance testing of evacuation lighting systems have been included.