How Much Light is Enough Light|
Article - August, 2016 By LarsonElectronics.com
How Much Light is Enough Light
Lighting choices vary, depending on the needs of the applicable location and personal preferences of individuals in the area. A “one size fits all” solution is rarely available when determining the lighting requirements of multiple environments.
For example, lighting configurations for an office may differ, compared to a packaging warehouse. Even if the two facilities were the same size, the type of work being carried out in the buildings dictate the properties or characteristics of the luminaries, as well as the type of lamps that must be installed for adequate illumination. When it comes to personal preferences, most people do not associate exact, numerical figures and measurements with lighting requirements. Individuals use broad terminologies, like “bright enough” or “poorly lit,” when describing the lighting conditions of a location.
This article covers basic descriptions that can help mainstream consumers and businesses understand how much light they need, and why some lighting configurations are more effective than others.
Offices and Indoor Spaces
Offices and indoor spaces have varied lighting requirements, depending on the tasks and operations being conducted in the location. A requirement of 20 foot candles is recommended for general spaces in offices. In areas where reading and detailed tasks are carried out, 50 foot candles of lighting is sufficient. Conference rooms and other areas where visually challenging tasks are occasionally performed may incorporate between 10-20 foot candles. For special office spaces, such as health or medical establishments where visual tasks of low contrast are conducted, an observation of 100-200 foot candles is recommended.
One must also factor in levels of reflections from nearby devices and components around the office, such as floors (20-40 percent), walls (50 percent maximum), furniture (25-45 percent) and machines (50 percent maximum). When installing lamps in the location, fixtures that are widely spaced may promote the creation of shadows. Objects in between such spaces may become sources of shadows. Additionally, when sitting with one’s back to or directly under primary sources of light, such as natural sunlight from the window or overhead lighting, it is possible to generate shadows on surfaces. Because of this, one should recreate the general room or office layout and test lighting conditions from areas where work is performed, such as the desk, copy machine, printer and etc.
In most cases, office employees are not equipped with or do not have access to professional devices that measure light intensity. As a solution, it is possible to use the following questions when determining the lighting conditions of the location:
Can work be carried out optimally under the lighting configuration?
Are there any shadows present in the room?
Is illumination steady (no flickering)?
Does visual strain occur when performing tasks in the space?
Are there any sources of glare?
Uneven or poorly distributed light will appear as dark spots in the interior space. If one’s eyes are readjusting to different conditions around the room, it is likely that the lighting conditions are inconsistent. The following solutions can be applied to correct inconsistent light distribution errors: improve reflective qualities of walls and ceilings using paint, remove obstruction (dirt or tinted panels) found on fixtures, or replace poorly performing luminaries.
Lighting requirements in warehouses vary greatly, because a range of tasks are being performed in the facility. Areas with high activity, such as loading bays and inspection rooms, will require brighter illumination, compared to a section of the location with low activity, such as a storage room with only 5-10 recommended foot candles. Moreover, the size of materials or products being handled may also dictate the amount of light needed in the warehouse. For example, an active area that handles small items may require an average of 20-50 foot candles, while an area that handles large items may need 10-20 foot candles.
As mentioned earlier, foot candle measurements may not be useful for individuals without knowledge on lighting specifications. The following questions may help gauge the lighting conditions of a warehouse:
Can labels be read thoroughly without squinting or visual stress?
Are shadows from machines and objects causing visual strain?
Can all signs around the warehouse be seen clearly from all angles?
Is there too much or too little reflected light from nearby objects, walls and machines?
One of the most common tasks in a warehouse is identification. Reading labels and documents associated with materials or products are conducted throughout the facility at various points throughout the warehousing process. Because of this, one must take contrast levels into consideration when testing the sufficiency of light levels. For example, black lettering on white paper is relatively easy to see, even under inconsistent or poor lighting conditions. On the other end of the spectrum, gray lettering on a dark blue background can be difficult to perceive, sometimes even with support from a handheld light. Like office spaces, the reflective nature of objects should be carefully considered. For example, if the business uses white boxes inside the warehouse, less light may be needed for adequate illumination.
Facilities that specialize in works carried out by machines must have bright lights to ensure safety in the workplace. Machines that process sheet metal or are used for printing and finishing should incorporate 50-100 foot candles of lighting. Storage areas for machines and machine in-feeds may apply 5-10 foot candles.
The following questions may be used to assess the lighting conditions of a machining facility:
Can all of the machine’s parts be seen clearly?
Do shadows casted on the machine jeopardize the safety of the operator?
Does visual strain occur under the presence of the lights during machining?
Can the lighting system support long periods of operation?
Common issues related to machine lighting includes odd angles and contrast levels. Massive industrial machines are shaped differently, and various parts, including large levers, deep indentions and exit or output points, may prevent light beams from fully illuminating the work area. To improve lighting conditions around odd angles, businesses may install fixtures that emit light horizontally or small, powerful luminaries close to the area that cannot be reached with general, overhead fixtures. During inspection (for industrial machines that specialize in printing labels), operators may incorporate different types of lights to achieve high contrast levels. For example, infrared light is efficient in neutralizing contrasting components, and diffused light may help create even backgrounds for code readings.
Unlike indoor spaces, outdoor locations are prone to constantly changing variables that make lighting conditions tricky to manage. During the day, sunlight may illuminate an area adequately (sometimes excessively, as sunny conditions provide illumination up to 10,000 lux). After sunset, artificial lights are needed to support activities in the location, which can come from lights in nearby structures. For dark public areas, 20-50 foot candles is recommended.
Below are some questions that can help determine the level of lighting in outdoor spaces:
Do the lights cause visual strain?
Are objects and signs in the environment distinguishable from a distance?
Does the space appear generally gloomy or unsafe?
The type of activities in the outdoor space may determine the lighting requirements of the area. Building entrances and vital outdoor locations may support up to five foot candles, and infrequently used entry points could do well with one foot candle. Parking lots, substations and backgrounds (fences, walls and etc.) can benefit from two foot candles of lighting. Piers, active storage yards, service stations (pump island area) and focal points of gardens, may support up to 20 foot candles.
Painting and Color Matching
Color matching and painting facilities, such as paint spray booths, have strict lighting requirements due to the detailed nature of the tasks involved during operations. A typical standard for painting facilities is 100-150 foot candles at a height of three feet. The type of tasks may also dictate the level of lighting required: dripping, simple spraying and ordinary hand painting may incorporate 20-50 foot candles lighting measurements. Fine hand painting and finishing may require between 50-500 foot candles, depending on the complexity of the tasks.
Questions for determining adequate light levels:
Are there any shadows present in the facility?
Is illumination consistent throughout the painting room?
Can colors be identified clearly?
Are workers able to read documents and labels without visual strain?
Is the presence of glare affecting work conducted in the room?
Can workers operate machinery and equipment safely?
Color temperature and CRI ratings are major factors in color matching and painting rooms. Furthermore, most facilities use white paint on walls, floors and ceilings to boost the lighting conditions of the area. Industrial lighting guidelines for businesses that specialize in color matching or painting usually provide more than enough illumination for work to be carried out seamlessly.
Below is a shortlist of lighting products from Larson Electronics:
Dimmable Explosion Proof High bay LED fixture (C1D1, 150 watts, 17,500 Lumens)
Dimmable High Mast LED Light Fixture (IP67, 160 Watts, 21,600 Lumens)
LED wall pack light (IP68, 60 watts, 5400 lumens)
LED bulb (ETL Listed, 28 watts, 3,500 lumens, four-foot T8 lamp)
30’ Diesel Powered LED Light Plant (2,000 watts, 240,000 lumens, 7.5KW genset)