Written October 17, 2019
Illumination GuidelinesA 20-30-50** (2-3-5)** Public areas with dark surroundings, such as parking lots, building night-lights, exterior and interior. B 50-75-100** (5-7.5-10)*’ Simple orientation areas, hallways, corridors, etc. C 100-1 50-200** (10-15-20)*’ Working areas where occasional tasks, for some, are performed, such as: counting, stacking, loading, banding — in general, many of the activities performed in shipping areas. D 200-300-500+ (20-30-50)+ General office illumination, high contrast of large sized printed materials, typed originals, as well as many areas of printing production where close scrutiny is not a consideration, but general lighting for an entire area is required.
Stencil generation and coating, developing and reclaiming, etc. E 500-750-1000+ (50-75-100)+ Areas where closer inspection and evaluation take place. General lighting is also popular for office environments where readability of medium contrast and poorly printed matter is expected. Art generation, trimming, and where many finishing procedures take place. F 1000-1500-2000+ (100-150-200)+ Low contrast visual work, very small type or hard to read printed matter.
Difficult inspection and close scrutiny of printed material. G 2000-3000-5000++ (200-300-500)++ Performance of visual tasks as in ‘F’ but a consideration of prolonged exposure and very difficult inspection as well as fine assembly of component parts where applicable.
• Maintained in service ** General lighting throughout room + Illuminance on task ++ Illuminance on task obtained by a combination of general and local (supplementary) lighting Source: Illuminating Engineering Society Lighting for Specialized Areas Because there are different requirements for lighting in various types of applications, specialized lighting is a very important consideration. Several areas in a typical plant stand out more than others and require a little more attention to uniform, non-uniform, and task/ambient lighting. There are minimum levels of illumination for specific visual tasks.
These levels may be achieved using general lighting or a combination of general lighting and supplementary lighting. When supplementary lighting is utilized, general lighting should contribute at least one-tenth of the total illumination and should be no less than 20 foot-candles. Supplementary lighting, particularly when used in conjunction with modular office furniture, has resulted in significant energy savings. Open Office Design There are several approaches to lighting an open office area.
Usually the approach selected depends on the number and height of the workstation dividers as these can dramatically affect the light levels and uniformity on the desk. Watch out for partition-mounted cabinets and bookshelves as these can create shadows over large areas of the desk. The three basic approaches to open plan office lighting design are uniform, non-uniform, and task/ambient. Uniform lighting means that the main lighting source provides the majority of the lighting in the space.
This is effective if the main tasks do not require high light levels, otherwise the higher light levels required can become very expensive. With non-uniform lighting, areas of higher illuminance are mixed with areas of lower illuminance. This approach works well when the locations of all the furniture are known ahead of time, so that circulation areas can be designed for lower illuminance and task areas can be designed for a higher illuminance. Task/ambient lighting means the ambient lighting provides a level that is lower than required by the tasks, and supplemental task lighting is provided.
Non-uniform and task/ambient lighting designs can reduce initial equipment costs and operating expenses. The type of design approach should take into account possible future changes in the space. The lighting system should be flexible to accommodate changes without creating glare or visibility problems.