Ergonomical illumination in real world

  • View

  • Download

Embed Size (px)


Posional, Angular, other methods of lighting to improve human efficeincy

Text of Ergonomical illumination in real world

  • 1. A Special Thanks for the sake of Contributions from AJAY K DWARAGANATH P GOWTHAM M

2. Lighting or illumination is the deliberate use of light to achieve a practical or aesthetic effect. Lighting includes the use of both artificial light sources like lamps and light fixtures, as well as natural illumination by capturing daylight. Proper lighting can enhance task performance, improve the appearance of an area, or have positive psychological effects on occupants. 3. What is the significance of good lighting? Office work is visually demanding and requires good lighting for maximum comfort and productivity. "Good" lighting means providing enough illumination so that people can see printed, handwritten or displayed documents clearly but are not blinded by excessively high light levels (a cause of glare). What are signs of poor lighting? The most common complaints resulting from poor lighting are: difficulty seeing document or screen (too much light or glare, or too little light or shadows), eyestrain, eye irritation, blurred vision, dry burning eyes, and headaches. 4. Parameters of illumination 5. Equivalent Spherical Illumination: Measures the effectiveness of lighting systems. Visual Comfort Probability: Is a direct-brightness ratio. Task Illumination: Measures the quantity of light at the work surface. 6. Vision factors - Contrast - or reflectance difference - between a task and its background - Intensity range and control of light source - Spectrum of light source and resulting color rendering effect - Direction of light source Comfort factors - Contrast between the task area and the general room view - Control of glare in either task or general view - The lightness of the space - The luminous texture of the space - Spectrum of the light sources - Direction of the light sources - The perception of controlling intensity - through dimming or switching 7. * 90-100 percent of the illumination is directed downward to work surface * Creates glares, reflections, and shadows 8. 60-90 percent of light is directed down-ward, with remainder directed upward and then reflected back downward. Shadows are less of a problem with direct lighting systems. 9. * 90-100 percent of light is directed upward,which then is diffused and is reflected downward. * Eliminates most shadows and glares. * This system is recommended for most types of offices. 10. * 60-90 percent of the light is directed up- ward and then reflected downward * Remainder of light is directed downward * Shadows and glare are more problematic than with indirect lighting. 11. * 40-60 percent of light is directed to work surface with remainder reflected down-ward. * Shadows and glare are more noticeable than with semi-indirect. 12. General lighting provides uniform illumination over the whole working area and does not limit positioning of the work 13. * Localised lighting provides different levels of illumination in different parts of the same working area. * It matches the level of illumination to the needs of specific tasks 14. Local lighting is usually a combination of background lighting and a luminaire close to the actual work area 15. In general all exterior installations should: achieve a reasonably uniform illuminance on all relevant work areas; avoid glare to the users of those areas and to occupants of nearby areas. 16. Direct light fixtures project 90 to 100 percent of their light downward toward the work area. Direct lighting tends to create shadows. 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. 17. 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. 18. 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 (see-through) covers made usually 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. Different types of light fixtures 19. Ceiling Height Distance from (H) Wall (D) 8 Feet 24 inches 10 Feet 36 inches 12 Feet 48 inches 20. YES NO 21. Lamp type Angle for exclusion zone Tubular fluorescent 10 degrees lamps Discharge lamps 20 degrees with a fluorescent coating Discharge and 30 degrees incandescent lamps which allow a direct view of the arc tube or the filament Line of sight 22. Poor lighting can cause several problems such as: * Insufficient light - not enough (too little) light for the need. *Glare - too much light for the need. *Improper contrast (based on glare). *Poorly distributed light. *Flicker. 23. Glare is more when mounting height of the light is lowered, since the lighting unit approaches horizontal line of sight Lighting unit close to horizontal line of sight Lighting unit away from horizontal line of sight Glare is more Glare is comparatively less 24. Glare is worse in large rooms since the lighting unit from far off the room slides towards the horizontal line of sight GLARE 25. Disability glare from a light fitting Distracting reflection close to the line of sight The reflection of a window is masking information on the screen 26. In case of fluorescent lighting, light emitting from side panes produces glare. Hence broad-on side view will have more glare. But in end-on view the apparant area of bright side panels is diminished and so glare is reduce Broad-on side view End-on side view GLARE 27. Suitable Lighting positions 28. Activity Typical locations/ Average Minimum types of work illluminance measured (lux) lx illuminance (lux) lx Movement of people, Lorry park, corridors, 20 5 machines and vehicles circulation routes Movement of people, Construction site 50 20 machines and vehicles clearance, excavation in hazardous areas; and soil work, loading rough work not bays, bottling and requiring any perception of detail canning plants Work requiring limited Kitchens, factories 100 50 perception of detail assembling large components, potteries Work requiring Offices, sheet metal 200 100 perception of detail work, bookbinding Work requiring Drawing offices, factories 500 200 perception detail of fine assembling electronic components, textile production 29. Various colors possess different reflectance values. Lighter colors tend to reflect a greater percentage of light than do darker colors. Among the lighter colors cool colors create calm and retiring mood and warm colors create warm and cheerful mood. 30. Cool colors create calm and retiring moods. Warm colors create warm and cheerful moods Gray has a sleep-inducing effect. Colors tend to create different moods Impact of Color 31. THANK YOU