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18 Cards in this Set
- Front
- Back
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What is Theme 6 - Lighting going to leave me with? |
1. Describe the ergonomical requirements of lighting and the effects of bad lighting 2. Distinguish between illuminance, luminance, reflection and contrast 3. Be able to explain the legal requirements of light in the workplace 4. Discuss the effect of lig• ht in work 5. What is phototropism and its impact on visual perception 6. Explain glare, its source, types and how to reduce it |
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What is Light? |
• Light is the region of the electromagnetic spectrum that is observable by the human vision and the eye. • The electromagnetic wave length ranges from 380 - 780 nano-meters • The electromagnetic spectrum includes - y rays, x-rays, UV-rays, infrared, FM, TV, microwaves and radio waves |
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What is perceptual constancy? |
Perceptual Constance is the ability to perceive an object one is familiar with as non-changing (size, shape, brightness) regardless of the stimuli changes that occur |
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What is Luminance and Illuminance? |
Illuminance is the light that lands onto a surface, measured in lux and Luminance is the light that reflects off that surface measured in candela |
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What is reflectance and contrast? |
Reflectance is the ratio of the luminance and the illuminance of a surface Contrast is the striking difference between between to states, in this context, light •Contrast is the most important consideration to ergonomics (which concerns itself with finding the appropriate contrast in the working environment) |
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What is intensity and distribution of light? |
intensity is the level of brightness, the intensity varying in accordance to the task requirements Distribution of Light is the ideal and even spread of light observed through luminance and reflection throughout the entire visula field. Eyestrain occurs with workplace having high amounts of intensity |
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What are the legal parameters and requirements for light in the workplace? |
1. Every employer must ensure every workplace in their undertaking is lit in accordance with illuminance standards specified by the Schedule to these regulations. 2. Specialized lighting must be provided for particular work, irrespective of if the work is listed in the Schedule (i.e. surgery using around 2000lux) 3. The employer must ensure the lighting available is used |
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What does some Research identify? |
The increase of lux leads to the increase of productivity. • this can be flawed due to the complexity of the work (leather factory) • Hawthorne studies on supervision |
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What is the concluded effect of light on performance? |
High increase in illumination show slow increase of improvement alongside light increases until it plateaus. Changing features of the task can influence the visual performance of the individual The Age of the observer has a large impact on the results |
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What are some of the other research findings? |
Improved luminance did not affect the performance of the primary visual field but improve the errors on the secondary auditory task The idea is that higher levels of luminaction reduce the strain on information processing allowing the brain to process other information better |
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What are the effects light have on the workplace? |
Negative effects include: discomfort, eye strain and headaches and glare Positive effects include: decrease in accidents by 5% indirect to 20% direct, Performance increase between 4% and 35% |
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What is Phototropism? |
Phototropism is the way our gaze is involuntarily drawn to bright objects in our visual field. • There are advantages and disadvantages to this |
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What is glare? |
Glare is experienced when the eye experiences a brighter intensity of luminance on an object the eye is not accustomed to This can also be described as an imbalance of the object's luminance in the perceptual visual field |
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What are the sources of glare? |
Direct Glare is when the light source intensity is experienced in the field of view Reflected Glare is experienced when light is being reflected by a surface • Research points toward glare causing an increase of errors made |
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What types of glare does on get? |
Discomfort Disability Glare Blinding Glare |
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How can these types of glare be reduced? |
1. Adjustment through placing the light source 2. Sunken or change the angle of the roof light 3. Assist the worker with screens or move the worker 4. Uniform levels of brightness throughout the worspace |
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What is the association between artificial lighting and natural lighting and work productivity? |
Little proof to support natural light is better to artificial light windowless spaces are associated with dissatisfaction Artificial light can be spread across the spectrum and varied opposed to uniform light |
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Why is natural light presumed to be better than artificial office lighting? |
1. Windows offer visual relief and have psychological value 2. There are biochemical and behavioral effects - Vitamin D for calcium metabolism 3. Seasonal Affective Disorder which associates depression with autumn and winter 4. Photo-therapy - using light to aid recovery of mental illness |
