Chapter 1

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.2Human FactorsA quality lighting environment is planned to optimize the person-in-environment systemInvolves a knowledge of current research and a thorough assessment of the project

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.3Physiological FactorsResearch shows light has negative and positive effects on health:Negative effects: Eyestrain, headaches, dizziness, skin cancer, and premature aging of skin and eyesResearch is exploring effects of lighting on growth and development of infants

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.4Physiological FactorsCircadian rhythm coordinates bodily functions for being awake and sleepingLight therapy successful in helping to regulate biological clock associated with circadian rhythm

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.5Physiological FactorsProblems related to circadian rhythms are associated with seasonal affective disorders (SAD)SAD: A condition associated with an individuals inadequate exposure to sunlightEffects of SAD: Depression, weight gain, lack of concentration, and sleeplessnessMany people experience SAD during time of year when days are the shortest

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.6Physiological FactorsBureau of the Census estimates 16 million people in US have a visual impairment: People with vision impairments require special lighting accommodationsPopulation includes all age groups, but dominated by elderly

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.7Physiological FactorsAgeReduction in size of pupilDecreased elasticity of musclesYellowing and thickening of the lensPresbyopia:Decrease in eyes elasticity and thickening of lensAffects visual acuity and ability to see objects at close range

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.8Psychological Factors ResearchTopics include: Characteristics of natural and electrical light sources and their behavioral and psychological effects on peopleLighting effects on special populations, including individuals with Alzheimers disease, cancer, AIDS, infants, and the elderly

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.9Psychological Factors ResearchResearch focused on understanding which characteristics of electrical light sources affect people:Specific lampsColor rendering indexColor temperaturesQuantity of lightIntensitySpectral compositionDistribution patterns

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.10Psychological Factors ResearchEarly lighting research investigated effects of quantity of light on productivity in the workplace:Demonstrated that quality lighting improved worker productivity and the increase in performance offset the cost of lighting systems

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.11Psychological Factors ResearchCurrent research regarding effect of lighting on productivity is inconclusive:Improved performance may be the result of a higher level of satisfaction with working conditionsControl over ones environment, including lighting, is a significant factor in employee satisfaction

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.12Psychological Factors ResearchGenerally, the type of luminaire and light distribution patterns does not affect worker performanceProper lighting for the computers VDT is required to enhance worker productivity

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.13Psychological Factors ResearchLight affects emotions, cognitive processes, memory, communication, and perceptions Effect of lighting on moodsDifferences in moods for men and women Flynn concluded people prefer warm and dim lights, compared to cool and bright sources

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.14Psychological Factors ResearchMood can also be affected by lighting patterns in a space:Uniform lighting patterns viewed as monotonous and boringBecomes more pronounced when tasks are repetitive and require a long period of time to complete

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.15Psychological Factors ResearchA connection between stimulation and the spectral distribution of a light source:Rea reported a blue spectrum stimulates rods in eyesNavvab suggests bluer light should be used in workplace

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.16Psychological Factors ResearchProper amount of stimulation can:Increase attentivenessReduce fatigueAlter perceptions of timePromote positive moodsToo much stimulation can cause anxiety and stress

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.17Psychological Factors ResearchPeople with visual impairments and dementia are more inclined to be adversely affected by stressful lighting environments

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.18Psychological Factors ResearchStress can occur:In a dark spaceA building that is unfamiliarAn emergency situationTo help alleviate stress wayfinding lighting and adequate signage should be well planned

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.19Universal DesignConsiderVisual acuityManual dexterityPlacement of luminaires, switches, and outletsVisual acuity affected by:Illumination levelType of lampDistributionColor temperature and color renderingBallastAbility to control lighting

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.20Universal DesignWall switches and luminaires should be intuitive to use and easy to operateRocker or touch switches are the easiestSwitches and dimmers should be accessible

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.21Universal DesignPlacement of luminaires, switches, and outlets should be accessible to people with disabilities, including individuals in wheelchairs:Average range of reach is 24ADA specifies:Wall-mounted luminaires mounted 27- 80 AFF should not extend more than 4 from wall Luminaires at or below 27 AFF may protrude any amount

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.22Universal DesignADA specifies:Lowest element of a suspended luminaire should allow for 80 of clear headroomFreestanding luminaires mounted on posts may overhang 12 horizontally and 27- 80 AFF

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.23Universal DesignWall switches and outlets - Universal access is 15 to 48 AFFElectrical receptacles on walls mounted no less than 15 AFF Convenient location for wall switches and outlets is 38 and 18 AFF

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.24Universal DesignADA requires signage in the 100 to 300 lux range (10 to 30 footcandles)Elevator thresholds should be a minimum of 50 lux (5 fc)

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.25Universal DesignNeed knowledge of specific needs of individualsRequires observations, interviews, and often researching special situationsPeople with visual impairments require illumination levels ~20% higher People with visual impairments often excessively sensitive to glare

Chapter 13Illumination and Human Factors 2006 Fairchild Publications, Inc.26Universal DesignThe RGIE study indicated that people with visual impairments need luminaires:Easy to adjustRemains fixed in desired positionDistributes light over a large areaConceals lamp from view