luminaires and lighting system

• Luminaires


  A device forming a complete lighting unit, which comprises of a light source and electric operating devices (transformer, ballast, ignitor, etc.)
• Luminaires


  • Direct light to desired locations, creating the required visual environment without causing glare or discomfort
• CIE Classification of Luminaires

  • Direct Lighting
  • Semi-direct Lighting
  • General Diffuse Lighting
  • Semi-indirect Lighting
  • Indirect Lighting
• Direct Lighting


  Luminaire directs 90 to 100 % of their output downward and 0 to 10% upward
• Semi-direct Lighting


  Distributions from semi-direct units is predominantly downward (60 to 90%) but with a small upward component (10 to 40%) to illuminate the ceiling and upper walls
• General Diffuse Lighting


  Downward and upward components of light from surface mounted and suspended luminaires are about equal ( each 40 to 60% of total luminaire output)
• Semi-indirect Lighting


  Lighting system which emit 60 to 90%of their output upward
• Indirect Lighting


  They are those which direct 90 to 100% of the light upward to the ceiling and upper sidewalls
• IEC Classification of Luminaires


  • Class 0
  • Class I
  • Class II
  • Class III
• Class 0 Luminaire


  Luminaire in which basic type insulation is provided for protection against electric shock
• Class I Luminaire


  Electrically insulated and provided with a connection to earth. Exposed metal parts that could become live in the event of basic insulation failure are protected by grounding
• Class II Luminaire


  Designed and constructed so that protection against electric shock does not rely on basic insulation only, reinforced or double insulation
• Class III Luminaire


  Protection against electric shock relies on supply at Safety Extra Low Voltage (SELV)
• Lighting System Classification


  • General Lighting
  • Localized General Lighting
  • Local Lighting
• General Lighting


  Lighting system which provide an approximately uniform level of illumination on the work plane over the entire area
• Localized General Lighting


  Consists of a functional arrangement of luminaires with respect to the visual task or work areas (aka task lighting)
• Local Lighting


  Provides lighting only over a relatively small area occupied by the task and its immediate surround
• Lumens (Zonal Cavity) Method


  Widely used for determining the average horizontal illuminance of a space
• Coefficient of Utilization


  The multiplier that accounts for the fraction of the total flux that is being utilized at the work plane