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Solid-State Roadway Lighting Design Guide: Volume 1: Guidance (2020) / Chapter Skim
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Chapter 4 - Tunnels and Underpasses
Pages 29-31

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From page 29...
... Using a luminance meter that continuously measures the brightness of the tunnel portal and that is connected to an adaptive SSL can provide improved tunnel lighting lighting system that has a large number of dimming levels allows for systems with more discrete control of more precise control of required lighting. lighting levels in the tunnel to compen In contrast, traditional HID tunnel lighting systems switch lumi- sate for the lighting conditions outside naires on or off via con­tactors throughout the day to achieve three to the tunnel.
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From page 30...
... Using fewer step levels and holding the levels for longer periods causes the system to use higher light levels than required. An LED system with adaptive controls allows for continuous dimming of the system throughout the day to achieve required lighting levels.
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From page 31...
... Often temperatures at a tunnel ceiling can be higher than ambient temperatures, so the design of the SSL luminaire must account for those elevated temperatures. Key Issues for LED in Tunnels • Use an adaptive control system with luminance sensors outside the tunnel for better control of required threshold and transition zone lighting.
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Key Terms

  • tunnel portal
  • lighting design
  • required lighting
  • luminance values
  • lighting conditions

  • daytime lighting
  • adaptive controls
  • luminance meter
  • lighting levels
  • ssl technology

  • adaptive control
  • supplemental daytime
  • conditions outside
  • darker tunnel
  • luminance sensors

  • daytime luminance
  • pavement luminance
  • approach luminance
  • egress lighting
  • required threshold

  • ambient lighting
  • achieve required
  • evaluate tunnel
  • hid tunnel
  • improved tunnel

  • tunnel interior
  • required luminance
  • required values
  • threshold luminance
  • lighting requirements


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