visible transmittance

[7.5.3.17] VT or Tvis

NOTE: This term was added in RP-16-17 Addendum 1.

The fraction of incident luminous flux that is transmitted through a material.

In daylighting: The fraction of luminous flux in the solar spectrum that is transmitted through a material or glazing system.  

Also known as visible light transmittance (VLT).

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