visible light transmission

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visible light transmission

Visible Light Transmission (VLT) is a measurement of the amount of visible light waves that transmit through a material. Measured as a percentage, VLT values for vision glazing, like insulated glass units (IGU) that transmits a direct beam of light, typically range between 40-70%. Utilizing the power of diffusion, Kalwall transmits much lower percentages of visible light but produces superior daylight levels by scattering light waves deeper into spaces without glare or hot spots. As a result, common VLT values for Kalwall are between 12-20% although some applications may call for somewhat higher or lower VLT values. The comparison below shows the distinct behavior of visible light transmitted through Kalwall versus an insulated glass unit (IGU) using our daylight modeling software. Want to optimize your daylighting design? Want to compare vision glazing with Kalwall? Submit your design, via your local sales representative, for this complimentary service.

 


 

Kalwall = Glare-free Daylighting

glare free daylighting

Insulated Glass = Glare-filled Daylighting

glare filled daylighting

 

 

Performance Data: 2-3/4” (70mm) Panel

FRP Face Sheet Combinations Visible Light Transmission (VLT) % by NFRC 202 Solar Heat Gain Coefficient @ 0° by NFRC 201
Exterior FRP Interior FRP 0.53 U 0.29 | 0.23 U 0.22 | 0.14 U 0.18 | 0.10 U 0.05 U 0.53 U 0.29 | 0.23 U 0.22 | 0.14 U 0.18 | 0.10 U 0.05 U
Crystal White 37% 26% 13% 7% 20% 0.33 0.31 0.18 0.14 0.27
White White 23% 16% 9% 4% 14% 0.26 0.25 0.16 0.11 0.20
Crystal Crystal 58% 35% 14% 9% N/A 0.55 0.36 0.20 0.14 N/A

 

Performance Data: 2-3/4” (70mm) Panel

FRP Face Sheet Combinations Visible Light Transmission (VLT) % by ASTM E-972 Solar Heat Gain Coefficient @ 0° *
Exterior FRP Interior FRP 0.53 U 0.29 | 0.23 U 0.22 | 0.14 U 0.18 | 0.10 U 0.05 U 0.53 U 0.29 | 0.23 U 0.22 | 0.14 U 0.18 | 0.10 U 0.05 U
Aqua White 29% 17% 6% 4% 15% 0.45 0.24 0.14 0.10 0.21
Rose White 30% 18% 6% 4% 16% 0.46 0.24 0.15 0.10 0.21
Ice Blue White 35% 20% 8% 6% 21% 0.54 0.28 0.17 0.12 0.26
Greenish Blue White 25% 14% 5% 3% 14% 0.50 0.23 0.14 0.10 0.19

 

Performance Data: 4” (100mm) Panel

FRP Face Sheet Combinations Visible Light Transmission (VLT) % by NFRC 202 Solar Heat Gain Coefficient @ 0° by NFRC 201
Exterior FRP Interior FRP 0.55 U 0.15 U 0.08 U 0.05 U 0.55 U 0.15 U 0.08 U 0.05 U
Crystal White 37% 13% 5% N/A 0.52 0.09 0.04 N/A
White White 23% 11% 4%+ N/A 0.38 0.06 0.04* N/A
Crystal Crystal 58% 17% 6% N/A 0.65 0.11 0.07 N/A

 

Air Gap Only Fiberglass ‘Batts’ Lumira® Aerogel

U-value SI conversion: 1.0 W/m²K = 0.176 Btu/hr/ft²/°F

U-values shown in bold denote thermally-broken grid core panels.
Visible light transmission (VLT) – NFRC 202, ASTM E-972 (approximate) as noted. VLT percentages over 30% are not recommended for most Kalwall applications.
Panel U-values include panel grid-core by NFRC 100 or 102. NFRC certified system U-values vary depending on framing. Project-specific Information available by request.
Shading Coefficient (SC) is equal to 1.15 times the Solar Heat Gain Coefficient (SHGC). *By calculation only (not by NFRC 201). By calculation only (not by NFRC 202)