HVAC
Building Control
Fire Safety
Your friend in indoor comfort & safety systems
Home Company Services Case Studies References Agencies Daikin-Vrv Handbook Fires / Hotels Links Save Energy Contact Us
Eco Homes

Solar Water Heeating

Solar Electric Systems
Wind Turbines
Passive Solar Heating
Passive Solar Cooling
Water Conservation
Building Material
Ground Source Heat Pumps
Eco Cases
Save Energy
Solar Water Heating
Solar Electric Systems
Wind Turbines
Passive Solar Heating
Passive Solar Cooling
Building Material
Water Conservation
Ground Source Heat-Pumps
Green Hotels

Glass &Windows Selection

Standalone Systems
Grid Connected Systems
Hybrid Systems
Back-up Systems
Solar Cells
Solar Arrays
Inverters
Change Controller
Direct Systems
Indirect Systems
Thermosiphons
Draindown Systems
Pool Heating Systems
Turbines
Hybrid Systems
Grid Systems
Water Pumping
Using Wind Energy
Enviromental Aspects
Buyer's Guide
Solar Collectors
Flat Plate Collectors
Evacuated Tube Collectors
Concentrating Collectors
Transpired Collectors
Solar Control Systems
Big Hotel Fires
Hotel Fire Cases
Fire Hazard Classification
Hotel Sprinkler Systems

Hotel Fire News

Ask The HvacMan
Air Handling Units
Cooling Towers
Heat Recovery
Psycometry

Steam Generation

Glass Transmittance

Glass Transmittance

Transmittance refers to the percentage of radiation that can pass through glazing. Transmittance can be defined for different types of light or energy, e.g., visible transmittance, UV transmittance, or total solar energy transmittance.

Transmission of visible light determines the effectiveness of a type of glass in providing daylight and a clear view through the window. For example, tinted glass has a lower visible transmittance than clear glass. While the human eye is sensitive to light at wavelengths from about 0.4 to 0.7 micrometers, its peak sensitivity is at 0.55, with lower sensitivity at the red and blue ends of the spectrum. This is referred to as the photopic sensitivity of the eye.

More than half of the sun's energy is invisible to the eye and reaches us as either ultraviolet (UV) or, predominantly, as near-infrared. Thus, total solar energy transmittance describes how the glazing responds to a much broader part of the spectrum and is more useful in characterizing the quantity of solar energy transmitted by the glazing.

With the recent advances in glazing technology, manufacturers can control how glazing materials behave in these different areas of the spectrum. The basic properties of the substrate material (glass or plastic) can be altered, and coatings can be added to the surfaces of the substrates. For example, a window optimized for daylighting and for reducing heat gains should transmit an adequate amount of light in the visible portion of the spectrum, while excluding unnecessary heat gain from the near-infrared part of the electromagnetic spectrum.

On the other hand, a window optimized for collecting solar heat gain in winter should transmit the maximum amount of visible light as well as the heat from the near-infrared wavelengths in the solar spectrum, while blocking the lower-energy radiant heat in the far-infrared range that is an important heat loss component. These are the strategies of various types of low-emittance coating

Glass & Windows 101
Glass Reflectance
Glass Absorptance
Glass Emittance
Back to Glass&Windows

 

 
 
Google
 
Web www.iklim.com
  Discuss on the Message Board
   
 
  http://www.iklimnet.com
 
Book & Magazine
Interstate Bank Fire
Beverly Hills Club Fire
MGM Fire
Firehause Magazine
Special Fires
Hotel Fires
Ship Fires
Industrial Fires
Warehouse Fires

Restaurant/Nightclub Discotheque-Fires

High Rise Fires
Fires
Fires ABC
Big Building Fires
Book About Fires
Fire Stats
Fire Board

Books About Fires

Hotels
Enviroment
Energy Save
Hotels & Legionella
Green Hotels
Hotel Design Books
Control Software