|
|
Quick
For more detailed information click on Performance Data or go to Performance.
 Visible Light Transmisson |
 Visible Light Reflectance |
 Ultra-Violet Elimination |
 Fading Reduction Coefficient |
 Shading Coefficient |
 Solar Heat Gain Coefficient |
 R Value |
 U Value |
 Sound Transmission Loss |
 Sound Transmission Class |
 Weighted Sound Reduction |
 Coolness Factor |
 Perceived Sound Reduction |
 Window Efficiency Rating System |
Look for these symbols when choosing your glass to help make your decision easier. If you are looking for particular properties in your glass selection make note of the associated icons below. Each glass type has a list of the applicable icons below it's description.
These icons should be used as a general guideline for your selection. You'll also find icons related to special manufacturing parameters including CIP Laminate, Screen Printing and Toughening.
 Available Thickness |
 Reflective Coating |
 Low E Coated |
 Laminated Glass |
 Good Glare Control (rated VLT 70% or lower) |
 Good Fading Reduction (rated - FRC 0.5 or lower) |
 Good Solar Control (rated S/C 0.6 or lower) |
 U Value (rated - U Value 3.00 or lower) |
 Condensation Reducing |
 Good Sound Reduction (rated - PSR 40% or higher) |
 Fire Resistant |
|
 Can Be CIP Laminated |
 Can Be Screen Printed |
 Can Be Toughened |
 Can Have Metro Protect |
Quick
The sixth edition of the Metro Glasstech online catalogue.
This online catalogue provides a complete guide to Metro GlassTech's product and service range. Every effort has been made to ensure the catalogue is as up to date and comprehensive as possible. If you need any further information, please don't hesitate to contact a Metro GlassTech representative.
Finding your way around is easy, with clear headings on each page and a consistent layout in line with our previous catalogue. Each section has a different colour to make it clear where you are in the catalogue. For navigation, page numbers appear at the bottom of each page, along with forward and back buttons.
Each product has comprehensive relevant technical information, so we have developed a range of quick reference symbols that will assist you in selecting the most appropriate product for your application.
A full explanation for each performance data symbol can be viewed in Performance.
A glass dictionary is provided. This is a useful guide to terms and product names used in the glass industry and throughout this catalogue.
|
Performance information on many glass products is shown in these performance diagrams. They are a quick way of evaluating the performance of similar glass products.
The diagrams depict a pane of glass with data relating to temperature and solar gain for both the inside and outside.
Refer to performance for comprehensive explanations of the icons used in the performance diagrams.
To
the right hand side of each performance diagram is a swatch showing a photographic
sample of the glass.
These were photographed specifically for the catalogue to provide as accurate a comparison as possible. Reflective glass types have been shown with a slight reflection.
Quick
Visible
Light Transmission
The percentage of visible light transmitted through the glass. VLT is measured
in the 380-780nm wavelength range perpendicular to the surface. The higher
the percentage the more daylight. Also known as Tv, Tvis, LT and VT.
Visible
Light Reflection
The percentage of visible light that is reflected by the glass surface,
measured in the 380-780nm wavelength range perpendicular to the surface.
The VLR can be given as the reflection from the external surface 1 or internal
surface 2. The higher the percentage the more reflection. Also known as
LR, VR and Rvis
Ultraviolet
Elimination
The percentage of ultraviolet radiation eliminated by the glass, measured
over the 290-380 nm wavelength range. The higher the percentage the less
UV is transmitted. This value is calculated from the percentage transmission
of ultraviolet (Tuv). Therefore UV Elimination = 100 - Tuv
Fading
Reduction Coefficient
The ratio of fading reduction of a glass type when compared to the fading
protection of 3mm clear float. The FRC of 3mm clear float is by definition
1.0 and represents the minimum fading protection offered by standard glazing.
The lower the fading reduction coefficient, the better the fading protection
offered.
Solar
Heat Gain Coefficient
The measure of the total solar energy transmittance entering a building
through the glazing as heat gain. It is the total heat transmission of
direct solar transmission and that proportion of absorbed radiation that
is re-radiated into the building from the action of heat absorbing glass.
The lower the SHGC the better the glass restricts heat energy transmission.
Also known as the Solar Factor (SF) or g.
Shading
Coefficient
The ratio of the total solar heat gain through a particular glass compared
to the total solar heat gain through 3mm clear float glass. (86%) The shading
coefficient of 3mm clear float is by definition 1.0 and represents a base
glass performance. The lower the shading coefficient the less heat gain
and thus more shading is provided by the glass. The shading coefficient
is calculated as SC = SHGC / 0.86
Window
Efficiency Rating System
The complete WERS rates the performance of windows including frames in
various defined New Zealand climate zones. For this catalogue star ratings
apply to centre of glass only (WERS cog) to compare glass
types and a maximum rating of five stars indicates the best performance
possible. Ratings in star and half star values are given, with five stars
indicating the premium performance. Refer Section 12 (Page 105) for a full
explanation of each star type.
U
Value
The U Value is the measure of air to air heat transfer through glass due
to the thermal conductance of the glazing and the difference between indoor
and outdoor temperatures. It is expressed as W/m2K (Watts per m2 per 1° Kelvin)
or W/ m2 °C. 1 Kelvin equals 1°C. The U value is a measure of the
rate of heat gain or heat loss through the glazing due to environmental
differences between outdoor and indoor air. It is measured at the centre
of the glass (cog).The lower the U Value the lower the heat transfer, the
better the insulation.
Coolness
Factor
The Coolness Factor (or luminous efficacy) is the visible light transmission
divided by the shading coefficient.
CF = VLT / SC. It is a useful means of comparing different
glass types in terms of the trade-off between light transmission and heat
control in selecting glass. Glass types with a coolness factor of 1 transmit
as much light as heat, those with a coolness factor lower than 1 transmit
more heat than light and those with a coolness factor greater than 1 transmit
more light than heat
R
Value (Total Thermal Resistance)
The R Value is the value of thermal resistance of a building element which
is the sum of the surface resistances on each side plus each component
of a building element. It is the inverse of the U Value R=1/R and is expressed
as m2 °C/W.
Sound
Transmission Loss
The average Sound Transmission Loss is useful for determining the effectiveness
of glazed panels to isolate exterior noise (e.g. traffic) from a building.
It is derived from the average of the measured transmission loss at eighteen
1/3 octave frequency bands between 100Hz and 5000Hz, or 16 bands from 125
to 4000Hz. Average STL is measured in decibels (dB), the higher the average
STL figure, the more effective glazing will be in reducing sound transmission.
Sound
Transmission Class
The Sound Transmission Class is useful for determining the noise reduction
offered by internal building elements such as partitions and walls. It
is a measure that relates the sound reduction performance against sounds
which normally occur inside a building (such as voices, telephones, music
etc). STC is a numerical class rating and cannot be compared with the STL.
It is derived from a best fit curve comparison of a reference STC curve
to the insulation curve. The higher the STC rating, the better the overall
sound reduction.
Weighted
Sound Reduction Index
The Weighted Sound Reduction Index incorporates frequency modified correction
for the human ear’s response. The RW is
reported in dB and is a composite rating of sound reduction at frequencies
from 100 - 5000Hz. Numerically, it is comparable to the STC values but
the numbers are in dBA.
Perceived
Sound Reduction
The percentage by which the human ear detects a lessening in sound pressure
or noise is known as the Perceived Sound Reduction. A 10dB reduction in
sound pressure level is generally perceived as a halving of the original
noise. Sound reduction values are ‘weighted’ and used to calculate
the perceived sound reduction as a ratio relative to the RW for
3mm clear float. The dB difference in the RW value
for a glass type when compared to 3mm float is calculated as a perceived
sound reduction percentage. For other sound indices see Section
11.4.5 and 11.4.6
