Glass and Glazing Flashcards
materials in clear glass
silica sand +
small amounts alkaline salts (ex. lime, potash, soda)
annealed glass aka
float glass
annealed glass
manuf. process:
pouring molten glass,
on bed of molten tin.
slowly cool.
heat-strengthened glass
manuf. process:
glass heated to 1100ºF,
slowly cooled.
2x strength annealed glass.
heat-strengthened glass
use:
solar-induced thermal stresses,
cyclic wind loading.
tempered
manuf. process:
subjecting annealed glass to a special heat treatment,
heated to 1150ºF and quickly cooled.
process sets up compressive stresses @ outer surface,
and tensile stresses @ inner surface.
4x stronger.
tempered
typ thickness:
⅛” to ⅞”.
tempered glass breaking scheme
breaks into tiny pieces, instead of dangerous shards.
laminated glass
manuf. process:
two or more pieces of glass,
bonded by polyvinyl butyral resin.
when broken, interlayer tends to hold together.
laminated glass
use:
bullet resistance,
sound control
laminated glass thickness:
13/64” to 3”
tinted glass or heat absorbing glass
not used at
differential expansion
not used where combination direct sun/shade,
will crack under thermal load.
solution: tinted glass often heat strengthened/tempered.
ratio solar heat gain at specific fenestration,
to shg at ⅛” clear glazing.
doesn’t include frame/spacer effects.
shading coefficient:
ratio solar heat gain through glazing/wdw,
to total solar radiation incident on glazing/wdw.
solar heat gain coefficient:
gives light-green color,
to ordinary float glass.
pros: exceptional clarity, light/color transmission.
low-iron glass:
clear or tinted glass, coated w thin layer,
of metal or metallic oxide.
placed on inside face of exterior lite.
color: silver, copper, golden, earthtone shades
reflective glass:
fabricated of two or three sheets,
hermetically sealed air space of ¼-½”.
can be made w heat-strengthened, tempered,
reflective, tinted, laminated.
insulating glass:
smooth or patterned surface,
used primarily fire-rated, in non-hazardous locations.
50% stronger than annealed glass.
cannot be tempered.
wire glass:
mesh of wire embedded in middle of sheet.
conceals floor and ceiling in curtain wall construction
spandrel glass:
used as the opaque glass,
permanently fuse ceramic frit color,
to back of heat-strengthened or tempered glass.
typ single sheet w insulation behind.
spandrel glass:
selectively reflects certain wavelengths.
very thin coating (few atoms) of metal or metal oxide,
on surface of glass or thin film.
transmits visible light and short wave solar radiation,
but reflecting long-wave heat radiation.
low-emissivity glass:
low-emissivity film most effective when located:
middle of glass
u-value 0.23
used as a general category term.
either dark tint or milky white opaque,
changes to transparent when electric current is applied.
electrochromic glazing:
electrochromic glazing:
type provides light control
electrochromic glazing
electrochromic glazing:
type provides light and privacy control
SPD (suspended particle device)
electrochromic glazing:
type provides privacy control
polymer-dispersed liquid crystal film
polymer film between two layers glass,
in translucent, offers full visual privacy.
still lets significant light through,
so not good for light control.
polymer-dispersed liquid crystal film
light-absorbing microscopic particles, dispersed in liquid suspension film, between 2 layers transparent conductive material. can be totally opaque (privacy). variation w rheostat switch.
SPD (suspended particle device)
inorganic ceramic thin-film coating on glass,
range from transparent to heavily-darkened.
never totally opaque, so not good for privacy.
variation w rheostat switch.
electrochromic glazing
