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process of adhering and sealing.
mechanical device, normally spring loaded, used in hung windows to
counterbalance the weight of the sash during opening and closing.
hardware in hung window jamb that connects the balance with the sash.
composite of three windows, usually made up of a large center unit and
two flanking units at 30- or 45-degree angles to the wall. A bay
projects from the wall of the structure.
molding or stop placed around a window frame to hold the glass in
place by pressure.
cylindrical form of aluminum just prior to the extruding process.
glazing term referring to the dimension of the glazing leg which
overlaps the edge of the glass.
composite of four or more window units in a radial or bow formation
gently curved contour. Bow windows also project from the walls of the
type of external casing which frames windows and doors. Exterior
casing around window to cover jambs and provide means for nailing
Thermal Unit -- a basic measurement of heat. One BTU equals the amount
of heat needed to raise one pound of water 1 degree Fahrenheit. (A
match contains approximately one BTUs, and a well-insulated house in
the Ottawa region may require 90 million BTU for space heating over
the year). The metric equivalent is 1054.35 Joule.
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type of window with a side-hinged sash that opens like a door
-- the best window for catching breezes and providing
window unit in which the single sash cranks outward, to the right or
left. Projecting window hinged at the sides and usually opening
outward like a door.
of various widths, thickness and shapes applied to the framework of
window and door units. Interior casing is a flat, decorative moulding
which covers the inside edge of the jambs and the rough opening
between the window unit and the wall. Exterior casing (or brick mould)
serves the same purpose, while it also is an installation device
through which nails are driven to install the window unit into the
used to seal fixed and movable construction joints and prevent
center of glass--All
glass area of a window except that within 2.5" (10cm) from the edge of
the glass -- used in measuring and calculating glazing performance
such as R-values and U-values.
feet per minute - a unit of measure used in air infiltration
testing, e.g., "maximum .10 cfm per foot of sash perimeter."
a double-hung window, the bottom rail of the upper sash and the upper
rail of the lower sash, where the lock is mounted. The top rail of the
lower sash and the bottom rail of the upper sash which meet when a
double-hung window is closed. Both pieces should be weather stripped
for maximum weatherability.
generic term referring to any of a variety of window units with one or
more curved frame members, often used over another window or door
aluminum material locked to the outside faces of many window products
to provide a durable, low-maintenance exterior surface.
window placed vertically in a wall above one "s line of vision to
provide natural light -- often at the intersection of two offset roof
venting or fixed window above other windows or doors on an upper
outside wall of a room.
of Meeting Rail - a reference line used to locate integral
mullions and/or size oriel (unequal) sash, e.g., "the height of the
lower sash shall be 22" from the frame sill to CMR."
act of trapping solar radiation and converting it to heat.
glazing selections on a window-by-window basis to fulfill a
prioritized set of objectives -- e.g., comfort, energy efficiency
(both summer and winter), UV protection, natural lighting, desired
aesthetics, views, and budget.
change of a gas to a liquid state. Because warm air can hold more
water vapor than cold air, as warm air cools its ability to hold water
vapor is reduced. Excess moisture condenses on the warm side of glass.
e.g., condensation on the outside of a glass of ice-water.
process of heat transfer whereby heat moves directly through a
material by molecular agitation.The handle of a cast-iron frying pan
becomes hot due to conduction.
transfer of heat through a given material -- see U-value which is the
measure of conductivity, the inverse of R-value.
process of heat transfer whereby heat energy is transferred from one
location to another -- created by the motion of air resulting from a
difference in temperature and the action of gravity.
double-hung window in which the upper sash is shorter than the lower
outside perimeter of window sash/vent; used when defining the AAMA air
Resistance Factor - an indication of a window"s ability to resist
condensation (the higher the better).
visual attractiveness of a home as seen from the street -- often the
first impression. Realtors see curb appeal as an influential factor in
evaluating and selling homes.
hardware only operable with a tool or key.
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percentage of visible light that glazing transmits through a
window -- a standard clear dualpane has a daylight
transmittance of 82%.
process of cutting away the metal on the bottom of an aluminum thermal
break cavity once the two-part polyurethane has reached full strength,
thus creating a thermally broken extrusion.
porous crystalline substance used to absorb moisture and/or sealant
solvents from within the sealed air space of an insulating glass unit.
project wind load to be determined by the architect and expressed in
psf, e.g., "the project design load shall be 38.7 psf, both positive
by AAMA. One for each window style. It provides a code for
architectural selection, e.g., TR-5000 = DH-C45 = Double Hung -
Commercial Grade - 45 psf Design Pressure.
substance used to absorb moisture from air within IGUs.
temperature at which water vapor will condense as warm, moist air is
perforated steel block through which aluminum or vinyl is extruded.
direct gain passive solar system utilizes south-facing windows to open
a house to the sun. A large window area accepts direct sunlight while
thermal mass serves as storage.
space which protrudes from the roof of a house, usually including one
or more windows.
of two panes of glass in a window to increase energy efficiency and
provide other performance benefits.
double glazing panel (dgp)--A
removable interior glass panel which creates an air space between the
exterior glazing and itself. It provides improved insulation and
condensation control and allows for between-glass shading options such
as muntins, blinds and pleated shades.
double strength glass--(DSB)
window unit that has two operable sashes which move vertically in the
frame. Two vertically sliding sash which by-pass each other in a
single frame. Sashes typically fit within vinyl balances and tilt out
and remove for safe, easy cleaning.
molding placed on the top of the head brickmold or casing of a window
method of securing glass in a window frame with a dry, preformed,
resilient gasket, without the use of a glazing compound.
material that has two or more levels of flexibility. An example is the
weatherstripping used between the frame and sash of a casement
dual durometer bead--a
vinyl glazing bead with a softer flap against glass and a harder
section inserted into sash member.
single lites glazed into a split sash with an airspace, not
hermetically sealed, between the two single lites.
windows joined together, one in front of the other, to provide
superior sound control.
panes of glass with a single airspace, held together by an edge spacer
-- the most economical IGU.
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edge of glass--The
glass area within 2 1/2" (10cm) of the edge of a window.
window with specific release hardware and minimum clear opening size
to allow occupants to escape through the window in case of a fire.
painting process by which the aluminum is grounded and the paint
carries a positive electric current. This creates a magnetic
attraction between the paint and the aluminum allowing for uniform
paint coverage on all exposed extrusion surfaces.
or the ability to radiate heat in the form of long-wave radiation.
to close the ends of a subsill so the water will not leak out the
ends. It makes the subsill a complete water trough allowing it to
collect excess water and drain it to the exterior.
Propylene Diene Monomer - a weather resistant synthetic rubber
from which many flexible gaskets for windows are made.
Propylene Diene Monomer - a weather resistant synthetic rubber
from which many flexible gaskets for windows are made.
Rating number developed by CSA (Canadian Standards Association) to
compare the thermal performance of windows. Measured in watts per
square meter (W/m2).
for handles etc.
mulling window frame jambs that, when slipped together, permit
expansion/contraction while preserving strength and watertightness.
wood parts which are nailed to the interior edges of the window jamb
to extend it in width and adapt to a thicker wall. The inside edge of
extension jambs should be flush with the finished wall surface.
Interior casing is then nailed into it.
glazed from the exterior of the building.
process of shaping aluminum or vinyl by forcing it through a die.
finished form after pushing aluminum or vinyl through the die.
form produced by forcing material through a die.
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architectural term referring to the arrangement of windows in
a wall. From the Latin word, "fenestra," meaning window.
arrangement of windows in a building.
form of pile weatherstrip that has a plastic mylar fin centered in the
pile. This fin reduces air infiltration and ensures weatherstrip
contact throughout the window's life.
means of joining individual pieces of wood together to form longer
lengths. The ends of the pieces are machined to form a set of
interlocking fingers, which are then coated with adhesive and meshed
together under pressure.
stationary window or door that does not open -- also referred to as a
window frame with the head, jamb, and sill exterior perimeter leg
longer than the interior perimeter leg.
thin strip of metal or synthetic material that diverts water away from
a window or skylight. A metal or plastic strip attached to the outside
of the side jambs and head to provide a weather barrier, preventing
leakage between the window frame and wall.
glass with flat, parallel surfaces formed on the surface of a pool of
material placed in the airspace of the insulating glass windows to
enhance the appearance and improve the performance of the window.
enclosure in which window sash or door panels are mounted. Outside
members of a window unit which enclose the sashes. Composed of side
jambs, head jamb and sill.
of a head, jambs, and sill to form an opening into which sash or door
French hinged door--Hinged
door(s) which have wider panel members around the glass.
French sliding door--A
sliding door which has wider panel members around the glass, giving
the appearance of a French hinged door.
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rubber or plastic pliable material used to separate glazed
glass and aluminum or vinyl.
in a window or door; the act or process of fitting glass or
panels into the sash or frame of the window.
installation of glass into a window or door sash. Also refers to the
type of glass used in the process.
molding or stop around a window frame to hold the glass in place by
pressure. A vinyl or wood strip, applied around the perimeter of the
glass on the exterior of the window sash, for holding the glass in
part of the sash or door panel which holds the glass in place.
property of glass that permits the transmission of short-wave solar
radiation, but is opaque to long-wave thermal radiation. The interior
of a car heating up in direct sun illustrates the greenhouse effect.
term referring to windowpane dividers or muntins, usually a type of
assembly which may be detached for cleaning.
inserts for windows or door glazing that add a traditional touch --
available as fixed or removable inserts, in wood, brass, or vinyl.
bars in varying thicknesses and profiles sealed between insulating
glass panels to simulate muntin bars.
concealed, strong, right-angled shape used to reinforce mitered
corners in tubular aluminum extrusions
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main horizontal member forming the top of the window or door
flat board, cut to fit the contour of a Bow or Bay window, for
installing between the head jambs and the flat wall surface to finish
off the area which would normally be ceiling.
u-shaped extrusion slipped over the frame head that, when pushed up,
closes the gap above the window after window installation.
horizontal framing member placed over the rough opening of a window to
prevent the weight of wall or roof from resting on the window frame. A
beam across the top of the rough opening for a window or door. Headers
rest on jack studs and support the weight of the wall above the window
unit. They are often constructed out of doubled 2x6?s, 2x10?s or
method to join PVC frame and/or sash members by heating the cut ends,
squeezing them together, and allowing the assembly to cool.
process where glass or aluminum extrusions are heated and cooled to
make these materials harder and stronger.
hermetically sealed unit--an
insulating glass unit that is sealed against moisture. The unit is
made up of two lites of glass, separated by a roll-formed metal spacer
tube (at the full perimeter) which contains a moisture and/or solvent
absorbing material. The unit is then completely sealed, creating a
moisture free air space.
extrusion having an enclosed cavity within it.
window unit in which the top of the sash swings inward.
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Glass Certification Council - directs a certification
program of periodic accelerated laboratory testing and
unannounced plant inspections to ensure sealed insulating
glass performance is in conformance with ASTM E 774-88.
inside snap trim--used
in retrofit work to cover the inside gap between the new window and
the existing opening.
solar radiation -- the total radiation striking an exposed surface.
Insulating Glass Unit (IGU)--A
combination of two or more panes of glass with sealed air space(s)
between panes -- dualpanes, tripanes, and quadpanes. Also referred to
as thermopanes or sealed units.
pieces of glass spaced apart and hermetically sealed to form a unit
with an air space between. Heat transmission through this type of
glass may be as low as half that without such an air space. A
combination of two or more panes of glass with a hermetically sealed
air space between the panes of glass. This space may or may not be
filled with an inert gas, such as argon. Two sheets of glass bonded
together in a unit to enclose a captive air space. Units are
constructed with a metal spacer inside the outer perimeter. The outer
edges are sealed. Spacers contain desiccant material for absorbing and
holding any remaining moisture in the air space.
material with high resistance (high R-value or low U-value) that is
used to retard heat flow. Air, Argon, or Krypton gas spaces between
panes of glass provide insulation in IGUs.
frame member trapped within the master frame to separate vents or
glazed from the interior of the building.
design feature which enables sash to become engaged with one another
heat produced in the interior of a dwelling from the operation of
lights, appliances, etc.
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framing members, generally 2x4?s, which form the inside of the
window or door rough opening. They support the header and run
down to the sole plate.
main vertical members forming the sides of a window or door frame.
Side jambs are the vertical pieces of a window frame. The head jamb is
the horizontal piece across the top. The vertical member of a window
a modern double-hung window, the track installed inside the jambs on
which the window sashes slide. Vinyl or metal covering applied to the
side jambs of double hung and single hung windows. They are generally
formed to include an integral balance system and stops for the
exterior and interior surfaces of the sash.
hardware device into which a window locking latch engages for
security. The receiving portion of a lock that interlocks with the
lock arm. It?s mounted to the upper sash check rail on a double hung
or single hung window and the inside surface of the sash stile on a
small bay window used above counter-height in kitchens -- allows for a
wider view and an inside sill for herbs and flowers.
knocked down (kd)--Product
components that are shipped unassembled, e.g., the frame for a
sliding glass door.
inert, colorless gas used instead of air in sealed spaces between
panes of glass in insulating glass units to increase insulation.
Provides greater insulation than Argon.
type of safety glass comprised of two pieces of glass with a clear
left or right--location
information, always outside looking in, that can be used to specify
direction, e.g., "the operating sash slides to the right."
handle or grip installed or routed into the bottom rail of the lower
sash of a double hung or single hung window
separately framed piece of glass in a window or door. A traditional
double-hung window, for instance, often has several lights divided by
muntins in each sash. Such windows are described as six-over-six,
eight-over-one, twelve-over-twelve, etc., to indicate the number of
lights in each sash. Sometimes spelled 'lite.' A single (monolithic)
glass pane or piece.
low e or low-emissivity (low-e)
glass--a transparent coating applied to a
glass surface to separate long wave (heat) energy and short wave
(light) energy. The long wave is reflected back to the heat source.
The short wave is allowed to pass through the coating. A special type
of glass having a transparent material fused into its surface which
acts as a thermal mirror.
low e glass--Low
Emissivity glass with a transparent coating which acts as a thermal
mirror -- used to increase a window's insulating value, block or
increase heat flow, and reduce fading.
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u-channel of soft PVC which is wrapped around the edge of the
glass, cushioning the glass against the aluminum or vinyl.
This process allows for unrestricted expansion and contraction
space in a masonry wall left open for windows or door. The opening in
a masonry wall to accept a window or door unit, the same as a rough
opening in a frame wall. The header (or lintel) in a masonry opening
is usually a steel beam.
part of a hung window where the two sash meet and create a weather
original finish produced on aluminum by extruding.
slot or rectangular cavity cut into a piece of wood to receive another
strong wood joint made by fitting together a mortise in one board and
a matching projecting member (tenon) in the other.
to any short or light bar, either vertical or horizontal, used to
separate glass in a sash into multiple lights. Also called a
windowpane divider or a grille.
extrusion that joins panning perimeter legs that extend over existing
in the sash which are exterior (outside of the glass exterior face),
internal (in the insulating glass airspace), or true (dividing the
glass) which appear to or actually divide the glass into smaller lites
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vinyl or metal flange integrated into (or attached to) the
perimeter of a window frame for installation onto the rough
opening?s header, jack studs and rough sill. A continuous
nailing fin may surround the frame as with an all-vinyl window
or a nailing fin may be affixed to the head and side jambs as
with a vinyl clad window frame.
synthetic rubber having physical properties closely resembling those
of natural rubber. It has extremely good weather and temperature
resistance, both heat and cold, with ultraviolet stability.
which, when extended, restricts the sash opening to a predetermined
used for decoration, diffusion, or privacy. The pattern is
rolled into the hot glass during glass manufacturing.
window or door that opens -- also referred to as a vent unit or
metal arm and gear device which allows for easy opening and closing of
projecting windows; e.g. casement and awning windows.
window with unequal sash.
compass direction that a structure faces. To optimize heat-gain, the
major facade of a building should face South (a variation as much as
30 degrees east or west of south will not seriously affect
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large, arch-top window flanked by smaller windows on each
framed sheet of glass.
refers to the separate panel or panels in a door frame.
an opaque glazing material or the operating portion of a sliding glass
set of extrusions which are fastened to a new window to cover the
exterior perimeter of an existing opening in a retrofit application
a double-hung window, a strip of wood applied to the jamb to separate
solar heating system which operates on natural thermal processes, and
that uses no external mechanical power to move the collected heat.
Generally, the building's structure itself forms the solar system.
glass doors, often used for access to a deck or terrace.
picture frame casing--The
use of casing on all four sides of the interior of a window. The stool
and apron at the sill are replaced with casing.
large stationary (non-ventilating) window which is designed for a
maximum view without obstruction.
type of window using only fixed units -- best for a clear view and
shade of folded fabric which can be installed like regular shades or
between the panes of glass of a window.
window frame which has an extended perimeter leg 1" back from the
window exterior plane, which becomes a nailing fin for new
per square foot - a measurement of air pressure used in window
testing, e.g., 1.56 psf (25 mph) or 6.24 psf (50 mph).
Vinyl Chloride - in rigid frame/sash members, and in flexible
special coating "sprayed" directly onto glass while it is still in a
molten state, resulting in a permanently embedded surface coating.
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measurement of heat resistance (the higher, the better). R
value = the number 1 divided by the U value. Resistance to
thermal transfer or heat flow. Higher R-value numbers indicate
greater insulating value.
direct process of heat transfer through space by means of
electromagnetic waves. Energy in the form of rays of light is
transferred from body to body without heating the intermediate air.
top and bottom horizontal members of the framework of a window sash or
door panel. a horizontal sash member.
system consisting of two snap-together extrusions used to contain a
window frame head and jambs in a masonry type opening. It allows for
deflection and inconsistencies in the openings.
measurement in percentage of the visible light reflected back into a
room. For ease of seeing to the outside, a lower rating is better
radiation that strikes an exposed surface (like a window) after being
reflected from the ground, trees, buildings, snow, etc. Reflected
radiation can provide a significant amount of heat when vertical
windows are used.
with metallic coatings applied onto or into the glass surface to
reduce solar radiant energy and visible light transmission
relative heat gain--A
measurement of the total heat gain through glazing for a specific set
expressed as a percentage of the maximum possible humidity at a given
or simulated muntins and bars designed to provide a divided light
appearance. Generally made of wood, they are applied to the inside of
the sash against the glass surface for easy removal.
opening built into a frame wall to receive a window or door unit. It
is formed with a header along the top that?s supported by jack studs
on each side. The rough sill at the bottom is supported by cripples. A
rough opening is generally greater in width and height than the window
or door unit. The framed opening in a wall into which a window or door
unit is to be installed.
horizontal framing piece, usually a 2x4, which forms the bottom of the
rough opening. It is toe-nailed into the jack studs and supported by
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inner frame which holds glass in operable and fixed window
operating portion of a hung or horizontal sliding window. A
single assembly of stiles and rails made into a frame for holding
glass. The framework holding the glass in a window unit. It?s composed
of two stiles (sides) and two rails (top and bottom).
coiled spring or spiral system integrated into the jamb liners to
allow double hung or single hung sashes to open and close. They also
allow the sashes to remain open in varied positions..
double-hung windows, the rope or chain which attaches the sash to the
protruding handle screwed to the inside bottom rail of the lower sash
on a double-hung window. Available on all Pella double-hung windows.
a cam-action lock applied to the check rails of a double/single hung
window, or sliding window to pull the check rails tightly together.
They are also applied to the open edges of a projecting window to seal
the sash tightly to the frame. Sash locks provide security and
in jamb track that reduces sash travel on hung windows.
older double-hung windows, the concealed cast-iron weights which are
used to counterbalance the sash.
continuous screw track in an extrusion. The track is designed to
accept a specific diameter sheet metal screw to provide a secure means
of fastening extrusions without the use of reinforcement.
Insulating Glass Unit.
flat board cut to fit the contour of a bow or bay window that?s
installed between the sills and the flat wall surface. They provide a
seat or shelf space.
Glazing Certification Council - administers tempered glass testing
and certification program.
measure of how well glazing blocks solar heat gain relative to 1/8"
clear glass under the same conditions. The lower the shading
coefficient, the better the unit blocks solar heat.
wedges used to secure the window or door unit in the rough or masonry
opening in a square, level and plumb position during and after
narrow, fixed or operating sash on either or both sides of a door to
light an entryway or vestibule. Narrow fixed units mulled or joined to
door units to give a more open appearance. Tall, narrow, fixed or
operating sash on either or both sides of a door to light an entryway
narrow fixed unit joined to one or more doors, providing a more open
bottom of a door or window frame.
main horizontal member forming the bottom of the frame of a window or
door. The horizontal piece that forms the bottom of a window frame. It
is generally slanted down to the outside to shed standing water. The
lower horizontal member of a window frame.
that, when applied below the window, permits the gap below the window
to be closed after window installation.
row of bricks, cement blocks or stones laid horizontally at the bottom
of a masonry opening.
simulated divided light--A
method of constructing windows in which muntins are affixed to the
inside and outside of a panel of insulating glass to simulate the look
of true divided light.
of single panes of glass in a window. Not as energy-efficient as
single strength glass--(SSB)
double-hung type of window in which the top sash is fixed or
special window set into a roof to provide natural light.
type of window with one fixed sash, and one that slides sideways --
good where outside clearance is limited.
window with two or more sashes that slide horizontally past each other
within the frame.
absorption of heat from the sun -- the amount of solar radiation
(measured in BTUs) received by a surface.
solar heat gain coefficient--The
fraction of incident solar radiation entering a home through the
windows -- the lower the number, the better the window is at blocking
heat gain. See Solar Shield.
shielding or blockage of the sun's heat.
solar tempered house--A
dwelling that obtains a large part of its heat from the sun.
percentage of total solar energy that glazing transmits through a
window -- a standard clear dualpane has a solar transmittance of 71%.
bottom horizontal piece in a frame wall, usually single or double
2x4?s. The wall is nailed into the deck or rough floor through the
extruded shape other than a hollow or a semi-hollow extruded shape.
Less costly to produce compared to semi or hollow shapes.
Sound Transmission Class (STC)--A
rating measure for the ability of glazing to block out sound from
outside sources. The higher the STC rating the better the sound
blockage (and the quieter the home).
mounted between floors of a building. It is usually made opaque to
hide building components.
type of window with distinct shapes, such as octagons, round-tops,
ellipticals, rakeheads -- virtually any shape can be custom
coating deposited on glass or film atom-by-atom in a precise process
inside a vacuum chamber.
Transmission Class - describes acoustical control for interior
panels, and, even though inadequate, is currently the only criteria
for exterior windows. The higher the number, the better the product is
at resisting typical sound frequencies excluding airplane and train
vertical sash member. The vertical side pieces of a window sash or
door panel. The main vertical members of the framework of a sash or
interior trim piece on a window which extends the sill and acts as a
narrow shelf. The interior horizontal trim piece at the bottom of the
window frame. The shelf-like piece that projects into the room.
molding used to hold, position or separate window parts.
to extrusions positioned to collect water leakage through mullions and
products and drain it to the exterior. Used where high performance
water resistance is required and for windows joined with mullions. It
runs continuously across the opening width and can be spliced together
to cover wide openings. The ends are sealed with end dams.
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that has been heat-treated to become more than three times
stronger -- also known as safety glass because it breaks into
small pebbles rather than jagged shards. It is used in sliding
glass doors and windows susceptible to impact or breakage.
manufactured to withstand greater than normal forces on its surface.
When it breaks, it shatters into small pieces to reduce hazard. Glass
that has first been cut to size, then heated to a very high
temperature and then rapidly brought back to room temperature. It will
withstand severe punishment from a blunt object; however, any pointed
object will break the glass instantly and the glass will crumble into
many, very small pieces.
rectangular projection cut out of a piece of wood for insertion into a
air space or insulating material which prevents the direct coupling of
a cold surface to a heated surface.
element of low conductivity (polyurethane) placed between elements of
higher conductivity (aluminum) to reduce the flow of heat and cold.
addition of a thermal insulating material between two thermally
direct coupling of a cold surface to a heated surface, allowing heat
transfer via conduction.
amount of heat storage capacity available in a given material or
assembly. Thermal mass in a home (tile floors, stone fireplace, etc.)
will absorb excess heat generated during the day and store it until
ambient temperature drops.
radiation emitted by a warm body -- the sun.
ability of a material to impede the flow of heat. See R-value.
the organic paint finish on aluminum to endure a tight bond and long
other than clear, with a color cast or tint. Typically tinted glass
absorbs and blocks heat, and reduces visible light transmittance.
of special formulation to produce light reducing and/or heat absorbing
glass products (bronze, gray or green).
total unit --A
basis for measurement, evaluation and performance comparison of
different glazing configurations, established by a formula combining
R-values of the frame area, edge of glass area, and center of glass
glazing such as frosted glass, which transmits electromagnetic
radiation (light) but causes scattering so that a clear image cannot
A window installed above another window or door.
small window that fits over the top of a door or window, primarily for
additional light and aesthetic value.
glazing which transmits light without diffusion, and which can be seen
insulating glass unit consisting of three panes of glass with two
internal air spaces.
true divided light--A
term which refers to windows in which multiple individual panes of
glass or lights are assembled in the sash using muntins.
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measurement of heat transmission. The U value of a window is
measured by the number of BTU's that will pass through each
square foot of area per degree of temperature difference from
one side of the window to the other (the lower, the better). U
value = the number 1 divided by the R value
ultraviolet radiation (uv)--Electromagnetic
radiation from the sun, with wavelengths shorter than visible light --
UV-caused fading of furnishings, artwork, etc. after prolonged
exposure to direct sunlight can be a problem. Classical measurement of
UV transmittance (300 -- 380 nm) is generally used to indicate fading
potential and to compare UV-blocking performance of various glazing
casement locking system which secures the window at two locking points
by operation of one handle.
sum total of one window width and one window height expressed in
of heat flow-value through the complete heat barrier, from room air to
outside air. The lower the U-value, the better the insulating value
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operating portion of a window that swings or projects in or
window or door that opens, to provide ventilation.
window or door unit that opens or operates.
plastic material used by some window for cladding or entire window
visible light transmittance--The
percentage of visible light (380 to 760 nanometers) that is
transmitted through glazing. Visible light transmittance is affected
by special coatings and the number of panes of glass or film in an
insulating glass unit.
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warm edge spacers--Insulating
spacers used to seal panes of glass in the manufacture of
insulated glass units -- edge conductivity is lessened for
improved window energy performance and reduced condensation
wave length selective--"Intelligent"
coatings such as Low E2 and Heat Mirror allow for glazing combinations
to permit selective gain or shielding of the sun's heat, while letting
in visible light.
sections of material used to prevent air leakage around operable
windows and doors -- usually foam gasketing, metal strips, or vinyl.
material or device used to seal the openings, gaps or cracks of
venting window and door units to prevent water and air infiltration.
flexible, continuous gasket that ensures a high compression seal
between the glass and glazing bead by applying pressure.
opening cut into a window sill and/or sash rail to allow water to
drain to the exterior.
amount of pressure exerted by the wind on a window or door generally
expressed in pounds per square foot (psf).
exerted on a surface by moving air.
expressed as width first, then height
clear or obscure glass having a layer of diamond or square pattern
wire mesh embedded in the glass lite.
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"XO" sliding window--"O"
indicates fixed sash = left sash slides and right sash is fixed.
"XX" sliding window--"X"
indicates moving sash = both sash operate.