air infiltration rate
the amount of air leaking in and out of a building through cracks in walls, windows, and doors (the lower, the better). Usually expressed as cfm per square foot of window area.

ANSI
American National Standards Institute - a clearing house for all types of standards and specifications.

casement window
a window in which the operating vents move out (casement outswing) or in (casement inswing) from the master frame. Each vent is hinged on the vertical axis to permit easy operation.

condensation
when the air inside an enclosure is warmer than the air outside the enclosure, the moisture vapor in the interior air will condense, creating small water droplets at the intersection of dissimilar materials (aluminum and gaskets).

dome
the spherical shape associated with skylights.

double pitch design
pertaining to two opposite roof slopes, e.g., sloping North and South; also referred to as a ridge connection.

Double strength glass
(DSB) 1/8" thickness.

egress window
a window with specific release hardware and minimum clear opening size to allow occupants to escape through the window in case of a fire.

electrostatic
a 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 extrusion surfaces that are exposed when the assembled window is installed and closed.

extrude
the process of shaping aluminum or vinyl by forcing it through a die.

extrusion
the finished form after pushing aluminum or vinyl through the die.

factory-glazed pyramid
pyramid-shaped skylights for commercial or residential use, offered in standard sizes ranging from 4'0" to 8'0", in a 7:12 roof pitch. Arrive assembled and factory glazed to the job site ready to set on a prepared curb eliminating on-site installation. Also known as the pre-glazed pyramid skylight.

folding glass wall
a folding stackable glass wall system capable of opening up to 92% of the original rough opening. Commonly used to separate rooms or to install around pool enclosures.

glazing
the process of installing glass or panels into the sash or frame of the window.

heat fusion
(welding) method to join PVC frame and/or sash members by heating the cut ends, squeezing them together, and allowing the assembly to cool.

Heat Mirror™
a triple-ply insulating glass unit (IGU) utilizing a polyester internal film with a special coating to reflect heat, but allows light to pass through. Heat Mirror is a trademark of Southwall Technologies Inc.

heat treating
the process where glass or aluminum extrusions are heated and cooled to make these materials harder and stronger.

hermetically sealed unit
an insulating glass unit (IGU) 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 desiccant (moisture and/or solvent absorbing material). The unit is then completely sealed, creating a moisture free air space.

hollow extrusion
a tubular extrusion having an enclosed cavity within it. It is usually stronger, although more costly, than a solid extrusion.

hung window
a window in which the operating sash move up and down within the master frame. The weight of each operating sash is counterbalanced with balances to permit easy operation.

insulating glass unit (IGU)
two 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.

interlock
a design feature which enables sash to engage one another when closed.

jamb
the vertical member of a window frame.

laminated glass
two or more lites of glass bonded together with a plastic inner layer. A typical application is a car's windshield.

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.

monolithic
a single lite or pane of glass.

mullion
an extrusion that joins panning perimeter legs that extend over existing mullions.

nite latch
hardware which, when extended, restricts the sash opening to a predetermined dimension.

obscure glass
mainly used for decoration, diffusion, or privacy. The pattern is rolled into the hot glass during glass manufacturing.

patio room
a modular wall system designed with single pane glass.

projected window
a window in which the operating vents move out (project out or awning) or in (project in or hopper) from the master frame. Each vent is hinged on the horizontal axis to permit easy operation.

psf
pounds per square foot - a measurement of air pressure used in window testing, e.g., 1.56 psf (25 mph) or 6.24 psf (50mph).

PVC
Poly Vinyl Chloride - in rigid frame/sash members, and in flexible gaskets.

pyramid
a square base design, typical to skylights, with all four slopes rising to form a point.

R value
a measurement of heat resistance (the higher, the better). R value = the number 1 divided by the U value.

rafter
the structural main "rib" of a glazed structure available in straight and bent.

rail
a horizontal sash member.

reflective glass
glass with metallic coatings applied onto or into the glass surface to reduce solar radiant energy and visible light transmission.

ridge
an extrusion at the top of the structure which all sloping rafters marry into.

sash
the operating portion of a hung or horizontal sliding window.

screens
usually mounted on the window or door exterior, depending on sash, vent, or panel operation. Screens provide ventilation and transparency and are usually one of three types: insect screens to resist insects, protection screens to resist glass breakage and casual vandalism, or security screens to resist forced entry or escape.

sill
the lower horizontal member of a window frame.

single pitch
design pertaining to a single slope of a roof on a skylight, solarium or sunroom, also known as a lean-to design.

Single strength glass
(SSB) 3/32" thickness.

sliding glass door
a door in which the operating panel slides sideways within the master frame. Each operating panel has rollers to permit easy operation. Also called a patio door. Usually used in applications where passage to exterior patios is required, while providing weather resistance and security. Not to be confused with mall or entrance sliding doors which provide security, but little or no weather resistance.

Sliding window
a window in which the operating sash sideways within the master frame. Each operating sash has glides or rollers to permit easy operation.

solarium
a thermally broken frame and insulated glass unit which makes a room addition to a home or business. Offers energy savings in the moderate price range.

solid extrusion
an extruded shape other than a hollow or a semi-hollow extruded shape. Less costly to produce compared to semi or hollow shapes.

straight eave lean-to
describing the angular connection or transition between the vertical front wall and sloping roof of a solarium, sunroom, or skylight.

sunroom
a thermally broken modular vertical panel wall system with double insulated performance glass, topped off with a 4"-6" thick insulated foam panel roof. Offers maximum ventilation in the moderate price range.

tempered glass
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. Typical applications include a car's side and back windows, sliding glass doors, and entrance doors.

thermal break
an element of low conductivity (polyurethane) placed between elements of higher conductivity (aluminum) to reduce the flow of heat and cold.

tilt window
a hung window in which the lower sash is removed by raising the sash 4", releasing the tilt releases while supporting the sash weight, and releasing the sash pivot bars to remove the sash from the master frame. The top sash removal is similar. A tilt window cannot be a side load window.

tinted glass
glass of special formulation to produce light reducing and/or heat absorbing glass products (bronze, gray or green).

U value
a 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.

united inches (UI)
the sum total of one window width and one window height expressed in inched.

vent
the operating portion of a window that swings or projects in or out.

wind load
the amount of pressure exerted by the wind on a window or door generally expressed in pounds per square foot (psf). Not to be confused with a project's location "Basic Wind Speed", which is usually expressed in miles per hour (mph).

window size
always expressed as width first, then height.

window style
the description of the way a window operates, e.g., hung, sliding, casement, etc.

wire glass
1/4" clear or obscure glass having a layer of diamond or square pattern wire mesh embedded in the glass lite. It cannot be tempered and is not an approved safety glazing material.

"XX" sliding window
Since "X" indicates the moving sash, this is a window in which both sash operate.

"XO" sliding window
Since "O" indicates the fixed sash, this is a window in which the left sash slides and right sash is fixed, looking from the outside in.