The surrounding or encompassing atmosphere.

Manufactured by pouring molten glass onto a bed of molten tin which is then cooled, annealed glass is the product that most people think of as "plate" glass. This flat glass product has little residual surface compression and must be handled with care to minimize thermal stress. It breaks into sharp shards when shattered.

Colored translucent glass, often called art glass, opalescent glass, cathedral glass or stained glass, is also produced by the rolling process, but generally in small, batch type operations. There are usually variegated colors within each sheet produced and no two sheets will match for hue. Thickness will vary within a sheet as well as from sheet to sheet. The maximum thickness produced is usually 1/8". When used as a glazing material, art glass should be glazed in the same manner as tinted / heat absorbing glass. Art glass cannot be tempered

Chemical or mechanical restraint systems that improve the performance of security window film during blasts, high winds and smash-and-grab break-ins.

A temporary change in the gas density, pressure and velocity of the air surrounding an explosion point. If the initial change is discontinuous, it is referred to as a shock wave. If the initial change is gradual, it is known as a pressure wave.

The violent rise in air pressure above normal atmospheric pressure (14,786 lbs. per square inch)

British Thermal Units are the amount of heat required to raise the temperature of one pound of water one degree Fahrenheit (1 BTU = 252 Calories).

Clear glass consists of silica sand with added alkaline salts such as lime potash and soda. It is colorless and has a visible light transmittance ranging from 75% to 92%, depending upon thickness. It constitutes the bulk of the flat glass that is used.

The process of applying window film to a piece of glass from edge to edge. A small untreated area of glass remains, which is referred to as a “daylight gap”.

The negative pressure effect felt on the roar face of a structure as the blast wave moves away from the building.

The ratio of radiant energy emitted by a surface to the radiant energy emitted by a black body of the same temperature.

Figured / patterned glass is produced domestically by the continuous pour process in thicknesses of 1/8" to 7/32". A pattern etched on one or both of the rollers is reproduced on the glass. Colors are available but are extremely limited. This type of glass is frequently called "obscure" or "decorative" glass. The pattern diffuses detail of objects viewed through the glass, it does not obscure them. The degree of diffusion achieved is a function of the pattern and whether the pattern is on one or both sides. Some patterns cannot be tempered for safety glazing use because of their depth.

The float glass process accounts for over 90% of the flat glass presently produced in the United States. In this process, molten glass is poured continuously from a furnace onto a large bed of molten tin. The molten glass literally floats on the tin, spreading and seeking a controlled level in the same manner as water poured onto a smooth, flat surface. In the controlled level seeking process, the molten glass is allowed to spread to width of 90" to 140", depending upon the furnace size and glass thickness being produced. The glass slowly solidifies as it travels over the molten tin. It is then cooled under controlled conditions. Afterward, it emerges as a continuous ribbon of glass at essentially room temperature. The product is now flat, fire-finished, and with virtually parallel surfaces.

(1) Glass is made to withstand from between 3000 to 5000 psi (210 to 350 kg/cm) of edge stress. (2) When edge stress exceeds edge strength, breakage occurs. (3) Edge strength depends on glass size, thickness, how it is cut, and treatment of edge by glazier. (4) A straight clean edge is the strongest. (5) Damaged edges can reduce edge strength by up to 50%.

Heat strengthened glass is fabricated by a process similar to that of tempered glass. Some equipment can produce both. The glass is heated to approximately 1100° F and the cooling process is slower than for tempered glass. The strength developed is about twice that of annealed glass.

Areas particularly affected by solar radiation and the imbalance of solar energy.

The amount of energy generated in an explosion. It can be either positive (impact force) or negative (suction force) energy. Impulse is measured by integration of the pressure / time curve recorded in an explosion.