The glazing industry's involvement in fire protection and specialty products is entering an era of explosive growth, creating new markets and opportunities.

In the mid-1970s, Vegla, a division of Saint-Gobain glass works in Europe, developed a glass panel which performs as a fire retardant and as a shield from heat radiation for substantial periods of time. The glass, which they named Contraflam, was originally developed to be used in applications for the nuclear industry. It was to create visual access to the reactor power core while providing a radiation barrier. Contraflam was tested in walls up to seven feet thick, and while it provided vision, its radiation blocking capabilities were found to fall short of the stringent parameters for protection required by the nuclear industry. These tests, however, proved its effectiveness against fire and heat radiation in units of only a few inches thick.

Contraflam's structure is fairly simple, two or more panes of tempered glass separated by a cavity filled with gel and sealed around the perimeter to form a transparent panel. Contraflam gel by itself is completely transparent and non-distorting. In the gelatinous state, it exerts little hydrostatic pressure on the exterior lites of the transparent panel, giving it flat surfaces with uniform gel thickness and providing undistorted optical properties. The capacity of the gel to absorb and diffract heat is the key to its fire protective quality.

The gel is a combination of sodium chloride and water, ideal for the dissipation of the tremendous energy generated by a 1,700° fire. This combination blocks the fire energy through evaporation and the retardant capabilities of sodium. During a fire, the outer tempered lite shatters, exposing the gel. The gel forms a crystallized crust with small air void from the burning of the sodium. This crust provides isolation to the heat. Eventually, this crust of crystallized compound is completely burned away, and the heat transfers into the next layer, continuing the cycle.

This process works gradually through the gel to the unexposed face. As a result of the energy dissipation and insulation created by the gel crust, the temperature on the outer, unexposed glass pane remains less than 140° degrees, hand touchable, for the duration of the rated time. The time rating of the wall or door is to be tested to determine the gel thickness and overall thickness of the glass.

As vital as the performance of Contraflam glass is, the frame system used with this glass is of equal importance. Contraflam will only perform to the specified ratings when installed in an insulated frame tested in conjunction with the Contraflam units. The UL 439 frame was the first frame tested and approved for use with Contraflam. New versions of this framing system are being tested to further reduce the installation time and to reduce expense.

This framing system has many limitations, however, and also cannot be used in doors. For these reasons, O'Keeffe's, Inc., developed and patented a framing system, "GPX" Glassprotex, comprised of a steel core, insulating materials, protective plates, and claddings of aluminum, bronze, stainless steel, wood, or almost any material that can be surface applied, etc., to provide the finish desired.

The framing system allows unlimited expanses for use in atriums, elevator lobbies, hospitals or prisons, computer rooms, or any fire-rated area where clear vision is desirable. The Glassprotex product line can be used in fire-rated areas 20, 30, 45, 60, and 90 minutes. Both door and wall systems, along or in combination, carry Underwriters Laboratories and Warnock-heresy fire-rating approvals for these rating areas.

To obtain a fire rating from these laboratories, a product must pass both the time/ temperature and the hose stream tests. The hose stream test blasts the tested unit with water as it leaves the test chamber in its red hot condition.

An important factor is that Glassprotex is considered a transparent panel which stops the passage of fire and radiant energy from passing through the door or wall system. In the 90 minute time/temperature test using the prescribed fire temperature of 1,700° Fahrenheit, the average heat measured on the non-fire side was 130° Fahrenheit, well below the gain to 250° allowed by the test.

Wireglass and similar products are restricted to certain size limitations since they do not stop the passage of heat radiation through the glass and therefore cannot pass this test. Because the Glassprotex system stops heat radiation, it is not limited to the current 1,296" of vision area.

The largest single panel of Contraflam currently tested is 4'0" x TO". These transparent wall panels may be installed side by side or stacked vertically to form unlimited vision, not the 1296" total or the 25% of wall area now by code in walls.
Contraflam is manufactured with tempered glass and meets safety as well as fire codes. This critical feature should be noted because other fire rated products have recently been introduced which meet fire, but not safety parameters.
In fact, there is much confusion in the marketplace relative to wireglass and safety. Wireglass is not a safety glass.
When exposed to fire or impact, it will break into razor-sharp shards, and not crumble in the manner of tempered safety glass. Wireglass has been allowed for use in some safety glazing applications through a limited exclusion in the safety code.
A side benefit of Glassprotex is that it blocks a substantial amount of sound transmission. Commercial building elements are typically selected by their Sound Transmission Class (STC) rating.

Products rated in the STC 40 range provide a "medium" degree of sound isolation. Products rated at or above STC 50 provide a "high" degree of sound isolation. Normal windows have ratings in the STC 30 range. The rating for the 30-minute rated Glassprotex is STC 42. For the 90-minute Glassprotex line, the rating is STC 46.

Prisons and correctional institutions are obvious targets for the marketing of the Glassprotex product line. To protect the safety of correctional officers, administrative personnel, and the general public, the glazing material selected must be able to withstand physical attacks during riots or other disturbances. Breakage can mean that inmates gain access to high security areas, weapons, control rooms, or to the outside.

Currently, there are glazing materials that can withstand this kind of attack. These glazing materials provide high levels of protection for containment, small arms, and other physical assault, but provide limited fire protection.
For security and fully rated fire protection, Glassprotex can be made impact resistant and bullet-proof by incorporating laminated polycarbonates. The polycarbonate material can either be laminated directly to the exterior of the panel, or incorporated within the unit.

In general, the applications of Glassprotex described apply to interior installations, but it may also be used for exteriors. To protect the integrity of the gel from extreme temperature variations, an exterior glass panel must be applied to the Contraflam with a spacer to form an insulated exterior unit. Units can be provided with tinted, reflective, heat mirror, or any currently available glass makeup to satisfy a particular performance or aesthetic requirement.

The Glassprotex door system is shipped with the doors factory glazed. The doors are prepared for hardware, with the pivots, panic devices, and related hardware ready for field installation. Windows and wall systems ship knocked-down if they are not single panels, with the framing installed and the Contraflam panels placed in the frames.

The transparent panel technology which has developed over so many years, now allows building officials an additional complement of building materials for their efforts to provide safety and protection. The glazing professional will also benefit from the rapid expansion of fire and security glazing products. To do so, however, will require a diligent effort to gain knowledge of and experience with these glazing products.