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Everything you wanted to know about FireLite products
(but were afraid to ask...)
Background | Surface Grades | Safety Rated Products | General Info
What is it?
FireLite is a fire-rated glazing material which is different from ordinary window glass in that it is classified as a true ceramic. Because ceramic is resistant to high temperatures, FireLite is ideal for use in fire-rated doors and windows. Since FireLite looks and feels like ordinary glass, we often refer to it as "glass" or "glazing" to avoid confusion.
Why ceramic?
Ceramic is particularly well-suited for fire-rated applications because, unlike ordinary window glass, ceramic has a very low coefficient of thermal expansion. Just like steel and almost any other material used in building construction today, ordinary glass expands dramatically when subjected to the high temperatures inherent in a structural fire. This high level of expansion causes ordinary glass to break at a relatively low temperature of approximately 250° F. As a point of comparison, FireLite maintains its stability even in extreme conditions where temperatures may exceed 1800° F.
This low coefficient of expansion is also required for the glass to withstand thermal shock. Thermal shock occurs when hot glass is subjected to the rapid cooling effects of a sprinkler system or fire hose. The "shock" of the rapid change of expansion causes the glass to shatter, sometimes explosively. Because of the pervasive use of automatic sprinklers for fire suppression, and because fire fighters use fire hoses to attack a fire, the ability to withstand thermal shock is critical for fire-rated glazing. Stating that a fire-rated glazing product can withstand thermal shock is to say that it passed what is known as the hose stream test. As a point of clarification, fire-rated glass is required by US building codes and test standards to pass the hose stream test for use in all applications which require a fire rating of 45 minutes or higher. Beware of products that state that they can "withstand thermal shock from sprinklers" but then say that they "have not passed the hose stream test." There is no meaningful middle ground: Either a product does pass the hose stream test or it does not. Remember, if a product does not pass the hose stream test, then it may shatter or explode when hit by water, thus leaving no protection against the transfer of fire and deadly smoke. (Note: in Canada, all fire-rated glazing must pass the hose stream test.)
Does it have a tint?
A common question concerning FireLite is whether or not the product has any perceptible color. Due to the fact that ceramic is comprised of different basic ingredients than those used in the fabrication of ordinary window glass, FireLite appears to have a slight auburn tint, versus the blue or green hue commonly associated with window glass. In the case of window glass, the blue or green color tends to disappear once the glass is installed in a frame and light no longer refracts directly through the edge of the glass lite. This phenomenon is also true of FireLite, which tends to possess a neutral color once installed in a door or window frame.
What's the difference between Premium and Standard Grade FireLite?
"Premium Grade" FireLite is polished on both surfaces so that it is very nearly distortion free. "Standard Grade" FireLite is not polished, and therefore does have some visible distortion, which some liken to "antique" glass. For applications where such distortion could be a concern, we strongly recommend obtaining samples prior to specification.
What causes the distortion? Ceramic is manufactured in the manner all glass was made prior to the invention of the "float" method. Instead of the glass being "floated" on hot tin, it is drawn out between rollers. The rollers leave a slight surface distortion on the glass. The polishing process requires grinding the surfaces to a smooth finish.
TGP is the only source in North America offering polished, virtually distortion-free ceramic.
What's the difference between FireLite NT and FireLite Plus?
FireLite NT and FireLite Plus are the members of the FireLite family that meet all safety impact requirements (ANSI z97.1, CPSC 16 CFR 1201 Categories I and II) required for glazing applications in or near a door or near the floor. (Learn more about these safety impact test standards.)
FireLite NT meets all safety impact requirement via a film applied to one side of the glass. FireLite NT is available in both Premium and Standard Grades.
FireLite Plus meets all safety impact requirements by laminating two pieces of Premium FireLite together. FireLite Plus only uses Premium Grade FireLite in its make-up because laminating two pieces of Standard Grade FireLite together would increase the distortion to a degree most would find unacceptable. Also note that the laminate for FireLite Plus is a very special, fire-rated laminate. (Typical laminates are oil-based and are highly flammable.)
FireLite NT can be a more economical choice than FireLite Plus when addressing the need for fire-rated and safety impact-rated glazing. However, for high traffic areas or for areas prone to abuse (such as many applications in K-12 schools) FireLite NT (or any filmed product) may not be the best choice due to the exposed film that, while not obviously visible or soft, can be damaged by a well-pushed cart or "determined" teenager. For such applications, the extra up-front cost of FireLite Plus may be easily justified compared to the cost of maintaining a filmed product over an extended period of time. Indeed, FireLite Plus is a much more common choice than FireLite NT for our customers when addressing glazing applications in K-12 schools.
Note that FireLite cannot be tempered. Tempering is a process of applying heat (typically) to glass, taking advantage of the coefficient of expansion, to strengthen the glass. As discussed above, FireLite's physical properties don't change when heated, hence the need for different methods than tempering for strengthening the glass to meet safety impact standards.
May FireLite be cut?
FireLite can be cut much like ordinary glass. A self-lubricating, sharp cutter (Toyo brand) is recommended. FireLite NT should be scored on the non-film side. The film may then be cut with a razor blade. FireLite Plus must be scored on both sides, the laminate then heated by a torch and cut with a razor blade.
Care should be taken not to cut off the permanently etched FireLite NT or FireLite Plus logo with fire-rating and listing information as this logo certifies to the Authority Having Jurisdiction is acceptable.
May FireLite be sand-blasted or etched?
FireLite may be sand-blasted or lightly etched without voiding the fire-rating or warranty.
What is Obscure FireLite?
Obscure FireLite is FireLite that has been treated at the factory for an obscure finish. The finish resembles that of a shower door.
Does FireLite get thicker according to fire-rating?
No, FireLite does not get thicker as fire-ratings increase. It is always either 3/16" thick (FireLite, FireLite NT) or 5/16" thick (FireLite Plus). This makes FireLite an excellent choice for replacement of wired glass (typically 1/4" thick) since the nearly identical thicknesses will allow the existing fire-rated frames to be retained.
How might I acquire a sample of FireLite?
FireLite is a considerably more expensive product than typical window glass. Consequently, we only provide samples to architects looking to specify the product or to contractors with active projects. If the nature of your request fits one of these scenarios, please request a sample kit.
Other Questions?
Check our Fact Sheet, CSI Format Specifications, email sales@fireglass.com or call 1-800-426-0279. We're here to help!