You Bet Your Glass: a Brief History of Safety Glass
By Jennifer Young
In 1903, French chemist Édouard Bénédictus stumbled upon the creation of shatter-proof glass when he accidentally dropped plastic cellulose nitrate into a glass beaker. He discovered that when the glass became coated with this film, it would shatter, but not break. Bénédictus patented the glass in 1909, but automakers had no interest in the expensive, labor-intensive material. The majority of this first laminated glass, called Triplex, could be found in the glass eyepieces of World War I gas masks.
At that time, carriages were in the midst of a glass crisis. Some manufacturers began to install carriages with plate glass windshields to protect drivers and passengers from strong winds. However, when debris from the road flew up to strike the glass, it inevitably shattered and caused more harm to the carriage’s occupants that they’d have experienced without it.
In the U.S., the auto industry would experience just the same thing, but on a more pronounced scale. Although laminated safety glass had been invented decades earlier, the auto industry didn’t begin to offer it until the 1920s. In fact, Ford’s early Model T didn’t actually come standard with a windshield at all. Customers had to order it as a special option for $100. Most early vehicles would simply be outfitted with the same brittle plate glass used in home construction. Yet, as speeds crept up and collisions increased, it became evident automakers like Ford needed a safer option.
The use of the auto safety glass (laminated glass) for windshields and passenger windows not only decreased injuries from shattered glass, but also helped reduce the risk of passenger ejections during collisions. The safety glass provided a much stronger barrier than regular glass. Studies have shown that a person is ten times more likely to die in an auto accident if they are ejected from the vehicle than if they were to remain inside.
In a perfect world, auto manufacturers would have continued to install car windows with auto safety glass, but manufacturers began to experiment with tempered glass to reduce costs. Unfortunately, tempered glass does shatter when it’s broken. While it does not pose the same risks as regular glass, it also does not provide a barrier for car occupants during collision as laminated glass does. In situations where the car’s roof is compromised as it tends to be in rollover situations, the risk for ejection increases because the tempered glass will not act as any sort of barrier.
Each year, nearly 40,000 vehicle occupants are ejected from their vehicles. Partial ejections also occur, heightening the risk for life-threatening injuries. As one might imagine, it’s been ‘lawsuit city’ for a number of automakers, including Ford, who opted to use tempered glass rather than auto safety glass for some windows (i.e. like the Explorer) even though testing demonstrated that the tempered glass did not perform like auto safety glass.
Today, car makers are required to use auto safety glass for vehicles’ windshields, but not for passenger or rear windows. This glass has to meet safety standards outlined by the National Highway Safety Administration. Many of the administration’s safety requirements date back to the 1970s. Keep in mind that it’s well-known that auto safety glass used for all windows saves lives. About a thousand lives lost to partial vehicle ejections could have been prevented by the use of laminated auto safety glass.
Some car makers like BMW have taken the proactive step of offering optional DuPont laminated glass for front and back side windows. However, many car manufacturers would still prefer to save the $2.50 additional cost per window they’d have to spend for auto safety glass installation.
It is possible for auto makers to make auto safety laminated glass a standard feature for all windows, but it might take many more lawsuits to get there. With new advances in recycled glass and smart glass, that $2.50 cost per laminated glass window might also shrink down to a price car makers are willing to spend.