Automotive Glass Replacement Shops

SIC 7536
AUTOMOTIVE GLASS REPLACEMENT SHOPS

This category covers establishments primarily engaged in the installation, repair, or sales and installation of automotive glass. The sale of the glass is considered incidental to the replacement.

NAICS Code(s)

811122 (Automotive Glass Replacement Shops)

Industry Snapshot

Automotive glass replacement shops catered to such common problems as windshields that were cracked or punctured—either by stones and other debris thrown up by the road—or by the sharp difference in temperature between the interior and exterior surfaces during the winter. They also repaired damage to other glass areas found on automobiles, as well as stopped leaks—traditionally one of the most challenging problem areas to correct. None of these repairs was of a type that drivers were likely to attempt for themselves.

Organization and Structure

Three types of businesses were available to fix and install automotive glass: those undertaking various kinds of glass repairs; those specializing in automotive glass; and those working on all parts of a vehicle body, including glass. Many repair businesses specializing in automotive glass were franchises connected to large chains.

Background and Development

The earliest automobiles were open bodied and traveled at such low speeds that windshields were hardly necessary. Only when automobiles became significantly faster and featured closed construction did the windshield and windows become significant features of automotive design, and hence of automotive repair.

Windshields were first introduced as an option on Ford's Model T in 1909, but became standard on all automobiles within a couple of decades. Windshields were originally flat, mounted at a right angle to the body of the vehicle, and upon shattering, would fly apart in numerous sharp fragments. As Caleb Hornbostel noted in Construction Materials, "Laminated glass was evolved as a result of developments within the automobile industry and to a lesser extent the plastic industry. The tremendous demand for shatter-proof glass for the closed automobile (in the late 1990s, over 90 percent of the total production of automobiles were closed cars) stimulated the glass industry into producing laminated glass."

Another important innovation occurred in 1932 when the French developed tempered glass. Although it eventually became the standard for side and rear windows, "tests demonstrated that tempered glass wouldn't work in windshields. While its resistance was great, it broke into patterns on impact that were so dense that vision was impaired," according to James L. Polak in Automotive Engineering. In addition, the very toughness of tempered glass represented a hazard when windshields were struck by the head of a driver or passenger in the event of an accident or sudden stop. Unlike laminated glass, it was too hard to give way, and thus could thus potentially cause severe injuries.

Though laminated glass would yield under such circumstances and could also be cracked more easily than tempered glass, its construction guaranteed that even the severest shattering would not lead to dangerous fragmentation—the plastic interlayer that was bonded between two sheets of glass to create the laminate adhered so strongly that no particle of glass could break free. The first laminated glass had celluloid interlayers, which proved apt to discolor in certain climates. Toward the end of the 1930s, the introduction of a polyvinyl butyryl (PVB) interlayer overcame this problem. The durability of PVB was further enhanced in the mid 1960s with a quadrupling of its impact resistance.

One-piece curved windshields—an expensive Chrysler option in 1934—became a Nash standard feature in 1949 and, like wraparound rear windows, spread quickly thereafter. General Motors applied the wrap-around design to windshields in 1954. The increased use of curved glass complicated installation and repair, requiring greater levels of care and precision, but also made possible improvements in styling and, ultimately, aerodynamic efficiency. With the advent of the oil crisis of the 1970s, streamlining became an economic, as well as aesthetic, priority. This was partially accomplished not only by curving windshields, but also by safely thinning (and thereby reducing the weight of) all automotive glass, and by flush glazing the joints between glass and body parts that had once required obtrusive metal trims.

Some manufacturers introduced green-tinted windshields in the 1940s, which soon became somewhat controversial. According to Polak, "Critics claimed that the shading would diminish night vision. Tests showed, however, that the night vision reduction would be negligible while the cut in glare from the day's sun and the night's headlights would be a significant improvement." Over-coming that controversy paved the way for such further refinements as the introduction of sun strips in the 1950s and, near the end of the next decade, of polarized windshields that were nonreflective and glare eliminating. In the 1980s, automotive designers took an important step toward overcoming the hazards of snow and frost with the introduction of electrically heated windshields.

Safety standards governing automotive glass durability and impact resistance were introduced by the American Standards Association (ASA) in the 1930s. Initially subject to voluntary compliance, these standards shortly became part of state and federal regulation, and thereafter were made more rigorous when the ASA became the American National Standards Institute (ANSI).

Another area of regulation of critical concern to automotive glass replacement shops was the possibility of instituting standards in relation to levels of windshield hazing. As explained in Automotive Engineering, "This phenomenon results from small craters created by salt, sand, and pebbles as they strike the glass, in addition to streaking caused by windshield wipers, ice scraping, and cleaning with abrasive substances. Haze caused by these factors not only tends to obscure drivers' vision of the road, but also contributes significantly to driver fatigue and impairs concentration." The institution of such standards seemed likely to generate a significant amount of business for automotive glass repair services, given that an estimated one percent of vehicles on the road had windshields with excess haze.

Current Conditions

Recent trends in automobile design have created an even greater need for replacement glass accessories: glass makes up more than 30 percent of a car's exterior surface area, an increase of approximately 30 percent from the early 1990s.

As of 1998, 5,542 operations made up the industry, employing 26,400 workers. The industry also had a total payroll of $681 million, and posted revenues of $3.68 billion. Of the total, 3,272 establishments in the industry staffed under 5 employees, 1,171 employed under 10 workers, and only 112 had over 20 employees.

Industry Leaders

At the end of the 1990s, the leaders in the automotive glass replacement industry were Harmon Glass Company, Inc. with $259.8 million in sales and 1,532 employees; Lear Siegler Holdings Corporation, posting $190.7 million in sales and 3,400 employees; Auto Glass Specialists Inc. with $56.1 million and 540 employees; Diamond/Triumph Auto Glass, Inc., with $31.2 million and 624 employees; and Diversified Glass Services, Inc. with $25.0 million and 500 employees.

Workforce

Automotive glass installers and repair personnel received training either from classes in glazing or by learning on the job. They had to exercise care and precision in the removal of broken and sharp-edged glass, in cutting and fitting sheets of glass with the requisite degree of accuracy, and in fitting such strips and seals as were necessary to achieve a weatherproof finish.

Beginning in the late 1980s, the efforts taken to ease factory installation of increasingly large and complex glass shapes had obvious advantages to those repair businesses also engaged in the installation of such glass. The major breakthrough came with the introduction of modules, because these "provide almost a perfect seal in the vehicle since each module is precisely produced in the same mold and fits almost perfectly into the sheet metal opening," according to Joseph M. Callahan in Automotive Industries. "It's estimated that about a quarter of all windows in U.S. cars are now modular, with the expectation that it will reach 75 percent or more in the next several years," Callahan continued.

America and the World

As the foremost car culture in the world, the United States generated a great volume of general maintenance and repair business. In the area of automotive glass in particular, one key difference between the United States and Great Britain lay in the fact that windshields in the latter country were commonly made of tempered glass. In addition, European designers were leading the way with experiments in automotive double glazing. As Peter J. Mullins explained in Automotive Industries, "Two layers of glass, very precisely made with an air gap of a few millimeters between them, help to reduce … noise amplifications and also cut road and engine noise. One maker has even connected a small vacuum pump to the gap to evacuate the air and improve performance; another is circulating dry air to cut condensation."

Research and Technology

The overall trend in U.S. automotive design near the end of the twentieth century toward using increased expanses of technologically complex glass could only prove beneficial to businesses specializing in glass repair and installation. However, a problem associated with such an emphasis on glass in vehicle body design was the material's heavy weight, and hence its tendency to impair fuel economy and overall performance. Ward's Auto World reported that the amount of glass in American-made cars increased from 83.5 pounds in 1980 to 97.0 pounds in 1999. Polycarbonates were increasingly being considered as lighter alternatives to glass in automotive design, but no plastic had attained the resistance to scratching and discoloration that glass possessed. Another alternative was the use of thinner glass, about 70/1000ths of an inch thick compared to the conventional 88/1000ths. Eisenstein claimed that this change would reduce the weight of an average windshield by 3 pounds.

In addition to increasing weight, larger expanses of automotive glass also raised interior temperatures. In fact, about 71.7 percent of the typical sources of passenger compartment heat were attributable to glass. Moreover, the increased heat on plastic interior trim could lead to the release of vapors, which would tend to settle as a film on interior surfaces of the glass. Higher temperatures from greater reliance on glass were a particular cause of concern in the automotive industry because of impending legislation requiring the replacement of traditional airconditioning systems with more environmentally friendly but generally less efficient alternatives.

In response, automotive designers experimented with various kinds of films and tintings capable of reflecting or absorbing greater quantities of temperature-raising infrared light and with photochromic materials darkening or lightening in automatic response to the amount of sunshine. They also sought comparable methods of reducing the damage to interior plastics created by ultraviolet light. As Callahan pointed out, however, any new developments along these lines had to take into account that "the government requires that automotive glass transmit at least 70 percent of the visible light striking it."

Other innovations focused on overcoming problems associated with bad weather: devices not only for rapid melting of ice or snow on glass but also for defogging more efficiently and for controlling windshield-wiper operation through moisture sensitivity.