Glass. It's staggering that such a simple material is at the core of so many complex decisions facing facility managers at schools and universities. From old “standbys” such as vandalism, to ever-changing building codes, to protection against classroom violence and even terrorism, glass has become a vital component of every educational institution's design and planning.
Although glass presents many potential problems for schools, it plays a vital role in supplying a building with natural light, which can benefit student performance and well-being. So the question for facilities managers is how to select the proper window systems for their particular schools.
Student safety is a primary concern. Classroom violence, industrial accidents and external threats are top-of-mind concerns for parents and administrators. Central to these hazards is glass. The federal government says that flying glass shards are the No. 1 cause of injury during a blast or storm. Yet, given budgetary constraints, schools find it cost-prohibitive to replace existing windows in high-risk areas with tempered glass.
Keeping people safe
One cost-effective solution is safety glass film. Such films are being used in many of the world's most recognized commercial and government buildings. Retrofitted on existing windows, these laminates can improve glass safety significantly by binding shattered glass together should a window break as a result of a storm, accident or attack.
Schools and universities may be able to lower their insurance premiums by installing safety films.
As any member of a building-management team knows, vandalism is more than a nuisance. It also drains budgets. Replacing broken, scratched or otherwise marked windows is costly and time-consuming. Retail stores that emphasize aesthetics have turned to anti-graffiti glass films to help combat vandalism. An anti-graffiti film is a thin, transparent material that is applied to the exterior surface of windows. Should a vandal strike, only the layer of inexpensive film needs to be replaced, not an entire window or door.
Unlike blast-mitigating films, which must be installed by a trained and certified professional if they are to perform to standard, anti-vandalism films can be applied easily by a member of the facilities-management team. Many reputable glass-film manufacturers will conduct a brief training session to make certain property mangers can install the materials properly. A school can stock its own inventory of films that are pre-cut by the manufacturer to the exact specifications of the target windows.
Both types of films are clear and, once installed, they are virtually undetectable by the untrained eye. This design ensures that their use does not violate any historical-preservation standards by visibly altering the facade of classic buildings.
Sometimes legislation forces change, and school administrators do not have the luxury of choice. Oregon, for example, has limited the use of wired glass in all building structures. Ending the 1977 temporary exemption from federal regulation given to the wired-glass industry, the new code promises to affect school athletic centers because it prohibits wired glass in areas that are subject to human impact. Forward-thinking facilities managers may consider installing safety films on glass in the areas in question. This decision would reduce impact hazards, adhere to legislative requirements and save money.
Thinking about energy
Of course, not all glass films are designed to keep people safe. Another class of products, solar-control film, dramatically curbs heating and cooling costs by rejecting solar heat gain in summer months and, to a lesser degree, conserving heat in the winter. Studies have shown that solar-control films can reject as much as 80 percent of the solar heat and block more than 99 percent of harmful ultraviolet rays.
“If the average solar-control film reduces solar heat gain by 65 percent, then facility managers need to generate only about half of the energy to cool the building,” says Darrell Smith, executive director of the International Window Film Association. All solar films increase insulation, resulting in a 10 percent reduction in heat loss. Special low-e films can reduce heat loss in cold months by nearly 40 percent.
The precise reduction in a school's energy costs depends on a variety of factors — such as the building's location and glass surface area — making it impossible to provide a universal savings estimate. However, it is reasonable for glass-rich buildings in Arizona, California or Florida to lower HVAC consumption by as much as 20 percent. Many energy providers throughout the Sun Belt offer rebate programs as a further incentive to install solar-control films.
Another idea is to ask the glass film manufacturer to conduct an energy analysis of the target building. Some software can calculate what percentage of energy consumption is attributable to HVAC, lighting, computers and other cost centers.
Solar films either reflect solar energy with a reflective coating or absorb it through sophisticated dyes. But regardless of a film's structure, these materials help balance interior temperatures, increase student comfort and reduce the number of maintenance calls.
It is important to note that these films tend to be either reflective or tinted, so they may not be a viable option for historically recognized buildings.
For most buildings, it is sufficient to install solar films only on the glass that is most affected by solar energy gain, namely the south- and west-facing sides. Limiting installation to only the windows that are most affected by the sun's rays can help a school reduce upfront costs, and still see cost savings comparable to what it would realize had the entire building been filmed.
Larkin is the safety and security films manager for Madico, Inc., Woburn, Mass., a manufacturer of glass safety films and attachment systems.
36 to 41
Percentage of the sun's ultraviolet light rejected by insulated glass.
95 to 99
Percentage of solar ultraviolet light rejected by window films installed on glass.
13 to 29
Percentage of solar heat rejection with different types of clear glass and window systems.
Percentage of solar heat rejection from window film.
Source: International Window Film Association, www.iwfa.com