SpecialFocus

by Gerry Sagerman, Insulgard Security Products

Performance plastics play a vital role in protecting people against natural disasters. The International Building Code requires that all new critical emergency facilities (emergency operations centers, 911 call centers, police, fire and rescue stations) and K-12 schools built in the 250-mph wind zone must include a tornado safe room and the safe room must house all occupants of the school. This means that if you’re building one of these facilities, including schools, that is in the 250-mph wind zone, which spans from Texas to Wisconsin and Nebraska to Pennsylvania, you are required by code to include an area of the building designed and constructed to withstand an EF5 tornado and large enough for everyone in the school.

Insulgard Security Products^™ STORMDEFEND^™ TTH600 window system used in a classroom doubling as a tornado-safe room.

Design dilemma

These requirements present a dilemma for designers: Do they design a safe room that is a concrete bunker with no natural light that is used once or twice a year, or do they incorporate the safe room into the rest of the building so it can be used every day the school is open? If choosing the latter option, windows allowing natural light into the space are required to meet pressure and debris impact testing requirements for impact protective systems.

This testing consists of a 15-pound 2 x 4 being launched out of a cannon at 100 mph impacting multiple locations on the glass. As with ballistic testing, the result must be complete protection. Not only can the 2 x 4 not penetrate the glass, but there can be no spall or fragmenting coming into the interior. Nothing can penetrate the craft paper.

The only way to achieve this type of absolute protection with more than 5,000 ft-lb of energy at impact is by including polycarbonate in the glazing make-up. This must be done not only within the interior makeup but also as the inner-most surface of the safe side. This polycarbonate layer acts as a diaphragm and prevents any type of spall from penetrating the safe side. Using performance plastics in these glazing makeups, designers are able to use spaces such as classrooms, gymnasiums and cafeterias that require natural light to double as safe rooms in the event of a tornado.

The benefits of performance plastics can be found in all aspects of our lives so it should come as no surprise they also play a major role in protecting us from natural disasters. From polycarbonate hurricane shutters that protect our windows on the coast to combination glass/polycarbonate glazing used in windows that protect us from EF5 tornados, plastic continues to stretch the boundaries. In an insecure world, performance plastics helps to provide windows and doors that can keep us safe.