Hurricane Testing Concerns Window Industry

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Concern is growing over the requirement that windows and doors pass extremely stringent impact tests before they can be installed in new buildings or retrofitted into older structures in hurricane-prone areas. Sparked by the extraordinary damage that occurred in 1992's Hurricane Andrew, Dade County, Florida, as well as other jurisdictions, is now requiring that such impact tests be passed.

The requirement, well-enough intentioned, comes on the heels of investigations that showed that a leading cause of damage in buildings in the area which took the brunt of Andrew's fury, came as a result of loss of windows and doors. When such breaches in a building's envelope occur, pressures inside the building can cause walls and roofs to crumble.

The question that concerns the window and door industry is whether the regulations adopted to prevent future damage may have gone too far. A secondary concern is that a fear of such failures has fostered a new cottage industry of operators who purport to have easy solutions to the problem, such as field-applied film over existing glazing.

Manufacturers feel that building building officials and code writers have drawn a line in the sand. They've mandated a test and said that if a window or door cannot pass the test, it's no good.

Manufacturers feel that this all-or-nothing approach does not allow the industry to show incremental improvement, but takes it from where it was before Andrew to a brave new world too quickly. There's little doubt that the glass that has been traditionally used in windows is not sufficient to prevent damage from occurring.The stringent requirements that mandate virtual impenetrability are much too severe. As a result, most manufacturers will recommend the approved alternative solution of shuttering all openings.

To require that the glass within their fenestration products be virtually impenetrable would require major re-engineering of their products to accept glazing that is thicker, is filmed in between panes of glass (much like automobile windows), or be made of expensive alternative materials, such as plastics.

The industry is also concerned with the efficacy of the test procedures mandated by the new laws. These require that a 2 x 4 be fired at the window or door from a cannon that propels it at 50 feet per second, or 34 miles per hour. The test is considered by many to be too inconsistent in its results. Additionally, it requires that several cycles be performed in each test. This means that a particular window could withstand the first or second blow, but fail on a third impact, thus failing the test; a result which most feel is unfair.

The industry has proposed that a pendulum impact test, which can be carefully regulated to insure consistent results, be substituted for the cannon test. So far, this effort has stalled, says Ric Markway, vice president of technical services for the National Wood Window & Door Association.

Other concerns remain as well. A growing industry in areas where hurricane resistance is now mandated involves installation of field-applied film to existing windows. These films, applied to the center of the glass, present problems of their own. First, there is doubt whether they indeed offer the protection claimed. Secondly, such film can cause the whole pane of glass to be removed by an impact. They are being marketed as 'hurricane film,' but there is significant question as to whether they provide the claimed protection.

Another concern is that of fire officials. If impact-resistance glazing is the solution of choice, will such windows provide a barrier to rescue or escape attempts during a fire?

Manufacturers don't deny that there is a need to take steps to prevent the kind of damage that resulted from Hurricane Andrew. They're asking, however, that a sensible approach be undertaken to finding solutions.