Hatching a hurricane-resistant hatch
When the 2007 edition of the Florida Building Code added roof hatches to the list of products requiring testing and review, it became “somewhat difficult” for local building officials to administer because the test protocols had not been developed, according to Roger Joyce, executive vice president of the Bilco Co., West Haven, Conn.
Bilco, which has been manufacturing roof hatches since the 1940s, wasted no time collaborating with the Florida Building Commission on a new set of test protocols. The hatches were subjected to a rigorous round of tests, including large-missile impact, in a Florida laboratory. “Very close attention was paid to the anchorage of the product on different surfaces,” says Joyce. “The NOA defines the number and type of anchors that can survive the kind of pressures developed by hurricane-force winds.”
As a result of these efforts, Bilco’s Type S and Type NB steel and aluminum hatches received an NOA from Miami ––Dade County for conforming to high-velocity hurricane-zone standards.
Mark de Stefano, PE, president of De Stefano Engineering Group, Sarasota, Fla., helped Bilco design its roof hatches to meet hurricane-load conditions. De Stefano believes engineers and manufacturers should always work together to develop products that are realistic for each application. “The testing is good, but the problem I see in the field is that we’re relying totally on testing and not on engineering judgment,” he says. “Products need to be tested to failure and the failure mechanisms indicated on the NOAs, so that engineers can do some comparative analysis, and possibly save the building owner some money.”