Hurricane Certification means Impact Resistance, Design Pressure, and Installation


Too many companies simplify the very sophisticated components of true hurricane resistance, often in order to hide their own deficiencies. Issuing a piece of paper, without controlling proper specification and installation is as meaningless as providing a seat belt in a car. Henselstone has been at the forefront of hurricane testing, specification with architects and builders, and installation in the field. Dozens of homes that lived through Hurricanes Isabel, Ophelia, Irene, Earl, and Sandy unscathed are living proof of our dedication. Here are the pure and simple facts you ought to know about hurricane ratings:


The Rules:

The United States coastline has been categorized into five different wind borne debris zones : <120 mph, 120 mph to 129 mph, 130 mph to 139 mph, 140 mph to 150 mph and >150 mph. In each wind zone local and state building codes require certain ratings for buildings. These codes are either taken from the so-called "Dade County" requirements (named after this county pioneered the institution of more stringent product testing) or the American Society for Testing and Materials (ASTM), the basis for requirements in the International Building Code.  


The Tests:

All windows and doors have to pass a design pressure test, measuring of air infiltration, water resistance, and structural integrity at certain pressures, positive and negative (DP rating). For wind zones up to 120 mph a DP rating of 50 psf is usually required, 60 psf for wind zones up to 130 mph, 65 psf for wind zones up to 140 mph, 80 for wind zones up to 150 mph and 100 for larger than 150 mph. While in the beginning small missile impact tests were conducted with small steel balls to imitate flying gravel from flat roofs, most modern hurricane tests are either conducted with a 4.5 lbs (Missile C) or a 9 lbs (Missile D and E) piece of lumber. Depending on wind zone certification the missile is shot at a certain speed into three specimen either in one, two, or three impact points. The missile cannot penetrate. After the impact, the three specimen are cycled 9,000 times at varying positive and negative pressures (suction and pressure as exists in a hurricane) up to 1.5 times the Design Pressure rating. The glass cannot come out of the frames or show any openings larger than 2 inches. Henselstone's standard Design Pressure rating for all windows and doors is 65 psf positive and negative. All impact rated products pass the large missile impact test for wind zones up to 140 mph (missile D). 

The Specification: 

Architects and builders often find themselves in a mess of rules and regulations that impede creativity and efficiency. Henselstone engineers not only consult with the professionals to understand exactly what the customer is trying to achieve, we also provide detailed AutoCad drawings of wall conditions, in which our windows and doors will function. We detail how the opening should be built, how the window/door will be fastened, how to integrate the water proofing between window/door and walls, and how to trim the opening. All custom made to the customer's design! Over the last 12 years we have assembled an amazing collection of thousands of detail drawings. If we don't have it in our library, we will make one custom, free of charge.  

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The Installation: 

Products thus tested have to be installed into the wall with approved hurricane fasteners and water proofing materials that support the ratings. Most manufacturers do not offer installation and have little control over the materials used in the field. Most manufacturers also use materials and methods in the test specimen that will never be used in the field, such as silicone, wood braces for frames, and smaller wall-to-window/door gaps. Henselstone's installation materials, installation specifications, and methods are all certified with the products in the lab. Guaranteed!