The guidelines for the manufacture and testing of windstorm products are very different for hurricane and tornado protection. Testing procedures for both are designed to isolate, as much as possible, the loads and conditions to which a particular component is subjected during these events. However, in the case of tornado product testing, doors and window shutters are always tested together with the hardware with which they will be sold as a complete assembly.
The current standard hurricane test for Windstorm components features a 9 lb. 2x4 fired at a door at 35 mph, hitting the door with 350 ft. lbs. of force (simulating the force of 70 mph winds).
The Windstorm product testing for tornadoes is much more strenuous. The current tornado test for Windstorm products features a 15 lb. 2 x4 fired at a door at 100 mph, striking the door with 5000 ft. lbs. of force (and simulating the force of 250 mph winds).
Windstorm resistance guidelines for tornado assemblies focus primarily on states in the central region of the United States, from Texas up to Minnesota and Michigan.
While hurricane standards usually cover every building, residential and commercial, and every exterior opening, tornado standards only cover products used in tornado-resistant doors and window shutters in community shelters. These shelters could be located in a range of public buildings – but schools, hospitals, police stations and fire stations are the buildings usually incorporating shelters to protect occupants and our first responders.
Finally, most hurricane Windstorm products are standard products that have been modified to meet the guidelines (such as the use of welding instead of adhesives). Tornado products, on the other hand, are manufactured to be heavier and stronger than standard products. For example the hardened stainless steel in a Tornado Windstorm door strike is about four times thicker than a standard hurricane product. And shelter doors and shutters are usually secured with three points of latching. This ensures that our door assemblies can meet tornado testing requirements, and they will pass repeated cycles of opening and closing without failure.
Finding the Right Windstorm Product
Most companies provide Windstorm products that conform to the latest guidelines and codes. Even so, there are differences between the different manufacturers. Here are some things to consider:
- Not all Windstorm products are designed for tornado protection. In fact, many manufacturers don’t do tornado product testing at all. Make sure the products you buy address the needs of your specific Windstorm application. Also, if you need both tornado and hurricane products (as you might in a state like Texas), consider one company that has expertise in both areas and offers a full breadth of products.
- Not all product testing is the same (Part 1). Consider a company that does some initial R&D testing in-house. This can lead to a cost savings for the end-user, as it can save wasted steps and ensure that the right hardware is tested for the right applications. It also demonstrates that the company has in-house expertise, helpful when you need installation or design help.
- Not all product testing is the same (Part 2). It is an advantage for Windstorm products to feature independent third party certification. It’s not a code requirement (yet), but when product testing has been conducted by an organization like the American Testing Institute and features third-party certification, it should provide a higher level of security to architects and building officials. Products with a third-party certification “label” carry a metal tag or mark showing that they have been tested specifically for Windstorm applications.
- Does the company offer a wide range of Windstorm products including components that provide form as well as function? Some Windstorm products are offered with architectural-grade finishes, making them ideal for place like retail stores, movie theaters and other venues that call for performance and style.
- Are representatives from your company involved in the organizations that write and refine the Windstorm codes? If they are, these companies not only demonstrate a high degree of Windstorm product expertise and focus, but they also have a leg up on the latest testing standards and product developments.
When it comes to purchasing the right Windstorm solution for your building, there are many factors to consider. But the primary objective is always the same: keeping the storm out of the building, and keeping the building and the people inside it safe.