October 27, 2006
SHUTTER PROTECTION FOR BUILDINGS IN THE FLORIDA
By: Veronica Rose, Principal Analyst
You asked if Florida requires buildings situated in hurricane-prone regions to have shutter protection.
The Florida Building Code requires new buildings constructed in hurricane-prone regions of the state to be designed and constructed to withstand the impact of debris carried by high winds (wind-borne debris). To this end, new buildings located in regions the code designates as “wind-borne debris regions” (see Attachment 1) must meet one of two standards. They must either be designed to withstand wind pressures that occur when windows and doors are pierced in a storm (i.e., internal pressures) or (2) any exterior glass windows and doors must be made of shatter-resistant glass or protected by storm shutters to withstand external pressure.
In most cases, the wind-borne debris region extends about five miles inland from the coast: in others, considerably further. But in the Panhandle region, it extends only one mile inland. Thus, buildings outside the one-mile radius in the Panhandle do not have to meet the wind-borne protection standards, regardless of the wind speed in the area.
THE FLORIDA BUILDING CODE AND SHUTTER REQUIREMENTS
The Florida Building Code uses the America Society of Civil Engineers Standard (ASCE) Standard 7 as the basis for establishing wind-borne debris regions and wind-borne debris protection. The standard requires builders either to (1) construct buildings that can withstand the additional pressure that results when wind gets into a building through a hole in the wall or broken door or window and pressurizes it (like blowing air into a balloon) or (2) protect glazed openings in walls (e.g., windows and glass doors) from debris borne by high winds (Fla. Building Code Chap. 16).
The wind-borne debris protection region is any area where the basic design wind speed is 120 mph or greater and any area within one mile of the coast where the wind speed is less than 120 mph but greater than 110 mph. It includes all of Miami-Dade and Broward County, which are designated as a “high velocity zone,” because of their extreme vulnerability to hurricanes. Buildings in the zone must meet stricter design and construction standards than those that apply to the rest of the wind-borne debris region. The most notable, according to the Florida Building Commission, is the requirement “to protect the overall building (the entire envelope), including windows, with either shutters or impact-resistant glass.”
The wind-borne debris region extends about five miles inland in most cases and considerably further in others. But, in the Panhandle region (sections of northern Florida from the Walkula/Franklin County line to the western edge of Escambia County), the legislature designated the wind-borne region as the land within one-mile of the Gulf Coast. Thus, the wind-borne debris protection requirements do not apply to buildings outside the one-mile radius in the Panhandle, regardless of wind speeds. This Panhandle provision (commonly referred to as the “Panhandle exception”), has generated some controversy. Consequently, the state is in the process of changing it “through a multi-staged research program,” according to Rick Dixon of the Florida Department of Community Affairs.
Meeting the Shutter Requirement
The two major methods of satisfying the requirement for protecting a building against external wind impact are by installing impact-resistant glass or covering the openings with hurricane shutters. Impact-resistant glass is constructed with the equivalent of automobile windshield glass (impact-resistant glazing) which has a plastic film laminated between two
sheets of glass. Hurricane shutters are designed to be permanently attached or removable. They are available in a variety of strengths and sizes (e.g., aluminum or steel accordion, and roll-up).
After Hurricane Andrew, in 1992, Miami-Dade County established the first requirements for wind-borne debris protection and developed test requirements that shutter and impact-resistant glazing systems must pass, under the code (Fla. Building Code § 1626). Since then, the American Society of Testing and Materials (ASTM) has developed testing standards. Products must pass one of these tests to be accepted for use where protection is required. The exception is plywood panels that conform to a set of prescribed specifications, according to Rick Dixon of the Florida Department of Community Affairs.
Building Code Exemptions
The following buildings, structures, and facilities are exempt from the Florida Building Code and therefore the wind-borne debris protection requirements do not apply to them:
1. buildings and structures specifically regulated and preempted by the federal government;
2. non-residential farm buildings;
3. temporary buildings or sheds used exclusively for construction;
4. mobile homes used as temporary offices, except for the handicapped accessibility provisions;
5. electricity utility structures or facilities directly involved in generating, transmitting, or distributing electricity;
6. temporary sets, assemblies, or structures used in commercial motion picture or television production, or any sound-recording equipment used in production or off premises; and
7. chickees constructed by the Miccosukee Tribe of Indians of Florida or the Seminole Tribe of Florida. (A “chickee” is an open-sided wooden hut that has a thatched roof of palm or palmetto or other traditional material and does not incorporate any electrical, plumbing, or other non-wood features.)