Hurricane Louver Codes

Hurricane Louver Codes: An Historical Perspective

As more severe weather nears, the time is now to review relevant regulations.

On Aug. 24, 1992, Hurricane Andrew touched down in South Florida. Only the third Category 5 storm to make landfall in the U.S., it generated sustained winds of 165 mph and wind gusts in excess of 200 mph. The economic devastation was unprecedented: Florida homes and businesses were destroyed or damaged to the tune of $26.5 billion. This led to intense scrutinization of locally administered building codes. Investigations revealed widespread violations, drawing attention to a system in desperate need of an overhaul.

Today, the repercussions of Hurricane Andrew are still felt. Codes and requirements that originated in Florida have since been adopted in states such as Louisiana, Texas and New Jersey, where Hurricane Sandy caused an estimated $68 billion in damage in 2012.

That it is vitally important engineers and architects have a clear understanding of the rules governing architectural products should go without saying. If the wrong product is selected for a job, chances are good the inspector will flag it and delays will ensue.

Florida Building Code

In 1996, the Florida Building Commission—comprised of architects, engineers, contractors, building owners, and insurers—was established with the purpose of recommending changes to Florida’s building-code system. In 1998, the commission published the Florida Building Code, which governs all residential and commercial construction throughout the state.

The Florida Building Code consists of nine code books: Plumbing; Residential; Energy Conservation; Building; Mechanical; Test Protocols; Accessibility; Existing Building; Fuel Gas.

Louvers are mentioned in three of the books: Building, Mechanical, and Test Protocols.

The sixth edition of the Florida Building Code went into effect on Dec. 31, 2017. Though there are no notable changes concerning hurricane louvers, manufacturers were required to update their catalog information to reflect compliance with the latest edition. A common question concerns whether louvers approved for previous editions still are good to install. The short answer is yes.

The 2017 Florida Building Code applies to new construction. Louvers listed under a previous edition are acceptable for existing construction, provided the structure’s permit was created before Dec. 31, 2017.

Impact points for horizontal and vertical louvers.

Miami-Dade County’s Regulatory and Economic Resources Department is responsible for the safety and vitality of businesses and shopping areas throughout Broward and Dade counties in South Florida. It also is responsible for enforcing requirements for commercial construction there. For louvers and other products, Miami-Dade issues notices of acceptance (NOA) to manufacturers, indicating the manufacturers’ products are approved for use in South Florida.

I-Codes

Established in 1994, the International Code Council (ICC) has developed a comprehensive set of coordinated model construction codes—the International Codes (I-Codes)—that is widely recognized.

What is notable about the I-Codes is that both Miami-Dade and the Florida Building Commission derive their code requirements from them. All 50 states and the District of Columbia have adopted the I-Codes at the state and jurisdictional levels.

Testing Application Standards

Testing Application Standard (TAS) No. 100(A), Test Procedure for Wind and Wind Driven Rain Resistance and/or Increased Windspeed Resistance of Soffit Ventilation Strip and Continuous or Intermittent Ventilation System Installed at the Ridge Area, is Miami-Dade’s test for high-velocity wind-driven rain. It is required for louvers that are within 33 ft of grade, with the room behind the louver not having adequate water drainage or containing equipment that should not be exposed to moisture.

TAS No. 100(A) simulates 35-, 70-, 90-, and 110-mph winds with 8.8-in.-per-hour rainfall. During the 35- and 70-mph-wind simulations, water is not allowed to penetrate the louver. During the 90- and 110-mph-wind simulations, no more than 0.5 percent of the water volume is allowed to penetrate the louver. Horizontal louvers are tested in front of a damper assembly, as very few louvers can pass this test by themselves; the ones that do typically are vertical in design.

TAS 201, Impact Test Procedures, is a required missile-impact test referenced in the Florida Building Code and ASTM standards. For this test, a board made of southern pine that is 2 in. thick by 4 in. wide by 7 to 9 ft long, weighing 9 to 9.5 lb is shot at a louver at a rate of 50 ft per second (fps). Three test specimens are shot, and each test specimen must be impacted twice.

TAS 201 is a pass/fail test, meaning if any blades come loose from the louver’s frame, the louver is considered a failure.

Immediately following the TAS 201 test is the TAS 203, Criteria for Testing Products Subject to Cyclic Wind Pressure Loading, test. In this test, air is supplied to and exhausted from the chamber in accordance with a specific loading program at a rate required to maintain a certain pressure differential across the louver specimen. The load is applied in both the positive and negative directions. For a 150-lb-per-square-foot (psf) louver, testing would consist of:

• A 40-percent design load—in this case, 60 psf for 600 cycles;

• A 60-percent design load—in this case, 90 psf for 70 cycles;

• A 130-percent design load, which equates to 195 psf.

Like TAS 201, TAS 203 is also a pass/fail test.

TAS 202, Criteria for Testing Impact & Nonimpact Resistant Building Envelope Components Using Uniform Static Air Pressure, is known as the static-pressure test. Like TAS 201, it is referenced in the Florida Building Code and ASTM standards. For this test, a louver unit is encased in a plastic bag and tested in both directions at up to one-and-a-half the rated load. For instance, if a louver is rated at 150 psf, it would be tested at 225 psf.

TAS 202 is a pass/fail test.

AMCA 540

Publication of ANSI/AMCA Standard 540, Test Method for Louvers Impacted by Wind Borne Debris, was a major development that occurred between the 2010 and 2014 versions of the Florida Building Code. Incorporated into the 2017 version of the Florida Building Code, this test sees a 2-in.-thick-by-4-in.-wide board weighing 9 lb shot at a louver specimen with an air cannon, similarly to TAS 201.

There are AMCA 540 tests for basic protection and for enhanced protection. For basic protection, the board is shot at a louver at a rate of 50 fps; for enhanced protection, it is shot at a rate of 80 fps.

AMCA 540 is a pass/fail test.

AMCA 550

ANSI/AMCA 550, Test Method for High Velocity Wind Driven Rain Resistant Louvers, is one of the most difficult tests for louvers to pass. With this test, a louver is subjected to eight intervals of testing lasting from 5 to 15 minutes.

During an AMCA 550 test, water is sprayed at a louver, with a high-powered fan simulating wind speeds from 0 to 110 mph behind the water jets. The reason the test is so difficult to pass is that no more than 1 percent of the total amount of water is allowed to infiltrate the louver.

Conclusion

Understanding the codes and requirements for architectural products in areas prone to hurricanes and other severe weather will avoid the unnecessary delays and costs associated with selecting the wrong louver for an application.

With the wild weather we have experienced the last few decades, these regulations are here to stay. 

The product marketing manager for Ruskin’s louver and architectural product lines, Peter Blaha has 20 years of HVAC-industry experience. He is a member of AMCA’s Louver Task Force.

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