This course is part of the Mastering Movement™ Academy

AMCA publishes test standards that are universally accepted in the industry, and it provides third-party testing to confirm the accuracy of manufacturer data. AMCA’s members—companies that manufacture air movement and control products such as louvers—must agree to accurately represent the performance of their products according to AMCA guidelines set forth in a variety of AMCA publications and abide by a stringent code of ethics.

Once a project is awarded, the architect or specifier must review a louver’s submittal sheet, which reveals technical information that describes the louver’s performance. These submittal sheets help engineers assess if the louver selected for the project has the right performance attributes for their project’s requirements.

It is important to emphasize that neither AMCA nor manufacturers test or certify equipment in the field after installation to verify performance. Installation practices, location, and specific building orientation can all impact the performance of louver. However, manufacturers can perform tests of other specific or unique performance criteria, like storm resistance, in accordance with AMCA protocol. This type of performance testing is done on the manufacturer’s own equipment, and is very useful to validate the performance criteria of louvers that may have screens or unique design elements.

Still, the first step when specifying louvers to meet or exceed specific performance expectations is to understand the testing protocols of the AMCA. Louvers are designed to protect air intake and exhaust openings from the infiltration of unwanted water or particles while allowing airflow into the space, and different louver models offer varying levels of performance. In many cases, an architect or engineer chooses a certain louver system because it satisfies a specific performance requirement, so these AMCA standards are extremely important. AMCA Standard 500-L covers five testing protocols:

Pressure Drop

This test determines a louver’s resistance to airflow. Because some equipment needs air to operate effectively, airflow is an important factor. If an architect is considering a louver for a space containing this type of equipment, its pressure drop test results should be one of the first things to look at.

The pressure drop test requires air measurements for a number of intake/exhaust velocities and the resulting pressure drops. ANSI/AMCA Standard 500-L specifies that, for pressure drop, a 1219 mm × 1219 mm (48-inch-by-48-inch) louver sample shall be tested. The information on the louver’s submittal page reflects the results of the test.

Air Leakage

The air leakage test determines the relationship between the airflow leakage rate and the static pressure for a louver mounted in a test chamber. The test can help architects properly select an operable louver in its closed position for a building’s needs after considering airflow, the need for energy savings, and the importance of having a sealed building envelope.

Similar to the pressure drop test, there are five or more determinations that are taken at equal increments of pressure differential that cover a desired range during equilibrium conditions.

Water Penetration

The water penetration test is designed to determine the intake air velocity at which water begins to penetrate the louver. A common misconception is that the test reports how much water penetrates the louver during service conditions, but this is not the case. This test is meant to show how the louver will perform under what are considered typical conditions rather than heavy rains or windy conditions. It is important to understand that there is no wind at the face of the louver during this test, and the only airflow is being pulled through the louver from an intake source.

During the test, technicians release water droplets in front of the louver to mimic light rainfall at a minimum rate of .1 inches per hour as well as simulating water coming down and exterior wall at a rate of 3.28 L/m per linear meter (0.25 gpm per linear foot). At the back of the testing chamber behind the louver, an intake fan pulls air through the louver at a variety of intake speeds until water begins to come through the louver. This is a key test and an important one for AMCA because the space behind the louver needs to be kept dry, particularly when adequate drainage does not exist.

Wind-Driven Rain

During this test, a louver is set up in the testing chamber, a high-powered fan is set up in front of it to simulate 12.96 m/s (29 mph) winds or 22.35 m/s (50 mph) winds. Nozzles will spray water at the louver, simulating an external rainfall of 5.08 cm/hr (3 in./hr) when the fan is running at 12.96 m/s (29 mph) and at 20.32 cm/hr (8 in./hr) when the fan is running at 22.35 m/s (50 mph).

The test observes the water supply rate, the water penetration rate, and the airflow rate through the louver. Once the test is completed, a louver’s performance is marked by the quantity of water that penetrated the system during the test compared to the amount of water that would have passed through the test wall opening if the louver was not present. This comparison is what is referred to as the Efficiency. For the architect and specifier, the important information is the assigned class rating efficiency: Class A – 99% to 100% effective, Class B – 95% to 98.9% effective, Class C – 80% to 94.9% effective, and Class D – Anything below 80% effective.

The results of this test show efficiencies of the louver’s ability to reject wind-driven rain at up to 11 test points ranging from 0.0 m/s to 5.0 m/s. Most manufacturers also relay these test data points in terms of the intake velocity or intake Free Area Velocity. These intake velocities differ slightly from one louver to another; however, the value remains constant or all louver models and manufacturers in order to allow the specifier to compare apples to apples in design performance and expectations.

Wind-Driven Sand

The latest addition to the ANSI/AMCA Standard 500-L is the testing protocol for wind-driven sand. It measures a louver’s ability to resist intrusive sand. When air systems that lie behind the louver are exposed to sand particles, it can clog up air filters prematurely.

Adopted in December of 2015, this test introduces airborne dry sand particles at different airflow rates to the louver under test. The louver is mounted and sealed within the sand injection chamber, so all sand ingress measured has come through the louver’s blades only.

The size for the louver in this test is 1220 mm × 1220 mm (48.03 in. × 48.03 in.). The test is carried out with dry sand that is uniformly distributed through a blower while the pressure drop is documented. During the testing, the free area velocity is observed and recorded. Once the measured weight of the sand has been entirely injected into the test duct, the exhaust fan and sand injector blower will continue to run for two minutes. The sand that is prevented from passing the louver is collected by a vacuum cleaner, and the difference between the sand blown at the louver and the sand that is rejected by the louver is then documented.