The Benefits of Acid Etch Anodizing and how it is Superior to Caustic Anodizing

Acid EtchingRuskin continues to develop and optimize acid etch anodizing technology for louver production within its Juarez and Geneva plants.

Less Waste

Acid Etching is proven to be more environmentally friendly than the original caustic (alkaline) processes.  This is accomplished by reducing the amount of metal loss by up to 90% during the finishing process and resulting in less ‘sludge’ waste as a by-product culminating in lower disposal rates. Acid etching also conserves water, using lower amounts during the steps of rinsing as the caustic process demands several rinses. Some of the processes’ by-products are also recyclable and can be reused as one of the components that is made into aluminum.

A Superior Finish

Anodized Aluminum LouversA more consistent matte finish is also achieved by irregularities and imperfections such as extrusion lines or surface scratches being smoothed out to a level caustic anodizing cannot replicate. According to the Aluminum Anodizers Council, the process gives a finer more uniform pit distribution that is independent of the microstructure. This ultimately results in a better aesthetic appearance which can be extremely important in architectural products such as louvers. Less surface imperfections also mean a better tolerance to corrosion than previously achieved. With a smoother surface, anodize application will also result in a higher quality finish.  Solar glare from bright sunlight can also be reduced as gloss levels on the surface of the final product are decreased.

Better Production Times and Use of Resources

The complete acid etching procedure is more efficient over the traditional caustic etching resulting in an ultimate reduction of concentrated etching times by 80%. In taking less time to achieve the end result and needing lower tank temperatures, less plant energy is consumed making acid etch a more energy efficient process overall.

Acid Etching as a production process better meets the needs of Ruskin’s extrusion and preparation of its louvers for its customers, allowing it to provide a high quality aluminum product that requires low maintenance and inherently has a high resistance to corrosion.

Louver and Architectural Solutions

Aluminum louversWhile providing fresh air intake and exhaust, Ruskin Louvers can also provide different architectural styles to building design. With the variety of models, sizes, paint finishes available, and custom products, Ruskin Louvers can add unusual and appealing features to exterior and interior elevation. Ruskin louvers are available in depths ranging from 1.5″ to 12″ and can accommodate various blade angles with high free area.

Link to Ruskin Louver and Architectural Solutions

For more information about Ruskin’s complete louver product line, application and design support, and our state-of-the-art manufacturing capabilities, contact your local Ruskin representative nearest you or Contact Ruskin directly at (816) 761-7476.

Miami-Dade County Approval Tests for Louvers

Louver Building Miami DadeThe South Florida Building Code (SFBC) states that products installed on the exterior of buildings must be designed to withstand the severe conditions produced by hurricanes. However, the widespread failure of various building products during Hurricane Andrew in 1992 identified a need for stronger code enforcement. Recognizing that standardized testing and product control could assist enforcement, the Metro-Dade County (later changed to include all of Miami-Dade County) Florida Building Code Compliance Office (BCCO) developed a series of test protocols that subject products to the rigors of hurricane wind and rain conditions.

Miami DadeTo gain Miami-Dade County Approval, louvers may be required to pass as many as four different tests — three are structural and one measures wind driven rain penetration resistance. These tests are referred to as PA’s or Protocol and Application Standards.

PA-100(A): Wind Driven Rain Penetration Test

The Building Code Compliance Office (BCCO) requires this test if the room the louver is installed in is designed to be dry (room is not designed to drain water and/or houses items that are not water resistant). This test subjects the louver to high velocity winds and heavy simulated rainfall. Using a wind generator and water jets that inject the equivalent to 8.8″ per hour rainfall into the airstream, 15 minute tests are run at wind velocities of 35, 70, and 90 mph. The final 110 mph test is performed for 5 minutes. The louver must allow no water penetration at 35 and 70 mph, and only .05% penetration at 90 and 110 mph.

PA-202: Uniform Static Air Pressure Test

If a louver is installed in a room that can drain water and houses water resistant items, the wind driven rain test is not required. Instead, the PA-202 test is performed. In this procedure, the louver is installed in a chamber and uniform static air pressure is applied in positive and negative directions. Several pressure levels are applied in increasing magnitude until a load equal to 1.5 times the design windload is attained. Pressures are sustained for 30 seconds. The deflection of blades, frames and supports is measured during the test and the amount of recovery is checked afterwards. Throughout the test the anchorage system is also monitored for failure. Design windloads for hurricane applications can produce static pressures in excess of 28″ w.g. If the room is considered a closed structure that cannot withstand this pressure or if it houses equipment that cannot handle the pressure, the BCCO code requires the louver/damper assembly be subjected to the PA-201 and PA-203 tests.

PA-201: Large Missile Impact Test

Impact on Miami Dade LouverThis test simulates wind-driven debris that is often present in hurricanes. In the test, the louver assembly is impacted with a 2″x 4″ board weighing 9 lbs. and traveling at approximately 34 mph. At least three separate impacts are conducted and the louver must prevent the board from both penetrating the assembly or creating a significant opening.

PA-203: Cyclic Wind Pressure

This test is conducted only after the Missile Impact Test has been done. By simulating the forces applied to a louver by repeated severe wind gusts, this test exposes possible weaknesses in the assembly created by the missile impacts. In this test, the louver assembly is installed in a chamber similar to the Uniform Pressure test. However, the pressures are applied for only a few seconds and repeated several hundred times. Pressure is increased until 1.3 times the design windload is achieved. As in the PA-202 procedure, the deflection of the components and the anchorage system are examined.

Miami Dade Louver Cross SectionRuskin’s Hurricane Louvers

Ruskin’s Hurricane Louvers are designed to exceed impact resistance and windload requirements with predesigned proven installation methods. Ruskin was the first manufacturer to gain Miami-Dade County approval for louvers. These louvers are built to withstand up to 160 psf on some products based upon the criteria in TAS 201, 202 and 203 as well as AMCA 540/550.

Hurricane Louver Products

For more information about Ruskin’s complete product line, application and design support, and our state-of-the-art manufacturing capabilities, contact your local Ruskin representative nearest you or Contact Ruskin directly at (816) 761-7476.

Selecting the Right Louver for the Right Job


With the wide selection of louvers available today, choosing the proper louver for your application may appear to be a difficult task. However, by considering the requirements of the application and understanding what models are available, louver selection can be made much easier. In this article, we will examine factors that affect louver selection and some of the more common louver styles available today.

Selection generally starts with a desired airflow and practically any louver style will handle any amount of airflow if it’s made large enough. However, system designers usually have to deal with size constraints. The task then becomes finding a louver will handle the desired volume while providing adequate rain resistance and airflow characteristics. Here are some considerations:
• Rain Resistance – Rain penetration through louvers is usually undesirable. However, in applications where the louvers are close to water sensitive surfaces or devices, it can be extremely harmful. Are there provisions in the building for managing rain that may penetrate the louver during storms, such as floor or plenum drains? If not, will rain infiltration during storms create significant problems for the building? If rain penetration will be managed or is not harmful, a standard louver may be suitable. If the application cannot accept rain penetration, wind driven rain resistant louvers should be utilized.
• Pressure Drop – How much pressure drop is acceptable? This may be the deciding factor in the louver selection. Most standard louvers are designed to provide good air performance within their intended airflow range. While the airflow capacity of wind driven rain resistant models are usually higher, the additional airflow may create more pressure drop than with standard louvers. Keep in mind that published AMCA certified pressure drop performance does not include the effect of a bird or insect screen. This can add from 5% to 15% pressure drop depending on the screen type.

Other louver selection considerations:
• Sound – Is the louver going supplying air to a noisy area such as a generator or pump room? If so, acoustical designs are available to reduce sound penetration through the louver.
• Security and/or Sight Restriction – Louver applications in areas subject to frequent human contact may benefit from sightproof louvers. Sightproof models restrict see-through and provide less opportunity for vandals to penetrate the louver wall.
• Airflow Shut-off – For applications that only require airflow at certain times, operable or combination louvers are available that completely close the opening. Good choices for emergency generator or warehouse applications.
• Appearance – Is there a particular louver design or appearance desired? Or, does the louver need to blend with or match other elements in the building? For architectural louver applications, appearance is sometimes the most important feature. The appearance of louvers can be changed to fit a variety of needs with visible or hidden mullions, blade orientation and spacing, and the type of finish applied.
• Structural Integrity – Windloads have a considerable effect on louver construction, especially with louvers that are tall or in hurricane-prone areas. High windloads may make the use of certain types of louvers impractical, particularly thinline models due to their lightweight design.

Now that we’ve looked at some of the considerations for louver selection, let’s review some of the common louver styles available today.
• Standard Louvers – These are the standard horizontal blade models that have been available for many years. Typically, they are 4” to 6” deep and are tested in the AMCA “still air” water penetration test. These models feature fairly wide blade spacing that can provide good free area and pressure drop performance. However, their wide blade spacing makes them far less effective at rain protection than wind driven rain resistant models. To give an idea of airflow capacity, a popular 4” deep standard louver with drainable blades can handle approximately 400 cfm per ft² of louver face in a 4’ square size, and generates roughly .15” pressure drop. Common Standard Louver styles:
o Non-drainable blade louvers – The louver blades do not collect water, therefore rain water cascades from blade to blade. Most often used in weather-protected areas and continuous blade applications.
o Drainable blade louvers – The louver blades feature small gutters in their profiles that collect water and drain them to downspouts in the jamb frames (fig. 1). Better rain resistance than non-drainable models, but not effective in storm conditions. Often utilizes visible vertical mullions to enclose the downspouts.
o Sightproof louvers – Most often utilizes a chevron or inverted “Y” shaped blade to prevent see-through. Also prevents objects from being passed through the louver wall. Free area and pressure drop performance usually worse than other standard louvers requiring larger louvers for the same airflow.
o Thinline louvers – Louvers that are 1” to 3” deep. Generally made for PTAC or curtain wall applications. Also a good choice for small openings but not for large sizes or high windload situations.
• Wind Driven Rain Resistant Louvers – This louver style has developed in the last decade and utilizes new technology to minimize rain penetration. The louver depths typically range from 4” to 8”. The blades may be positioned horizontally or vertically and generally feature complex profiles. Blade spacing is much closer than standard louvers, ranging from 1” to 3” center to center in most cases. Unlike Standard Louvers, these are tested in AMCA’s Wind Driven Rain Penetration Test which simulates storm conditions (fig. 2). Louvers are subjected to heavy rain and wind effects. Many models provide over 99% efficiency at preventing water penetration. Looking at a 4’ square size, a popular 6” deep vertical blade wind driven rain resistant design will handle 900 cfm per ft² of louver face and generate roughly .35” pressure drop. Some characteristics of these louvers:
o Horizontal Blade Models – Look much like Standard Louvers, but with closer blade spacing (fig. 3). Performs well in the low weather condition test (3”/hr rain & 29 mph wind). Some continuous blade models are available.
o Vertical Blade Models – Provides the best performance. Some are 100% effective in the high weather condition test (8”/hr rain & 50 mph wind).
o Cost – Can be as much as 2 to 3 times as much as Standard Louvers, but in many cases can be ½ the size. And they offer rain protection not available with Standard Louvers in any size.
• Acoustical Louvers – The louver blades are filled with sound-deadening material, typically mineral wool or fiberglass. They are usually fairly deep, as much as 12”. These models can provide 10 to 12 db noise reduction in the lower octave bands in a Free Field condition. Free area is usually very low compared to other louvers, so Acoustical Louvers must be made larger to handle comparable airflow. For comparison, a common 12” deep model handles 200 cfm per ft² of louver face in a 4’ square size and generates roughly .10” pressure drop. Acoustical louvers most often utilize visible mullion construction.
• Operable & Combination Louvers – These models feature operable blades that can be closed when airflow is not required. The airflow shut-off capability prevents rain and humidity from entering the room when the louver is closed. Combination louvers feature a set of stationary blades in front of the operable blades that produce a consistent exterior appearance at all times. Airflow capacity per ft² is similar to that of Standard Louvers.

The louver styles described above make up the majority of louvers available, but there other louver products available. Hurricane resistant louvers, penthouses and equipment screens are some of the other products available for more specialized applications. Even though there are many louver products to choose from, their selection can be made easier with a basic understanding of what styles are available and their applications. Whatever your application, there probably is a louver available that will meet the requirements.

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