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.

Ventilation Rate Procedure for HVAC Systems in the Healing Environment

Ventilation Rate IAQ Procedure - Air MeasuringThe IBC/IMC, the AIA, and Chapter 7 of the ASHRAE Handbook—HVAC Applications all reference ANSI / ASHRAE Standard 62 for determining ventilation. ANSI / ASHRAE Standard 62 provides two methods for engineers to follow to determine the required minimum ventilation rate to achieve acceptable indoor air quality.

To obtain compliance for ventilation design, there are two procedures in the ASHRAE standard. The ventilation rate procedure states that acceptable IAQ is achieved by providing ventilation air of the specified quality and quantity to the space. The indoor air quality procedure identifies a method for achieving acceptable IAQ within the space by controlling known and specifiable contaminants.

Ventilation Rate Procedure

The ventilation rate procedure provides a more definitive, prescriptive procedure based on physiological needs and subjective evaluations. The indoor air quality procedure uses guidelines for the specification of acceptable concentrations of certain contaminants in indoor air —with no prescriptive formula for ventilation rates.

The Indoor Air Quality (IAQ) Procedure

The indoor air quality procedure typically does not result in lower outside air in healing environment applications since the various potential sources of contamination require ventilation rates to be equal to that of the ventilation rate procedure. Additionally, the indoor air quality procedure requires the designer to specifically identify how each of the known contaminants is to be dealt with. The problem facing system designers with this procedure is in determining the possible contaminants that may result from the eventual use/occupancy of the healing environment. For example, controlling formaldehydes, aldehydes, nitrogen dioxides, organics, etc., all need to be understood and accomplished with “engineering reason” when tackling this method. As a result, most designers opt for the more common ventilation rate procedure (VRP ) to determine outdoor airflow needs at the space and system levels. This method prescribes the outdoor air quality acceptable for ventilation, outdoor air treatment where necessary, ventilation rates, and the criteria for reductions of outside air where recirculation treatments occur.

ASHRAE also addressed maintenance of outside ventilation systems. ANSI /ASHRAE Standard 62-2001 identifies minimum ongoing operation and maintenance criteria. The requirements of this section apply to buildings and their ventilation systems and their components constructed or renovated. In section 8.4 of ASHRAE 62, it states:

At a minimum of once every three months or as specified in the Operations and Maintenance Manual, the outdoor air dampers and actuators shall be visually inspected or remotely monitored and determined to verify that they are functioning in accordance with the Operations and Maintenance Manual.

ANSI /ASHRAE Standard 62’s definition of a maintenance manual is as follows:

An operations and maintenance manual either written or electronic shall be developed and maintained on site or in a centrally accessible location for the working life of the applicable ventilation system equipment or components.

This manual shall be updated as necessary. The manual shall consist, at a minimum, of the operation and maintenance procedures, final design drawings, operation and maintenance schedules, and any changes made thereto and the maintenance requirements.

Measuring Air Quality

Ruskin Air Measuring Equipment

Ruskin has the most comprehensive line of air measuring and control solutions in the industry.  Products include differential pressure probes for high velocity applications, combination units that measure and maintain flow, and highly sophisticated, intelligent solutions that incorporate thermal dispersion technology with microprocessor based controls that communicate with any building automation system.


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.

Noisy Generators? No Problem Ruskin Has a Solution

acoustic-louver-generator-enclosureNoise levels related to diesel generators can usually exceed local codes and city ordinances, not to mention personal comfort levels, deeming noise management a necessity. In a lot of cases, an engine exhaust muffler is the only single form of noise management used to quiet the engine. The engine exhaust is simply one little element of the general noise caused by the generator system. Noise propagates from the engine, generator, radiator fan, turbocharger and also from the muffler casing itself. Varied issues conjointly arise when a large generator also is mobile.

North American Power and Controls a company that is recognized within the trade as a “Generator Packager.” NAP&C combines and assembles all the elements that complete the generator system, together with the engine, generator, fuel system, enclosure, controls, ventilation, acoustics and on this occasion the transport logistics.

Pacific Bell one of NAP&C’s customer’s, a well-known regional telecommunications company uses standby power to provide systems for their switching facilities. The necessity arose for a portable generator to be utilized to maintain power during the period of time the main building’s power was down for construction or in the event of emergency power failure.

The generator was required to be both mobile and quiet, since it would be running near business and residential areas. As a frequent and satisfied customer of Ruskin Sound Control, NAP&C turned to Ruskin to solve their generator acoustic problems. Ruskin has presented in the past a wide array of solutions with similar needs for cooling towers, mechanical plant rooms, pump rooms, tunnel ventilation and parking garage ventilation. NAP&C working together closely with experienced Ruskin engineers, a solution, capable of not only meeting, but surpassing the customers’ performance needs, was meticulously planned and a final design approved.

Ruskin acoustical panelsRuskin 2″ thick acoustic panels were chosen for the enclosure walls and roof, and because of the dynamic nature of placing an engine in a housing mounted on a trailer, the design team were confronted with many issues not the least of which was the acoustical attenuation prerequisites. Weight and strength constraints were the foremost limiting concern and acoustics became a secondary matter. However, referencing manufacturer’s sound power ratings for the un-enclosed generator model compared to acoustic measurements taken on site utilizing the Ruskin enclosure during actual operating conditions, sound levels were attenuated considerably.

Ruskin offers the most complete line of acoustic louvers / acoustic panels on the market, as well as standard louvers, sightproof louvers, hurricane/wind driven rain louvers, adjustable / operable blade louvers, blast resistant louvers, thinline louvers, drainable and non-drainable louver models, all in a variety of blade combinations including horizontal and vertical. With more than 50 years of experience designing, manufacturing and testing louvers, Ruskin knows what it takes to deliver “real” solutions for today’s louver applications. All Ruskin acoustic louvers are AMCA licensed for water penetration and air performance. The products are offered in standard galvanized steel or alternative aluminum construction, and can be supplied in a wide variety of finishes.

RSKN_Go_Green_LogoFor 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.

High Performance Air Systems – History of Ducted and Ductless Systems

Ducted or non ducted air systems

Ducted air systems are used in the majority of comfort cooling applications in North  America. In contrast, ductless refrigerant systems in Asia, and ductless water systems in Europe dominate their respective HVAC markets. These practices reflect the historical evolution of air conditioning in each market.

Use of the coal-fired basement furnace evolved in the in the late 19th and early 20th century in North America to keep coal dust and storage away from occupied spaces.  Coal was used for coal-fired boilers  or coal-fired furnaces.  Older buildings in the Northeastern part of the US used hydronic heat distributed via radiators.  District steam in New York City and other major cities gave rise to ‘cast-iron’ and the pipefitting trade.  With the invention of air conditioning, radiators were replaced with two to four pipe fan coil systems and existing pipe chases were upgraded to handle chilled water as well as hydronic heat.  This expertise and influence for water-based systems still exists today in the Northeast US.

Different factors influenced construction practices with the western expansion of the US.   Both wood and land was plentiful.   Demand for detached multi-room single-family homes grew at a rapid pace.   It became common practice to duct heated air from the basement furnace to all the rooms – first by gravity and then forced air.  Wood construction was common and the space between the wall studs and floor/ceiling joists became the ductwork.  After WWII, contractors invested heavily in duct-fabrication to satisfy the new construction demand for housing and quick-build commercial applications. When the market for central air conditioning began during the 1960’s and 70’s, it was easy to add an “A” coil (evaporator) to the top of the furnace and add a condensing unit outside. Because residential and commercial practices influence each other, the use of a common duct for both heating and cooling carried over to all commercial building types as well. DX (direct expansion) Rooftop VAV (variable air volume) exploded in the 80’s as the demand for cost-efficient and fast installation increased dramatically.

Air Conditioning CondensersEurope and Asia’s HVAC evolution was driven by different construction practices and constraints.  Europe’s path was/is similar to that of the Northeast US.  Older buildings (and there are a lot of them in Europe) allowed no provision for ductwork – masonry construction had no hollow walls.  These buildings were heated using piped radiation systems.    Contractors developed a strong pipe-fitting culture and engineers developed tremendous knowledge of designing water-based systems.   Hence, non-ducted water-based systems are still preferred today.

Asian apartments were/are predominantly one or two room.  Through the 1950’s, many were heated by a single kerosene heater. Again, construction was/is poured concrete or concrete blocks with no hollow walls. Central heating using hydronic radiators were rare. The window unit boom in the 1960’s and 70’s provided cooling and safer electric-strip heating in one device to satisfy the needs of these small living quarters that had no provision for piping or ductwork.  In the late 1970’s and 1980’s, the evaporator/heating and compressor/condenser were separated into indoor and outdoor components– hence, mini-split.  This was not only a quieter alternative to the ‘window-shaker’, but gave the owner back his/her outdoor view.  The next logical evolution was multiple DX fan coils from one condensing unit for commercial and multi-family applications.   VRF split systems with multiple indoor units were introduced for multi room applications.

Ducted or Non-ducted?

Ducted SystemAs the above history lesson shows, the driver for ducted or non-ducted has nothing to do with efficiency.  The driver has to do with simple evolution of HVAC in relation to cultural building market drivers.

When deciding which system to use, each has advantages and disadvantages dependent upon application, climate, building construction, and other factors.  Multi-family housing, dormitories, and hotel applications all are construction-types where a common air return is not permitted.  This  is the logical market for non-ducted products.  VRF provides an alternative to hydronic fan coil systems, water-source heat pumps, and PTAC’s.  Existing masonry buildings – where ducting may be too expensive to add – also is a sensible solution for non-ducted products. Several building types require a mix of system types. Health care applications are an excellent example of a mixed-use system approach (e.g., fan coils for patient rooms, ducted for common areas).

For other commercial applications – e.g., schools, education, offices, retail/restaurants, theaters, casinos, factories – a high performance ducted system makes sense from a total life-cycle cost standpoint.  Ducted systems offer lower installed cost, better efficiency (e.g., cooling with compressor-free outside air) and code compliant ventilation within the same system.

RSKN_Go_Green_LogoFor 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.

Smart cities to rise fourfold in number from 2013 to 2025 From CSE

Smart cities to rise fourfold in number from 2013 to 2025, IHS reports
According to a new report from IHS Technology, there will be at least 88 smart cities all over the world by 2025, up from 21 in 2013. Asia-Pacific will take over the lead in 2025.

The number of smart cities worldwide will quadruple within a 12-year period that started last year, proliferating as local governments work with the private sector to cope with a multitude of challenges confronting urban centers, according to a new report from IHS Technology.

There will be at least 88 smart cities all over the world by 2025, up from 21 in 2013, based on the IHS definition of a smart city. While the combined Europe-Middle East-Africa (EMEA) region represented the largest number of smart cities last year, Asia-Pacific will take over the lead in 2025. In all, Asia-Pacific will account for 32 smart cities of the total in nine years’ time, Europe will have 31, and the Americas will contribute 25.

City projects in the Americas are typically somewhat narrower in scope than those found in Europe. Unlike broad projects underway in cities like Vienna or Amsterdam, U.S. projects will often focus on a single functional area, such as mobility and transport.

Meanwhile, many of the budget issues facing government expenditures in the well-developed economies of Europe are not found to the same extent in the Asia-Pacific region. In effect, this has the potential to create more scope for investment in smart city projects in Asia-Pacific, where projects are sometimes based around creating new infrastructure, rather than replacing legacy systems.

Under the smart city definition of IHS, annual investment on smart city projects reached slightly over $1 billion in 2013, but will go on to surpass $12 billion in 2025.

Why smart cities?

Smart cities are emerging in response to an increasingly urbanized world dealing with scarce resources, along with the desire to improve energy efficiency. By providing appropriate technologies and solutions, smart cities can deal with issues such as congestion and energy waste, while also allocating stressed resources more efficiently and helping to improve quality of life.

For instance, as an increasing proportion of the world’s populations live in cities—3.42 billion in urban areas vs. 3.451 billion in rural areas as of mid-2009, according to the United Nations—services such as public transportation, energy provision or the urban road network are inevitably strained. Smarter solutions can be deployed to lessen the negative effects of growing urbanization, including the use of sensors to monitor traffic, or the implementation of smarter ticketing solutions to improve the use of public transport.

Smart cities can also help achieve energy-efficient targets. London, for example, is retrofitting both residential and commercial buildings to lessen carbon dioxide emissions. The city is also adopting charging infrastructure to support the introduction of 100,000 electric vehicles.

For areas of the world where water is a scarce resource, smart cities can allocate this precious resource, using sensors to manage water use or provide critical information on water-storage levels. In Santander, Spain, soil-humidity sensors detect when land requires irrigating for more sustainable water use.

Smart cities also can provide other benefits. They can generate new employment opportunities through the creation of projects, prevent citizens from moving away by improving quality of life within their jurisdictions, and reduce costs. In the case of cost reduction, cities are discovering the benefits of light-emitting diodes (LED) in street lighting, an area that can take as much as 40 percent of a city’s energy budget.

Figuring out investment returns

When considering the long-term viability of smart city initiatives, it is important to assess not just direct revenue-generating opportunity but also the broader return on investment, Arrowsmith said. This has implications for both the public and private sectors collaborating on smart city projects.

Because cities continue to face budget constraints, quantifying the level of cost reduction that can come about must be a top priority. Here the obvious effects of cost savings and other benefits can be measured.

Just as significant, however, are the intangible benefits to be derived. If city denizens feel that smart cities improve their way of life, the likelihood of them leaving is reduced, helping the city maintain revenue through the taxes that are collected. Meanwhile, territories can attract new talent or businesses dazzled by the prospect of living in a smartly functioning city. Ultimately, the intentions of smart city projects—and the associated return on investment—will depend on the smart city technologies being put to use, IHS believes.

Various business models offer opportunities

Smart city projects are typically deployed via partnerships between the public and private sectors. The main business models include build-operate-transfer (BOT), build-operate-comply (BOC) and municipal-owned-deployment (MOD).

The most common model is BOT, where city planners work closely with an external private partner that, in turn, develops the services and deploys the necessary infrastructure. The third party is also responsible for the operation and continued management of the infrastructure, until such time when it is transferred back to the city.

The BOC and MOD models, in comparison, assign varying levels of responsibility in the building, operation or maintenance of smart city projects for the public and private sectors that are involved in those works.

IHS Technology has research teams focused on automotive, industrial automation, physical security, gaming, digital signage and cellular communications. Bringing together these industry experts, in turn, has helped provide for the first time a substantive overview of the size, penetration rate and forecast growth of the embedded vision market.

This article originally appeared on Edited by Joy Chang, Digital Project Manager, CFE Media,

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energy conservation

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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