Tackling a transportation center or high-traffic, urban project? Consider corrosion-resistant finishes

FL-Orlanda-ITF-stretchforming (2)-courtesy of Acurlite

Orlando International Airport’s South Intermodal Terminal Facility.  Photos courtesy of Acurlite

Transportation facilities, transit oriented developments and other high-traffic city centers provide the connecting points and places that compose our urban landscapes and skylines. They also can present significant challenges in protecting exterior-facing architectural aluminum products. Without proper precautions and finishes, corrosion to finished aluminum components ultimately can damage the structural integrity of the building envelope and can lead to systemic failure.

 

Windows, storefronts, entrances and curtainwalls, sun shades, canopies, skylights, column covers, rain screens and exterior panels all commonly are manufactured from aluminum and integrally connect to a building’s façade. In almost any city, these architectural aluminum products are continually exposed to not only weathering, but to pollution and chemicals, as well as bumps and scuffs of pedestrians. While salt spray performance considerations usually are reserved for coastal conditions, it’s important to remember that salt mixture often is used to de-ice roads making it an equal concern in colder climates.

As a prominent part of the building’s exterior, the finished aluminum adds color and design to the project; this coating also protects the building from unsympathetic surroundings. The American Architectural Manufacturers Association (AAMA) continues to set the highest standard for architectural finishes, especially in highly corrosive environments. When selecting a coating that will be required to withstand such conditions, select either the highest-performing organic paint coating that meets the AAMA 2605 specification, or a Class I anodize that meets AAMA 611.

Orlando-_-ITF-webHigh-Performance Painted Coatings

High-performance, 70 percent polyvinylidene fluoride (PVDF) resin-based coatings give architects, specifiers and building owners the capability to select nearly any conceivable color or combination of colors, while shielding the building against weathering, pollution and aging.

PVDF is known for its exceptional chemical stability and excellent resistance to ultraviolet (UV) radiation. It is used in architectural applications as a coating on aluminum where it provides exceptional resistance to environmental exposure.

Cedar Avenue Transit Station-2

Minnesota’s Cedar Grove Transit Center Photos courtesy of Protean Construction & Mark Long

The carbon-fluorine bond, used in the 70 percent PVDF, including Kynar® 500 resin-based architectural coatings, is one of the strongest bonds known. These paint coatings can withstand enduring and intense UV radiation. Such attributes support long-term color- and gloss-retention, and chalk-resistance.

 

These highest-performing 70 percent PVDF coatings meet the most stringent, exterior, architectural specification AAMA 2605, “Voluntary Specification for High Performance Organic Coatings on Architectural Extrusions and Panels.” This specification requires paint coatings to meet rigorous testing performance standards including more than 4,000 hours of salt spray, and heat- and humidity-resistance.

Protean - Cedar Grove TransitCorrosion-Resistant Requirements

Section 8.8 of AAMA 2605 refers to the corrosion resistance requirements of all coatings that must pass these stringent guidelines:

  • Humidity –The sample is exposed in a controlled heat and humidity cabinet for more than 4,000 hours at 100 degrees Fahrenheit and 100 percent relative humidity. No formation of blisters to extent greater than “few” blisters, as defined by ASTM D714.
  • Cyclic corrosion testing (previous referred to as salt spray resistance) – Score the film sufficiently deep to expose the base metal. Expose the sample for 2,000 hours according to ASTM G85, Annex A5, dilute electrolyte cyclic fog/dry test. The sample must score a minimum rating of 7 on scribe or cut edges and a minimum blister rating of 8 within the test specimen field, as defined in ASTM1654.
  • South Florida exposure – The coating shall maintain its film integrity, color retention, chalk resistance, gloss retention and erosion resistance properties for a minimum of 10 years on the south Florida on-fence testing site.
  • Color retention – Maximum of 5ΔE Units (Hunter) of color change after the minimum 10-year exposure test. A ΔE unit is the variance or color difference measured on a vector scale from a specific point in the color space.
  • Cedar Avenue Transit Station-1 399X440 Duranar MICAChalk resistance – Chalking shall be no more than that represented by a No. 8 rating for colors and No. 6 for whites after 10 years of test fence exposure. Per ASTM D4214, chalking is measured on a numerical scale with higher numbers representing better chalk resistance.
  • Gloss retention – Gloss retention shall be a minimum of 50 percent after the 10-year exposure testing, as described by ASTM D 523.
  • Resistance to erosion – Less than 10 percent film loss after the 10-year exposure testing
  • AAMA notes that high humidity environments such as, but not limited to, seacoast or industrial environments, performance of corrosion resistance may be diminished.

 

Metro Transit shelter

Metro Transit’s New BRT Shelters Photos courtesy of Duo-Gard

High-Performance Anodize Finishes

 

Class I anodize finishes that meet or exceed all requirements of AAMA 611 “Voluntary Specification for Anodized Architectural Aluminum” also resist the ravages of time, temperature, corrosion, humidity and warping. Anodized aluminum withstands extreme temperature changes and weather conditions, constant exposure to vehicle exhaust, and daily use by passengers. Over-sprayed salt de-icing can be managed with a simple rinsing as needed. With basic cleaning and maintenance, architectural aluminum products enjoy a long life cycle.

Metro shelte3The anodizing process, because it is an integral part of the substrate, produces an oxide film that is uniform, hard and protects the rest of the aluminum substrate from deterioration – providing excellent wear and abrasion resistance. The coating produced is extremely durable, and the hardness of the surface is comparable to a sapphire—the second hardest substance on earth. This characteristic makes anodize an ideal choice for use in high-traffic areas where resistance properties are important.

TForge_2400-web

New York’s The Forge.   Photos by Arch Photo, Inc., Eduard Hueber

In the most challenging applications, anodize aluminum will perform as specified and will not reduce the service life of the aluminum, but may affect the natural beauty of the surface finish. Avoid any conditions that quickly can corrode an anodize finish such as mortar, cement and other alkaline materials.

To meet AAMA 611 requirements, Class I anodize must have a dry film minimum thickness of 0.7 mils to pass these stringent guidelines:

  • Abrasion Resistance (Michael Clarke Test) – A go/no-go abrasion test using abrasive papers coated with silicon carbide, garnet and glass, respectively. This is used to discriminate between films of the correct hardness and those that may give poor service because they are too soft. The specification grade of abrasive paper is Abrasive Type: Glass, Grade: “Flour,” Mohs’ Hardness Scale Number: 4.5-5.5.
  • Corrosion Resistance testing (previous referred to as salt spray resistance) –Expose the sample for 3,000 hours according to ASTM B117 using 5 percent salt solution. Test samples shall show no more than a total of 15 isolated spots or pits none larger than 1 mm in diameter, in a total of 381 cm of test area grouped from five or more test pieces.
  • South Florida exposure – The coating shall maintain its color retention, gloss retention and erosion resistance properties for a minimum of 10 years on the south Florida on-fence testing site.
  • Color retention – Maximum of 5ΔE Units (Hunter) of color change after the minimum 10-year exposure test.
  • Gloss retention – Gloss uniformity shall be within established gloss range.

 Durability and Sustainability

TForge_018-webAnodized aluminum is an inert, non-combustible material that is 100 percent recyclable and poses no health risks. At the beginning of the new millennium, Linetec and other environmentally responsible finishers, changed from the traditional caustic etching process to a more eco-friendly etch system allowing customers to use secondary (recycled) billet in the anodize process.

Small surface defects, such as those common in recycled material, are hidden by the eco-friendly anodize finish’s “frosty” matte appearance. Architects prefer the aesthetic of this matte finish. The resulting surface also reduces glare in bright sunlight. Gloss level reading is typically reduced from 15 to 25 with conventional anodize, down to a gloss level of 3 to 12 for eco-friendly color anodize.

The eco-friendly anodize process reduces landfill waste used with conventional etch processes by 75-80 percent. Landfill waste directly relates to the production of greenhouse gas. It also has the viscosity of water and will not collect in the small recesses of aluminum extrusions or narrow aluminum tubes, which enhances the durability and lifecycle of the finished architectural aluminum product.

cedar-ave-transit-berg-170607-8198-o.jpgFor painted architectural aluminum products, Linetec and the leading paint manufacturers recommend the use of a PVDF-based paint system on aluminum material for all corrosive environments. Offering the longest lifecycle, a 70 percent PVDF resin-based coating system, pretreated with chrome phosphate, along with an inhibitive chrome-rich primer should be used. This coating type meets or exceeds all the requirements of AAMA 2605.

Beyond ensuring the highest quality application, Linetec also is recognized as an industry-leading environmentally responsible finisher. It also captures the liquid paints’ volatile organic compounds (VOCs) content using a 100 percent air capture system and safely destroys the VOCs with a regenerative thermal oxidizer. Linetec then re-uses its heat energy byproduct to improve process energy efficiency. This process of re-use is completed before the material exits the paint line.

LinetecBrushedStainlessAnodize-web3Specification and Selection

To ensure the finish specified on your project’s architectural aluminum products contribute to its long life, durability and sustainability, download a free PDF of “Section 05 0513 Shop Applied Coatings for Metal 3-part Guide Specification.”

For personalized assistance in selecting the finish for your next transportation or high-traffic project, please contact us and we’ll be happy to assist you.

 

Choosing architectural painted coatings – 70% PVDF, 50% PVDF, Baked Enamel – What’s the difference?

man hands on window frameWhen selecting high-performance architectural coatings for aluminum building products including window, curtainwall, storefront, entrance and panel systems – there are three main choices for durable painted finishes: 70% PVDF, 50% PVDF and baked enamel.

70% PVDF resin-based coatings offer the ultimate protection in building performance.

No other coating system can withstand the rigors of nature and time like those based on the polyvinylidene fluoride (PVDF) resin, such as Kynar 500® or Hylar 5000®. The resin system determines the properties and performance of the paint. In a 70% PVDF coating, 70% of the resin component is PVDF.

Ideal for high-performance exterior-facing building products, 70% PVDF resin-based coatings meet the industry’s stringent requirements set by the American Architectural Manufacturers Association – AAMA 2605. They exhibit outstanding resistance to humidity, color change, chalk, gloss loss and chemicals to ensure a long lasting, durable finish.

Linetec-paint-chips-(9)-web-smallerAmong the most popular and reliable 70% PVDF resin-based coating families are:

  • AkzoNobel TRINAR®
  • PPG DURANAR®
  • Valspar Fluropon®
  • Sherwin-Williams SHER-NAR®

50% PVDF resin-based coatings offer an intermediate level of exterior protection.

Architectural painted finishes with 50% PVDF resin-based coatings that meet the AAMA 2604 specification provide good color and gloss retention in exterior applications. These coatings also offer good hardness and abrasion resistance, making it a frequent choice for storefront, doors, or other high-traffic areas.

Among the most popular and reliable 50% PVDF resin-based coatings are:

  • AkzoNobel ALUM*A*STAR® and ALUM*A*Escent®
  • PPG ACRYNAR®
  • Valspar Acroflur®

Baked enamel coatings offer a lower level of protection, typically for interior metal products.
Baked enamel finishes are acrylic/polyester coatings. Meeting the AAMA 2603 specification, the coatings are a one-coat system with poor resistance to color fading and chalking. For these reasons, they typically are used for interior applications where color retention, chalk, fade and weatherability is not required.

Among the most popular and reliable baked enamel coatings are:

  • AkzoNobel ACRA-BOND® ULTRA
  • PPG DURACRON®
  • Valspar Flurocryl

Learn more about architectural paint types by clicking here. For personalized assistance in selecting the best high-performance architectural coating for your aluminum building products, please contact Linetec’s regional sales managers, email sales@linetec.com or call 888-717-1472.

 

Architectural Coatings article offers AIA continuing education credits

Licenced Architect Earn 1 LU/HSW continuing education credit by reading Linetec’s Architectural Coatings article in this edition of Licensed Architect.

Achieving a smart synergy of aesthetic, performance and sustainable goals includes carefully selecting high-performance architectural coatings.

Whether building a new facility, renovating an existing one or updating a specific area, thoughtfully choosing the finish for a project’s metal building products and surfaces will ensure the longest lifespan.

Much more than enhancing appearance, a finish specification can be the difference in creating lasting performance and a lasting impression.

For durable, metal building products, the architectural industry most often relies on two types of finishes: anodize and paint. Both offer a long-lasting finish, but each has its own characteristics inherent in its application.

This article explains field performance, application processes, specifications and performances of architectural fluoropolymer (PVDF) paints, baked enamels, powder coating and anodize finishes including strengths, weaknesses, weatherability and environmental considerations.  Read article

Performance of an AAMA 2605 Paint Coating

Conservatory Interior 600X161

PERFORMANCE & LONGEVITY – SPECIFY AAMA-2605 PAINT COATINGS

Not all paint and powder coatings are created equally; not even all coatings that meet the AAMA 2605 specification. This specification requires paint coatings to meet rigorous testing performance standards including more than 2,000 hours of salt spray in accordance with the new ASTM G85, Annex 5 test and 4,000 hours heat- and humidity-resistance. For the most stringent, exterior application be sure the following pretreatment, primer and top coat guidelines are upheld.

 

PortCanaveralPainted aluminum coatings protect the building from unsympathetic surroundings. High-performance 70% fluorpolymer (PVDF) coatings can be selected in nearly any conceivable color or combination of colors, while shielding the building against weathering, pollution and aging.

 

The first, and arguably, the most important defense against a paint failure is proper pretreatment of the aluminum. Without proper pretreatment, premature failure of the finish system almost is guaranteed. Paint systems are designed to be applied over clean metal that has been properly pretreated. Pretreatment of the aluminum building components is crucial.

 

The most time-tested, proven pretreatment system for architectural aluminum products is a chrome-based conversion coating, such as chrome phosphate and chrome chromate. This process conforms to ASTM D 1730-03, Type B.

 

people-quoteOffering the longest life-cycle and true sustainability, chrome conversion coatings continue to be recognized by the world-class coating manufacturers, PPG, Valspar, Sherwin Williams and Akzo Nobel, as the most effective, robust pretreatment for aluminum. As a result, products installed along the seacoast and in other harsh industrial environments may not be warranted, or the warranty length and coverage may be compromised, if a chrome pretreatment system is not utilized.

 

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For critical adhesion between the paint and the aluminum surface, after the part has been pretreated, a primer coat is applied prior to the paint coating application. The primer coat ensures better adhesion of the paint to the surface, increased corrosion resistance, increased paint durability, and provides additional overall protection for the material being painted. Primer is designed to adhere to the aluminum surface and to form a binding layer that is better prepared to receive the paint. Because primers do not need to be engineered to have durable, weathering surfaces, they are instead engineered with specific chemistry to have improved filling and binding properties with the material underneath.

paint-system

The paint coating is then sprayed to meet the AAMA 2605 specification of a 30-microns or 1.2 mil total film thickness. When the formula of the paint coating dictates, a clear coat is applied over the paint top-coat. This protective layer shields the flake in metallic coatings and increases protection against ultra violet (UV) degradation of highly chromatic and exotic colors.

 

There are some AAMA 2605 coatings available that do not utilize a primer coat and/or may not contain a 70% fluoropolymer resin system. These coatings may perform satisfactory in color and fade, at least for the first five to ten years. However, it is Linetec’s belief, based on history, manufacturing testing and Linetec’s testing that the most robust paint finish system consists of a chrome conversion pretreatment, an intermediate primer coat, and a 70% fluoropolymer resin-based top coat.

Linetec mimics terra cotta’s look and feel in new painted finish

TerraCotta_166Linetec introduces a new paint finish to mimic the look and feel of natural terra cotta. The finish utilizes a 70% PVDF resin-based coating to achieve the highest levels of performance in an exterior environment and a texture additive to help replicate the natural feel of terra cotta.

“There is no doubt terra cotta wall panels have made a significant splash in the building façade market,” says Jon Close, Linetec’s vice president of sales and marketing. “Terra cotta offers a unique and attractive element to any building envelope. While this new finish cannot replicate all of the properties and design elements of terra cotta, we can offer a paint finish on wall panels that looks and feels like the real thing. And, we can do it at a cost that may better fit projects where terra cotta is desired, but cannot be afforded.”

In addition to affordability, Close also notes that aluminum wall panels painted with the terra cotta finish are lighter, can come in a large variety of shapes and sizes, and can be delivered in a shorter time frame. Furthermore, Linetec’s new paint is available in four color choices of terra cotta

As a 70% polyvinylidene fluoride (PVDF) resin-based coating, Linetec’s terra cotta painted finish meets the requirements of the American Architectural Manufacturers Association’s most stringent, high-performance specification standard, AAMA 2605-13. These architectural finishes are tested to exhibit outstanding resistance to humidity, color change, chalk, gloss loss and chemicals.”

As an environmentally responsible finisher, Linetec safely captures and destroys the volatile organic compounds (VOCs) present in liquid paints at the factory before arrival on the building site. These industry-leading practices complement other green building choices, such as using recycled aluminum content, and ensure a long-lasting, durable and sustainable finish.

For samples or more information about Linetec’s new terra coating paitned finish, and other services, please call 888-717-1472, email sales@linetec.com or visit www.linetec.com.

Paint Coatings offered by Linetec that meet AAMA2605

ArchResourceImage-withLinetec-WEB2The leading manufacturers of  high-performance, 70% Polyvinylidene Fluoride (PVDF) resin-based architectural coatings are PPG, Valspar, Akzo Nobel and Sherwin Williams. 

There are several paint types within the  70% PVDF resin-based coatings family including:

  • standard color two-coat systems, consisting of a primer and color coat (top coat),
  • two-coat mica systems, also consisting of a primer and color coat,
  • three-coat metallic, consisting of a primer, color coat and clear coat,
  • three- and four-coat bright and exotic colors. These systems include a primer, color coat, clear coat and sometimes a barrier coat.

70% PVDF coatings are available in tens of thousands of different colors; however there are some bright and vibrant colors that cannot be formulated without the use of cadmium or lead in the formulation.

70% PVDF coatings are also available in some specialty formulations such as:

  • energy-efficient, solar-reflective formulations (Fluropon® SR),
  • graffiti-resistant coatings (Duranar® GR),
  • antimicrobial coatings,
  • color-changing Kameleon™  paint coatings (Fluropon).

Linetec paint offerings listed by manufacturer that meet AAMA2605-14

Vendor
70% PVDF System Paint Finish Type
PPG Duranar Two-coat Standard
Duranar Sunstorm Two-coat Mica
Duranar XL Three- or Four-coat Metallic or Exotic
Valspar Fluropon Two-coat Standard
Fluropon Classic II Two-coat Mica
Fluropon Classic Three-coat Metallic
Fluropon Premiere Three-coat Bright or Exotic
Akzo-Nobel Trinar Two-coat Standard
Trinar Ultra Two-coat Lower VOC levels
Tri-Escent II Two-coat Mica
Trinar TMC Three-coat Metallic
Trinar TEC Three-coat Exotic
Sherwin Williams Shernar Two- or Three-coat Standard, Mica, Metallic or Exotic

To view the entire article, click here

Bright White Fluoropolymer Paint Coatings

Bright White Paint Coatings

Royal-Caribbean-CruiseBright whites are a popular design option in today’s architectural industry. These colors are available in high-performance, PVDF fluoropolymer resin-based paint systems and can be especially appealing as a unique architectural design statement.

Please be aware that special considerations should be observed when using these colors.
1.) Whites have a lower “hide” quality and are more transparent than most other colors.
2.) Many clean, bright whites require additional film thickness and/or additional coats to achieve the desired color and minimize color variation. This can increase cost of paint finishing. To ensure the correct estimates, the exact color should be specified at the time of the quote.
3.) Channels and inside corners are difficult to cover with any paint color, but tend to be more noticeable (gray) with whites. This is a naturally occurring phenomenon in electrostatic paint application and does not necessarily constitute a defect in the paint finish or application.

Clear Coat over Whites

Paint manufacturers do not recommended using a clear top coat over a white color paint. The clear top coat is not required and will not extend warranty periods. The application of a clear coat can affect the tone of the underlying color. The color coat typically shifts more yellow when a clear is applied. This is due to the fact that clear coats are not “water white” or colorless, but are actually a slightly yellow color. The degree of color change seen with a clear coat over a white is usually deemed unacceptable.

From an applicator standpoint, Linetec cannot guarantee color consistency when clear is applied over light colors. Clear coats over white will not substantially increase the gloss. The slight increase in gloss due to the clear coat will most likely not be noticeable to the human eye.

For more information on Linetec and our painting services visit our website at www.linetec.com.