American Galvanizing Association

American Galvanizing Association
Galvanize It! Seminar American Galvanizing Association SPEAKER NOTES: Enter the date and location of the seminar as well as the presenters names. A slide should be inserted after this one if the presenter wishes to identify the company he/she works for (REMINDER: This is the only place where your company name should be mentioned).

American Galvanizers Association
The American Galvanizers Association (AGA) is a non-profit trade association dedicated to serving the needs of after- fabrication galvanizers, fabricators, architects, specifiers, and engineers The AGA provides technical support on today's innovative applications and state- of-the-art technological developments in hot-dip galvanizing for corrosion control The American Galvanizers Association (AGA) is a non-profit trade association dedicated to serving the needs of after-fabrication galvanizers, fabricators, architects, specifiers, and engineers The AGA provides technical support on today's innovative applications and state-of-the-art technological developments in hot-dip galvanizing for corrosion control

Continuing Education Credit
American Institute of Architects Learning Units (HSW) Also, by attending this seminar presented by the American Galvanizers Association, those of you registered w/ the American Institute of Architects are eligible to earn 1 hour of continuing education in the Health, Safety, and Wellness Category (HSW). Engineers are eligible to receive Professional Development Hours through the National Council of Examiners for Engineering & Surveying. Please provide certificates to your state licensing board for approval. NOTE: The AGA’s Galvanize It! seminar is not eligible for PDHG credit in the state of Florida. National Council of Examiners for Engineering & Surveying Professional Development Hours

Continuing Education AIA/CES Policy on Endorsement: The following program is registered with the AIA/CES and does not include content that may be deemed or construed to be an approval, sponsorship, or endorsement of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. This course has been registered with the American Institute of Architects and CES and as such provides you with required credits toward your profession.

Continuing Education The American Galvanizers Association has met the standards and requirements of the Registered Continuing Education Providers Program. Credit earned upon completion of this program will be reported to RCEPP. A certificate of completion will be issued to each participant. As such, it does not include content that may be deemed or construed to be an approval or endorsement by NCEES or RCEPP.

Purpose of this Seminar
The purpose of this seminar is to inform and educate architects, engineers, and other specifiers about hot-dip galvanized steel and how it can address the growing corrosion problem throughout North America.

Learning Objectives At the end of this presentation you will be able to: Recognize the corrosion issues confronting the United States Describe how zinc coatings, specifically hot-dip galvanizing, can protect against steel corrosion Incorporate sound corrosion protection into the design of steel products that can significantly decrease maintenance costs over the life of a structure At the end of this presentation you will be able to: Recognize the corrosion issues confronting the United States Describe how zinc coatings, specifically hot-dip galvanizing, can protect against steel corrosion Incorporate corrosion protection decisions into the design of steel products that can significantly decrease maintenance costs over the life of a structure

Tour of the City PRESENTER NOTES: This is the general “Tour of the City” section. Past experience indicates that custom tailoring of this section to the particular area where the presentation is being given has a more profound effect on conveying the corrosion problem to the audience. Feel free to edit this section accordingly by adding photos from the city/surrounding area nearest the seminar site.

The Corrosion Problem I’d like to take you on a corrosion tour of the city, in order to show you sights that you see every day. Like me, before I became familiar with the benefits of galvanized steel, you most likely take corrosion for granted as a natural, unavoidable, uncontrollable condition that affects your city, your commute, and the tax bite you feel each and every day. Clockwise from upper left: New York (Manhattan), Boston, Miami

The Corrosion Problem Bridge in Denver, CO Bridge in Denver, CO
This is becoming an all-too-common occurrence throughout many cities across the nation. <Click> On closer look, you will see complete structural failure,with spalled concrete and exposed reinforcing steel. At great expense, many cities have created a “diaper-type” system to cover the underpass and catch spalling concrete so as not to threaten pedestrian and/or interstate traffic passing underneath. Bridge in Denver, CO Bridge in Denver, CO

The Corrosion Problem Corroded Trolley
This is a picture of the underbody of a trolley used on the urban streets of cities across the country. After years of use, and exposure to road salts and natural weathering, the painted steel has yielded to corrosion. As you can see, corrosion has eaten away sections of the steel frame rendering the trolley unsafe for use. Paint coatings, in some environments, will not provide adequate corrosion protection to ensure long-term service life for steel. Future trolley’s could remain in service longer with a more robust coating (a later slide in the duplex systems slides depicts a trolley that has been painted after galvanizing to ensure long life). Corroded Trolley

The Corrosion Problem Coors Field – Denver, CO
On a closer inspection of this railing at the Colorado Rockies’ baseball stadium, Coors Field, you’ll see blistering, peeling and rusting throughout the entire structure. Denver’s environment is extremely arid, but damage to the paint caused by normal wear & tear is nonetheless allowing corrosion to begin. And while corrosion itself is an obvious concern, in an environment such as this entertainment venue, safety and aesthetics are also relevant. Coors Field – Denver, CO

The Corrosion Problem Corroded Pier
Coastal environments are often very corrosive due to the increased salinity content in the air from the close proximity to the ocean. This picture illustrates this highly aggressive environment as you can see an extremely thick layer of paint has lost its battle with corrosion. Once the paint barrier has been breached corrosion will eventually spread to attack the entire steel structure. Structural properties of the steel are soon to be lost presenting an extreme safety hazard to anyone near the pier. Corroded Pier

Williamsburg Bridge - New York City, NY
The Corrosion Problem Lastly, here is a severely corroded beam from the famous Williamsburg Bridge, built in 1903 and located in New York City. When this photo was taken, the bridge was still in use and traveled by over 100,000 vehicles per day as well as train traffic on the deck below. Inspected in 1991 and subsequently closed for 7 months, the direct cost to repair the corrosion problems was $750 million. The indirect cost, that is to local businesses that relied on passersby and the inconvenience and time of commuters to take a less direct route to and from work was estimated to be $8.2 billion! That kind of money could have been wisely used to galvanize the bridge structural steel and pay for much other needed infrastructure. Williamsburg Bridge - New York City, NY

Corrosion Costs NACE, CC Technologies, & FHWA jointly produced a report in 2001 detailing the costs of corrosion $297 billion USD annually 3.1% of US GDP (1998) Hazardous Public safety, property damage, environmental contamination Natural Resources Waste production, increased energy consumption Public Outcry Traffic, inconvenience Costs of Corrosion - $$$$ - Increased Taxes According to the results of the 2001 Corrosion Costs & Preventive Strategies study, a joint effort among the National Association of Corrosion Engineers (NACE), CC Technologies, and the Federal Highway Administration (FHWA), the direct cost of metallic corrosion to the US economy is $297 billion per year. Projections for the highway and bridge section indicate that indirect costs would be 11 times greater than the direct costs. This demonstrates the overwhelming impact of corrosion on the US economy. By extending the life and durability of steel, not only will capital investments be less, but taxpayers will be saved money as well. When you design and specify, don’t think only of initial costs, but think of corrosion protection methods and life-cycle costs. Costs of Corrosion - Hazardous Corrosion control & public safety go hand-in-hand. For example, corrosion is one of the leading causes of pipeline accidents in the world. When a pipeline fails, the results can be devastating in terms of loss of life, property damage, and environmental contamination. Costs of Corrosion – Natural Resources Corrosion, if unchecked, contributes to waste, with dramatic environmental implications through process and plant failure. Further, the increased energy implications in replacing corroded structures are very significant in both financial and environmental terms. Specifiers must design and specify for the longest product life possible. By doing this, your project will not need to be replaced or rehabilitated as frequently. Early project failures require unnecessary consumption of natural resources. By protecting steel against corrosion, resources such as iron ore and energy will be saved. Costs of Corrosion – Public Outcry During renovation of the Williamsburg Bridge, the New York City Department of Transportation had to completely close it to traffic for seven months due to its deteriorated condition. Inspections at that time found 30 areas of major corrosion in the structure. At first is was decided to entirely replace the debilitated bridge, but building a new bridge in a different location would negatively impact businesses located near the Williamsburg Bridge. Replacing the bridge would have caused this main artery for vehicles to be closed for many more months. Already, the seven-month closure caused public infuriation. There is also train traffic across the bridge which had to be shut down for five months.

The Solution: Hot-Dip Galvanizing
Now that I’ve talked about the severe problem of corrosion, let’s talk about some solutions to the corrosion problem.

Barrier Protection Weathered Guardrail
Like paints, the hot-dip galvanized coating provides a barrier against corrosion by isolating the steel from the electrolytes in the environment, the steel will be protected and corrosion will not occur. This is known as barrier protection and the impervious nature of zinc metal makes it a very good barrier coating. Also, zinc corrodes approximately 1/10 to 1/40 the rate of steel depending on the environment, making zinc inherently less corrosive than steel. Weathered Guardrail

Cathodic Protection: Galvanic Series
ZINC - Anode STEEL - Cathode This arrangement of metals determines what metal will be the anode and cathode when the two are put in a electrolytic cell (arrangement dependent on salt water as electrolyte). This table shows a series of metals arranged in order of electrochemical activity in seawater (the electrolyte). Metals higher on the scale provide cathodic or sacrificial protection to the metals below them. Therefore, zinc protects steel. The scale indicates that magnesium, aluminum, and cadmium also should protect steel. In most normal applications, magnesium is highly reactive and is too rapidly consumed. Aluminum forms a resistant oxide coating and its effectiveness in providing cathodic protection is limited. Cadmium provides the same cathodic protection for steel as zinc, but for technical and economic reasons, its applications are limited.

Exposed Steel is Protected
Cathodic Protection Exposed Steel is Protected Zinc Coating Bare Steel As I’ve explained and you now know, zinc is anodic to steel; therefore, the galvanized coating will provide cathodic protection to exposed steel as well. When zinc and steel are connected in the presence of the electrolyte, the zinc is slowly consumed while the steel is protected. The zinc’s sacrificial action also offers protection where small areas of steel may be exposed due to cut edges, drill holes, scratches, or as the result of severe surface abrasion during rough handling or job site erection. Cathodic protection of the steel from corrosion continues until all the zinc is consumed. With a cathodically protective coating, such as galvanized steel, damaged areas will be protected by the surrounding zinc

HDG Process Steel is dipped in a series of tanks including solutions that remove impurities from the steel surface. The galvanizing reaction only occurs on perfectly clean steel. The steel is inspected after galvanizing to ensure conformance to the appropriate specifications. PRESENTER NOTES: Animation runs approximately 30 sec. Must have QuickTime installed to run animation.

Long-Lasting Zinc Protection
Zinc Patina Cathodic Barrier Long-lasting Protection Barrier Cathodic Zinc Patina A galvanized coating protects steel for extensive periods of time because, as you have learned earlier when we went over the Galvanic Series of Metals, zinc sacrifices itself to protect steel. The long-lasting protection that zinc affords steel is based on three factors: the zinc coating acts as a barrier against the penetration of water, oxygen, and atmospheric pollutants. the zinc coating cathodically protects the steel from coating imperfections caused by accidental abrasion, cutting, drilling, or bending. zinc protects steel due to the formation of zinc corrosion byproducts, or what is collectively termed the “zinc patina.” The formation of the zinc patina is critical in terms of delivering long-term corrosion protection.

HDG Process: Surface Prep
Zinc-iron metallurgical bond only occurs on clean steel Degreasing Removes dirt, oils, organic residue Pickling Removes mill scale and oxides Fluxing Mild cleaning, provides protective layer The metallurgical bond between zinc and steel is ensured by thoroughly cleaning the steel before immersing it into the molten zinc. As part of the galvanizing process, steel goes through several cleaning steps. The first cleaning solution, hot alkali, removes organic contaminants like dirt, water-based paint, grease and/or oil. After caustic cleaning, the article goes through a water rinse. Any epoxies, vinyls, or asphalt must be removed by mechanical means (grit-blasting, etc.) before steel is taken to the galvanizer. The second cleaning solution consists of an acidic solution that removes oxides and mill scale from the surface of the steel. The third surface preparation tank is called the pre-flux tank. This step serves two purposes: it’s a lightly acidic solution that cleans oxides and provides a protective layer to prevent any oxide formation prior to immersion in the galvanizing kettle. Caustic cleaning

HDG Process: Galvanizing
Steel articles are immersed in a bath of molten zinc (≈ 830 0F) > 98% pure zinc, minor elements added for coating properties (Al, Bi, Ni) Zinc reacts with iron in the steel to form galvanized coating. The true “galvanizing” phase of the process consists of completely immersing the steel in a minimum 98% pure zinc bath. The bath temperature is maintained at 815°F or higher (435°C +). The steel is lowered by crane hoist at an angle and at about 3 ft. per minute rate. This allows air to escape from tubular shapes or pockets that may be within the design of a fabricated piece and of course permits the molten zinc to displace the air. Approximately 5 – 7 minutes after complete immersion, the steel reaches the bath temperature and the metallurgical bond is complete. Zinc bath removal

HDG Process: Inspection
Steel articles are inspected after galvanizing to verify conformance to appropriate specs. Surface defects easily identified through visual inspection. Coating thickness verified through magnetic thickness gauge readings. The last phase of the process is the final inspection. A very accurate determination as to the quality of the galvanized coating is a visual inspection of the material. As stated earlier, if the steel surface is not properly and thoroughly cleaned, the zinc will not adhere to the steel. The inspection step of the galvanizing process will be covered in detail later in the seminar.

Hot-Dip Galvanized Coating Properties
Now that I’ve talked about the severe problem of corrosion, let’s talk about some solutions to the corrosion problem.

Metallurgical Bond Now that you’ve learned about the galvanizing process, let’s examine the actual coating itself. As was stated, galvanizing forms a metallurgical bond between the coating and the base metal. During galvanizing, the molten zinc naturally reacts with the iron in the steel to form a series of zinc-iron alloy layers. Pictured here is a photomicrograph of a cross-section of a galvanized steel coating. The first zinc-iron alloy layer, the Gamma layer, is approximately 75% zinc and 25% iron. The next layer, the Delta layer, is approximately 90% zinc and 10% iron. The third layer, the Zeta layer, is approximately 94% zinc and 6% iron. The last layer, which forms as the material is withdrawn from the zinc bath, is identical to the zinc bath chemistry, i.e. pure zinc. As you can see, the Gamma, Delta and Zeta layers form approximately 60% of the total galvanized coating, with the Eta layer making up the balance.

Edge Protection Same thickness at corner Micrograph of galvanized edge
As depicted in this photomicrograph, which is a cross- section of the edge of a galvanized part, the galvanizing process naturally produces coatings that are at least as thick at the corners and edges as the coating on the rest of the part. This is because the reaction between iron and zinc is a diffusion reaction and thus the crystalline structure of the coating forms perpendicular to the steel surface. As coating damage is most likely to occur at the edges, this is where added protection is needed most. Brush- or spray-applied coatings have a natural tendency to thin at corners and edges. Remember the picture of this sign? Galvanizing would have provided superior protection to these edges & corners. Micrograph of galvanized edge

Additional Benefits of HDG
Complete Coverage There are many additional benefits of hot-dip galvanized steel, one of which is the complete coverage that is afforded. Because the galvanizing process involves total immersion of the material into cleaning solutions & molten zinc, all interior & exterior surfaces are coated. This is a very important concept because corrosion tends to occur at an increased rate on the inside of some hollow structures where the environment can be extremely humid and condensation occurs. Hollow structures that are painted have no corrosion protection on the inside.

Variety of sizes and shapes A wide variety of shapes and sizes ranging from small nuts, bolts, and fasteners to larger structural pieces, to even the most intricately detailed artistic pieces, can be galvanized.

Availability Processing times are another example of an additional benefit to specifying hot-dip galvanized steel for corrosion protection. Some corrosion protection methods depend on proper weather and humidity conditions for correct application; hot-dip galvanizing can be accomplished rain or shine with turnaround and service to meet delivery schedules. Also, there will not be non-installation delays due to necessary curing times. Since zinc solidifies upon withdrawal from the zinc bath, it is possible for the material to be galvanized, transported to the job site, and installed on the same day. If the galvanized material does not need to be immediately installed, there is no problem with leaving the material out at the job site because UV rays do not compromise the galvanized coating’s integrity.

Galvanizing is Green Zinc is 100% recyclable as is the steel
Properties of zinc do not degrade w/ reprocessing Zinc is a natural element in the Earth’s crust The longevity of galvanizing means no additional energy exerted or waste created maintaining galvanized structures Zinc is infinitely recyclable without the loss of any physical or chemical properties. Approximately 30% of the world’s zinc supply comes from recycled zinc each year. More would be recycled if it were available.

Estimated Service Life of HDG
The atmospheric classifications are a guide to predicting corrosion rates for general environmental conditions. However, since applications and environments vary, the appropriate classification should be carefully selected on a job-by-job basis. Using this Life of Protection chart, developed using the Zinc Coating Life Predictor, lets look at the galvanized coating’s protective life in keeping with the five atmospheric environments just described. A galvanized coating’s protective life is determined primarily by the thickness of the coating and the severity of the exposure conditions. The thickness of a galvanized coating is expressed in “mil thickness.” One ‘mil’ is equal to one thousandth of one inch. So for instance, let’s say that you have a galvanized structure in a suburban atmosphere. According to ASTM A123 for a piece of steel with a thickness of 1/4 inch or greater, the minimum mil thickness requirement is 3.9 mils. More often than not, you will get greater than the minimum requirement when hot-dip galvanizing. A good average coating thickness is probably between 5 and 7 mils. But, let’s just say we have a coating of 5 mils. If you follow the 5.0 mils up to the suburban environment line and across, you’ll see you have approximately 120 years to 5% surface rust. This does not mean your project will be rusted away in 120 years, but what it does mean is that in 120 years 5% of your coating has corroded away leaving red rust, or blushing. Ninety-five percent of your coating is still intact and working as a barrier and cathodic protection system. At 5% surface rust there is no loss of steel integrity. Five percent surface rust, as shown on this chart, indicates that it is time to think about coating the galvanized surface by brush- or spray-applied corrosion protection method if disassembly for regalvanizing is not an option for extending the life of protection. Just as a note here, there is a difference between red rust and brown staining that the human eye can rarely detect. Brown staining is the iron oxide corrosion by-product from the iron content percentages found in the zinc- iron alloy layers of the Gamma, Delta and Zeta layers of the galvanized coating. Since its hard to tell the difference just looking at it, use a measurement gage and if there is any mil thickness measurement at all apparent, then you are looking at brown staining. Red rust will not have any mil thickness reading.

Other Zinc Coatings for Corrosion Protection
There are various other zinc coatings that are used for corrosion protection in numerous environments. However, they are often confused in the specification community due to the fact that they are all referred to as a form of “galvanizing”. It is important to select the appropriate zinc coating for the steel type and environment. Let’s take a look at a few of the most common types of zinc coatings.

Metallizing Shop or in-field application
Suitable for very large pieces Coating Properties: Thick coating Mechanical bond Less dense than HDG zinc layers No interior coverage Metallizing or zinc spraying is accomplished by feeding zinc in either wire or powder form into a heated gun, where it is melted and sprayed onto the steel using combustion gases and/or auxiliary compressed air to provide the necessary velocity. Metallizing can be applied to materials of nearly any size, although some limits on the complexity of the structure may apply due to limited access to recesses, hollows and cavities by the metal spray. Abrasive cleaning of the steel is required before metallizing to ensure adequate bond to the steel. Unlike hot-dip galvanizing, metallizing mechanically bonds to the steel surface with an absence of intermetallic alloy layers. This makes the coating less dense than HDG, although a greater zinc thickness can be achieved using metallizing, it often does not contain as much zinc as a thinner, more dense HDG coating would. Metallizing Appliation

Zinc Rich Paint Metallic zinc dust Barrier protection
Inorganic Organic Barrier protection Cathodic protection Limited Dependent on % Zn Use salt spray data to make performance claims Zinc-rich paints are classified as inorganic or organic based on the material used to bind the metallic zinc dust particles together. Inorganic coatings can often provide adequate corrosion protection in a single coat while organic zinc-rich paints are often top-coated with another layer of paint. Unique to other paint systems, zinc-rich paints exhibit limited cathodic protection abilities in addition to the barrier protection all paints provide. However, the cathodic protection is largely based on the amount of metallic zinc dust in the dry film and the applicator of the coating. Zinc-rich paints must be constantly mixed in order to maintain a homogenous mixture to promote metallic zinc dust contact once the paint is cured. The cathodic protection provided by zinc-rich paints is considerably less than the cathodic protection of pure zinc coatings. Zinc-rich paints are often portrayed by manufactures as “cold galvanizing” or equivalent to galvanizing based on data collected through accelerated salt spray testing. However, accelerated testing does not correlate to real world performance for hot-dip galvanized steels as the protective zinc patina is never allowed to form in accelerated conditions, significantly decreasing the life of the coating. Zinc Rich Paint Application

Sheet Galvanized Produced by a continuous in-line hot-dip process
Coil-to-coil process FPM “Air knives” remove excess zinc Pure zinc with little alloy layer Galvannealed (Zn-Fe) Galvalume (55% Al) Sheet galvanized products are often confused with the hot-dip galvanizing process as they both involve dipping bare steel in a tank of hot liquid zinc. In the sheet process, coils of steel sheet metal are fed as ribbon through a molten metal bath where it reacts to leave a protective zinc coating. The operation grew out of traditional after-fabrication hot-dip galvanizing into a very sophisticated process that can be used to apply thin and specific coating grades. These coating grades are in the form of a letter G, Z, and A followed by a coating weight in mass per area. This process is also called continuous galvanizing and is specified in ASTM A 653/ A653 M-02, Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy- Coated (Galvannealed) by the Hot-Dip Process. Common coating weights specified for sheet products are: G60, G90 and G185. These also exist as metric counterparts with G90 being equivalent to a Z275 coating. Other types of galvanized sheet are produced for specific applications. Galvanealed sheet is simply typical galvanized sheet steel that is heated to produce a coating consisting of entirely zinc-iron alloy layers. This provides a better surface for painting over. Other metals have been used in combination with zinc to increase the corrosion resistance of galvanized sheet steels. One product, galvalume sheet contains 55% aluminum. Another product, Galfan, contains 5% aluminum. Sheet Steel of Continuous

Sheet Galvanized ASTM A653 – specify total coating weights, most common G60 and G90 Weights represent total coating weight for both sides of the sheet Coating Weight (ounces/sq. ft.) Coating Thickness per Side (mils) G60 0.60 0.54 G90 0.90 0.81 The most commonly specified continuous galvanized sheet steels are G60 and The numbers in these designations represent the weight of zinc per total surface area for both sides of the steel sheet. Converting this to a thickness per side we can see that G60 coatings are approximately ½ mil thick and G90 coatings are approximately 0.8 mils thick. Coating thicknesses can be specified for continuous sheet, with thicknesses ranging from G30 to G235. It is important to specify the right thickness relative to the corrosiveness of a particular environment.

Electroplated Strip, sheet, or small parts Good formability Paintable
Smooth finish Slightly more expensive than sheet galvanized Good formability Paintable Electroplated coatings are applied to steel sheet, strip, and small parts by electrodeposition. Zinc coating is developed on the surface as zinc ions, in an electrolytic solution, are electrically reduced to zinc metal and deposited at the cathode. Parts are most commonly immersed in cyanide, alkaline non-cyanide, or acid chloride salt solution to apply the zinc coating. Electroplated parts are often passivated with a chemical following plating to increase corrosion resistance. The coatings are typically thin and are comprised of pure zinc. Since zinc is a soft metal, the formability of the steel is good after coating. The smooth finish produced from this coating process allows for easy painting as well. Electroplating Application

Zinc (Mechanical) Plating
Similar to electroplating used for fasteners and small parts Parts are tumbled in drum with zinc powder and glass beads mechanically bonded zinc Small iron and steel parts may be coated by drum tumbling with a mixture of proprietary promoter chemicals, zinc powder and glass beads. After cleaning, the parts, which are limited in size to about 8-9 inches and weighing less than one pound, are flash copper coated and loaded into a plating barrel. The barrel is then filled with chemicals, glass beads and zinc powder and tumbled. The tumbling action causes the beads to peen the zinc powder onto the part. Thickness is regulated by the amount of zinc charged to the plating barrel and the duration of tumbling time. Mechanical Plating Application

Other Zinc Coatings Metallizing Sheet Galvanized Hot-Dip Galvanized
Zinc-Rich Paint Electroplated This slide summarizes the differences of coating thicknesses among several zinc coatings. Many people use “galvanizing” as a generic term for all types of zinc coatings. All zinc coatings are not the same; in fact, their physical, chemical and corrosion resistance characteristics can be extremely different. This is a photomicrograph of various zinc coatings. The first depicts a metallized coating. Metallizing (or zinc spraying) is Coating consistency depends on operator skill, and coating variation is always a possibility. Coatings may be thinner at corners and edges. Metallizing does provide cathodic protection, although there are no zinc-iron alloy layers. The black areas on the photomicrograph are voids. Metallizing is 85% as dense as hot-dip galvanizing and is not bonded as strongly to the steel as hot-dip galvanizing. I’ve already covered hot-dip galvanizing after fabrication, which incidentally has a bond strength to the steel of about psi. Zinc painting consists of zinc dust in organic or inorganic binders. The white particles in this photomicrograph are zinc oxides. The black areas are the binders. Zinc-rich coatings are barrier coatings that also may provide limited cathodic protection, though the binder must be conductive or the zinc particles in contact with the steel to provide cathodic protection. Suitable zinc-rich paints provide a useful repair coating for damage galvanized coatings. Continuous galvanizing’s zinc coating thickness is minimal compared to that of hot-dip galvanizing after fabrication, with minimal zinc-iron alloy layers. However, barrier and cathodic protection are provided. Electroplating (or Electrogalvanizing) generally refers to zinc coatings applied to steel sheet and strip by electrodeposition in a steel mill facility. There are no zinc-iron alloy layers, however, barrier and cathodic protection is provided. These coatings are very thin and mainly used for interior applications.

Design & Fabrication There are some design considerations that should be addressed after the decision to hot-dip galvanize has been made. Since the process consists of a series of tanks in which the steel articles are immersed in, you can make minor changes in the way steel is designed and fabricated to promote a higher quality galvanized coating.

The most important rule of designing for galvanizing is that the designer, fabricator and galvanizer communicate every step along the way to optimize turnaround times & minimize costs, and produce top-quality galvanized steel. This triad of communication can prevent the disappointment of unmet expectations and the all-to- often litigation that results.

Materials Suitable for Hot-Dip Galvanizing
Most iron-containing (ferrous) metals can be hot-dip galvanized. The chemical composition of the material influences the galvanized coating’s characteristics. During galvanizing, the molten zinc reacts with iron in the material being galvanized to form a series of highly abrasion-resistant, corrosion-inhibiting zinc-iron alloy layers, which are normally covered by a layer of almost pure zinc. Cold-rolled, hot-rolled, cast-iron, weathering, and even 300 series stainless steels can and are galvanized.

Hot-Dip Galvanized Fasteners
Hot-dip galvanized fasteners are recommended for joining HDG structurals To enhance corrosion protection, hot-dip galvanized fasteners are recommended for structural assemblies. Importantly, using galvanized bolts for assembling hot-dip galvanized steel structures eliminates complications related to contacting dissimilar metals. Best practice suggests that bolted assemblies be sent to the galvanizer disassembled. Similarly, studs to be galvanized also should be supplied disassembled. There are guidelines to follow for undersizing male threads and overtapping nuts to allow for the dimensional increase in the threads from the zinc coating.

Steel Reactivity Silicon content in steels has a profound effect on the growth of the galvanized coating. This graph depicts the relative coating weight produced from varying levels of silicon in steel. Highest quality galvanized coatings are formed from steels containing less than 0.04% Si or have between 0.15 and 0.23% Si. However, steels that contain silicon outside these ranges will typically still produce an acceptable coating. It should be advised that when the silicon level falls outside these ranges a thicker, darker coating should be expected. The corrosion protection is identical, if not better, on steels with thick coatings because the service life is directly proportional to the coating thickness. Notice how the microstructure of the coating is dependent on the amount of silicon in steel. This is caused by faster coating growth and can produce coating finishes from a dull matte gray to a spangled silver. However, when the galvanized steel is put in service the coating progresses through its natural weathering process to produce a consistent finish.

Coating Appearance Newly Galvanized Newly Galvanized Newly Installed
Dull Coating No Spangle Newly Installed Newly Galvanized Commonly, steel chemistries with atypical levels of silicon, phosphorus, manganese & carbon tend to produce galvanized coatings made up primarily of zinc-iron intermetallic layers, with little or no free zinc layer. Visual - the coating may be matte gray due to the absence of the free zinc layer. The free zinc layer imparts the typical bright finish to a galvanized coating. Adherence – The coating tends to be thicker than a typical galvanized coating. While it is true that the thicker the coating, the longer the service life, excessively thick coatings that result from atypical steel chemistries can be prone to adhesion problems. Corrosion Resistance – Galvanizing is specified for corrosion prevention. While a matte appearance may occur, differences in appearance do not affect the corrosion protection provided. For all practical purposes the corrosion resistance of these coatings is equal to the more typical galvanized coating. When possible, galvanizers should be advised of the grade of steel selected in order to determine whether to utilize special galvanizing techniques that may mitigate the effect of atypical chemistries. Highly Spangle Shiny & Dull Coating

Combining Different Materials
Best practice suggests that using steels with similar chemistries results in the best-possible appearance match. If possible, materials with differing chemistries should be galvanized separately and assembled after galvanizing so that they can be matched for appearance. Again, it is important to understand that corrosion protection is not determined by shinier or more matte coating appearances.

Weathering of Galvanized Steel
Photo taken: 12/18/02 These photos illustrate how galvanized pieces with different appearances will weather and blend in with surrounding galvanized steel upon installation. The dull-gray section of guardrail on the left side of the top picture was taken from the interior of a stack of hot-dip galvanized guardrail that was exposed to moisture (humidity or rain) but not exposed to freely-flowing air. As a result, these sections of guardrail formed a zinc corrosion product film (wet storage stain) over a period of one week. The shiny section of guardrail on the right side of the above picture was galvanized and stored under cover while exposed to freely-flowing air. Both were galvanized on the same day. The photo below depicts the same guardrail sections 3½ months after they were first attached to the concrete barrier. The left section of the guardrail now matches the right piece of guardrail that was originally bright and shiny. When hot-dip galvanized steel with light to moderate wet storage stain is ultimately exposed to freely-flowing air, the zinc corrosion products react with carbon dioxide to form the matte gray zinc carbonate film that we recognize as the stable patina that gives hot-dip galvanized steel its incredible resistance to corrosion. The section on the right progressed in a normal fashion to the zinc carbonate stage, and the corrosion protection provided by each section is identical. Photo taken: 03/28/03

Dissimilar Thicknesses
Different thickness Zinc bath temperature at different times Similar thickness Maintain original shape It is also wise to design articles using similar steel thicknesses. Different thicknesses of steel in a single fabrication will reach the zinc bath temperature at different times and will have different cooling rates. Using similar thicknesses will help maintain the fabrication’s original shape and alignment.

Galvanizing Oversized Pieces
There is a wide range of kettle size capacity throughout North America, and facilities can accommodate fabrications in a significant range of sizes and shapes. Average kettle length is around 40 feet, although there are several kettles between 50 and 60 feet in length, and even one 82’. When an item is too large for total immersion in the kettle of molten zinc, but more than half of the item will fit into the kettle, the piece may be progressively dipped. Again, it is important to communicate with the galvanizer at every step in the design process to ensure best possible galvanizing. Progressive Dipping

Material Handling Because galvanizers use hoists and cranes to carry fabrications throughout the galvanizing process, lifting fixtures or holes should be incorporated into the design. All articles are immersed into the galvanizing kettles from overhead, so chains, wires, or other holding devices are used to support the material. Temporary lifting points are also an option. The fabrication’s weight is also important because of the handling process required to move items throughout the galvanizing facility. Talk to your galvanizer if it appears heavy weight will be a factor.

Venting & Drainage Vent Drain
Most galvanizers prefer to visually identify and verify external venting. Because items to be galvanized are immersed and withdrawn at an angle, vent holes should be located at the highest point and drain holes at the lowest. Providing adequate venting and drainage on steel parts promotes a higher quality finished product. It also prevents moisture from becoming trapped during fabrication of the steel. Trapped moisture, when heated up to galvanizing temperatures will vaporize to steam, increasing the pressure and may cause parts to explode upon galvanization, presenting a serious safety concern for galvanizing plant personnel. Vent holes are frequently left open, but can be closed after galvanizing. Aluminum plugs are available to plug such drain and vent holes as seen on this handrail tubing. Drain

Specifications & Inspection
Specifying hot-dip galvanizing is simply done by using ASTM specifications that ensure a top quality galvanized coating. Let’s take a look at the most important specifications relating to hot-dip galvanizing.

ASTM Standards for Galvanizing
Galvanized Products ASTM A 123 – general ASTM A 153 – small parts ASTM A 767 – rebar Supporting Specifications ASTM A 143 – embrittlement ASTM A 384 – distortion ASTM A 385 – high-quality coatings ASTM A 780 – repair ASTM D 6386 – surface prep for painting over When specifying hot-dip galvanizing as the means of steel corrosion protection, these specifications have been developed in order to produce a high quality coating. The most common specifications come from the American Society of Testing and Materials, commonly known as ASTM International. The three specifications that specifically pertain to processing hot-dip galvanized steel are ASTM A 123, A 153, and A Other specifications exist that include detailed design practices for hot- dip galvanizing and are referenced in the aforementioned specifications. ASTM A 123 is the specification governing the galvanizing of large structural steel products that are greater than 1/16” in thickness. Fasteners and small parts that are centrifuged are covered by ASTM A153. ASTM A 767 is the specification that specifically addresses the galvanizing of reinforcing steel. Certain finishing details, including a chromate quench, are included in this specification. 54

ASTM A 123 Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products Coating Thickness – material category and steel thickness Finish – continuous, smooth, uniform Adherence – should be tightly adherent through all expected uses of article ASTM A123 Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products: Covers the requirements for galvanizing by the hot-dip process on iron and steel products made from rolled pressed and forged shapes, castings, plates, bars, and strips. Covers both un-fabricated products and fabricated products, for example, assembled steel products, structural steel fabrications, large tubes already bent or welded before galvanizing, and wire work fabricated from uncoated steel wire. This specification also covers steel forgings and iron castings incorporated into pieces fabricated before galvanizing or which are too large to be centrifuged (or otherwise handled to remove excess galvanizing bath metal). Does not apply to wire, pipe, tube, or steel sheet which is galvanized on specialized or continuous lines, or steel less than 22 gauge thick. In the specification, Table 1, in conjunction with Table 2, indicates required minimum mil thicknesses. Figure 3 graphically represents the coating thickness inspection steps.

ASTM A 153 Standard Specification for Zinc Coating (Hot- Dip) on Iron and Steel Hardware Coating Thickness – material category, steel thickness, length Finish – continuous, smooth, uniform Adherence – should be tightly adherent through all expected uses of article ASTM A153 Standard Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware: Covers zinc coatings applied by the hot-dip process on iron and steel hardware. Is intended to be applicable to hardware items that are centrifuged or otherwise handled to remove excess zinc. Table 1 of the specification provides for a standard minimum coating thickness regardless of fastener dimensions.

ASTM A 767 Standard Specification for Zinc-Coated (Galvanized) Steel Bars for Concrete Reinforcement Coating Thickness – smooth or deformed (no wire), bar size Chromating –prevent reaction between fresh cement and recently galvanized material Bend Diameters – flaking and cracking due to fabrication are not rejectable. ASTM A767 Standard Specification for Zinc-Coated (Galvanized) Steel Bars for Concrete Reinforcement: Covers zinc coatings applied by the hot-dip process on steel reinforcing bars used in concrete. Table 1 of the specification provides for a standard minimum coating thickness based on the Bar Designation Size Number. Calls for the steel reinforcing bars to be treated with a solution of sodium dichromate or chromic acid to provide a passivation layer that prevents reaction with the zinc bars during the curing of the concrete. Although not yet approved within the specification, this step can be bypassed provided the concrete has at least 100 ppm of chromates in the admixture. Bars shall have NO bare spots and shall be free from tears or sharp spikes which make the bar hazardous to handle. Bars that stick together after galvanizing shall be rejected. Minimum bend diameters for finished bars are included in the specification to prevent the coating from flaking on bend radii.

ASTM A 780 Standard Practice for Repair of Damaged and Uncoated Areas of Hot-Dip Galvanized Coatings Zinc-rich paint, zinc-based solder, or metallizing Zinc-rich paint - most common but must have certain amounts of zinc dust as required by spec Zinc-based solder – good for small areas, closely mirrors typical HDG coating appearance Metallizing – excellent corrosion protection ASTM A780 Standard Practice for Repair of Damaged and Uncoated Areas of Hot-Dip Galvanized Coatings: Recommends three acceptable touch-up and repair methods Zinc-rich paint - most common but must have certain amounts of zinc dust as required by spec. Cheapest form of repair. Zinc-based solder – good for small areas, closely mirrors typical HDG coating appearance Metallizing – excellent corrosion protection, most costly of the three repair methods, but is the most similar to hot-dip galvanizing and ensures the most uniform corrosion protection of the three.

Costs Less & Lasts Longer
Hot-Dip Galvanizing When selecting corrosion protection systems for steel, it is important to consider the long term maintenance costs associated with the corrosion protection system and not just initial cost. The following slides compare the initial and life-cycle costs for hot-dip galvanaizing and some commonly specified paint systems. Costs Less & Lasts Longer

Quantitative Analysis
Initial cost vs. Life- cycle cost Based on galvanizing industry survey -nationwide 2006 KTA-Tator paper paint industry survey – nationwide Standard mix of steel products (structural, tubing, plate) 10,000 ft2 project A quantitative analysis comparing hot dip galvanizing to four paint systems used data collected from recent surveys. The galvanizing cost data was obtained through a recent survey of North American hot-dip galvnaiziers and the paint cost data is taken from a paper produced by KTA-Tator that lists costs of paint systems as well as their maintenance schedules in numerous ASTM classified environments. It is important to note that were the mix of steel products inclusive of mostly small structural steel and/or fabrications and a typical job size of 10,000 sq. ft. was used to perform the analysis. We will also assume that the steel will be used in a moderately industrial environment and we are going to look at a 50-yr. Life cycle.

www.galvanizingcost.com Survey data organized in a database
Based on specific project data input by the user, (job size & location, coating type, expected service life, etc.) The web site automatically calculates initial and life-cycle cost for the specified paint systems and hot-dip galvanizing

Initial Cost Material Shop cleaning labor Shop application Field labor
These four components of the overall initial costs were collected in the survey and included in the calculation. For galvanizing, there is just one component, the cost of galvanizing in the plant. The galvanizing process is inclusive of any cleaning, material and labor. Pneumatic Bulk Trailers

Initial Cost ($/ft2) Coating System $/ft2 Inorganic Zinc $1.31
Inorganic Zinc/Epoxy $2.09 Hot-Dip Galvanizing $1.92 Acrylic WB Primer/Acrylic WB Intermediate/Acrylic WB Topcoat $2.51 Inorganic Zinc Primer/ H-B Epoxy/Acrylic Urethane $3.07 It is not recommended that the initial cost for a corrosion protection system be the only analysis performed. However, if it is, galvanizing is still a solid choice, as it is less expensive initially than all but the two coat inorganic zinc/epoxy system and the one-coat, minimal-protection, inorganic zinc paint system. As is common, projects with many smaller components and structural steel will yield an initial galvanizing system cost lower than most paint systems. The galvanizing process efficiently accommodates bundles and groups of steel.

where NPV=NFV/(1+R)n and NFV = current cost(1+I)n
Life-cycle Cost Maintenance on a ‘practical’ (vs. ideal) cycle - unique to each paint system, as recommended by paint manufacturers NACE Model for NFV and NPV calculations 4% inflation 7% interest Maintenance repaint at 5% rust in a moderately industrial environment 30-Year Project Performance Although the initial cost of your corrosion protection system is important, the life-cycle cost per year should be the determining factor in the selection process. After all, if the cost per year to maintain a painted structure far exceeds another corrosion protection system such as galvanizing, the owner should logically make the decision to galvanize. Comparing the life-cycle costs of a galvanizing system to four paint systems, a practical maintenance cycle was used over the prescribed lifetime of the project. A 35 year lifetime for this analysis was selected as a realistic timeframe for a bridge before modification, even though in this moderately industrial environment, hot dip galvanizing would not need any maintenance until year 38. This is opposed to an ideal maintenance cycle, which would be even more costly for all of the paint systems. Since galvanizing requires no maintenance during this period of performance in a moderately industrial environment, it is not affected by this choice of a 35 year lifetime. The standard calculation for the time value of money was used. Avg. Cost/Year = NPV /n, where NPV=NFV/(1+R)n and NFV = current cost(1+I)n For: n, lifetime of the project NPV, net present value NFV, net future value R, interest rate I, inflation rate

Life-Cycle Cost ($/ft2) 50-Year Project Performance
Coating System $/ft2 Hot-Dip Galvanizing $1.92 Inorganic Zinc $3.21 Inorganic Zinc/Epoxy $4.83 Inorganic Zinc Primer/ H-B Epoxy/Acrylic Urethane $6.43 Acrylic WB Primer/Acrylic WB Intermediate/Acrylic WB Topcoat $7.98 When life cycle costs are considered, the clear choice for your corrosion protection system is hot dip galvanizing. In fact, this analysis does not even incorporate the hidden costs associated with all of the touchup and maintenance painting and full repainting that is required for all of the paint systems. If the practical maintenance cycle for paint is not strictly adhered to, life cycle costs could be significantly higher than indicated above. Depending on the location of the project, a highway bridge or a chemical plant with huge operating costs, the hidden costs can be enormous. Qualitatively and quantitatively, hot dip galvanizing is the logical choice for your corrosion protection system.

What Does All of This Mean?
Coating System Cost Hot-Dip Galvanizing $19,200 Inorganic Zinc $32,099 Inorganic Zinc/Epoxy $48,261 Inorganic Zinc Primer/ H-B Epoxy/Acrylic Urethane $64,302 Acrylic WB Primer/Acrylic WB Intermediate/Acrylic WB Topcoat $79,802 So, bringing our analysis to life, using the example of a 10,000 sq. ft. steel bridge, having 250 sq. ft./ton of surface area (average per NACE), the cost of the corrosion protection system over the 50- year life of the bridge would be as shown. Even if you think designing bridge members to fit into the galvanizing kettle may mean more erection time in the field and slightly more steel and connections, (by the way, 60’ kettles are now common and there is even an 82’ long kettle) those costs are generally small when compared to the savings indicated. When the hidden costs associated with the maintenance of paint systems is added to the analysis, galvanizing is still clearly the preferred choice. So, the next time you are asked to perform the miracle of specifying the best practical form of corrosion protection that can be applied for minimum cost while providing for the longest service life possible, conduct an economic analysis of the possible corrosion protection system and just say to yourself, “I’m too poor to buy cheap. Galvanizing makes sense.”

Duplex Systems: Painting & Powder Coating Hot-Dip Galvanized Steel
There are many situations where painting or powder coating over hot-dip galvanized steel is desirable. It is rapidly becoming more common as specifiers recognize the high life- cycle costs associated with providing no corrosion protection or simple painting of black steel.

Why Paint a Perfectly Good Galvanized Part?
Aesthetics Architects decision Identification Hostile Environment to Zinc Repair of Existing Galvanized Articles Extended Life of the Product Some of the reasons to paint/powder coat over HDG steel include: Aesthetics – typical applications may be light rail stations where the light poles, garbage cans, benches, and shelters are the same color/color scheme. Architects preference – first recognizing the need for corrosion protection, an architect may want to put a personal touch on a project or have his particular contribution stand out. Identification – paint schemes may be used to identify steam pipes v. gas v. water in a utility chase of a building. Safety orange is required for towers/poles greater than 200’ in height. Hostile Environments – chemical plants are harsh atmospheres for galvanizing alone and painting over is the best way to ensure little or no downtime for repairs of the facilities. Repair of Existing Galvanized Articles – when HDG steel exhibits substrate steel rust after many years, paint may be used to repair the area. Extending the Life of HDG – in the case of a bridge railing in place for 40 – 50 years, the zinc coating may be on average about 1 – 2 mils thick. To preserve the zinc coating and of course the structural integrity of the railing, paint may be applied to isolate the zinc from the atmosphere, effectively prolonging the service life of the railing. Light Rail Station

Galvanized Surface Coating Condition
Newly Galvanized Steel Partially Weathered Galvanized Steel Fully Weathered Galvanized Steel So, we have three states when hot-dip galvanized steel can be painted or powder coated as dictated by the formation of the zinc patina. The newly galvanized is less than 48 hours and is a good time to paint if the zinc surface is profiled. The partially weathered must be cleaned and then profiled. (approximately 48 hrs to 6 months) The fully weathered, zinc carbonate condition can be painted successfully after a simple cleaning. (6 months to 2 years) Let’s look at each condition in more detail. Painted Bridge Rail

Passivation Cycle Time 1 2 3 0 – 48 hrs. 48 hrs. – 6 mo.
6 mo. – 2 yrs. 1 2 Let’s look at the passivation cycle for HDG steel as this is key to understanding the surface preparation required to topcoat hot-dip galvanized articles: In the first 48 hours after galvanizing, zinc oxide, a loose powder forms over all or part of the zinc surface. The powder would obviously not be good for paint adhesion. Within the first 6 months, most of the zinc oxide combines with water molecules to form a gel-like, white substance called zinc hydroxide. The visible white powder may be referred to as white rust but this is really a misnomer. The zinc oxide and zinc hydroxide, within 6 – 24 months, combine with carbon dioxide in the air to form zinc carbonate. The zinc carbonate is tightly bound to the underlying zinc metal, non-soluble and fairly rough in surface. Since the galvanized steel surface exhibits different forms of oxidation during the first two years of service, the surface preparation methods must be geared to removing the specific oxides. 3

Sweep Blasting Here we show some box beams being sweep blasted prior to painting.

Duplex System Layers Fence Pole
The picture of a fence pole is simply to demonstrate the typical painting over galvanized steel process. The top shows the hot-dip galvanized zinc coating. The middle shows a primer that was used over the zinc coating. The bottom shows the top-coat. Fence Pole

Duplex System Synergistic Effect
Paint Provides Barrier for Galvanized Surface Galvanized Coating Provides Slow Corrosion Under Paint Paint Peeling due to Corrosion is Minimized Paint & Galvanizing together have 1.5x to 2.5x Life of Individual Lifetimes Paint is a barrier coating, slightly porous and susceptible to underfilm corrosion when used over black steel. When paint is applied over HDG, the paint is still slightly porous but the zinc corrosion products under the paint films are extremely slow to form and very small compared to iron oxide. So, the paint and galvanizing work in synergy. The paint prevents atmospheric attack on the zinc and the zinc prevents underfilm corrosion from cracking the paint. In several studies conducted in Europe, the synergistic effect means that the zinc-paint combination will last 1.5 to 2.5 times longer than the sum of the paint and zinc systems alone. So, for a 70 year galvanizing life and a 10 year paint life, the system will last from 120 – 220 years. Practically speaking, no paint lasts that long without being repainted. But what the synergistic effect means is that paint lasts longer, generally 1.5 to 2.0 times longer than if applied over black steel and the repaint cycle is thus longer. This represents a significant cost savings over the life of the project. Skaneateles Community Center

Galvanized Steel Project Applications
Now I’d like to show you some of the more prominent and newest uses of hot-dip galvanized steel.

Brooklyn Bridge Date Galvanized 1999 Sector Bridge & Highway
Environment Industrial Location New York, NY A galvanizer was contracted to galvanize over 2,700 tons (2,449 tonnes) of steel bridge deck grids. The steel grids were manufactured into concrete panels and shipped to be fitted into place on the 115-year-old bridge. Most of the decking was galvanized at night so that it would be ready the following night, off-peak time, for installation. The decision to use hot-dip galvanized steel in these decks was extremely smart. Hot-dip galvanized steel in concrete reduces the need for both short- and long-term maintenance. Other corrosion prevention systems rust inside the concrete creating expensive and time-consuming repairs.

CALTRANS District 7 HQ Date Galvanized 2004
Sector Building & Architecture Environment Urban Location Los Angeles, CA Caltrans is responsible for the planning, designing, constructing, operating and maintaining of California’s state highway system. Over time, their role has evolved to include rail and mass transit systems and hot-dip galvanizing has been their choice of corrosion protection almost exclusively. Caltrans demonstrated the partnership with galvanizing in a convincing fashion by integrating a hot-dip galvanized fascia into the design of their new headquarters, located in the historic civic center area of Los Angeles. Included in this visual image of what Caltrans does on a daily basis, i.e. design with hot-dip galvanizing, is the structural steel and handrail for the unique face of the building. With a worldwide image as a leader in transit engineering, Caltrans wanted to be sure that they have a maintenance-free, attractive face for all to see.

The Cloud at Fashion Show Mall
Date Galvanized 2003 Sector Building & Architecture Environment Urban Location Las Vegas, NV Located at the entrance to the Fashion Show Mall--one of the nation's largest shopping centers--the Cloud is its signature architectural piece. Hovering 128 feet above the 72,000 square-foot plaza, the Cloud provides shade during the day and doubles as an image projection surface at night for advertising and special events. The owner's objective for this project was to have a durable structure requiring the least possible maintenance. All of the Cloud's exposed steel was hot-dip galvanized, including 36-inch beams and the 30 cables connecting the structure to its hot-dip galvanized steel frame. A total of 412 tons of hot-dip galvanized steel was used to construct the Cloud, which is located in the heart of the Las Vegas.

Harrisburg Airport Transportation Facility
Date Galvanized 2004 Sector Building & Architecture Environment Urban Location Harrisburg, PA Hot-dip galvanizing was selected to protect the structural columns, girders, splice plates, tubing and stair framing of this parking garage and rental car facility from corrosion because it delivers a maintenance-free lifetime of 50 years or more. Beside this functional quality, the appearance of the zinc coating unified the facility with the surroundings of the airport itself. Use of galvanized steel also allowed for an open, flexible floor plan required for the first-level rental car facility through the use of exposed moment frames, while still protecting the structure from the corrosive road salts deposited within. According to the Harrisburg airport director, who had a very positive experience using hot-dip galvanized steel on the Manchester New Hampshire airport, the designers liked the strong contextual relationship between the a galvanized multimodal facility and the airport’s new terminal. The hybrid structural system, featuring hot-dip galvanized steel columns and beams in combination with precast double tees, gives the facility a visual openness and a compositional synergy with the mostly transparent envelope and metal cladding of the new terminal. Galvanizing – functional, versatile, and aesthetically appealing!

Cell Towers – Tree Application
Date Galvanized 2004 Sector Electrical, Utility & Communication Environment Rural Location California Although more cities and municipalities are requiring unobtrusive cell tower designs and appearances, hot-dip galvanizing continues to be the choice for corrosion protection. This is especially true for galvanized cell towers covered with a rubber bark and located in coastal and highly corrosive environments. Just as for a duplex system, the zinc provides an “under-bark” protection on the entire pole surface, around the many limb brackets welded in place, and complete coverage inside the cell tower pole itself. Special handling of each 12,000 pound pole was required to deliver a quality framework for these “not-so-real” palm and deciduous trees.

Leprino Foods Date Galvanized Unknown Sector Food & Agriculture
Environment Rural Location Waverly, NY As the world’s largest producer of mozzarella cheese, LePrino Foods chose hot-dip galvanized steel for the design of its new Waverly plant based upon its architecturally pleasing appearance and functionality. The challenges facing this project were multiple. Per the Food & Drug Administration (FDA), the interior steel of the plant had to be food-safe, completely washed down daily, and the bacteria used to make the cheese strictly contained in specific locations. Clearly, hot-dip galvanized steel was the most effective solution. It contains no volatile organic compounds, ensuring its suitability in a food- processing environment. The corrosive-resistant nature of the galvanized finish would easily withstand daily washing. And the zinc used in the hot-dip galvanizing process is naturally combative against bacteria, solving the potential problem of bacteria migration. An added bonus was the cost benefit of hot-dip galvanizing compared to paint. Another specific design feature implemented were drain and vent designs. As the FDA would not allow any (bacteria-friendly) cavities in the building design, the tubular holes necessary for venting and draining the building’s interior support columns during hot-dip galvanizing were sealed and repaired, to specification, after processing. This project’s designers met other obstacles with equal innovation. The complex task of conducting a total plant washdown every day was made easier by turning the building, in effect, “inside-out.” The galvanized frame was built on the outside of the building, and its skin was hung inside. The result? A highly-visible hot- dip galvanized steel food processing plant where extensive design communications ensured its success.

Piers 1 & 21 Replacement Date Galvanized 2002 Sector Water & Marine
Environment Marine Location Norfolk, VA This 90 by 1,500-foot structure heralds a new generation of piers at the Norfolk Naval Base, serving as a model for the rehabilitation or replacement of all the base's piers within the next 25 years. Its innovative design incorporates precast concrete pile caps, slabs, and edge beams protected by aesthetically pleasing hot-dip galvanized fenders and corner bolsters. Galvanizing was chosen to protect the 500 tons (per pier) of fenders and bolsters due to its proven ability to protect steel from corrosion in a seawater environment. The pier’s frames, access ladders, ramps, and walkway grating and handrail were also hot-dip galvanized. The design of the bolsters required substantial coordination between the designer, fabricator, and galvanizer in order to ensure adequate venting and drain holes for cavity spaces. This cooperation paid off even before completion of the pier, as a runaway barge struck one of the hot-dip galvanized bolsters. The project engineer later indicated that the barge would have destroyed the end of the pier if the galvanized bolster had not been in place. Hot-dip galvanizing delivered an aesthetic, functional, and durable element of the pier. The success of this project is clear, as the U.S. Navy now plans to rebuild all of its Norfolk piers over the next decade, with hot-dip galvanizing incorporated into its plans.

AGA Resources 1-800-HOT-SPEC (800.468.7732) aga@galvanizeit.org
Technical Library Galvanizing Insights e-Newsletter After this seminar, you will better understand the corrosion process designing and specifying for corrosion protection hot-dip galvanizing’s role in protecting steel from corrosion. You will gain access to the following resources and services that will make the job of designing and specifying a corrosion protection system much easier. Specification Hot Line Anyone with any type of question pertaining to hot-dip galvanizing after fabrication can call the AGA toll-free at HOT-SPEC to gain technical support and information Galvanizing on the Web The AGA homepage can be found at and allows for the ordering and downloading of our newest publications, as well as a listing of member galvanizers’ kettle sizes, locations, and phone numbers. There are numerous links to members and affiliated associations. Literature and Library If we are unable to immediately answer your questions, we have an extensive library to research various technical topics as well as different hot-dip galvanizing applications. Galvanizing Insights This free quarterly newsletter keeps specifiers up to date with galvanizing by providing helpful design tips, new project highlights, technical advice, and much more.

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