INSPECTION - American Galvanizers Association
INSPECTIONof hot-dip galvanizedsteel products
02A M E RI C A N GALV ANIZ ER S A SSOCIA TION
TABLE OFCONTENTSPURPOSE OF INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4TYPES OF INSPECTIONCOATING MEASUREMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5COATING THICKNESSCOATING WEIGHTFINISH & APPEARANCE: VISUAL INSPECTION . . . . . . . . . . . . . . . . . . . . 8DIFFERENT APPEARANCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8STEEL CHEMISTRYCOOLING RATESTEEL PROCESSINGSURFACE CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10BARE SPOTSBLASTING DAMAGECHAIN & WIRE MARKSCLOGGED HOLES/THREADSDELAMINATION AND PEELINGDISTORTIONDRAINAGE SPIKESDROSS INCLUSIONSEXCESS ALUMINUM IN GALVANIZING BATHFLAKINGFLUX INCLUSIONSOXIDE LINESPRODUCTS IN CONTACT/TOUCH MARKSROUGH SURFACE CONDITIONRUNSRUST BLEEDINGSAND EMBEDDED IN CASTINGSSTRIATIONS/FISH-BONINGSURFACE CONTAMINANTWEEPING WELDWELDING BLOWOUTSWELDING SPATTERWET STORAGE STAINZINC SKIMMINGSZINC SPLATTERADDITIONAL INSPECTION TESTING . . . . . . . . . . . . . . . . . . . . . . . . . 18ADHERENCE TESTEMBRITTLEMENT TESTBENDING TEST FOR REINFORCING STEELPASSIVATION TESTINGSAMPLING METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18FIELD INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19VISUAL OBSERVATIONSCREVICESDISSIMILAR METALS IN CONTACTAREAS WHERE WATER POOLSPREVIOUSLY TOUCHED-UP AREASCOMMON APPEARANCE ISSUESTOUCH-UP AND REPAIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21TOUCH-UP AND REPAIR METHODSRELATED ASTM SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 2016 American Galvanizers Association. The material in this publication has been developed to provide accurate and authoritative information about thetime to first maintenance of hot-dip galvanized steel after fabrication. This material provides general information only and is not intended as a substitute forcompetent professional examination and verification as to suitability and applicability. The publication of the material herein is not intended as a representationor warranty on the part of the American Galvanizers Association, Inc. Anyone making use of this information assumes all liability arising from such use.03
PURPOSE OFINSPECTIONHot-dip galvanizing is one of the most economical, maintenance-free corrosion protection systems available. Like anyother manufacturing process, hot-dip galvanized steel requires an inspection of the finished product to ensure compliancewith applicable specifications. The inspection process requires a clear understanding of specification requirements andcompliance measurement techniques to make an accurate assessment.A key feature of hot-dip galvanized (HDG) productsis durability, which yields decades of maintenance-freeperformance. For any environment, the time to firstmaintenance of HDG steel is directly proportional to thethickness of the zinc coating. To plan for this extendedservice life, the estimated time to first maintenance inatmospheric exposures can be seen in Figure 1.The difference between these specifications is the type of steelproduct covered by each. ASTM A123/A123M covers structuralsteel, pipe and tubing, flat/round bar, wire, reinforcing steeland assemblies of these steel products. ASTM A153/A153Mincludes small castings, nails, nuts, bolts, washers, and smallparts centrifuged after galvanizing to remove excess zinc. AndASTM A767/A767M covers only reinforcing steel bars.Coating thickness is an important requirement in thespecification and effectiveness of hot-dip galvanizing as acorrosion protection system. However, measuring coatingthickness is only one of the many specification requirementsin the inspection process. Other key requirements includeadherence, appearance, and finish.In Canada, the specification CSA G164 covers the requirementsfor all hot-dip galvanized articles, and ISO 1461 is the standardmost commonly used in Europe. In all cases, the inspection ofhot-dip galvanized steel is conducted at the galvanizing plantprior to shipment of the product.The requirements for hot-dip galvanized coatings are found in three ASTM specifications; A123/A123M Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products A153/A153M Specification for Zinc Coating (Hot-Dip) on Iron and Hardware A767/A767M Specification for Zinc-Coated (Galvanized) Steel Bars for Concrete ReinforcementTime to First Maintenance* (years)1009080Key70Rural60SuburbanTemperate Marine50Tropical e Thickness of Zinc (mils)4.0*Time to first maintenance is defined as the time to 5% rusting of the substrate steel surface.4.55.01 mil 25.4µm 0.56oz/ft2FIGURE 1: TIME TO FIRST MAINTENANCE OF HOT-DIP GALVANIZED COATINGSADDITIONAL RESOURCESThe American Galvanizers Association (AGA) offers a free online inspection course to trainindividuals on the proper inspection techniques and requirements for hot-dip galvanizedsteel products. Alternatively, the AGA offers a free app available in both the Apple andGoogle Play stores.galvanizeit.org/inspection04A M E RI C A N GALV ANIZ ER S A SSOCIA TION
Types of InspectionThere are a number of different inspections that can be conducted onhot-dip galvanized steel. The majority of these inspections happenimmediately after the coating is applied and has cooled to ambienttemperature, before it leaves the galvanizing facility, to verify therequirements of the specifications are met. However, once thehot-dip galvanized steel is being erected and after it is in place,ongoing field inspections are common. The next sections willreview the various types of initial inspection as well as best practicesfor field inspection.COATINGMEASUREMENTCOATING THICKNESS GRADEAs mentioned, the most scrutinized element in the inspection of hot-dipgalvanized steel is the coating thickness. The specifications provide minimumzinc coating requirements for a given material classes and measured steelthickness. The amount of coating can be specified by thickness or weightper surface area. The specifications include tables providing specificrequirements for thickness or weight per surface area based upon the steelpart type and the measured steel thickness.The minimum coating requirements specified by ASTM for different classes ofwork are summarized in Table 1 and Table 1A for ASTM A123/A123M, Table2 for ASTM A153/A153M (next page), and Table 3 for ASTM A767/A767M(next 001003.92.3100705TABLE 1A: C OATING THICKNESS GRADES FROMASTM A123/A123MMINIMUM AVERAGE COATING THICKNESS GRADE BY MATERIAL CATEGORY ASTM A123/A123MMaterial CategoryAll Specimens Tested [Steel Thickness Range (Measured), in (mm)] 1/16( 1.6) 1/16 to 1/8( 1.6 to 3.2) 1/8 to 3/16( 3.2 to 4.8) 3/16 to 1/4( 4.8 to 6.4) 1/4 to 5/8( 6.4 to 16.0) 5/8( 16.0)Structural Steel45657575100100Strip and Bar4565757575100Plate4565757575100Pipe and rcing BarTABLE 1: MINIMUM COATING THICKNESS FROM ASTM A123/A123M (SEE TABLE 1A FOR INFORMATION ON COATING THICKNESS GRADE)05
MINIMUM AVERAGE COATING THICKNESS BY MATERIAL CLASS- ASTM A153/A153MMinimum Weight of ZincCoating, oz/ft2 (g/m2)of SurfaceMinimum Thickness,Mils (Microns)Average ofSpecimensTestedAny IndividualSpecimenAverage ofSpecimensTestedAny IndividualSpecimen2.00 (610)1.8 (550)3.4 (86)3.1 (79)B-1 - 5/8in (15.88mm) and over in Thickness and over15in (381mm)in length2.00 (610)1.80 (550)3.4 (86)3.1 (79)B-2 - Under 5/8in (15.88mm) in Thickness and over 15in (381mm) inlength1.50 (458)1.25 (381)2.6 (66)2.1 (53)B-3 - Any Thickness and 15in (4.76mm) and under in length1.30 (397)1.10 (336)2.2 (56)1.9 (48)Class C - Fasteners over 3/8in (9.52mm) in diameter and similar articles,washers 3/16in (4.76mm) and greater in thickness1.25 (381)1.00 (305)2.1 (53)1.7 (43)Class D - Fasteners 3/8in (9.52mm) and under in diameter, rivets, nailsand similar articles, washers under 3/16in (4.76mm) in thickness1.00 (305)0.85 (259)1.7 (43)1.4 (36)Class of MaterialClass A - Castings, Malleable Iron, SteelClass B - Rolled, Pressed and Forged Articles(Except those which would be included underClass C or D)Note: Length of the piece, stated in Classes B-1, B-2 and B-3, refers to the finished dimensions of the piece after fabricationTABLE 2: MINIMUM COATING THICKNESS FROM ASTM A153/A153MMINIMUM COATING THICKNESS BY CLASSASTM A767/A767M (REINFORCING BARS)Coating ClassMass of ZincCoating, (g/m2)oz/ft2 of SurfaceClass IBar Designation size No. 10 (3)915 (3.00)Bar Designation size No. 13 (4) & Larger1070 (3.50)Bar Designation size No. 10 (3) & larger610 (2.00)Class IITABLE 3: M INIMUM COATING THICKNESS FROM ASTM A767/A767MCoating ThicknessCoating thickness refers to the thickness of the final hot-dipgalvanized coating. Two different methods can be used tomeasure the coating thickness of hot-dip galvanized steel; amagnetic thickness gauge and optical microscopy. Utilizing amagnetic thickness gauge is a non-destructive, simple way tomeasure coating thickness. There are three different types ofmagnetic thickness gauges.The Pencil-Style Gauge (Figure 2)is pocket-size and employs a springloaded magnet encased in a pencillike container. Its accuracy dependson the skill of the inspector, thusthe measurement should be mademultiple times.FIGURE 2: PENCIL-STYLE GAUGE06A M E RI C A N GALV ANIZ ER S A SSOCIA TION
The Banana Gauge (Figure 3) measures coating thicknessin any position, without recalibration or interference fromgravity.FIGURE 3: BANANA GAUGEThe Electronic or Digital Thickness Gauge (Figure 4) is themost accurate and easiest to use. Electronic gauges can alsostore data and perform averaging calculations.Coating WeightCoating weight refers to the mass of hot-dip galvanized coatingapplied to a product for a given surface area. Two differentmethods can be used to measure the coating weight of hot-dipgalvanized steel. The first method uses a process called weighgalvanize-weigh, and is only appropriate for single specimensamples. Weigh-galvanize-weigh measures the weight of asteel part after it has been cleaned, and again after it has beengalvanized. This technique only measures the zinc metal addedto the steel and will underestimate the total coating weight byup to 10 percent.The second method is a destructive technique called weighstrip-weigh, and again, is only appropriate for single specimensamples. Weigh-strip-weigh measures the weight immediatelyafter a galvanized part is cooled, and again after the coatinghas been stripped off the part using an acid solution. Theweigh-strip-weigh renders the part unusable as the coating isremoved. The weights must then be divided by the surface areaof the steel part to determine a value that can be compared tothe specification requirements.FIGURE 4: DIGITAL THICKNESS GAUGEThe specification ASTM E376 Practice for Measuring CoatingThickness by Magnetic-Field or Eddy Current (Electromagnetic)Examination Methods contains procedures for measuringcoating thickness as accurately as possible.The other method to measure coating thickness, opticalmicroscopy (Figure 5), is a destructive technique that exposesthe edge of a coating under an optical microscope. The samplemust be sectioned, then mounted and polished to show theexposed edge of the hot-dip galvanized coating. The calibratedeyepiece of an optical microscope can then determine thethickness of the coating. Since this technique destroys thepart being measured, it is only used as a referee method forresolving measurement disputes.FIGURE 5: OPTICAL MICROSCOPY07
VISUAL INSPECTION FORFINISH & APPEARANCESeveral factors can affect the finish and appearance of hot-dip galvanized coatings. Some of these factors can becontrolled by the galvanizers while others cannot. The inspection of finish and appearance is done with an unmagnifiedvisual inspection, which is performed by fully observing all parts and pieces of a hot-dip galvanized product or assemblyto ensure all specification requirements have been met. Visual inspection is done in order to observe surface conditions(both inside and out) and to check all contact points, welds, junctions, and bend areas. The visual inspection should becompleted at the galvanizing facility before the part is shipped.CASE STUDYDifferent AppearancesHot-dip galvanized (HDG) steel is specified because The appearance of the hot-dip galvanized coating can vary fromit provides maintenance-free corrosion protection for piece to piece, and even section to section of the same piece.Common appearances for hot-dip galvanized steel immediatelydecades. However, some architects and engineers under- after galvanizing include bright and shiny, spangled, matte gray,utilize HDG because of concerns about its appearance. and/or a combination of these. There are a number of reasons forDue to steel chemistry, fabrication processes, and other the non-uniform appearance; however, it is important to noteappearance has no bearing on the corrosion protection of thefactors, the initial appearance of hot-dip galvanized steel piece. Furthermore, in time, after exposure to the environment, allcan vary from bright and shiny to matte gray, or a mixture of galvanized coatings will take on a uniform, matte gray appearance,as seen in the Case Study.both. Many specifiers erroneously equate the appearanceof the coating with coating quality. It is important to notethe durability of galvanized coatings is not determined by the appearance, but rather by the zinc coating thickness. Regardless ofthe external appearance of the coating initially, all galvanized pieces will protect steel from corrosion for decades. Additionally,as the galvanized steel weathers, initial variances in appearance will fade, producing a uniform, matte gray coating.A great example of this transformation is the canopied walkway at Mark Twain Elementary in Riverside, CA. The galvanizedcanopies were installed in October of 2006, and the initial coating appearance varied (left photo) from bright and shiny to mattegray on the same beam. In June of 2009, the structure was revisited to examine the appearance and performance. The beams arenow all uniformly matte gray with little to no visible difference in appearance (right photo). Additionally, as hot-dip galvanizingprovides 75 years or more of maintenance-free corrosion protection, the beams show no signs of rust staining or corrosion damage.Hot-dip galvanized steel not only provides superior corrosion protection, but once in service will also sustain an aestheticallypleasing, uniform matte gray appearance for decades without maintenance. Preventing unsightly corrosion and rust staining, aswell as costly maintenance will provide Mark Twain Elementary with a structure both easy on the eyes and the budget well intothe future.OCTOBER 200608A M E RI C A N GALV ANIZ ER S A SSOCIA TIONJUNE 2009
Steel ChemistryCOATING THICKNESS CURVE250Zinc Thickness (Relative)The most common reason for galvanized steel to have differentappearances is the chemistry of the steel pieces. There are twoelements of steel chemistry which most strongly influence thefinal appearance; silicon and phosphorous. Both elementsare catalysts to coating growth, and the thicker coating isresponsible for the differing appearance.Silicon is added during the steel-making process todeoxidize the molten steel. The recommended siliconcomposition for steel to be galvanized is either less than0.04% or between 0.15% and 0.22%. Steels outside theseranges are considered reactive steels and can be expectedto form zinc coatings thicker than average. The SandelinCurve (Figure 6) compares the zinc coating thickness to themass percentage of silicon in the steel.In addition to producing thicker coatings, highly reactivesteels tend to have a matte gray or mottled appearance insteadof a typical bright coating. This difference in appearance isa result of the rapid zinc-iron intermetallic growth. Thisgrowth of the intermetallic layer is out of the galvanizer’scontrol; however, if he is aware of the steel’s compositionbeforehand, he can utilize some process controls to minimizethe effect. Figure 7 shows the differences between the alloyformations on steel with recommended silicon ranges (left)and those of reactive steels (right). Though the appearanceand microstructure differ, the increased coating thickness canbe beneficial in some respects as the time to first maintenanceis linearly related to coating thickness.2001501005000.10.20.30.4% Silicon in the SteelFIGURE 6: SANDELIN CURVESimilar to silicon, the presence of phosphorus influences thereaction between molten zinc and steel. Figure 8 shows steelwith phosphorus levels over 0.04% which produces mattegray coating areas and a rough surface with ridges of thickercoating where there is increased intermetallic growth.FIGURE 7: RECOMMENDED SILICON VS. REACTIVE STEELFigure 9 shows connected galvanized pieces with differentappearances due to steel chemistry. This is often observedwhen connecting different types or thicknesses of steel, butcan also occur on similar pieces. Another common place thisis found is in welded areas, as the silicon content of the weldrod can influence appearance. Regardless of the appearance,all of these products have an equal amount of corrosionprotection and meet the specification requirements.FIGURE 8: R OUGH COATING DUE TO PHOSPHOROUS LEVELSOVER 0.04% (ACCEPTABLE UNLESS HANDRAIL)FIGURE 9: SHINY VS. DULL (ACCEPTABLE)09
Cooling RateA steel part with both dull and shiny coating can also bethe result of a different cooling rate. In Figure 10, the outeredges of the product were cooled rapidly, allowing a freezinc layer to form on top of the intermetallic layers. Thecenter of the product remained above 550 F longer and themetallurgical reaction between zinc and iron continued inthe solid state, consuming the free zinc layer, resulting in amatte gray look. As the product weathers, the differences inappearance will become less noticeable and the overall colorwill turn a uniform, matte gray.FIGURE 11: GRAY COATING DUE TO PROCESSING (ACCEPTABLE)Steel ProcessingThe fabrication and processing of the steel can also create abright or dull appearance in galvanized products. The toprail in Figure 11 has a winding pattern of dull gray areascorresponding to the process used during the making ofthe tube. The stresses in the steel from processing affect theintermetallic formation and can result in this striped look.The corrosion protection is not affected, thus these partsmeet the specification.FIGURE 10: GRAY COATING DUE TO UNEVEN COOLING RATE(ACCEPTABLE)Surface ConditionsWhen inspecting the finish of the hot-dip galvanized coating,a variety of surface conditions can be observed. Several factorscan affect the finish of the galvanized coating – some of thesefactors can be controlled by the galvanizer while others cannot.The specification requirement for finish is the coating must besmooth, uniform, and continuous. There are many subjectiveinterpretations for what that means; however, the key towhether surface conditions are acceptable or not relates to itseffect on the long-term corrosion performance. If the surfacecondition will not lessen the long-term corrosion resistance ofthe piece, it is acceptable. On the other hand, if the conditioncompromises the life of the coating, it is cause for rejection.Bare SpotsBare spo
60 2 .4 1 .4 60 425 65 2 .6 1 .5 65 460 75 3 .0 1 .7 75 530 80 3 .1 1 .9 80 565 85 3 .3 2 .0 85 600 100 3 .9 2 .3 100 705 TABLE 1A: COATING THICKNESS GRADES FROM ASTM A123/A123M MINIMUM AVERAGE COATING THICKNESS GRADE BY MATERIAL CATEGORY ASTM A123/A123M Material Category All Specimens Tested [Steel Thickness Range (Measured), in (mm)] 1/16 ( 1.6)
INSPECTION INFORMATION 1.1 SUBJECT PROPERTY Commercial building xxxxxx Glendale, California 1.2 INSPECTION DATE Thursday February 25, 2016 1.3 INSPECTION TIME 2:30 p.m. . This inspection and report has been performed in accordance with the California Real Estate Inspection Association (CREIA) Standards of Practice which is incorporated herein .
1. AASHTO M111, Zinc (Hot Dip Galvanized) Coatings on Iron and Steel Products 2. AASHTO M232, Zinc Coating (Hot Dip) on Iron and Steel Hardware c. American Galvanizers Association (AGA) 1. The Inspection of Products Hot Dip Galvanized After Fabrication 2. Powder Coating over Hot Dip Galvanized Steel, Powder Coating Journal, Feb 2004,
transporting students. The pre-trip inspection consists of two parts: a stationary inspection and an operating inspection. The stationary inspection consists of an interior and exterior inspection. The exterior inspection is also known as the “daily walk-around.” The operating inspection is performed while the bus is being driven.
Preliminary Inspection Responsibilities 1. Read and understand the job specification 2. Attend the pre-job conference 3. Become aware of safety hazards and responsibilities 4. Prepare inspection forms and inspection plan 5. Inspection of jobsite conditions 6. Inspection of materials 7. Inspection of equipment 8. Monitor ambient conditions
inspection? We will consider a full home inspection or 4-pt Inspection as an exception to the UPC home self-inspection. The inspection must be no older than 12 months in age and contain pictures and inspection notes outlining the condition of the home (the roof, air/hea
Jun 27, 2019 · 2021 SUTTON AVE CINCINNATI OH 45230 County HAMILTON Building Approval Date 03/09/1988 Use Group/Code E Occupancy Limit 49 Maximum Under 2 ½ Fire Inspection Approval Date Food Service Risk Level Inspection Information Inspection Type Quality Monitoring Inspection Scope Partial Inspection Notice Unannounced Inspection Date End Time 06/27/2019
Hot-Dip Galvanizing for Corrosion Protection: A Guide to Specifying and Inspecting Hot-Dip Galvanized ReinforcingSteel Table of Contents: 2004 American Galvanizers Association. The material in this publication has been developed to provide accurate and authoritative information about painting over hot-dip galvanized steel after fabrication.
An Introduction to Literary Criticism and Theory Before we begin our examination and study of literary theory, it is important that we define exactly what literary theory is and is not, identify some of the main characteristics of such, as well as identify some of the key differences between traditional “literary criticism” and “literary theory.” While literary criticism since the late .
