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Coating ReportGuard rails on the Kamanjab -Omagange Road in NamibiaEnsuring that hot dip galvanizing will standup to its reputation for long term corrosionprotection, Association staff will passionatelypursue any opportunity to eliminateunnecessary misconceptions and disputes.As part of the association’s effort toeducate and improve the frequentineffective communication betweenend clients and the galvanizer, often viaa number of contracting parties, thespecifiers finish expectations and themanufacturer and galvanizer’scommitment to the quality of the finalproduct, etc. we include for yourreading, this report by the Association.The Hot Dip Galvanizers Associationwas requested to inspect the hot dipgalvanized coating on certain guardrails in Phase 1 and 2, on the roadbetween Kamanjab to Omagange,Namibia.Sponsored by the manufacturer, I flewto Windhoek and then accompaniedby the supplier, drove about 500kmNorth of Windhoek, where we overnighted in Kamanjab and drove afurther 80 km in the morning to thesite. I report as follows:Unless specifically requested for otherreasons, hot dip galvanizing is normallyspecified primarily for corrosionprotection. For this reason, the twomost important inspection criteria ofhot dip galvanizing are coatingthickness and coating continuity.Photos 1 and 2 above show the installed and about to be installed guardrails on the road fromKamanjab to Omagange, Namibia.Coating thicknessA number of coating thicknessreadings were taken at numerouslocations indicating an upper coatingthickness of 88µm, a minimum of47µm and a mean of about 70µm.Although in excess of the minimumcoating thickness required by theSANS 121 (ISO 1461) specification,the coating thickness is acceptable.Photo 3. Photo 4.26 Hot Dip Galvanizing Today Volume 5 Issue 4 2008
Coating ReportThe specification requires that forsteel thickness equal to and greaterthan 1.5mm but less than 3mm thick,the local coating thickness is to be aminimum of 45µm with a mean of atleast 55µm. The guardrail material is2.6mm thick.As life of a zinc coating, no matterhow applied is more or lessproportional to its thickness in agiven environment, the thicker coatingwill provide a substantially longer lifethan a thinner coating.Photo 5. Photo 6.Coating continuityApart from some coating damage as aresult of insufficient appropriatepackaging particularly when itemssuch as these are transported overhuge distances, some uncoated areasas a result of lumps and bumps beingremoved by mechanical damage andsome zinc ash deposits, the coatingcontinued on page 28...Photo 7. Photo 8.ZincorA Division of Exxaro Base Metals (Pty) LtdSupplier of zinc metal....the answer to corrosion protection.Plover Street, Struisbult, Springs, 1559PO Box 218, Springs, 1560Tel: (011) 812-9500 Fax: (011) 363-3293Website: www.exxaro.comOHSAS 18001ISO9001ISO14001Volume 5 Issue 4 2008 Hot Dip Galvanizing Today 27
Page 1: 2008 Volume 5 Issue 4HOT DIP GALVAN
Page 4: CommentsExecutive Director’sComme
Page 7 and 8: Awards EventVolume 5 Issue 4 2008 H
Page 9 and 10: Tubes, pipes and scaffoldingneutral
Page 11 and 12: ABECO TANKS - THE NAME THAT HOLDS W
Page 13 and 14: Water storageBenefits of the BOTANK
Page 15 and 16: TechnicalTechnical differences betw
Page 17 and 18: Duplex CoatingsDuplex coated Lula p
Page 19 and 20: Duplex CoatingsUnderstanding qualit
Page 21 and 22: Duplex Coatingsdocumenting and reso
Page 23 and 24: Duplex CoatingsRelative humidity an
Page 25 and 26: EducationMeasuringcoatings on metal
Page 27: Member’s CornerGalvadip has their
Page 31 and 32: Coating ReportGeneral commentIn man
Page 33 and 34: Bread bakery exchanger coilinvestig
Page 35 and 36: W amoshaIt is noteworthy that sever
Page 37 and 38: Miss Conceptionsreserves were 200 0
Page 39 and 40: Walter’s CornerWalter’s CornerS
Page 41 and 42: Case StudyNo. 16/2008Case StudyRais

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