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Slurryblasting Standards
www.international-marine.com
October 2004
SL26/P
I4031
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New ZealandNorthern IrelandNorwayPakistanPanamaPapua New GuineaPeoples Republic of ChinaPeruPhilippinesPolandPortugalQatarRepublic of IrelandRomaniaRussiaSaudi ArabiaSingaporeSloveniaSouth AfricaSouth KoreaSpainSri LankaSwedenTaiwanThailandTurkeyU.S.A.UkraineUnited Arab EmiratesUnited KingdomUruguayVenezuelaVietnamWestern SamoaYemen
Unless otherwise agreed in writing, all products supplied and technical advice orrecommendations given are subject to the Conditions of Sale of our supplyingcompany.
,International and all products mentioned in this brochure are trademarks of orare licensed to Akzo Nobel. © Akzo Nobel, 2004
International Paint Ltd, Stoneygate Lane, Felling, Gateshead NE10 0JY.Tel: +44 (0)191 402 2775 Fax: +44 (0)191 401 2320
www.international-marine.com
Slurryblasting StandardsContents
1. Introduction2. Format3. Explanatory Text4. Procedure For Using The Standards
5. Notes6. References7. Visual Standards
IntroductionSlurryblasting is a technique for cleaning surfaces with a mixture of fresh water and abrasive where the elimination, or control of abrasive dust is required. Two slurryblasting systems are commonly encountered:
• Pressurised water abrasive blasting, which uses water to propel the abrasive.
• Air abrasive water blasting, which uses compressed air to propel the abrasive.
This visual standard has been prepared by using pressurised water abrasive blastingbut the photographs are representative of both preparation methods.
The surfaces produced by slurryblasting are initially identical to those produced by dryabrasive blasting because the abrasive cuts and deforms the metal surface producinga bright appearance. This bright appearance quickly changes due to ‘flash rusting’,which occurs when the surface drys off.
This visual standard has been prepared to help International Paint Technical Serviceand Technical Sales personnel advise on the recommended standard of slurryblastingand the acceptable level of flash rusting allowed prior to the application of ourproduct range. All surface preparation and coating application work is theresponsibilty of the applicator. All products and advice supplied are subject to ourstandard conditions of sale.
FormatThe standard consists of a series of colour photographs which depict the condition ofunpainted steel surfaces prior to and immediately after surface preparation byslurryblasting. It then shows these surfaces with varying degrees of flash rusting.
Explanatory Text
3.1 Initial Rust Grades
The standard illustrates two initial rust grades of steel from which the millscale hasrusted away. They are designated as grades C and D, and are comparable to the rustgrades C and D described in the ISO 8501-1:1988 surface preparation standard andthe SSPC VIS-1-89 surface preparation standard of the Steel Structures PaintingCouncil. The definitions are:
Rust Grade C: Steel surface completely covered with rust but with little, or slight pitting under normal vision.
Rust Grade D: Steel surface completely covered with rust, on which general pitting is visible under normal vision.
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3.2 Blast Standards
The standard illustrates grade C and D surfaces prepared by slurryblasting to twodifferent degrees of cleanliness. They are designated SB2 and SB21⁄2 and arecomparable to Sa2 and Sa21⁄2 described in the ISO 8501-1:1988 surface preparationstandard and to SSPC-SP6 and SSPC-SP10 of the Steel Structures Painting Councilsurface preparation standards.
The definitions are:
SB2 Thorough Slurryblast Cleaning
When viewed without magnification, the surface shall be free from visible oil, grease,dirt, most paint coatings and foreign matter. Any remaining contamination shall befirmly adherent.
SB21⁄2 Very Thorough Slurryblast Cleaning
When viewed without magnification, the surface shall be free from visible oil, grease,dirt, rust, paint coatings and foreign matter except for slight staining. Slight stainingshall be limited to light shadows, streaks or minor discolourations.
3.3 Degrees of Flash Rusting
The standard illustrates three grades of flash rusting. Light flash rusting, designated L,moderate flash rusting, designated M, and heavy flash rusting, designated H.
The definitions are:
L: Light Flash Rusting
When viewed without magnification, small quantities of light tan-brown rust willpartially discolour the original metallic surface. This discolouration may be evenlydistributed, or in patches, but it will not be heavy enough to easily mark objectsbrushed against it.
M: Moderate Flash Rusting
When viewed without magnification, a layer of light tan-brown rust will obscure theoriginal metallic surface. This layer may be evenly distributed or patchy in appearance,but it will be heavy enough to mark objects brushed against it.
H: Heavy Flash Rusting
When viewed without magnification, a heavy layer of dark tan-brown rust willcompletely obscure the original metallic surface. This layer of rust will be looselyadherent and will easily mark objects brushed against it.
Procedure for Using the Standard4.1 Select the photograph of rust grade that most closely resembles the rust grade ofsteel to be cleaned. Previously painted steel can be classed as either C or D grade,depending upon the degree of pitting. See note 5.1.
4.2 Select the photograph depicting the degree of cleaning that has been specified.For example, if the initial rust grade is D and thorough slurryblast cleaning is specified(SB2), use photograph D SB2.
4.3 Compare the prepared surface with the photograph selected immediately afterslurryblasting but before the surface has flash rusted to evaluate the degree ofcleaning. See note 5.2.
4.4 Prior to painting, compare the flash rusted surface with the flash rustingphotographs. For example, D SB2 L, D SB2 M, D SB2 H, to evaluate the degree offlash rusting that has occurred.
4.5 Check that the paint product specified is suitable for overcoating the degree offlash rusting that has occurred. See note 5.4.
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Notes
5.1 Painted Steel
The photographs in this standard were prepared from unpainted steel but they arealso suitable for depicting the appearance of painted steel after slurryblasting.
5.2 Inspecting Slurryblasted Surfaces Prior to Flash Rusting
When large areas are slurryblasted, flash rusting which obscures the original blaststandard may occur before an inspection can be carried out. Establishing the requiredstandard by blasting a small test area prior to the main blast may help, providing therest of the job is blasted to the same standard. Methods of ensuring the rest of thejob is blasted to the same standard will vary from project to project.
5.3 Chemical Corrosion Inhibition
Flash rusting can be prevented by the use of water soluble chemical corrosioninhibitors. These inhibitors may leave a crystalline layer on the steel surface as thewater evaporates which can then lead to a loss of adhesion and osmotic blistering ifcoatings are applied over this type of surface. International Paint do not recommendthe use of corrosion inhibitors to hold wet blasted surfaces. If inhibitors are used, theymust be thoroughly washed off with fresh water before International Paint productsare applied.
5.4 Removal of Flash Rusting
When flash rusting is too heavy for coating application, it may be removed or reducedby brushing with a hard bristle brush or by washing down with high pressure freshwater. High pressure washing will cause the area to re-rust but it is possible to reducethe degree of flash rusting from heavy to light using this method.
5.5 Removal of Wet Abrasive from Slurryblasted Surfaces
Wet abrasives will tend to stick to slurryblasted surfaces. This abrasive must beremoved prior to paint application. This can be done by fresh water washing or bybrushing the surface when it is dry.
5.6 Surface Profile
This standard makes no attempt to depict or define surface profile. However,slurryblasting will produce a surface profile similar to that produced by dry abrasiveblasting.
5.7 Soluble Salt Removal
This standard makes no attempt to define levels of soluble salts remaining onslurryblasted surfaces or to relate degrees of flash rusting to remaining soluble salts.However, all slurryblasting systems wash the surface as it is blasted and soluble saltlevels will generally be lower on slurryblasted surfaces than they are on dry abrasiveblasted surfaces.
References
6.1 Steel Structures Painting Council. SSPC-VIS 1-89‘Visual Standard for Abrasive Blast Cleaned Steel’.
6.2 International Standards Organisation ISO 8501-1:1988‘Preparation of steel substrates before application of paints and related products - visual assessment of surface cleanliness’.
Degree of Flash Rusting
D SB21⁄2 L: Light flash rusting
D SB21⁄2 M: Moderate flash rusting
D SB21⁄2 H: Heavy flash rusting
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Visual Standards
Rust Grade Standards
Rust grade C
Rust grade D
Preparation Standard D SB21⁄2
Rust grade D
D SB21⁄2 Rust grade D Slurryblasted to an Sa21⁄2 equivalent
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53121 IP SlurryBlasting leaflet 10/14/04 3:32 PM Page 5 Dave Tas
Preparation Standard C SB2
Rust grade C
C SB2 Rust grade C Slurryblasted to an Sa2 equivalent
Degree of Flash Rusting
D SB2 L. Light flash rusting
D SB2 M. Moderate flash rusting
D SB2 H. Heavy flash rusting
Degree of Flash Rusting
C SB2 L. Light flash rusting
C SB2 M. Moderate flash rusting
C SB2 H. Heavy flash rusting
Preparation Standard D SB2
Rust grade D
D SB2 Rust grade D Slurryblasted to an Sa2 equivalent
Preparation Standard C SB21⁄2
Rust grade C
C SB21⁄2 Rust grade C. Slurryblasted to an Sa21⁄2 equivalent.
Degree of Flash Rusting
C SB21⁄2 L. Light flash rusting
C SB21⁄2 M. Moderate flash rusting
C SB21⁄2 H. Heavy flash rusting
Preparation Standard C SB21⁄2
Rust grade C
C SB21⁄2 Rust grade C. Slurryblasted to an Sa21⁄2 equivalent.
Degree of Flash Rusting
C SB21⁄2 L. Light flash rusting
C SB21⁄2 M. Moderate flash rusting
C SB21⁄2 H. Heavy flash rusting
Degree of Flash Rusting
C SB2 L. Light flash rusting
C SB2 M. Moderate flash rusting
C SB2 H. Heavy flash rusting
Preparation Standard D SB2
Rust grade D
D SB2 Rust grade D Slurryblasted to an Sa2 equivalent
Preparation Standard C SB2
Rust grade C
C SB2 Rust grade C Slurryblasted to an Sa2 equivalent
Degree of Flash Rusting
D SB2 L. Light flash rusting
D SB2 M. Moderate flash rusting
D SB2 H. Heavy flash rusting
Visual Standards
Rust Grade Standards
Rust grade C
Rust grade D
Preparation Standard D SB21⁄2
Rust grade D
D SB21⁄2 Rust grade D Slurryblasted to an Sa21⁄2 equivalent
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53121 IP SlurryBlasting leaflet 10/14/04 3:32 PM Page 5 Dave Tas
Notes
5.1 Painted Steel
The photographs in this standard were prepared from unpainted steel but they arealso suitable for depicting the appearance of painted steel after slurryblasting.
5.2 Inspecting Slurryblasted Surfaces Prior to Flash Rusting
When large areas are slurryblasted, flash rusting which obscures the original blaststandard may occur before an inspection can be carried out. Establishing the requiredstandard by blasting a small test area prior to the main blast may help, providing therest of the job is blasted to the same standard. Methods of ensuring the rest of thejob is blasted to the same standard will vary from project to project.
5.3 Chemical Corrosion Inhibition
Flash rusting can be prevented by the use of water soluble chemical corrosioninhibitors. These inhibitors may leave a crystalline layer on the steel surface as thewater evaporates which can then lead to a loss of adhesion and osmotic blistering ifcoatings are applied over this type of surface. International Paint do not recommendthe use of corrosion inhibitors to hold wet blasted surfaces. If inhibitors are used, theymust be thoroughly washed off with fresh water before International Paint productsare applied.
5.4 Removal of Flash Rusting
When flash rusting is too heavy for coating application, it may be removed or reducedby brushing with a hard bristle brush or by washing down with high pressure freshwater. High pressure washing will cause the area to re-rust but it is possible to reducethe degree of flash rusting from heavy to light using this method.
5.5 Removal of Wet Abrasive from Slurryblasted Surfaces
Wet abrasives will tend to stick to slurryblasted surfaces. This abrasive must beremoved prior to paint application. This can be done by fresh water washing or bybrushing the surface when it is dry.
5.6 Surface Profile
This standard makes no attempt to depict or define surface profile. However,slurryblasting will produce a surface profile similar to that produced by dry abrasiveblasting.
5.7 Soluble Salt Removal
This standard makes no attempt to define levels of soluble salts remaining onslurryblasted surfaces or to relate degrees of flash rusting to remaining soluble salts.However, all slurryblasting systems wash the surface as it is blasted and soluble saltlevels will generally be lower on slurryblasted surfaces than they are on dry abrasiveblasted surfaces.
References
6.1 Steel Structures Painting Council. SSPC-VIS 1-89‘Visual Standard for Abrasive Blast Cleaned Steel’.
6.2 International Standards Organisation ISO 8501-1:1988‘Preparation of steel substrates before application of paints and related products - visual assessment of surface cleanliness’.
Degree of Flash Rusting
D SB21⁄2 L: Light flash rusting
D SB21⁄2 M: Moderate flash rusting
D SB21⁄2 H: Heavy flash rusting
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Slurryblasting Standards
www.international-marine.com
October 2004
SL2
6/P
I403
1
ArgentinaAustraliaBahrainBelgiumBrazilBulgariaCanadaChileColombiaCroatiaCubaCyprusDenmarkEcuadorEgyptEstoniaFijiFinlandFranceGermanyGreeceHong KongIcelandIndiaIndonesiaIranItalyJapanKuwaitLatviaLithuaniaLuxembourgMalaysiaMaltaMexicoNetherlands
New ZealandNorthern IrelandNorwayPakistanPanamaPapua New GuineaPeoples Republic of ChinaPeruPhilippinesPolandPortugalQatarRepublic of IrelandRomaniaRussiaSaudi ArabiaSingaporeSloveniaSouth AfricaSouth KoreaSpainSri LankaSwedenTaiwanThailandTurkeyU.S.A.UkraineUnited Arab EmiratesUnited KingdomUruguayVenezuelaVietnamWestern SamoaYemen
Unless otherwise agreed in writing, all products supplied and technical advice orrecommendations given are subject to the Conditions of Sale of our supplyingcompany.
, International and all products mentioned in this brochure are trademarks of orare licensed to Akzo Nobel. © Akzo Nobel, 2004
International Paint Ltd, Stoneygate Lane, Felling, Gateshead NE10 0JY.Tel: +44 (0)191 402 2775 Fax: +44 (0)191 401 2320
www.international-marine.com