Weld Replica Visual Comparator – NACE SP0178
The visual comparator mentioned In Appendix C is a molded plastic replica that illustrates various degrees of surface finishing for welds prior to coating and lining. Full-seam welds, skip welds, butt welds, and lap welds, and others are depicted.
NACE International, https://www.nace.org
Surface Preparation Commentary for Metal Substrates – SSPC-SP COM
Surface Defects, Section 4.4
Coatings tend to draw thin and pull away from sharp edges and projections, leaving little or no coating to protect the underlying steel, thereby increasing the potential for premature coating failure. This results in poor coating film quality. Other features of steel that are difficult to properly cover and protect include crevices, weld porosity, laminations, etc. These considerations are discussed below. The high cost to remedy these surface imperfections requires weighing the benefits of remedial methods, such as edge rounding or grinding, versus a potential coating failure.
Poorly adhering contaminants, such as weld slag residues, loose weld spatter, and some minor surface laminations, may be removed by abrasive blast cleaning. Other surface defects, such as steel laminations, weld porosities, or deep corrosion pits, may not be evident until after abrasive blast cleaning is completed. Therefore, the timing of such surface repair work may occur before, during, or after preliminary surface preparation operations have begun.
Summary of Current SSPC Abrasive and Surface Preparation Standards – Table 1A
| SSPC Standard | Description |
| SSPC-AB 1 Mineral and Slag Abrasives | Definition of requirements for selecting and evaluating mineral and slag abrasives used for blast cleaning |
| SSPC-AB 2 Cleanliness of Recycled Ferrous Metallic Abrasive | Cleanliness requirements for a recycled work mix and a description of the test procedures. |
| SSPC-AB 3 Ferrous Metallic Abrasives | Requirements for chemical and physical properties of iron and steel abrasives. |
| SSPC-AB 4 Recyclable Encapsulated Abrasive Media | Requirements for physical properties and cleanliness of abrasive media encapsulated in a compressible non-uniform cellular matrix. |
| SSPC-PA 17 Conformance to Profile/Surface Roughness/ Peak Count Requirements | A procedure suitable for shop or field use for determining compliance with specified profile ranges on a steel substrate. |
| SSPC-SP 1 Solvent Cleaning | Removal of oil, grease, dirt, soil, salts, and contaminants by cleaning with solvent, vapor, alkali, emulsion, or steam. |
| SSPC-SP 2 Hand Tool Cleaning | Removal of loose rust, loose mill scale, and loose paint to degree specified, by hand chipping, scraping, sanding, and wire brushing. |
| SSPC-SP 3 Power Tool Cleaning | Removal of loose rust, loose mill scale, and loose paint to degree specified, by power tool chipping, descaling, sanding, wire brushing or wire impact tools, and grinding. |
| SSPC-SP 5/NACE No. 1 White Metal Blast Cleaning | Removal of all visible rust, mill scale, paint, and foreign matter by blast cleaning by wheel or nozzle (dry or wet) using sand, grit or shot. |
| SSPC-SP 5 (WAB)/ NACE WAB-1* White Metal Wet Abrasive Blast Cleaning | Same level of cleanliness as SSPC-SP 5/NACE No. 1, but achieved by wet abrasive blast cleaning. Level of flash rust permissible immediately prior to coating application must be specified. |
| SSPC-SP 6/NACE No. 3 Commercial Blast Cleaning | Removal of all visible rust, mill scale, paint, and foreign matter by blast cleaning. Staining is permitted on no more than 33% of each 9 in2 area. |
| SSPC-SP 6 (WAB)/ NACE WAB-3 Commercial Wet Abrasive Blast Cleaning | Same level of cleanliness as SSPC-SP 6/NACE No. 3, but achieved by wet abrasive blast cleaning. Level of flash rust permissible immediately prior to coating application must be specified. |
| SSPC-SP 7/NACE No. 4 Brush-Off Blast Cleaning | Blast cleaning of all except tightly adhering residues of mill scale, rust, and coatings, while uniformly roughening the surface. |
| SSPC-SP 7 (WAB)/ NACE WAB-4 Industrial Wet Abrasive Blast Cleaning | Same level of cleanliness as SSPC-SP 7/NACE No. 4, but achieved by wet abrasive blast cleaning. Level of flash rust permissible immediately prior to coating application must be specified. |
| SSPC-SP 8 Pickling | Complete removal of rust and mill scale by acid pickling, duplex pickling, or electrolytic pickling. |
| SSPC-SP 10/NACE No. 2 Near-White Blast Cleaning | Removal of all visible rust, mill scale, paint, and foreign matter by blast cleaning. Staining is permitted on no more than 5% of each 9 in2 area of the cleaned surface. |
| SSPC-SP 10 (WAB)/NACE WAB-2 Near White Metal Wet Abrasive Blast Cleaning | Same level of cleanliness as SSPC-SP 10/NACE No. 2, but achieved by wet abrasive blast cleaning. Level of flash rust permissible immediately prior to coating application must be specified. |
| SSPC-SP 11 Power Tool Cleaning to Bare Metal | Complete removal of all rust, scale, and paint by power tools, with resultant minimum surface profile of 25 μm (1 mil). |
| SSPC-SP 14/NACE No. 8 Industrial Blast Cleaning | Between SP 7 (brush-off) and SP 6 (commercial). The intent is to remove as much coating as possible, but tightly adherent rust, mill scale, and coating can remain on 10 percent of each 9 in2 area of the cleaned surface. |
| SSPC-SP 14 (WAB)/NACE WAB-8 Industrial Wet Abrasive Blast Cleaning | Same level of cleanliness as SSPC-SP 14/NACE No. 8, but achieved by wet abrasive blast cleaning. Level of flash rust permissible immediately prior to coating application must be specified. |
| SSPC-SP 15 Commercial Grade Power Tool Cleaning | Between SP 3 and SP 11. Removes all rust and paint but allows for random staining on up to 33% of each 9 in2 area of surface; requires a minimum 25 μm (1 mil) profile. |
| SSPC-SP 16 Brush-Off Blast Cleaning of Coated and Uncoated Galvanized Steel, Stainless Steels, and Non-Ferrous Metals | Requirements for removing loose contaminants and coating from coated and uncoated galvanized steel, stainless steels, and non-ferrous metals. Requires a minimum 19 μm (0.75 mil) profile on bare metal substrate. |
| SSPC-SP WJ-1/NACE WJ-1 Waterjet Cleaning of Metals–Clean to Bare Substrate | Cleanest waterjetting level, requires the cleaned metal to be free of all visible oil, grease, dirt, rust and other corrosion products, previous coatings, mill scale, and foreign matter. |
| SSPC-SP WJ-2/NACE WJ-2 Waterjet Cleaning of Metals–Very Thorough Cleaning | Requires the cleaned metal surface to be free of all visible oil, grease, dirt, rust, and other corrosion products except for randomly dispersed stains of rust and other corrosion products, tightly adherent thin coatings, and other tightly adherent foreign matter over no more than 5% of each 9 in2 area of the cleaned surface. |
| SSPC-SP WJ-2/NACE WJ-3 Waterjet Cleaning of Metals–Through Cleaning | Requires removal of all visible contaminants as in WJ-2 above. Randomly dispersed staining as described in WJ-2 is limited to no more than 33% of each 9 in2 area of the cleaned surface. |
| SSPC-SP WJ-4/NACE WJ-4 Waterjet Cleaning of Metals–Light Cleaning | Requires removal of all visible oil, grease, dirt, dust, loose mill scale, loose rust and other corrosion products, and loose coating. Any residual material shall be tightly adhered to the metal substrate. |
Abrasive Characteristics, Section 7.1
Selecting the appropriate type of abrasive for the job is important because the type of abrasive can have a significant influence on the appearance of the blast cleaned surface, productivity, and subsequent cleanup. Abrasives vary in hardness, particle size distribution, shape, bulk density, friability, waste generation, and recyclability. The following is a discussion of these characteristics and how they influence abrasive performance. Some physical data on non-metallic abrasives are given in Table 4.
Table 4, Approximate Profile Height of Blasted Steel Using Different Sized Non-Metallic Abrasives*
| Abrasive | Profile Height | ||||
| 1 mil | 1.5 mil | 2 mil | 2.5 mil | 3-4 mils | |
| Silica Sand | 30/60 mesh | 16/35 mesh | 16/35 mesh | 8/35 mesh | 8/20 mesh |
| Steel Grit | G 80 | G 50 | G 40 | G 40 | G 25 |
| Steel Shot | S 110 | S 170 | S 280 | S 280 | S 330 |
| Garnet | 80/100 mesh | 30/100 mesh | 30/60 mesh | 20/60 mesh | 20/40 mesh |
| Aluminum Oxide | 100 grit | 50 grit | 36 grit | 24 grit | 16 grit |
* These profile heights are typical if the nozzle pressure is between 90 and 100 psi.
Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates – ASTM C136
Significance and Use, Section 5.1
This test method is used primarily to determine the grading of materials proposed for use as aggregates or being used as aggregates. The results are used to determine compliance of the particle size distribution with applicable specification requirements and to provide necessary data for control of the production of various aggregate products and mixtures containing aggregates.
Preparation of steel substrates before application of paints and related products — Tests for the assessment of surface cleanliness — Part 3: Assessment of dust on steel surfaces prepared for painting (pressure-sensitive tape method) – ISO 8502-3
Abstract
ISO 8502-3:2017 describes a method for the assessment of dust remaining on cleaned steel surfaces prepared for painting. It provides pictorial ratings for the assessment of the average quantity of dust. It also provides descriptive classes for the assessment of the average size of the dust particles.
Table 1: Dust Particle Size Classes
| Class | Description of dust particles |
| 0 | Particles not visible under 10x magnification |
| 1 | Particles visible under 10x magnification but not with normal or corrected vision (usually particles less than 50 µm in diameter) |
| 2 | Particles just visible with normal or corrected vision (usually particles between 50 µm and 100 µm in diameter) |
| 3 | Particles clearly visible with normal or corrected vision (particles up to 0.5 mm in diameter) |
| 4 | Particles between 0.5 mm and 2.5 mm in diameter |
| 5 | Particles larger than 2.5 mm in diameter |
Standard Test Methods for Field Measurement of Surface Profile of Blast Cleaned Steel – ASTM D4417
Summary of Test Method – Section 3
Method A—The blasted surface is visually compared to standards prepared with various surface profile depths and the range determined.
Method B—The depth of profile is measured using a fine pointed probe at a number of locations and the arithmetic mean of the maximum peak-to-valley distances is determined.
Method C—A composite plastic tape is impressed into the blast cleaned surface forming a reverse image of the profile, and the maximum peak to valley distance measured with thickness gage specifically designed for use with the replica tape method.
Surface Preparation Standards
ASTM D2200 Standard Practice for Use of Pictorial Surface Preparation Standards and Guides for Painting Steel Surfaces
ASTM D4258 Standard Practice for Surface Cleaning Concrete for Coating
ASTM D4259 Standard Practice for Abrading Concrete
ASTM D4261 Standard Practice for Surface Cleaning Concrete Masonry Units for Coating
ASTM D4262 Standard Test Method for pH of Chemically Cleaned or Etched Concrete Surfaces
ASTM D4263 Standard Test Method for Indicating Moisture in Concrete by the Plastic Sheet Method
ASTM D4285 Standard Test Method for Indicating Oil or Water in Compressed Air
ASTM D4417 Standard Test Methods for Field Measurement of Surface Profile of Blast Cleaned Steel
ASTM D6386 Standard Practice for Preparation of Zinc (Hot Dip Galvanized) Coated Iron and Steel Product and Hardware Surfaces for Painting
ASTM D7127 Standard Test Method for Measurement of Surface Roughness of Abrasive Blast Cleaned Metal Surfaces Using a Portable Stylus Instrument
ASTM D7393 Standard Practice for Indicating Oil in Abrasives
ASTM D7396 Standard Guide for Preparation of New, Continuous Zinc Coated (Galvanized) Steel Surfaces for Painting
ASTM F1869 Standard Test Method for Measuring Moisture Vapor Emission Rate of Concrete Subfloor Using Anhydrous Calcium Chloride
ASTM F2170 Standard Test Method for Determining Relative Humidity in Concrete Floor Slabs Using in situ Probes
ICRI 310.1R Guide for Surface Preparation for the Repair of Deteriorated Concrete Resulting from Reinforcing Steel Corrosion
ICRI 310.2R Selecting and Specifying Concrete Surface Preparation for Sealers, Coatings, Polymer Overlays, and Concrete Repair
NACE No. 1/SSPC-SP 5 White Metal Blast Cleaning
NACE No. 2/SSPC-SP 10 Near-White Metal Blast Cleaning
NACE No. 3/SSPC-SP 6 Commercial Blast Cleaning
NACE No. 4/SSPC-SP 7 Brush-Off Blast Cleaning
NACE No. 6/SSPC-SP 13 Surface Preparation of Concrete
NACE SP0287 Field Measurement of Surface Profile of Abrasive Blast-Cleaned Steel Surfaces Using a Replica Tape
NAPF 500-03 Surface Preparation Standard for Ductile Iron Pipe and Fittings In Exposed Locations Receiving Special External Coatings and/or Special Internal Linings
SSPC-AB 1 Mineral and Slag Abrasives
SSPC-AB 2 Cleanliness of Recycled Ferrous Metallic Abrasives
SSPC-AB 3 Ferrous Metallic Abrasive
SSPC-AB 4 Recyclable Encapsulated Abrasive Media (in a compressible cellular matrix)
SSPC-PA 17 Procedure for Determining Conformance to Steel Profile/Surface Roughness/Peak Count Requirements
SSPC-SP 1 Solvent Cleaning
SSPC-SP 2 Hand Tool Cleaning
SSPC-SP 3 Power Tool Cleaning
SSPC-SP 11 Power Tool Cleaning to Bare Metal
SSPC-SP 15 Commercial Grade Power-Tool Cleaning
SSPC-SP 16 Brush-Off Blast Cleaning of Coated and Uncoated Galvanized Steel, Stainless Steels, and Non-Ferrous Metals
SSPC-SP COM Surface Preparation Commentary for Metal Substrates
SSPC-VIS 1 Guide and Reference Photographs for Steel Surfaces Prepared by Dry Abrasive Blast Cleaning
SSPC-VIS 3 Guide and Reference Photographs for Steel Surfaces Prepared by Hand and Power Tool Cleaning
ISO 8501 Preparation of steel substrates before application of paints and related products – Visual assessment of surface cleanliness –
Part 1: Rust grades and preparation grades of uncoated steel substrates and of steel substrates after overall removal of previous coatings
Part 2: Preparation grades of previously coated steel substrates after localized removal of previous coatings
Part 3: Preparation grades of welds, edges and other areas with surface imperfections
ISO 8502 Preparation of steel substrates before application of paints and related products – Test for the assessment of surface cleanliness
Part 3: Assessment of dust on steel surfaces prepared for painting (pressure-sensitive tape method)
Part 4: Guidance on the estimation of the probability of condensation prior to paint application