Scopes

This procedure covers the requirements for the procedures of blasting and application of the protective coating systems to be used on the interior and exterior surfaces of production facilities.

References

2.1       SSPC-PA1 – Shop, Field and Maintenance Painting of Steel.

2.2       SSPC-PA2 – Measurement of Dry Coating Thickness with Magnetic Gauges.

2.3       SSPC-SP1 – Solvent Cleaning.

2.4       SSSC-SP2 – Hand Tool Cleaning.

2.5       SSPC-SP3 – Power Tool Cleaning.

2.6       SSPC-SP5 – White metal Blast Cleaning.

2.7       SSPC-SP6 – Commercial Blasting Cleaning.

2.8       SSPC-SP7 – Brush-off Blast Cleaning.

2.9       SSPC-SP10 – Near White Blast Cleaning.

2.10      SSPC-SP16 – Brush-off blast cleaning of non-ferrous metals.

2.11      ASTM A123 – Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products.

2.12      ASTM A153 – Standard Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware

2.13      ASTM D4541 – Standard Test Method for Pull-Off Strength  of  Coatings  Using  Portable Adhesion Testers

2.14      BS EN ISO 1461 – Hot dip galvanized coatings on fabricated iron and steel articles. Specifications and test methods

2.15      ISO 4624 –  Paints and varnishes – Pull-off test for adhesion

2.16      ISO 8501 – Visual assessment of surface cleanliness

2.17      ISO 8502 – Test for assessment of surface cleanliness

2.18      ISO 8503 – Surface roughness characteristics of blast-cleaned steel substrates

2.19      ISO 8504 – Surface preparation methods

2.20      Project specification

 

Surface preparation

 General

3.1.1     Steel surface shall be completely dried out and free from burrs, weld spatters, flux, rust, loose scale, dirt, grease, oil and other foreign matter before any paint is applied.

3.1.2     All edges shall be rounded a minimum radius of 2 mm, flame cut areas shall be ground flush.

3.1.3     Flange faces, thread and other functional surfaces shall be protected during blasting.

 

Surface preparation by blast cleaning

3.2.1     Blasting abrasive of carbon steel and low alloy steel shall steel grit.

3.2.2     Blasting of stainless steel shall be carried out by sweep blast with dry, non-iron containing abrasive (e.g. garnet, aluminum oxide), glass pearls or stainless steel shot.

3.2.3     The blasting profile and angular anchor pattern shall recommend by the paint manufacturer or a minimum requirement of their respective primers or mentioned in table 1 (see in the attachment).

 

3.2.4     The temperature of steel surface shall not less than 30C above dew point and when the relative humidity of the air is greater than 85%.

3.2.5     Archived surface after blasting shall be free of all dirt, mill scale, rust, corrosion products, oxides, paint, or other foreign matters except little light shadows or streaks or slight discoloration caused by rust stain, mill-scale oxides; or thin, tight residues of paint or coating that may remain.

3.2.6     Primer coat should apply within 4 hours after completion blasting

3.2.7     The Swedish standards SIS 05 5900 provide to support visual comparison.

 

Surface preparation by hand and power tool cleaning

3.3.1     Power tool cleaning shall be in accordance with SSPC-SP-3 “Power Tool Cleaning”. Prior to power tool cleaning, grease, and salts shall be removed by solvent cleaning. Care shall be exercised in the use of power tools to prevent excessive roughening of the surface and the formation of ridges and burrs.

3.3.2     Metal surfaces for which blast cleaning is specified but which, because of their location cannot be so treated, shall be 100% power tool cleaned.

3.3.3     Where welds occur within this area or when these areas cannot accommodate a power disc, power impact tools shall be applied (vibratory and rotary hammers, needle guns, chisels) followed up by wire brush cleaning. The wire brush shall be the same material with the steel.

3.3.4     Where the surface being prepared lies adjacent to a previously coated surface the power tool cleaning shall overlap beyond the coated surface by a minimum of 25 mm.

 

Galvanizing preparation

3.4.1     All welding slag and burrs shall be removed. Surface contaminants and coatings, which can’t be removed by other normal chemical cleaning process in the galvanizing operation, shall be removed by swept blast

3.4.2     After immersion in the molten zinc the shapes shall not be subjected to any scraping or wiping which will reduce uniformity of coating.

Painting system

4.1       The painting systems shall follow project specification or approval painting data sheets.

4.2       All paints shall strictly apply in accordance with the paint manufacturer’s recommendation.

4.3       Paint mixing of different manufacturer will not be permissible. A complete system shall be from one manufacturer, with all coats been compatible.

4.4       Every possible precaution shall take care to prevent dust before and during painting processes. All paint surfaces shall be dried, free from condensation and efflorescence before the application of next subsequent precedence coat.

4.5       Painting shall not be carried out in wet weather unless carried out under recommended humidity and is approved by the paint manufacturer’s representative or client.

4.6       Any paint surface found to be non-conforming to the required quality shall be repainted. The paintwork shall be adequately protected during and after pre-treatment and paint operations.

 

4.7       Particular care shall be taken to prevent rusting and/or contamination of cleaned surfaces. The cleaned surfaces shall be painted promptly within a reasonable prior after cleaning to prevent detrimental corrosion and recontamination.

4.8       All paints and coating material, thinners, solvents, etc. shall be stored in accordance with the paint manufacturer’s recommendations.

4.9       The  stem  area  of  the  valves  shall  not  be  painted  and  protected  from  any  inadvertent  Application of paint and/or solvents. The stem area shall apply a thin layer of grease to provide corrosion protection.

Testing and inspection

5.1       The following tests shall be carried out if specified in the work order during paint trials and during the work and shall be reported in a format agreed with the Client.

5.2       Contractor shall record each step of the coating operation by elapsed time after start of abrasive blasting. Time, temperature and humidity shall be recorded, a minimum of twice each shift, each day that blasting and coating operation are performed.

5.3       Visual Inspection: an individual coat and completed coatings shall make readily accessible for visual inspection. Coatings shall be smoothly and free from dry spray, pinholes, blisters, craters and excessive sagging.

5.4       Profile check:  the profile height shall be spot checked by means of a surface profile gauge (e.g. Elcometer 123).

5.5       Film thickness: the paint manufacturer’s recommended minimum wet and dry film thickness shall be obtained before start of work.

5.6       Acceptance criteria: each coat shall inspect by painting inspector in accordance with SSPC-PA2 or Client’s specifications.

5.7       Additional test: optional test requirement to project specifications

Repair

6.1       This repair procedure covers the repair methods for the damaged surfaces caused by burns, weld, scratches, impact, etc. after fabrication or a during fabrication, handling, storage, shipping, erection, etc.

6.2      Damaged areas shall be repaired by

6.2.1      Minor defects shall be touched up.

6.2.2       Major defects shall be re-blasted and re-painted against.

6.3       Repaired painting coat shall be same or compatible to the painting system specified in the painting procedure.

6.4       Edges of the breaks shall be feathered and the designed number of prime and finish coats applied with a coating repair overlap of at least 25mm.

6.5       Repair damaged galvanizing will be touch-up spray/brush by organic zinc greater than 90% volume.

 

Report

Inspection record and procedure download here.

 

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