BN-SP-R2 Specification for Internal Coating

Table of Contents

1. Scope
2. General
3. Standards
4. List of Surfaces not to be Coated
5. Surface Preparation
6. Preparation of Coating Material
7. Application of Coating
8. Quality Control
9. Precautions
10. Guarantee
11. Attachments

1. Scope

1.1 This specification covers the minimum requirements for the surface preparation and the application of internal coatings for carbon steel vessels and tanks.

1.2 In addition to the requirements of this specification, the coating manufacturer's instructions shall be carefully followed. In case of conflict, the more stringent requirements shall govern. In such cases the Contractor shall inform Purchaser immediately in writing.

1.3 The Coating Contractor shall ascertain that the surfaces included in his Scope of Work are fit to receive the surface preparation and specified coatings. All defects which will impair the lifetime of internal coatings, such as weld spatters, sharp or rough edges, laminations, cavities, tack welds, open seams and the like, shall be reported to Purchaser in writing.

The Contractor shall allow sufficient time to Purchaser to have the imperfections corrected before abrasive blastcleaning is commenced.

Commencement of the coating application means acceptance of the surface by the coating contractor.

1.4 Coating Work not Covered by this Specification:

1.4.1 Special internal coatings such as "baked on" products etc.

1.4.2 Exterior surfaces.

2. General

2.1 All operations shall be performed by skilled workmen. Standards of workmanship and materials not described in this specification shall be in accordance with generally accepted good practice. Tools and equipment to be used shall be clean, in good condition and of a design acceptable to Purchaser.

2.2 No work shall be executed during adverse conditions.

2.3 The work shall commence after successful pressure testing of vessel or tank. The coating shall be applied in a progressive way.

2.4 The applied and cured coating shall:

1. protect the coated surfaces against corrosion caused by the process fluids as stipulated in section 11, attachment A;
2. protect the process fluids against contamination by corrosion products;
3. not release substances which may change colour, smell or taste of the process fluids;
4. the required protection shall be effective for continuous exposure up to the maximum operating temperature of vessel or tank.

2.5 The design of scaffolding shall be such, that:

1. contact with the surface to be coated shall be avoided;
2. poles shall be plugged or capped prior to abrasive blasting to prevent ingress of abrasive and dirt;
3. ample clearance is obtained to clean and coat the surface properly;
4. spraying can be performed at right angles;
5. planking does not need to be moved during coating application;
6. the coating will not be damaged during dismantling and removal of the scaffolding;

2.6 Inside tank or vessel, clean and soft footwear shall be worn.

2.7 Lighting shall be ample and allow for proper and safe execution of scaffolding, cleaning and coating work.

3. Standards

In this specification reference is made to the following standards:

1. Steel Structures Painting Manual (SSPC), volume 1 and 2.

2. International Standard Organisation, ISO 8501-1 : Visual assessment of surface cleanliness

3. American Society for Testing and Materials, ASTM.

3.1 Abbreviations as Used in this Specification

"SSPC" : Steel Structures Painting Council

"MDFT" : Minimum Dry Film Thickness in Micrometers

"MAC" : Maximum Allowable Concentration.

“LEL” : Lower Explosion Limit.

4. List of Surfaces not to be coated

4.1 Capillary tubing of temperature instruments.

4.2 Surfaces made of stainless steel, non ferrometals, plastics, fibreglass, and the like.

4.3 Heating coils and other heating appliances.

4.4 Galvanised surfaces.

4.5 For crude oil storage tank:

• the roof;
• the shell and the internals over 50 cm and up.

5. Surface Preparation

5.1 Before any surface preparation is commenced or any primer or coating is applied, the surface shall be completely dry, free from weld spatter, flux, loose scale, dirt, dust, grease, oil and other foreign matter.

If the surface has been exposed to a polluted, e.g. salt laden atmosphere, it shall be washed down with clean fresh water. Surface preparation shall include the thorough removal of abrasive blasting materials and dust i.e. blown-off with compressed air, remaining weld spatters, welding flux and surface lamination.

Where rectification has been necessary on blast cleaned surfaces, the particular areas shall be reblasted to remove all rust and slag, and to restore adequate profile for the adhesion of the primer, leaving the overall prepared surface dry, clean and in all respects fit to be painted.

5.2 All cleaned surfaces shall comply to the required surface preparation standards at the moment the (primer) coating is applied.

5.3 Description of Surface Preparation Methods

5.3.1 Solvent Cleaning as per SSPC-SP1

Solvent cleaning shall precede other methods of surface preparation and the application of any coat, whenever dirt, oil, grease and other substances, harmful to lifetime or appearance of the coating are present.

These agents shall be removed by means of clean solvents (such as white spirit), or suitable cleaning compounds. After the use of water soluble compounds the surfaces shall be rinsed with an ample amount of potable water, and then be allowed to dry thoroughly before any further step is taken.

Only clean brushes and rags shall be used.

For the rinsing of SS items, only solvents shall be used.

5.3.2 White Metal Blastcleaning as per ISO 8501-1 Grade Sa 3

Equivalent to:

SSPC-SP 5.

All millscale, rust, primer (including shopprimer), paint, coating or other foreign matter shall be completely removed. The cleaned surface shall be equal in appearance to the Pictorial Standard ISO 8501-1 Sa3 as a minimum.

5.4 The blast cleaned surfaces shall provide a good anchor pattern, as advised by Coating Manufacturer.

5.5 Blastcleaning shall not be carried out when the surface temperature of the item is less than 3°C above the dewpoint of the surrounding air, or when the humidity of the air is greater than 85%.

6. Preparation of Coating Material

6.1 The coating materials shall be stored in accordance with the Coating Manufacturer's directions.

6.2 All containers shall be factory sealed and be clearly marked with Paint Manufacturer's name or initials or recognised trade mark, a description of the contents, including specification number, colour reference number, the method of application for which it is intended, the batch number and the date of fabrication.

The containers shall remain closed until the contents are required for use.

6.3 The oldest material of each kind shall be used first.

6.4 Coating material which proves deteriorated in any way shall be replaced.

6.5 Before use, the coating materials shall be mixed in a manner which will ensure break-up of all lumps, complete dispersion of all components, and a uniform composition.

Intermixing of different brands or types of paints is not allowed.

6.6 To achieve a uniform blend and a proper dispersion, separately packed pigments shall be mixed into the base material.

6.7 Two component materials shall be mixed in accordance with the Coating Manufacturer's instructions.

Containers of hardener or catalyst shall be emptied completely into the base material.

No more material shall be prepared than can be used within the time designated by the coating manufacturer as "pot-life".

A possible extension of this "pot-life" by the addition of thinners is prohibited.

6.8 Mixing shall be done on a well ventilated, clean and dust-free area.

All mixing shall be done by mechanical means.

The mixing appliances shall be clean.

6.9 Thinner shall only be added to the materials when necessary for proper application, and in accordance with the Coating Manufacturer's instructions.

6.10 When the use of thinner is permitted (refer paragraph 6.9), the required amount shall be added to the materials during the mixing process only.

The addition of any other ingredient by the coating applicator is prohibited.

6.11 The type of thinner used shall comply with the Coating Manufactur­er's instructions.

6.12 Immediately before use, all mixed coating materials shall be strained.

6.13 During use, the materials shall be stirred sufficiently to maintain a uniform composition.

Coatings containing heavy or metallic pigments that have a tendency to settle shall be kept in suspension by a mechnical agitator or stirrer.

7. Application of coating

7.1 Any surface, prepared in accordance with section 5.0 of this specification, shall be completely covered with primer or coating within 4 hours after the surface preparation is ceased.

However, when corrosion becomes visible before the first coat is completely applied, then the application of primer or coating shall be ceased immediately (refer paragraph 5.2). The surface preparation shall be repeated, but not before surrounding wet coats have been allowed to cure properly. In this case, blastcleaning shall overlap by a minimum of 25 mm into any adjacent coated areas.

In order to facilitate the blasting program the use of a holding primer may be considered. Holding primer must be compatible with the lining system and applied in strict accordance with manufacturers recommendations.

7.2 The coating materials shall be applied by the tools as advised by the Coating Manufacturer.

When spray application is recommended, supplemental brushing is required to obtain adequate protection at crevices, bolts, rivets, weld, edges, and all other surfaces where the MDFT cannot be reached by spraying only. This brushing shall precede the spray application.

The use of brushes with handles longer than 40 cm and the use of rollers is not allowed.

7.3 To the maximum possible extent, each coat shall be applied as a smooth and continuous film of uniform thickness, free of pores. The applied primer shall cover the blastcleaning profile adequately, (refer paragraph 5.4).

7.4 There shall be a minimum of application marks in the applied coats.

Any sags or runs shall be brushed out while the coat is still wet.

7.5 Each coat shall be applied to the MDFT as specified.

Excessive thickness may be detrimental to the performance of the tank lining and will have impact on the final curing time before tank is put into service.

Coating manufacturers recommendations on maximum allowable thickness on the lining system are to be strictly observed.

7.6 The Coating Manufacturer's instructions regarding intercoat interval in combination with minimum and maximum ambient and substrate temperatures shall be strictly observed i.e.:

7.6.1 Application shall not be carried out when the substrate temperature of the items is less than 3°C above the dewpoint of the air inside vessel or tank, or when the outside air temperature is expected to drop below 0°C before the material has dried.

7.6.2 Epoxy based materials shall not be applied when the substrate temperature is below 8°C, or when the air temperature is expected to drop below 0°C within the next 24 hours.

7.6.3 Substrate shall not have an elevated temperature which may be detrimental to appearance or lifetime of the applied coats.

7.7 Subsequent coats shall be of a distinctly different shade. Tinting, if required, shall be performed by the Coating Manufacturer only.

7.8 Tank bottoms and the lower part of tank wall and vessels shall be prepared and coated after complete removal of the scaffolding.

7.9 The completed coating shall be allowed to cure for 7 days at least before the tank is filled with any liquid. During the curing time ample ventilation shall be provided by the Coating Contractor to remove solvent vapours.

During the curing of inorganic zinc coatings, the relative humidity as advised by the Coating Manufacturer shall be observed.

8. Quality Control

8.1 It shall be the Coating Contractor's responsibility to inspect and approve each operation included in his scope of work, such as inspection of areas to be coated, (paragraph 1.3), cleaning, surface preparation and the application of each coat.

However, Purchaser reserves the right to inspect any or all of the operations. Inspection and approval of materials and/or workmanship by Purchaser shall not be construed as relieving the Vendor of his responsibilities.

Defects found by any party shall be corrected before any next operation is commenced.

8.2 Coating Contractor shall report in writing on the results of their inspection on the hold points such as:

• examination of surface to be prepared, check for imperfections, sharp edges, grease, etc., which are to be removed prior to blastcleaning;
• dewpoint;
• surface temperature of item to be treated;
• degree of blastcleaning;
• blastcleaning anchor pattern profile;
• thickness first coat (primer, state type and make)
• thickness final coating (state type and make of coating).
  • Note: Coating Contractor shall provide the instruments required to perform above quality control. Instruments shall be calibrated prior to their use.
  • Coating Contractor shall provide the Coating Manufacturer's data sheets for the selected primers/coatings.

8.3 Blastcleaning anchor pattern/profile shall be checked with a Keane Tator Surface Profile Comparator, Depth micrometer, Replica Tape test or Rugo test.

8.4 The Dry Film Thickness of the applicable primers and coatings shall be checked with a "Mikrotest F" gauge, and "Elcometer" banana type) gauge, or equivalent. The MDFT represents the value after correction of the value for the obtained blastcleaning profile.

(Wet-film thickness check gives an early indication on the dry film thickness to be achieved).

Frequent checks (in order of five spot measurements in triple per 10 m²) shall be carried out.

The average of the five spot measurements shall be within the specified thickness, while single spot measurements are permitted to be down to 80% of the specified thickness. The single gauge readings, however, making up the spot measurement, can underrun by a greater amount.

8.5 The final inspection shall deal with the general appearance, overall film thickness, missed areas, pinholing, cracking, flaking, blistering, flush surface at coated flange facing to facilitate the proper installation of gaskets, etc.

All defects found shall be corrected to the full number of coats.

In the event the MDFT has not been obtained, an additional compatible coat shall be applied in consultation with coating manufacturer.

Excessive thickness may have to be removed by sanding unless unconditionally accepted by coating manufacturer.

8.6 The entire coated surface shall be tested on the presence of pinholes with a suitable detector. Type and voltage shall:

1. be harmless to sound coatings;
2. be in accordance with the Coating Manufacturer's recommendations.

The check shall be performed by an experienced employee of the Coating Contractor and be witnessed by Purchaser.

8.7 Areas where pinholing is detected shall be repaired as recommended by Coating Manufacturer.

8.8 Destructive testing methods (which will impair the lifetime of the coating) are not allowed.

9. Precautions

9.1 During coating application and drying, the interiors shall be kept properly ventilated to remove solvent vapours. The concentration of these vapours shall be kept well below the Maximum Allowable Concentration (MAC) value of the solvents used.

9.2 The compressed air to be used shall be free of oil and water. Adequate separators and traps shall be provided, installed in the coolest part of the system. They shall be emptied regularly to prevent carry over of water and oil. Accumulations of oil and moisture shall be removed from the air receiver by regular purging.

9.3 During the execution of the work the Coating Contractor shall take all necessary steps to:

1. protect nearby equipment and machinery against damage caused by abrasives, dust or other foreign matter;
2. seal off nozzles against the entry of abrasives;
3. prevent coating from touching surfaces not intended to be coated. Special care shall be taken to prevent metallic zinc containing coating material to touch stainless steels;
4. protect prepared surfaces and drying coats against contamination by detrimental agents (including water);
5. protect seals of floating roofs against damage.

9.4 Coats damaged by detrimental agents shall be removed and the surface shall again be prepared and coated as specified.

9.5 Surfaces not to be coated, but accidentally soiled shall be adequately cleaned.

9.6 Mechanical damage to the dried coats shall be prevented by all means and by all parties involved.

Any damage caused shall be repaired to the full numbers of coats.

9.7 Rags and other waste, soiled with painting material, shall be kept in tightly closed containers and outside any vessel, tank or building until removed disposal.

10. Guarantee

10.1 The required guarantee period and guarantee requirements for the specified coating systems shall be as per requisition, unless stated otherwise under this chapter.

11. Attachments

A. Coating Systems

B. Approved Cleaning Compounds

C. Approved Coating Manufacturers

Coating Systems

NOTES:

1. The figure given between brackets for each coat means: The minimum dry film thickness in micrometers.
2. For crude oil storage tanks the bottom shall be completely coated, the shell and the internals to a height of 50cm up only.
3. For approved cleaning compounds and coating manufacturers refer to Attachments B and C.

Approved Cleaning Compounds

1. Industrial Cleaner

As supplied by:
Arkenbout
Gouderakstraat 45
3079 DB Rotterdam
The Netherlands

2. Turco Jetclean No. 1

As supplied by:
Turco Chemical Production N.V.
P.O. Box 48
6710 BA Ede
The Netherlands

3. Vecom B-24

As supplied by:
Vecom B.V.
P.O. Box 27
3140 AA Maassluis
The Netherlands

Approved Coating Manufacturers

1. AKZO NOBEL Coatings B.V.
Rijksstraatweg 31 / P.O. Box 3
2170 BA Sassenheim
The Netherlands

2. Ameron B.V.
J.F. Kennedylaan 7 / P.O. Box 6
4190 CA Geldermalsen
The Netherlands

3. Carboline Benelux B.V.
Schoonhovenseveer 31-33 / P.O. Box 62
2964 GB Groot-Ammers
The Netherlands

4. Hempel Coatings B.V.
James Wattweg 2 / P.O.Box 258
3130 AG Vlaardingen
The Netherlands

5. International Paint B.V.
Kleidijk 88 / P.O.Box 856
3161 HJ Rhoon
The Netherlands

6. Sigma Coatings B.V.
Parmentier Plein 13 / P.O.Box 1037
3088 GN Rotterdam
The Netherlands