spe77_310

MESC SPECIFICATION Revision: 04-November-2005.

SPE 77/310 Page 1 of 7

This document is restricted. Neither the whole nor any part of this document may be disclosed to any third party without the prior written consent of Shell Global Solutions International B.V., The Netherlands. The copyright of this document is vested in this company. All rights reserved. Neither the whole nor any part of this document may be reproduced, stored in any retrieval system or transmitted in any form or by any means (electronic, mechanical, reprographic, recording or otherwise) without the prior written consent of the copyright owner.

PAINTING AND COATING OF VALVES

ATTENTION: THIS SPECIFICATION IS NOT REFERRED TO IN CENTRALLY-CODED MESC DESCRIPTIONS. ITS USE MAY LEAD TO LOCALLY-CODED ITEMS. ADDITIONAL SPECIFICATIONS MAY BE SELECTED FROM CATEGORIES A AND B OF INTRODUCTION 77 SECTION FIVE.

1 INTRODUCTION

1.1 SCOPE: This MESC specification covers the minimum requirements for surface preparation and painting of valves, other than the standard production series of valves which may be painted in accordance with the manufacturer's standard.

The additional requirements of this specification shall be considered to be part of the description of the valves, when referred to in a requisition or purchase order.

1.2 The applicable paint system is specified in the relevant requisition or purchase order.

2 REFERENCES

In this specification, reference is made to the following publications:

NOTE: Unless specifically designated by date, the latest edition of each publication shall be used, together with any amendments/supplements/revisions thereto.

ASME B 46.1 Surface texture (surface roughness, waviness and lay).

ISO 4628 parts 1 to 6 Evaluation of degradation of paint coating.

ISO 8501 - 1 Pictorial surface preparation standard for painting of steel surfaces.

SSPC - SP1 Steel Structure Painting Council-USA; Solvent cleaning standard-SP1.

DEP30.48.00.31-GEN Painting and coating for new construction projects.

DEP 40.48.00.30-GEN Paints and paint materials.

3 PAINTING REQUIREMENTS

3.1.




necessary, an alkaline cleaning agent.

All bolt holes shall be solvent-cleaned prior to blast cleaning.

All sharp edges shall be removed.

Shot blasting of valves shall not be done in final assembled condition.

Die stamped markings shall be highlighted after painting.

3.1.2 Carbon steel and low alloy steel

Mill scale, rust, corrosion products, paint or any other foreign matter shall be removed by blast cleaning in accordance with ISO 8501-1 to the grade specified for the respective paint system (ref. 3.3)

The required degree of surface roughness (RZ- peak to valley height) after blast cleaning shall be between 30 and 80 micrometers to ASME B46.1.

The blast-cleaned surface shall be brushed with clean brushes made of hair, bristle or fibre, blown-off with compressed air (free from oil and water) or vacuum-cleaned to remove all traces of blast-cleaned products from the surface, pockets and corners.

3.1.3 High alloy steel

High alloy steel surfaces shall be painted in the following cases only when: 1) insulated between 50 ºC and 200 ºC; 2) in contact with a salt-laden atmosphere; 3) insulated and below 0 ºC; 4) specifically indicated by the Principal.

If surfaces are to be painted, a suitable pre-treatment in the form of a light blast-cleaning with a suitable abrasive such as aluminium oxide or "Vasilgrit" (a proprietary grade based on an inert aluminium silicate) shall be given to ensure proper adhesion of the subsequently applied paint system (ref. 3.3)

Note: paint shall be zinc free.




3.2 PAINT APPLICATION

3.2.1 General

Each coat is to be applied uniformly over the entire surface. All runs and sags shall be brushed out immediately or the paint shall be removed and the surface re-coated.

During application of each coat all areas such as corners, edges, welds, small brackets, bolts, nuts and interstices shall receive additional paint to ensure that these areas have the minimum specified dry-film thickness and to ensure continuity of coating.

3.3 PAINT SYSTEMS (see also appendix 1)

3.3.1 General

The top coat colour of valves shall be light grey to Shell's standard colour card no. 1, except for: - Epikote based coal tar paint - Subsea valves, which shall be yellow to Shell's standard colour card no. 4 or white.

Hand wheels shall be painted with two coats of black alkyd enamel, each with a thickness of 30 micrometers minimum.

One of the following coating systems shall be applied. The dry-film thickness is minimal.

3.3.2 System 1

For carbon steel and low alloy steel valves, aboveground and underground, from minus 50 ºC up to a maximum operating temperature of 120 ºC.

- Blast cleaning to grade SA 2.5, - One coat of 40 micrometers thickness of zinc rich 'Epikote' based paint and - One coat of 125 micrometers thickness high build 'Epikote' paint.

3.3.3 System 2

For carbon steel and low alloy steel valves, underground and sub sea, from ambient temperature up to a maximum operating temperature of 120 ºC.

- Blast cleaning to grade SA 2.5, - One coat of 40 micrometers thickness of zinc rich 'Epikote' based primer and - One coat of 350 micrometers thickness of 'Epikote' resin based coal tar paint in minimal two layers.

3.3.4 System 3

For high alloy steel valves, aboveground and sub sea, from minus 200 ºC up to a maximum operating temperature of 120 ºC and underground, from minus 50 ºC up to a maximum operating temperature of 200 ºC.

- Light blast cleaning with a suitable abrasive such as aluminium oxide or vasilgrit,




- One coat of 40 micrometers thickness of zinc-free 'Epikote' based primer and - One coat of 125 micrometers thickness of high build 'Epikote' paint.

3.3.5 System 4

For carbon steel and low alloy steel valves, marine and sub sea, from minus 50 ºC up to a maximum operating temperature of 120 ºC.

- Blast cleaning to grade SA 2.5, - One coat of 40 micrometers thickness of zinc rich 'Epikote' based primer, - One coat of 125 micrometers thickness of high build 'Epikote' paint and - One coat of 75 micrometers thickness of high build 'Epikote' paint.

3.3.6 System 5

For carbon steel and low alloy steel valves, aboveground, from ambient temperature up to a maximum operating temperature of 500 ºC.

- Blast cleaning to grade SA 3 and - One coat of zinc silicate of 60-100 micrometers in thickness.

3.3.7 System 6

For high alloy steel valves, aboveground and marine, from 120 ºC up to a maximum operating temperature of 200 ºC.

- Light blast cleaning with a suitable abrasive such as aluminium oxide or Vasilgrit and - Two coats of heat-resisting silicon aluminium paint, each with a thickness of 30 micrometers.

4 MATERIALS

4.1 All materials shall be supplied in the manufacturer's original containers, durably and legibly marked with the description of the contents.

4.2 The storage and preparation of paints and other coating materials shall be in accordance with the manufacturer's instructions, unless specified otherwise.

5 INSPECTION, TESTING AND REPAIR




5.1 INSPECTION

Inspection shall be carried out on samples taken at random from the total lot of valves. The total number of samples from the lot shall be 1%, but with a minimum of one.

The Principal shall have the right to inspect the paint work at any stage and to reject any tools, instruments or materials, which do not conform to the specification.

Finished paint work shall have the correct shade, degree of gloss and evenness and be free from tackiness after drying/curing and from cracks, holidays, runs, sags, wrinkles, patchiness, brush or roller marks, or other defects that may be deleterious to the quality of the coating.

5.2 TESTING

The surface preparation and paint work shall be tested as follows: -

- SURFACE ROUGHNESS The surface roughness shall be checked with a micrometer depth gauge or specially designed surface profile meters, such as Rugotest no. 3 or Keane Tator surface profile comparator.

- FILM THICKNESS The dry-film thickness shall be checked with calibrated film thickness gauges, using the magnetic resistance or eddy currents principle.

- PINHOLES The continuity of the coating shall be checked with a high-voltage spark test, the pinhole detection device shall be set to 6 V per micrometer of average coating thickness. The test apparatus shall be a low-pulse direct-current detector.

- CURING The degree of curing of 'Epikote' resin-based paint systems shall be checked by determining the resistance of the coating to Methyl Ethyl Ketone (MEK). After rubbing the coating for one minute with a rag soaked in MEK, the coating shall not be softened. Test by scraping with a fingernail.

- ADHESION/COHESION The adhesion of the primer to the steel substrate and the inter coat adhesion of the subsequent coat(s) and primer after curing shall be determined by making a v-shaped cut through the coating with a sharp knife. The adhesion is satisfactory if the film cannot be peeled by the knife either from the substrate or between the coats. Excessive force to the extent of coating rupture should leave portions of the film adhering tightly to the surface.




5.3. REPAIR OF DEFECTS OR DAMAGES

Any defect or damage that may occur shall be repaired before the application of further coats. If necessary, the surface shall be stripped and re-painted.

Areas which are to be over-coated shall be thoroughly cleaned and free from grease, oil and other foreign matter, and shall be dry. The surfaces shall then be prepared to the standard as originally specified.

Subsequently, additional compatible coats shall be applied, until they meet the specification. These additional coats shall blend in with the final coating on adjoining areas.

Damaged areas of primed surfaces with zinc-rich primers shall be painted after cleaning with one coat of zinc-rich 'Epikote' resin-based primer.

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