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DEP SPECIFICATION
THERMAL SPRAY COATINGS OF ALUMINIUM
DEP 30.48.40.31-Gen.
February 2012
DESIGN AND ENGINEERING PRACTICE
2012 Shell Group of companies All rights reserved. No part of
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PREFACE
DEP (Design and Engineering Practice) publications reflect the
views, at the time of publication, of Shell Global Solutions
International B.V. (Shell GSI) and, in some cases, of other Shell
Companies.
These views are based on the experience acquired during
involvement with the design, construction, operation and
maintenance of processing units and facilities. Where deemed
appropriate DEPs are based on, or reference international,
regional, national and industry standards.
The objective is to set the standard for good design and
engineering practice to be applied by Shell companies in oil and
gas production, oil refining, gas handling, gasification, chemical
processing, or any other such facility, and thereby to help achieve
maximum technical and economic benefit from standardization.
The information set forth in these publications is provided to
Shell companies for their consideration and decision to implement.
This is of particular importance where DEPs may not cover every
requirement or diversity of condition at each locality. The system
of DEPs is expected to be sufficiently flexible to allow individual
Operating Units to adapt the information set forth in DEPs to their
own environment and requirements.
When Contractors or Manufacturers/Suppliers use DEPs, they shall
be solely responsible for such use, including the quality of their
work and the attainment of the required design and engineering
standards. In particular, for those requirements not specifically
covered, the Principal will typically expect them to follow those
design and engineering practices that will achieve at least the
same level of integrity as reflected in the DEPs. If in doubt, the
Contractor or Manufacturer/Supplier shall, without detracting from
his own responsibility, consult the Principal.
The right to obtain and to use DEPs is restricted, and is
granted by Shell GSI (and in some cases by other Shell Companies)
under a Service Agreement or a License Agreement. This right is
granted primarily to Shell companies and other companies receiving
technical advice and services from Shell GSI or another Shell
Company. Consequently, three categories of users of DEPs can be
distinguished:
1) Operating Units having a Service Agreement with Shell GSI or
another Shell Company. The use of DEPs by these Operating Units is
subject in all respects to the terms and conditions of the relevant
Service Agreement.
2) Other parties who are authorised to use DEPs subject to
appropriate contractual arrangements (whether as part of a Service
Agreement or otherwise).
3) Contractors/subcontractors and Manufacturers/Suppliers under
a contract with users referred to under 1) or 2) which requires
that tenders for projects, materials supplied or - generally - work
performed on behalf of the said users comply with the relevant
standards.
Subject to any particular terms and conditions as may be set
forth in specific agreements with users, Shell GSI disclaims any
liability of whatsoever nature for any damage (including injury or
death) suffered by any company or person whomsoever as a result of
or in connection with the use, application or implementation of any
DEP, combination of DEPs or any part thereof, even if it is wholly
or partly caused by negligence on the part of Shell GSI or other
Shell Company. The benefit of this disclaimer shall inure in all
respects to Shell GSI and/or any Shell Company, or companies
affiliated to these companies, that may issue DEPs or advise or
require the use of DEPs.
Without prejudice to any specific terms in respect of
confidentiality under relevant contractual arrangements, DEPs shall
not, without the prior written consent of Shell GSI, be disclosed
by users to any company or person whomsoever and the DEPs shall be
used exclusively for the purpose for which they have been provided
to the user. They shall be returned after use, including any copies
which shall only be made by users with the express prior written
consent of Shell GSI. The copyright of DEPs vests in Shell Group of
companies. Users shall arrange for DEPs to be held in safe custody
and Shell GSI may at any time require information satisfactory to
them in order to ascertain how users implement this
requirement.
All administrative queries should be directed to the DEP
Administrator in Shell GSI.
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TABLE OF CONTENTS
1. INTRODUCTION
........................................................................................................5
1.1
SCOPE........................................................................................................................5
1.2 DISTRIBUTION, INTENDED USE AND REGULATORY CONSIDERATIONS
.........5 1.3 DEFINITIONS
.............................................................................................................6
1.4 CROSS-REFERENCES
.............................................................................................7
1.5 SUMMARY OF MAIN
CHANGES...............................................................................7
1.6 COMMENTS ON THIS
DEP.......................................................................................7
1.7 DUAL
UNITS...............................................................................................................7
2. GENERAL REQUIREMENTS
....................................................................................8
2.1
GENERAL...................................................................................................................8
2.2 DOCUMENT
HIERARCHY.........................................................................................8
2.3 SAFETY
......................................................................................................................8
2.4 COMPANY
ACCESS................................................................................................10
2.5 PRE-JOB
MEETING.................................................................................................10
3. MATERIALS
.............................................................................................................11
3.1 BACKGROUND
........................................................................................................11
3.2 THERMAL SPRAY COATING
..................................................................................11
3.3
SEALER....................................................................................................................11
3.4 TOP
COAT................................................................................................................11
4. SURFACE PREPARATION
.....................................................................................12
4.1
GENERAL.................................................................................................................12
4.2
CLEANING................................................................................................................12
4.3 ABRASIVE BLAST CLEANING
................................................................................12
5. COATING
APPLICATION........................................................................................15
5.1
GENERAL.................................................................................................................15
5.2
EQUIPMENT.............................................................................................................15
5.3 ACCESS
...................................................................................................................15
5.4 HOLDING
PERIOD...................................................................................................15
5.5
MASKING..................................................................................................................15
5.6 THERMAL SPRAYING
.............................................................................................16
5.7 COATING
THICKNESS............................................................................................16
6.
QUALIFICATION......................................................................................................18
6.1
GENERAL.................................................................................................................18
6.2 TSA-VENDOR
QUALIFICATION..............................................................................18
6.3 THERMAL SPRAYER
QUALIFICATION..................................................................19
6.4 QUALIFICATION
TESTS..........................................................................................19
6.5 SUMMARY OF QUALIFICATION TESTS AND ACCEPTANCE
CRITERIA............20 7. QUALITY ASSURANCE AND
CONTROL...............................................................21
7.1
GENERAL.................................................................................................................21
7.2 RESPONSIBILITY OF CONRACTOR AND COATING CONTRACTOR
.................21 7.3 QUALITY PLAN
........................................................................................................21
7.4 TESTING OF COATING
PROPERTIES...................................................................22
7.5 SUMMARY OF QUALITY CONTROL TESTING AND ACCEPTANCE
CRITERIA
.................................................................................................................25
7.6 QUALITY
RECORDS................................................................................................25
7.7 INSPECTION PERSONNEL AND
EQUIPMENT......................................................25
7.8 FINAL
INSPECTION.................................................................................................25
8. COATING
REPAIR...................................................................................................27
8.1
GENERAL.................................................................................................................27
8.2 FIELD WELDS
..........................................................................................................27
9. STORAGE AND HANDLING
...................................................................................28
10. REFERENCES
.........................................................................................................29
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APPENDICES
APPENDIX 1 INSPECTION AND TEST PLAN THERMAL SPRAY ALUMINIUM
APPLICATION NEW EQUIPMENT
................................................................31
APPENDIX 2 EXAMPLE OF INSPECTION FORM FOR TSA APPLICATION
....................34
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1. INTRODUCTION
1.1 SCOPE
This DEP specifies requirements and give recommendations for
thermal sprayed aluminium coatings for the purpose of corrosion
control for both atmospheric conditions and beneath insulation or
fireproofing as applied to onshore and offshore structures,
equipment and piping, etc.
TSA coatings are used when the period to first coating
maintenance is 25 years or where protection against corrosion under
insulation (CUI) is required.
The following aspects of the thermal sprayed aluminium coating
system are covered:
surface preparation; thermal spraying; coating materials;
prequalification; quality assurance and control, and; repair
procedures.
This DEP may also be applied when thermal spray coatings are
specified for corrosion control on immersed and buried surfaces,
equipment and structures.
The TSA coating may be applied either in the shop or in the
field (on-site). The particular coating application system and
procedures require approval by the Principal and, if applicable,
the Contractor, prior to production coating operations.
Thermal spray coatings use high heat, and aluminium dust can
ignite and explode under certain conditions. Rigorous safety
precautions are required when thermal spray coatings are applied,
particularly automated thermal spray aluminium coatings. See
(2.3).
This DEP is a revision of the DEP of the same number dated July
2008; see (1.5) regarding the changes.
1.2 DISTRIBUTION, INTENDED USE AND REGULATORY CONSIDERATIONS
Unless otherwise authorised by Shell GSI, the distribution of
this DEP is confined to Shell companies and, where necessary, to
Contractors and Manufacturers/Suppliers nominated by them. Any
authorised access to DEPs does not for that reason constitute an
authorization to any documents, data or information to which the
DEPs may refer.
This DEP is intended for use in facilities related to oil and
gas production, gas handling, oil refining, chemical processing,
gasification, distribution and supply/marketing. This DEP may also
be applied in other similar facilities.
When DEPs are applied, a Management of Change (MOC) process
shall be implemented; this is of particular importance when
existing facilities are to be modified.
If national and/or local regulations exist in which some of the
requirements could be more stringent than in this DEP, the
Contractor shall determine by careful scrutiny which of the
requirements are the more stringent and which combination of
requirements will be acceptable with regards to the safety,
environmental, economic and legal aspects. In all cases, the
Contractor shall inform the Principal of any deviation from the
requirements of this DEP which is considered to be necessary in
order to comply with national and/or local regulations. The
Principal may then negotiate with the Authorities concerned, the
objective being to obtain agreement to follow this DEP as closely
as possible.
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1.3 DEFINITIONS
1.3.1 General definitions
The Contractor is the party that carries out all or part of the
design, engineering, procurement, construction, commissioning or
management of a project or operation of a facility. The Principal
may undertake all or part of the duties of the Contractor.
The Coating Contractor is the party that manufactures or
supplies equipment and services to perform the duties specified by
the Contractor.
The Manufacturer/Supplier is the party that manufactures or
supplies equipment and services to perform the duties specified by
the Contractor.
The Principal is the party that initiates the project and
ultimately pays for it. The Principal may also include an agent or
consultant authorised to act for, and on behalf of, the
Principal.
The Applicator is the party that applies the thermal spray
coating.
The word shall indicates a requirement.
The word should indicates a recommendation.
1.3.2 Specific definitions
Term Definition
Arc spray A form of thermal spraying where two consumable metal
wires are fed independently into the spray gun. These wires are
charged and an arc is generated between them. The heat from this
arc melts the incoming wire, which is then entrained in air jet
from the gun and deposited onto a substrate
Bend test 180 bending of a sample on a mandrel.
Companion coupon
Rectangular steel coupon, prepared for qualification of thermal
spray coating materials and coated concurrently with the workpiece
for quality control and inspection.
Dew point The temperature of a given air/water-vapour mixture at
which, under atmospheric pressure, condensation starts.
Flame spray A form of thermal spraying where the wire spray
material is melted in a gaseous oxygen-fuel flame and deposited
onto a substrate.
Feather Smooth tapered transition between thermal spray coating
and the adjacent non-coated surface.
Holding period
Time between the completion of the final surface blasting and
completion of the thermal spraying.
Overspray The portion of the thermal spray deposit that is not
deposited on the desired area of the workpiece.
Rust bloom Discoloration indicating the beginning of rusting,
bleeding through the interconnecting pores of the thermal spray
coating.
Sealer A thin paint coating, about 40 m thick, that is absorbed
into the pores of the thermal spray coating and seals the coating
surface.
Shift Production run of which the beginning and end coincide
with a change in personnel.
Soluble salt contaminants
Water-soluble salts, such as chlorides and sulphates, which
contaminate the steel surface and cause rust bloom and premature
coating failure.
Thermal spray
Application of metallic coating by means of arc- or flamespray
equipment.
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Term Definition
Topcoat Paint coat applied over a sealed thermal spray
coating.
TSA Thermally Sprayed Aluminium.
1.4 CROSS-REFERENCES
Where cross-references to other parts of this DEP are made, the
referenced section number is shown in brackets ( ). Other documents
referenced by this DEP are listed in (10).
1.5 SUMMARY OF MAIN CHANGES
This DEP is a revision of the DEP of the same number dated July
2008. This has been a major rewrite and it is impractical to list
the changes here.
1.6 COMMENTS ON THIS DEP
Comments on this DEP may be sent to the Administrator at
[email protected], using the DEP Feedback Form. The DEP Feedback
Form can be found on the main page of DEPs on the Web, available
through the Global Technical Standards web portal
http://sww.shell.com/standards and on the main page of the DEPs
DVD-ROM.
1.7 DUAL UNITS
This DEP contains both the International System (SI) units, as
well as the corresponding US Customary (USC) units, which are given
following the SI units in brackets. When agreed by the Principal,
the indicated USC values/units may be used.
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2. GENERAL REQUIREMENTS
2.1 GENERAL
TSA shall be used when the period to first coating maintenance
is 25 years or where protection against corrosion under insulation
(CUI) is required.
Thermal spray coatings specified in this DEP shall be applied by
either arc or flame spraying, using a solid metal wire. Powder
consumables, high velocity oxy-fuel (HVOF) and plasma techniques
shall not be used.
Thermal spray aluminium coating shall not be sealed when
applied:
(i) to immersed components;
(ii) under insulation (to protect against CUI); or
(iii) to buried components (e.g. buried piping).
When TSA is used for immersed conditions, additional cathodic
protection by means of sacrificial anodes may be required.
When TSA is used under fireproofing or insulation material, the
materials used for fireproofing or insulation shall be selected
such that, when exposed to water, the environment that the TSA
coating is exposed to remains within a pH range of 4 to 8. However,
it is acceptable to use TSA under perlite insulation which, in the
presence of water, can develop a pH of approximately 10.
For new construction of equipment, consideration should be given
during the design such that the surface which requires TSA should
be accessible for grit blasting and TSA application. NACE SP0178
and/or ISO 12944-3 should be taken as a guideline for this.
Examples where design for TSA access should be considered in the
equipment design are (1) the clearance between insulation support
rings and shell should be twice the thickness of the ring to enable
grit blasting and TSA coating application of shell section behind
the rings and (2) the name plate bracket design should be such that
shell can be grit blasted and TSA coated behind bracket.
Finished prefab piping shop welds may be TSA coated in shop
prior to (field) hydrotesting as permitted under clause 3.3.1 of
DEP 74.00.10.10-Gen.
2.2 DOCUMENT HIERARCHY
In the event of conflicts between contract documents, As For
Construction (AFC) drawings, specifications and other referenced
standards, the following document hierarchy shall apply:
Contract or agreement (including any approved exceptions); AFC
drawings latest revisions; Principals specifications (including
project specific information); Industry Standards (e.g. ISO,
NACE).
2.3 SAFETY
2.3.1 General
Thermal spray coatings may involve the use of hazardous
materials, operations, and equipment. This DEP does not address all
of the potential safety concerns associated with their use.
TSA coating application should be considered as hot work and
associated safety precautions should be taken.
It is the responsibility of the Contractor and/or Applicator to
establish appropriate safety and health requirements, and determine
any regulatory requirements or limitations prior to use.
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Health, Safety and Environment concerns should be identified and
included in the detailed coating procedure and pre-job discussions.
All surface preparation and coating application systems shall
undergo a complete safety inspection and checkout prior to use.
Adequate exhaust/ventilation equipment shall be used, as
required, for removal of any air contaminated products to achieve
acceptable air quality standards and to protect personnel.
When personnel are working in confined spaces, adequate
ventilation and spark-proof lighting shall be provided.
All personnel shall be provided with approved personal
protection, e.g. protective clothing, safety glasses, safety shoes,
hard hats, goggles, respirators, earplugs, fresh-air-fed hood and
any other necessary safety equipment. All safety equipment shall be
maintained in good working condition.
Adequate warning signs shall be prominently displayed at all
access points to areas where abrasive blasting and thermal spraying
is in progress.
Thermal spraying is a safe process when performed by an
Applicator who follows the recommended precautionary measures, has
a proper understanding of thermal spraying practices, has knowledge
and skill, and exercises care in using thermal spray equipment.
Thermal spray equipment should have safety devices that stop the
spray process as well as the wire feeding when the safety handle is
released. For re-starting the process, a two hand operation is
required.
Coating work pieces shall be electrically grounded (earthed) as
required to eliminate static charges associated with surface
preparation and coating operations.
2.3.2 Hazardous components
Potential thermal spray hazards include exposure to flame, heat,
vapours, (metal) dust, fumes, gases (CO exposure), noise, (from the
spray gun) and arc ultraviolet (UV) radiation. Additionally,
improperly used thermal spray equipment can create potential fire
and explosion hazards from the fuel and carrier gases and a
potential electrical shock hazard from the electrical and
electronic equipment and charged wire spools. To minimize hazards,
safety precautions should be followed. Thermal sprayers shall
comply with the procedures in the safety regulations, the
Manufacturer/Suppliers technical manuals, and the material safety
data sheets.
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2.3.3 Safety measures
Source of risk factors, consequences, and recommended safety
measures for thermal spray coatings are listed below and should
include the following barriers:
Source Risk Safety measures
Heat from spray gun Flame from spray gun
Burn injuries Fire CO exposure
Wear non-flammable, heat-resistant clothing, in compliance with
ISO 11611 for arc spray and ISO 11612 for flame spray. Wear
respirator equipment
Noise from spray gun Ear damage Wear suitable ear protectors
UV-exposure from arc spray
Irritation / damage of eyes
Wear dark (welder's) glasses, face shield or helmet
Metal (spray) dust Irritation of airways / lungs Fire Dust
explosions
Wear hood with forced air supply when using arc spray,
particulate respirator when using flame spray. Water shall not be
used; Use dry sand, or Class D fire-extinguisher. Regular cleaning
of floor and equipment to remove metal spray dust (good
housekeeping).
Heavy weight of gun Overstraining muscles Regular job rotation
during spraying.
Heat from life equiment
Heat stresses Regular job rotation during spraying.
2.4 COMPANY ACCESS
The Principals representative, including independent inspectors
or consultants as may be engaged by the Principal, shall be
permitted access to the coating application site at any time to
conduct performance analyses, including quality control tests of
the materials being used.
The Principals representative has the right to reject any or all
work or equipment that in his/her opinion does not conform to these
requirements. Any work that in the opinion of the Principals
representative does not comply with these requirements shall be
rectified at the Contractors expense.
The Principals representative has the right to request quality
control tests at any time in addition to those completed at
pre-determined intervals.
2.5 PRE-JOB MEETING
The Applicator shall schedule a pre-job meeting to ensure that
job requirements are fully understood.
The personnel present at the meeting shall include, but not be
limited to, the Principals representative, and the Applicators
representatives for coating supervision, quality control and
safety. If required a technical representative of the
Manufacturer/Supplier shall be present.
Roles and responsibilities shall be clarified at the pre-job
meeting, such as when the Principal deals with the Applicator, who
are the focal points and how administration procedures are
executed. Technical aspects, such as: qualification of
vendors/sprayers, application procedures, equipment, Inspection
Test Plan (ITP) shall be discussed. It shall be confirmed that all
parties have the latest version of the Contract, technical
specifications, AFC drawings and ITP.
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3. MATERIALS
3.1 BACKGROUND
Aluminium and its alloys provide both barrier and cathodic
protection to a steel substrate. Thermal spray aluminium coatings
may be specified as protective coatings for atmospheric exposure,
under thermal insulation, hot surface and (sea) water immersion
applications.
The recommended service temperature of aluminium for
non-immersion services is -45C to 595C (50F to 1,100F).
3.2 THERMAL SPRAY COATING
For application of thermal spray coating in accordance with this
DEP, the chemical composition of the metallic wire material used
shall meet the following requirements:
Aluminium in accordance with ISO 209 Grade 1100. Alternative
Grade 1350 aluminium shall only be used with specific approval of
the Principal.
3.3 SEALER
Sealers are designed to fill the porosity of the thermal spray
coating, and not to build film thickness.
The sealer shall have sufficiently low viscosity to penetrate
into the pores and seal the surface of the thermal spray coating.
The dry-film thickness (DFT) of the sealer shall not exceed 40 m
(1.5 mils). TSA coating shall not be sealed when applied:
To components that are to be immersed (e.g. in sea water); Under
insulation (to protect against CUI); To components (e.g. piping)
that are to be buried.
TSA coatings may be sealed when used under atmospheric
conditions, e.g. to prevent fouling of the surface, or when a
particular decorative finish, or safety colours are required.
The following sealer materials shall be used:
Epoxy: to a maximum temperature of 120C (248F); Silicone: to a
maximum temperature of 450C (840F).
3.4 TOP COAT
Topcoats applied on thermal spray coating shall be chemically
compatible with the sealer and shall be applied according to the
instructions of the paint Manufacturer/Supplier.
TSA coatings may be topcoated when used under atmospheric
conditions, and when a finishing colour is required, e.g. for
safety markings, visual appearance, etc. The following coating
system shall be used:
Epoxy sealer, maximum DFT 40 m (1.5 mils); Aliphatic
polyurethane topcoat, maximum DFT 40 m (1.5 mils).
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4. SURFACE PREPARATION
4.1 GENERAL
All edges to be coated shall be rounded off by grinding to a
radius of 2 mm (1/8 in) minimum. Flame cut areas and weld spatter
shall be ground flush.
Cleaning of surfaces shall be done by dry blast cleaning, in
accordance with ISO 8504-2.
Fabrication should be complete before surface preparation
begins.
Alternative surface preparation, such as power tool cleaning,
grinding, etc., shall be permitted only by specific approval of the
Principal and when the surface preparation acceptance criteria, as
specified in this DEP, can be achieved. The Applicator shall
provide a detailed application procedure and the ITP shall have
QA/QC to verfy the surface profile.
Stainless steel surfaces shall not be treated with carbon steel
cleaning tools or tools previously used on carbon steel.
4.2 CLEANING
Prior to the blast cleaning and/or thermal spraying, the surface
shall be free of any contamination and any excessive rust scale
shall be removed. Salt contamination of parts that have been stored
in and exposed to the open air shall be removed prior to blast
cleaning.
If emulsion or detergent type degreasers or Teepol/fresh water
solutions are used, this treatment shall be followed by copious
rinsing with fresh and clean potable water or pressure water/steam
wash.
All welded areas and appurtenances shall be given special
attention for removal of welding flux in crevices. Welding spatter,
slivers, de-laminations and underlying mill scale not removed
during fabrication and exposed before and during blast cleaning
operations shall be removed by the best mechanical means. Edges
shall be smoothed or rendered flush.
If non-conformances occur on blast-cleaned surfaces and
reblasting is required these areas shall be pre-cleaned as
initially specified.
4.3 ABRASIVE BLAST CLEANING
4.3.1 General
No blasting work shall be carried out when the temperature of
the steel surfaces is less than 3C (5F) above dew point of the
surrounding air, or the relative humidity of the air is greater
than 85%. Dew point determination shall be in accordance with ISO
8502-4.
Blast cleaned steel surfaces shall not be touched by bare
hands.
If the surface being cleaned lies adjacent to a coated surface,
the blast cleaning shall overlap the coated surface by at least 50
mm (2-1/8 in). The edges of the existing coating system shall be
feathered. The remainder of the existing coated surface shall be
properly protected with shields or screens to prevent any over
blast damage.
No acid washes, cleaning solvents or other chemical treatments
shall be used on metal surfaces after they have been blast cleaned.
This restriction includes inhibitive washes intended to prevent
rusting.
If present, contaminants (including salts) shall be removed by
solvent washing, by water washing or steam cleaning, and the
affected areas re-blasted. The luminance for visual examination for
contaminations shall be at least 500 lux.
If non-conformances occur on blast-cleaned surfaces and
reblasting is required the areas shall be re-blasted to minimum Sa
2, in accordance with ISO 8501-1.
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4.3.2 Abrasives
Abrasives for blast-cleaning steels shall be in accordance with
Table 1. Test methods shall be in accordance with the tests
specified in ISO 11127. Abrasives shall be supplied with
certification documentation traceable to batches of material to
check that the abrasive meets the requirements as specified in the
relevant ISO standard.
The conductivity of abrasives to be used shall be a maximum of
50 S/cm. The Principal shall approve the use of alternative
abrasive materials.
The abrasives shall be free from oil, grease, moisture, chloride
contamination, etc.
For blasting stainless steel, non-(free) iron containing
abrasive shall be used, e.g. Garnet, or aluminium oxide.
Shot blasting material shall not be used.
Table 1 Abrasives specification
Type Generic Name Characteristics Standard
Iron grit > 1.7 % carbon ISO 11124-2 Metallic
Steel grit 0.8% to 1.2% carbon ISO 11124-3
Staurolite Iron/aluminium silicate ISO 11126-9 Natural mineral
Garnet Calcium iron silicate ISO 11126-10
Coal slag Aluminium silicate ISO 11126-4 Synthetic mineral
Aluminium oxide Crystalline corundum ISO 11126-7
4.3.3 Blasting equipment
The compressed air shall be free of water and oil. Adequate
separators and traps shall be provided, installed in the coolest
part of the system. The presence of oil and water shall be
determined in accordance with ASTM D 4285 at least two (2) times
per twelve (12) hours and following every compressor start-up. The
air discharge temperature shall not exceed 100C (210F).
Blasting nozzles shall be replaced when the specified minimum
blast pressure, surface cleanliness and surface profile can no
longer be achieved.
Blasting equipment, its operators and the object being blasted
shall be properly earthed to prevent the occurrence of
electrostatic discharges.
Abrasive blast cleaning equipment shall be of an intrinsically
safe construction and equipped with a remote shut-off valve
triggered by the release of a dead man's handle at the blasting
nozzle.
If air-operated equipment is used, the operator's hood or
headgear shall be positive pressure fed by clean, cool air supplied
through a filter, to prevent blast cleaning residues from being
inhaled.
4.3.4 Surface cleanliness
At the time of application of the thermal spray coating, the
surface finish shall be minimum Sa 2, in accordance with ISO
8501-1.
4.3.5 Surface roughness
Checks on surface roughness shall be made at least once per 100
m (1070 ft) of prepared surface, with a minimum of three
measurements per day per shift.
The surface roughness shall be measured by means of replica
tape, in accordance with ISO 8503-5. Other, proprietary testing
techniques may be used, as agreed by the Principal.
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The surface roughness for thermal spray coatings shall be
between 75 m and 110 m (3 mils and 4.5 mils), in accordance with
ISO 8503-5. The surface shall have a sharp angular profile.
4.3.6 Dust contamination
Dust levels shall be checked at least once per 100 m (1070 ft)
of prepared surface, with a minimum of three measurements per day
per shift.
The dust level of the blast cleaned surface at the time of
coating shall not exceed quantity rating 1 in accordance with ISO
8502-3.
4.3.7 Soluble salt contamination
The level of salts shall be tested at least once per 100 m (1070
ft) of prepared surface, with a minimum of three measurements per
day per shift.
The maximum total allowable soluble salts level on the surface
shall not exceed 20 mg/m2, and shall be measured in accordance with
ISO 8502-6 and ISO 8502-9. Other, proprietary field-testing
techniques may be used if agreed by the Principal.
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5. COATING APPLICATION
5.1 GENERAL
The following items shall not be coated:
Valve stems, flange faces, instrumentation components (pressure
gauges, etc), and any other machined contact surfaces.
Electrical wiring and cabling, plastics, rubber, and glass.
Nameplates, permanent labels, or instruction decals.
At areas where TSA cannot be applied due to equipment geometry
or inaccessible due to spacing between the TSA gun and surface to
be sprayed, a technical assessment should be performed to determine
the appropriate coating system to be applied. These areas shall be
kept to a minimum.
5.2 EQUIPMENT
The TSA coating should be applied using either a manual, fully
automated, or semi automated system, depending on the particular
piping or component geometry and area(s) requiring coating. The TSA
coating may be applied either in the shop or in the field
(on-site). The particular coating application system and procedures
shall require approval by the Principal and, if applicable, by the
Contractor, prior to production coating operations.
Generally, arc spray application should be used for new
equipment in the shop and flame spray application for maintenance
and on-site application.
The thermal-spray equipment shall be set up, adjusted and
operated according to the instructions and technical manuals of the
Manufacturer/Supplier or thermal spray Applicator.
The thermal-spray equipments spray-parameter set-up shall be
validated with a bend test (8.2.5) at the beginning of each shift
or crew change. The Principal shall receive a copy of the spray
parameters set-up.
5.3 ACCESS
All surfaces of the structure that have to be coated shall be
visible and within reach of the operator by a safe method.
Personnel involved in surface preparation, coating application, and
inspection shall be able to move safely and easily on all parts of
the structure in conditions of good lighting.
Scaffolding shall be constructed in accordance with local
regulations and the requirements of the Principal.
Surfaces which are to be blasted and coated should be
sufficiently accessible to allow the operator adequate space to
work in.
5.4 HOLDING PERIOD
Time between blasting of the steel surface and thermal spraying
shall be no greater than four (4) hours. If the holding period
exceeds 4 hours, the surface cleanliness shall be re-checked and
when the surface cleanliness is not in agreement with this DEP, the
surface shall again be cleaned and abrasive blasted in compliance
with this DEP.
5.5 MASKING
Areas not to be covered by thermal spray coating shall be
protected by masking. Self-bonding tapes, hardwood, rubber,
silicone rubber, or metallic masks should be used. Precautions
shall be taken to ensure that the masking material does not
contaminate the surface to be sprayed. If contamination has
occurred, the surface shall again be cleaned and abrasive blasted
in compliance with this DEP.
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5.6 THERMAL SPRAYING
No thermal spray coating work shall be carried out when the
temperatures of the steel surfaces is less than 3C (5F) above dew
point of the surrounding air, or the relative humidity of the air
is greater than 85%. Dew point determination shall be in accordance
with ISO 8502-4.
Before starting, and during flame spraying, the surface to be
coated shall be warm enough to prevent moisture (present in flame)
from condensing on the substrate. If condensation on the substrate
occurs, the surface should be preheated up to minimum 60C (140F).
In any case, oxidation of the surface during preheating shall be
avoided. This pre-heating can also be required to minimise the
internal stresses of the TSA layer on the steel substrate. This can
be validated with the bend test on companion coupons.
The specified coating thickness shall be applied in several
crossing passes. The coating tensile bond strength is greater if
the spray passes are kept thin. Laying down an excessively thick
spray pass increases the internal stresses in the TSA and decreases
the ultimate tensile bond strength of TSA. The suitability of the
crossing-pass thickness shall be confirmed with a bend test.
TSA coated surfaces shall not be in direct contact with carbon
steel, e.g. TSA coated pipe and steel support. A non-metallic
layer, e.g. PTFE, or elastomer strip should be used to avoid direct
contact between a TSA coated surface and its steel counterpart.
The spray equipment shall be operated in accordance with the
Manufacturer/Suppliers instructions and thermal sprayers
procedures.
5.6.1 Rust bloom
If rust bloom, blistering or a degraded coating appears at any
time during thermal spraying, the following procedure shall
apply:
Stop spraying; Mark the rejected sprayed area; Re-prepare the
rejected areas to the requirements of (8).
5.6.2 Feathering
The edges of the existing thermal spray coating shall be
feathered by abrasive blasting to provide a 50 mm to 75 mm (2 in to
3 in) overlap with the newly applied thermal spray coating.
5.7 COATING THICKNESS
Thickness of the TSA coating systems shall be in the range of
250 m to 500 m (10 mils to 20 mils);
The sealer coating shall have a maximum DFT of 40 m (1.6 mils).
The topcoat shall have the following DFT:
Epoxy sealer: maximum DFT 40 m (1.6 mils); Aliphatic
polyurethane finish coat: maximum DFT 50 m (2 mils).
5.8 SEALER AND TOPCOAT
Sealers shall be applied within 24 h after thermal spraying, if
the sealer application is performed indoors the time between
thermal spraying and sealer application may be increased to 48
h.
If moisture is present or suspected in the TSA pores, the steel
shall be heated up to 65C (149F) to remove moisture prior to the
sealer application. If possible, the steel from the reverse side of
the TSA shall be heated to minimize oxidation and contamination of
the TSA prior to sealing.
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Sealer, thinners (to lower viscosity of sealer), and topcoats
(paint) shall be supplied in unopened, clearly identified
containers. Handling, mixing and storage of sealer, thinner, and
coating materials shall be in accordance with the coating
Manufacturer's/Suppliers specifications. Sealers and coating shall
meet the local restrictions on Volatile Organic Compound (VOC)
content.
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6. QUALIFICATION
6.1 GENERAL
Each TSA-vendor and each individual TSA-sprayer shall be
pre-qualified before they are allowed to apply TSA for Shell
projects and operating companies.
This DEP may be used for general qualification purposes or for
specific projects.
General pre-qualification is performed for the purpose of an
overall qualification of the TSA-vendor, but is not necessarily
related to a specific project. Note: For this purpose Shell
companies may use the list of Technically Accepted Manufacturers
and
Products maintained by Shell Projects and Technology.
6.2 TSA-VENDOR QUALIFICATION
The TSA-Vendor qualification consists of the following
points:
a) review of application equipment and coating material
information, with as a minimum: Abrasives - name of product and
Manufacturer/Supplier, mesh size,
cleanliness report; Blasting and thermal spray equipment - type
and name of the
Manufacturer/Supplier; Spray material - name of
Manufacturer/Supplier, wire size, chemical
composition; Sealer - name of product and
Manufacturer/Supplier.
b) review of quality plan including surface preparation and
application procedures
c) review coating repair method
d) witness the coating application on the required test panels
and coupons
e) witness the coating testing, including sealer inspection.
f) witness coating repair application
The surface preparation shall be as specified in (4) of this
DEP. During the qualification the surface preparation procedure and
testing shall also be witnessed.
Arc or flame spraying application and both manual and mechanised
application techniques are allowed.
For each application process the qualification program is
required. This means that per application method, the following
test panels/coupons shall be coated:
i. two test pieces B1 according ISO 14918.
ii. at least 3 test coupons (150 mm x 150 mm, thickness 1.8 mm)
(6 in x 6 in, thickness thickness 70 mils) for bend testing.
iii. test panel, thickness 6 mm (1/4 in), with minimum surface
area of 1 m2 (1070 ft2 ) (also for sealer application).
iv. 2 test panels (200 mm x 200 mm x 6 mm), (8 in x 8 in x 1/4
in).
The applied coating thickness shall be 250 m minimum and 500 m
maximum (10 mils to 20 mils).
Testing shall be done according the test procedures in this
DEP.
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6.3 THERMAL SPRAYER QUALIFICATION
Before an individual thermal sprayer is qualified by the
Principal, it shall be shown that the individual applicator is
qualified in compliance with ISO 14918 for both manual and
mechanised application techniques. The qualification tests, as
specified in ISO 14918, Annex B.1 and B.9, shall be witnessed and
certified by an independent third party authority.
Individual sprayers shall be qualified in accordance with ISO
14918 requirements. Additional qualification tests as specified in
(6.4) shall be executed, and shall be witnessed by the Principal or
a delegate of the Principal. This qualification can be done during
the TSA-Vendor qualification.
For the test coupons, the same type of base steel shall be used
as the actual component, or structure to be coated. Surface
preparation, coating material, spray technique, coating thickness,
etc., shall comply with this DEP.
The coating repair methods proposed by the Contractor shall also
be qualified, in compliance with this DEP.
6.4 QUALIFICATION TESTS
6.4.1 Visual inspection of TSA-coating
The TSA coated surface on all test plates shall have a uniform
appearance, no blisters, bare patches, defects, or non-adhering
coating.
6.4.2 TSA-coating thickness
The coating thickness on all test plates shall be minimum 250 m
(10 mils). Local thickness of the thermal sprayed coating, e.g. at
corners, shall be maximum 2x the specified minimum thickness.
At least five measurements are taken at every 500 cm2 (78 in2)
of the test plates.
6.4.3 Bend test
Each thermal sprayer shall prepare and spray a minimum of three
companion bend test coupons [dimensions 150 mm x 50 mm, thickness
1.8 mm (6 in x 6 in, thickness thickness 70 mils)]. The thermal
spray bend test coupons shall not be sealed or topcoated. The
coating thickness shall be as specified in this DEP.
The bend test entails bending at least three thermal spray
coated steel coupons through 180 on a 13 mm (1/2 in) diameter steel
mandrel.
Should any one of the bend tests fail the acceptance criteria
specified in Table 2, the thermal sprayer may make one additional
attempt to qualify by spraying and testing a further three coupons.
Should any one these fail, the sprayer shall be deemed to have
failed the qualification test.
6.4.4 Adhesion test
Each thermal sprayer shall apply TSA at the required thickness
onto a test panel (thickness 6 mm (0.25 in)), with a minimum
surface area of approximately 1 m2 (10.7 ft2). The coated surface
shall not be sealed or topcoated.
The adhesion strength between the thermal spray coating and the
steel substrate shall be measured by means of a portable,
self-aligning, hydraulic controlled adhesion tester in accordance
with ISO 4624. The adhesive between the dolly and the thermal spray
coating shall be an epoxy.
A minimum of three pull-off adhesion tests shall be conducted.
Should any one of the pull off adhesion tests fail the acceptance
criteria, specified in Table 2, the thermal sprayer may make one
additional attempt to qualify by spraying and testing a further
panel. Should any one of the subsequent pull-off adhesion tests
fail, the sprayer shall be deemed to have failed the qualification
test.
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6.4.5 Sealer
If a sealer is specified, then following completion of the
pull-off adhesion tests, the test panel used shall be sealed with
the same sealer material that is to be used for the thermal sprayed
component or structure, and which shall comply with this DEP.
The sealed surface area of the thermal spray coated test panel
shall be examined by means of a microscope with minimum 10x
magnification. The sealed surface shall show 100% coverage, and no
open pores shall be present at the surface.
6.5 SUMMARY OF QUALIFICATION TESTS AND ACCEPTANCE CRITERIA
Table 2 Qualification test requirements for TSA vendor and
sprayer
Property Test method Measurements Acceptance criteria ISO
Qualification
ISO 14918, Annex B.1 and B.9
Thickness, visual, adhesion
Full compliance with ISO 14918
Coating appearance
Visual inspection 100% of surface Uniform appearance, no
blisters, bare patches, defects, or non-adhering coating
Coating Thickness
ISO 2808 (6.4.2) All surfaces 250 to 500 m (10 to 20 mils)
Coating Adhesion
ISO 4624 (6.4.4) At least 3, at random
> 7 MPa (1000 psi) (single measurement)
Overall quality
Bend test (6.4.3) At least 3 Minor cracks, with no coating
lifting or spalling, see Figure 1.
Sealer Visual inspection (6.8)
100% of surface 100% coverage, no open pores present at the
surface
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7. QUALITY ASSURANCE AND CONTROL
7.1 GENERAL
The Principal or their Representative shall have the right to
inspect, check or review, at all times, any or all of the
activities, equipment, inspection equipment or product designated
for the work. All parts of the work shall be accessible for this
purpose.
An independent third party authority to be agreed by the
Principal shall carry out regular quality checks. However, in no
way does this relieve the Contractor of any responsibility with
respect to the quality of the coating work.
The Principals Representative assigned to the coating
application work shall be given at least four hours' notice of any
change in the schedule of the coating activities.
Whenever any section is to be assembled that will prevent
subsequent inspection of an area, the Principals Representative
shall be notified in time, so that inspection and repair activities
can be carried out before proceeding with the assembly.
Both the applicator and the Manufacturer/Supplier of the coating
materials should implement a quality management system in
accordance with ISO 9001.
7.2 RESPONSIBILITY OF CONRACTOR AND COATING CONTRACTOR
The Coating Contractor is responsible for the quality of the
work, which shall be performed in accordance with this DEP, and all
other relevant documents such as site regulations, safety rules and
requirements, product data sheets, referenced standards and
codes.
The Contractor shall be responsible for all Quality Assurance
and Control activities.
The Contractor shall schedule a pre-job meeting to ensure that
job and quality requirements are fully understood. Attendees shall
include a representative of the Principal, the Contractors job
superintendent, the Coating Contractor, his coating supervisor and
the Contractors coating inspector.
For all coating work, the Contractor shall submit appropriate
work plans and a quality plan for implementing the requirements of
this DEP for review by the Principal. The quality plan shall fully
reflect the requirements of this DEP.
Unless otherwise agreed, the Contractor shall supply all the
weather protection, scaffolding and any other equipment necessary
to ensure that the work is carried out in accordance with this DEP
and the agreed programme. This includes, for example, heating and
air-drying equipment.
The Coating Contractor shall protect all equipment, structures
and any other areas from mechanical damage, environmental damage,
blockage or obstruction, or damage, caused by the coating work.
Copies of this DEP, the work plans and the quality plan shall be
made available to the coating Contractor's representative at the
site and the Contractor shall be familiar with their contents.
7.3 QUALITY PLAN
The quality plan of the Coating Contractor shall comply with ISO
14922-1 and ISO 14922-2.
Before commencing any work, a written project-specific quality
plan shall be submitted to the Principal for approval, at least 4
weeks prior to start executing work. This plan shall include:
a) A sequence for the various activities in relation to the
total work to be done;
b) Detailed scope of the work to be done including, per item or
area, the required surface preparation and coating system to be
applied;
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c) Full details of the blast and thermal spray equipment
including, where appropriate: dehydration, temperature, any other
environmental control measures, methods of access, etc.;
d) Details of coating materials used, including datasheets,
certificates;
e) Details of the personnel involved in the work together with a
clear definition of their responsibilities and lines of
communication;
f) Detailed procedures and plans for testing and inspection
including the methods and equipment to be used and the frequency of
their application and acceptance criteria; a typical Inspection and
Test Plan (ITP) is shown in Appendix 1.
g) Details documenting the essential steps in achieving
quality;
h) Dew point determination table;
i) Calibration methods of the inspection equipment;
j) Qualification of abrasive blasting and thermal spraying
personnel.
Following review and approval by the Principal, the project
quality plan may be updated and revised during the work, as and
when required. All revisions shall be submitted to the Principal
for approval prior to being included in the quality plan.
7.4 TESTING OF COATING PROPERTIES
7.4.1 Coating appearance
The thermal spray coating shall be free from defects such as
blisters, spatter, cracks, loose particles, areas with bare
substrate steel, etc., when examined with a microscope with 10x or
higher magnification.
Sealer visual inspection shall be performed for every 50 m2 (538
ft2) of manually sprayed, and for every 100 m2 (1076 ft2) of
mechanised sprayed coating. The sealed surface shall show 100%
coverage, and no open pores shall be present at the surface, when
examined with 10x or higher magnification.
7.4.2 Coating thickness
The specified TSA thickness range is 250 m to 500 m (10 mils to
20 mils). Spot checks shall be carried out during thermal spraying
of the coating to ensure that the specified coating thickness is
being maintained
The coating thickness shall be measured by means of a thickness
meter based on eddy-current or electromagnetic techniques, in
accordance with ISO 2808, methods 7B (magnetic-flux), 7C
(magnetic-induction) or 7D (Eddy-current).
For duplex stainless steel, continuous calibration is required
and for austenitic stainless steel, it is required to use the
Eddy-current method.
When TSA thickness readings are not possible on non-magnetic
substrates such as stainless steel, the use of companion coupons
made of carbon steel should be considered.
The coating thickness gauge shall be calibrated on the blasted
steel surface.
Based on the shape and size of the surface the number of
measurements shall be specified in agreement with the
Principal.
For flat surfaces, coating thickness measurements shall be taken
along a straight line. The average value of five readings taken in
a line at 25 mm (1 in) intervals shall be determined.
For complex geometries, a spot measurement shall be taken.
Thickness is determined by the average value of five readings taken
on a local area of approximately 10 cm2 (1.6 in2).
For the acceptance of an inspected area the following thickness
criteria shall apply:
Local thickness of the thermal sprayed coating shall not be
lower than 90% of the specified minimum thickness (7.5);
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Local thickness of the thermal sprayed coating, e.g. at corners,
shall be maximum 2x the specified minimum thickness.
If the thermal spray coating local thickness is less than 90% of
the specified minimum value (7.5), the thermal sprayer shall apply
additional layers to meet the thickness requirement.
If the local thickness is greater than the specified maximum
value, the Principal shall be notified for resolution of this
discrepancy. The pull-off adhesion test may be performed on a
coating with excessive thickness to check its integrity (maximum
thickness is 1000 m (40 mils)).
Any unacceptable applied thermal spray coating shall be blasted
off and a new coating applied, in compliance with this DEP.
The thermal sprayer shall record all areas with coating
thickness outside the specified minimum or maximum value.
7.4.3 Adhesion strength
The adhesion strength between the thermal spray coating and the
steel substrate shall be measured by means of a portable,
self-aligning, hydraulic controlled adhesion tester in accordance
with ISO 4624.
The adhesive between the dolly and the thermal spray coating
shall be an epoxy.
On test panels, the pull-off adhesion strength for thermal spray
coating shall be minimum 7 MPa (1000 psi) for any single
measurement. Three measurements shall be performed per test panel.
If one of the three measurements falls below the minimum specified
value of 7 MPa (1000 psi), but not lower than 6.3 MPa (900 psi),
the coating shall be accepted.
If any one value is less than 6.3 MPa (900 psi) or if two or
more readings are below 7 MPa (1000 psi), the thermal sprayed
surface shall be blasted off and a new coating applied, starting
from the location where the last acceptable pull-off strength was
measured.
Pull-off adhesion tests directly on the work piece shall be
performed at least once per 100 m (1070 ft2) of prepared surface,
with a minimum of three measurements per sprayer per shift. The
adhesion strength shall be minimum 8.4 MPa (1200 psi) (no cut shall
be made around the dolly). The adhesion test shall be stopped when
the value of 8.4 MPa (1200 psi) is reached, so no damage to the
work piece is taken place.
7.4.4 Bend test
During the thermal spray operation, steel companion coupons
shall be used to monitor the quality of the thermal spray
coating.
The bend test entails bending at least three steel coupons
(dimensions 150 mm x 150 mm, thickness 1.8 mm) (6 in x 6 in,
thickness thickness 70 mils) through 180 on a 13 mm (1/2 in)
diameter steel mandrel.
For the test coupons, the same type of steel shall be used as
for the actual component or structure to be coated. Surface
preparation, coating material, spray technique, coating thickness,
etc., shall comply with this DEP.
Three companion coupons shall be abrasive blasted and sprayed to
the specified minimum thickness range and a minimum of three bend
tests shall be performed once per 100 m (1070 ft2) of thermal
sprayed surface, with a minimum of three bend tests per day per
shift, and/or after any change in parameter settings of the spray
apparatus. When the test has shown a repeatable sufficient
performance, the Principal may decide to reduce the test frequency.
The thermal sprayed coupons for the bend test shall not be sealed,
or topcoated.
Typical bend test arrangement, visual appearance of pass and
fail samples and acceptance criteria are shown in Figure 1.
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Figure 1 Bend test arrangement: visual appearance and acceptance
criteria for pass and fail samples
If the bend test is failed, the thermal spray operation shall be
stopped, and corrective action shall be taken before thermal
spraying is continued.
7.4.5 Water spray test
When specified by the Principal, the water spray test should be
executed immediately after TSA application. The TSA coated surfaces
shall be wetted with potable water. After 24 hours, continuous
wetting the surface shall be re-examined for any signs of rusting
or bleed thru. If these areas are present, the coating thickness in
these areas shall be measured. If the coating thickness is below
250 micron (10 mils) the section needs to be repaired. A low
pressure sweep blast on this area should be performed and
additional TSA shall be applied.
The water spray test is applicable to 100 % of the coated
surface.
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7.5 SUMMARY OF QUALITY CONTROL TESTING AND ACCEPTANCE
CRITERIA
Table 3 Test requirements for TSA coating during TSA coating
production
Property Test method Measurements Acceptance criteria
Coating appearance
Visual inspection 100 % of surface Uniform appearance, no
blisters, bare patches, defects, or non-adhering coating
Coating Thickness
ISO 2808 (7.4.2) All surfaces 250 to 500 m (10 to 20 mils)
Coating Adhesion
ISO 4624 (7.4.3) At least 3, at random > 7 MPa (1000 psi) on
test plate > 8.4 MPa (1200 psi) on work piece
Overall quality
Bend test (7.4.4) At least 3 Minor cracks, with no coating
lifting or spalling, see Figure 1.
Coating thickness
Water spray test (7.4.5) 100 % of surface No discolouration,
rusting or bleed thru
7.6 QUALITY RECORDS
The coating Contractor or Applicator shall keep and submit to
the Principal accurate records of all relevant data of the surface
preparation, spray process, sealer and topcoat materials.
The documentation shall include as a minimum:
Record of contract / design review; Surface preparation abrasive
material type and size, cleanliness of abrasive,
compressed air cleanliness, surface cleanliness, surface
profile;
Material certification; Thermal spraying procedure
specification; Thermal spraying procedure approval test records;
Thermal sprayer approval certification; Pre and post treatment and
procedures specification records; Dimensional reports, including
coating thickness; Records of repairs or new thermal spraying.
Quality records shall be submitted to the Principal after
completion of the coating work together with the calibration
certificates of the testing and measuring instruments. Quality
records should be retained for a minimum period of 5 years.
7.7 INSPECTION PERSONNEL AND EQUIPMENT
All inspection personnel shall be individually certified by a
recognized Accreditation / Inspection Agency, e.g. NACE, Lloyds,
DNV, TV or Velosi, to be agreed by the Principal.
The Contractor shall provide and use all inspection equipment
necessary to ensure that the specified conditions and quality
requirements are achieved.
7.8 FINAL INSPECTION
As part of the Quality Assurance (QA), a final inspection shall
be conducted prior to acceptance of the thermal spray coating work.
This final inspection shall include a visual check of the
appearance and overblast of the coating work, and checks on total
thickness of coating system, when completed.
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The Contractor and the Principal shall both be represented and
they shall sign an agreed acceptance form as part of the warranty
agreement.
As part of the acceptance procedure, the Contractor shall
prepare a report including the following:
1. General
Name of the Contractor / Applicator and the responsible
personnel. Scope of work. Dates when work was carried out. Copies
of the work and quality plan. Deviations from this DEP and the
quality plan.
2. Inspection equipment
Type and calibration of instruments used. 3. Surface
preparation:
Condition of surface before preparation. Checks of surface
cleaning as specified in this DEP.
4. Coating application
Information on coating materials being applied (i.e. spray
material, sealer, topcoat, etc.).
Checks of coating application as specified in this DEP. Check on
thickness of the applied coating.
5. Inspection reports
Copy of the inspection reports of the Contractor. Inspection
reports from an independent third party. Qualification and
production test results.
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8. COATING REPAIR
8.1 GENERAL
The Applicator shall produce a coating repair procedure, to be
agreed by the Principal. Only qualified coating repair methods
shall be used, in compliance with this DEP. This repair procedure
shall be verified and approved during the qualification trials
(6)
If the thermal spray coating has been mechanically damaged and
bare substrate metal is observed, the coating shall be repaired,
including the local (repair) application of a new sealer, and/or
topcoat, if applicable.
The damaged area shall be pre-cleaned, followed by local blast
cleaning to a minimum of Sa 2.5, in compliance with this DEP.
Edges of the remaining existing coating system shall be
feathered by abrasive blasting, and the remainder of the adjacent
coated surface shall be properly protected.
Local (repair) application of thermal spray coating shall be in
compliance with this DEP, including local (repair) application of
new sealer and topcoat.
When the size of the defects is small, it may be acceptable to
use a liquid paint to repair the damage. The maximum defect size
allowable for liquid paint repair shall be 10 cm2 (1.55 in2). The
use of liquid paint repairs shall be approved by the Principal.
If the thermal spray coating only shows local surface damage,
the area shall be pre-cleaned, followed by local sweep blasting.
The adjacent coated surface shall be properly protected (masking).
The locally restored thermal spray coating, including sealer / top
coat, shall meet the minimum thickness requirements.
Arc-spray coating should not be applied on existing
flame-sprayed coating because of the risk of coating delamination
damage. However, flame-sprayed coating applied on existing
arc-sprayed coating is acceptable.
If only the sealer or topcoat has been damaged, the surface
shall be prepared by abrasion with medium coarse abrasive paper
until a clean bright surface is visible. Edges of the remaining
coating at the location of the repair shall be feathered. The
re-applied sealer / topcoat system shall be compatible with the
existing coating system.
8.2 FIELD WELDS
It is recommended to have a cutback length of 100 mm to 200 mm
(4 in to 8 in) to prevent disbonding issues with the TSA applied on
the pipe body during welding.
Weld spatter shall be ground flush.
Prior to the blast cleaning and/or thermal spraying, the surface
at the field weld to be coated shall be free of any contamination
and any excessive rust scale shall be removed.
Cleaning of the field weld surface shall be done by dry (vacuum)
blast cleaning, to at-least Sa 2.5, in accordance with ISO
8501-1.
The steel surface roughness shall be between 75 m and 110 m (3
and 4.5 mils), in accordance with ISO 8503-5. The surface shall
have a sharp angular profile.
Edges of the remaining existing coating system shall be
feathered by abrasive blasting, and the remainder of the adjacent
coated surface shall be properly protected.
Surface preparation and coating application for field welds
shall comply with this DEP.
Arc-spray coating shall not be applied on existing flame-sprayed
coating because of the risk of coating delamination damage.
However, flame-spray coating applied on existing arc-sprayed
coating is acceptable.
Prior to commencement of field weld application, the Coating
Contractor shall perform a qualification trial based on the
proposed work method and equipment used for the field weld
application.
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9. STORAGE AND HANDLING
For coated components, canvas or nylon slings should be used for
lifting, and wooden, rubber or plastic blocks shall be applied
during transportation. Coated objects, pipes, etc. should be stored
and handled in such a manner as to prevent damage.
To avoid damage of the coating, the Contractor should supply all
the necessary protection when storing coated components in the open
air prior to construction.
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10. REFERENCES
In this DEP, reference is made to the following publications:
NOTES: 1. Unless specifically designated by date, the latest
edition of each publication shall be used,
together with any amendments/supplements/revisions thereto.
2. The DEPs and most referenced external standards are available
to Shell staff on the SWW (Shell Wide Web) at
http://sww.shell.com/standards/.
SHELL STANDARDS
Shop and Field Pressure Testing of Piping Systems DEP
74.00.10.10-Gen
AMERICAN STANDARDS
Design, Fabrication, and Surface Finish Practices for Tanks and
Vessels to Be Lined for Immersion Service
NACE SP0178
Standard Test Method for Indicating Oil or Water in Compressed
Air ASTM D 4285
INTERNATIONAL STANDARDS Aluminium and Aluminium Alloys Chemical
Composition ISO 209
Paints and Varnishes - Determination of Film Thickness ISO
2808
Paints and Varnishes Pull-off Test for Adhesion ISO 4624
Preparation of Steel Substrates Before Application of Paints and
Related Products. Visual Assessment of Surface Cleanliness. Rust
grades and preparation grades of uncoated steel substrates and of
steel substrates after overall removal of previous coatings
ISO 8501-1
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
(Presssure-Sensitive Tape Method)
ISO 8502-3
Preparation of Steel Substrates Before Application of Paints and
Related Products - Tests for the Assessment of Surface Cleanliness
- Part 4: Guidance on the Estimation of the Probability of
Condensation Prior to Paint Application
ISO 8502-4
Preparation of Steel Substrates Before Application of Paints and
Related Products - Tests for the Assessment of Surface Cleanliness
- Part 6: Extraction of Soluble Contaminants for Analysis - The
Bresle Method
ISO 8502-6
Preparation of Steel Substrates Before Application of Paints and
Related Products - Group B: Methods for the Assessment of Surface
Cleanliness - Part B9: Field Method for the Conductometric
Determination of Water-Soluble Salts
ISO 8502-9
Preparation of steel substrates before application of paints and
related products Surface roughness characteristics of blast-cleaned
steel substrates Part 5: Replica tape method for the determination
of the surface profile
ISO 8503-5
Preparation of Steel Substrates Before Application of Paints and
Related Products - Surface Preparation Methods - Part 2: Abrasive
Blast-Cleaning
ISO 8504-2
Quality Management Systems - Requirements ISO 9001
Preparation of Steel Substrates Before Application of Paints and
Related Products - Specifications for Metallic Blast-Cleaning
Abrasives
ISO 11124-2
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Preparation of Steel Substrates Before Application of Paints and
Related Products - Specifications for Metallic Blast-Cleaning
Abrasives - Part 3: High-Carbon Cast-Steel Shot and Grit
ISO 11124-3
Preparation of Steel Substrates Before Application of Paints and
Related Products - Specifications for Non-Metallic Blast- Cleaning
Abrasives - Part 4: Coal Furnance Slag
ISO 11126-4
Preparation of Steel Substrates Before Application of Paints and
Related Products - Specification for Non-Metallic Blast-Cleaning
Abrasives Part 7: Fused Aluminium Oxide
ISO 11126-7
Preparation of Steel Substrates Before Application of Paints and
Related Products - Specification for Non-Metallic Blast-Cleaning
Abrasives Part 9: Staurolite
ISO 11126-9
Preparation of Steel Substrates Before Application of Paints and
Related Products - Specifications for Non-Metallic Blast-Cleaning
Abrasives - Part 10: Almandite Garnet
ISO 11126-10
Preparation of Steel Substrates Before Application of paints and
Related Products - Test Methods for Non-Metallic Blast-Cleaning
Abrasives
ISO 11127
Protective Clothing for Use in Welding and Allied Processes ISO
11611
Protective Clothing - Clothing to Protect Against Heat and Flame
ISO 11612
Paints and Varnishes - Corrosion Protection of Steel Structures
by Protective Paint Systems
ISO 12944-3
Thermal Spraying - Approval Testing of Thermal Sprayers ISO
14918
Thermal Spraying - Quality Requirements of Thermally Sprayed
Structures - Part 1: Guidance for Selection and Use
ISO 14922-1
Thermal Spraying - Quality Requirements of Thermally Sprayed
Structures - Part 2: Comprehensive Quality Requirements
ISO 14922-2
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APPENDIX 1 INSPECTION AND TEST PLAN THERMAL SPRAY ALUMINIUM
APPLICATION NEW EQUIPMENT
No Item/Process Process description
Requirement Test Frequency Project Specification section
DEP 30.48.40.31 section
Responsible parties (HOLD points, etc)
Remarks
1.0 Pre-job meeting Check quality
plan As per specification
7.3
Qualification of TSA sprayers
Pass test criteria as per specification
6.3 to 6.5
Safety issues 2.3 2.0 Checks before Surface preparation
Visual
inspection and cleaning before blasting
Free from oil grease and other contamination
All 4.2
Check blasting equipment
Per shift 4.3.3
Check blasting material
Per shift 4.3.2
Atmospheric conditions
Per shift 4.3.1
Tool air conditions
Free from oil and water
Per shift/daily 4.3.3
3.0 Inspection after surface preparation Cleanliness Sa2.5 All
4.3.4 Surface
roughness 75 110 m (3 - 4,5 mils)
Once per 100 m2 (1070 ft2) Minimum 3 measurements per day per
shift
4.3.5
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No Item/Process Process description
Requirement Test Frequency Project Specification section
DEP 30.48.40.31 section
Responsible parties (HOLD points, etc)
Remarks
Chloride contamination
< 20 mg/m2 Once per 100 m2 (1070 ft2) Minimum 3 measurements
per day per shift
4.3.7
Dust level Class 1 Once per 100 m2 (1070 ft2) Minimum 3
measurements per day per shift
4.3.6
4.0 Checks before TSA application Atmospheric
conditions Per shift 5.6
Verification of TSA-application apparatus
Per shift 5.2
Verification of Al-wire
Per shift 3.1
Tool air conditions
Free from oil and water
Per shift/daily
5.0 TSA application 5.6 6.0 Inspection after TSA application
Visual
inspection Free from blisters, cracks, spatters, etc.
all 7.4.1
Coating thickness
250 500 m (10 20 mils)
7.4.2
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No Item/Process Process description
Requirement Test Frequency Project Specification section
DEP 30.48.40.31 section
Responsible parties (HOLD points, etc)
Remarks
Adhesion
Duplicate pull-off test on plate Duplicate pull-off test on
equipment
> 7 MPa (1000 psi) > 8.4 MPa (1200 psi)
(non-destructive)
Per sprayer per day, i.e. 2 dollies on testplate per sprayer Per
shift/daily
7.4.3
Bend test Pass acceptance criteria
3 coupons per sprayer per day
7.4.4
Water spray test
No rusting or bleeding through
After TSA application
7.4.5
7.0 Final inspection 7.8
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APPENDIX 2 EXAMPLE OF INSPECTION FORM FOR TSA APPLICATION
Inspection results:
Clint : Inspector :
Project : Coordinator :
Sprayer Location : Date :
Contractor /main supplier:
Present during inspection:
example
No Process description Requirement Results Item OK NOK NA
1 Checks before Surface preparation Preparation of welds No
sharp edges, radius >3 mm
min.
Visual inspection and cleaning before blasting
Free from oil grease and other contamination
Checkblastingequipment
Checkblastingmaterial
Atmospheric conditions Max 85% RH min. 5C max 35C surface 3
above DP.
Tool Air conditions Free from oil and water
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2 Checks after surface preparation Atmospheric conditions Max
85% RH min. 5C max
35C surface 3 above DP.
Cleanliness Sa 2
Surface roughness 75 110 m (3 4.5 mils)
Chloride contamination < 20 mg/m2
Dust level Class 1
3 Checks before TSA application Atmospheric conditions Max 85%
RH min. 5C max
35C surface 3 above DP.
Verification of TSA-application apparatus
Verification of Al-wire AA1100
Tool Air conditions Free from oil and water
4 Checks after TSA application Visual inspection Free from
blisters, cracks,
spatters, etc.
Coating thickness 250 500 m (10 20 mils) See general
Adhesion > 7 MPa (1000 psi) on test coupon min 8.4 MPa (1200
psi) on workpiece (none destructive)
See general
Bend test Pass acceptance criteria
Water spray test
5 Checks contractors QA/QC documentation Check reports from
applicator Complete and up to date
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The following Items have been inspected: Description:
No. No. of test dollies
Item Pull-off adhesion test.
Pull off adhesion testing 1 1
Pull off adhesion testing 2 1
Pull off adhesion testing 3 1
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1. INTRODUCTION1.1 SCOPE1.2 DISTRIBUTION, INTENDED USE AND
REGULATORY CONSIDERATIONS1.3 DEFINITIONS1.4 CROSS-REFERENCES1.5
SUMMARY OF MAIN CHANGES1.6 COMMENTS ON THIS DEP1.7 DUAL UNITS
2. GENERAL REQUIREMENTS2.1 GENERAL2.2 DOCUMENT HIERARCHY2.3
SAFETY2.4 COMPANY ACCESS2.5 PRE-JOB MEETING
3. MATERIALS3.1 BACKGROUND3.2 THERMAL SPRAY COATING3.3 SEALER3.4
TOP COAT
4. SURFACE PREPARATION4.1 GENERAL4.2 CLEANING4.3 ABRASIVE BLAST
CLEANING
5. COATING APPLICATION5.1 GENERAL5.2 EQUIPMENT5.3 ACCESS5.4
HOLDING PERIOD5.5 MASKING5.6 THERMAL SPRAYING5.7 COATING
THICKNESS
6. QUALIFICATION6.1 GENERAL6.2 TSA-VENDOR QUALIFICATION6.3
THERMAL SPRAYER QUALIFICATION6.4 QUALIFICATION TESTS6.5 SUMMARY OF
QUALIFICATION TESTS AND ACCEPTANCE CRITERIA
7. QUALITY ASSURANCE AND CONTROL7.1 GENERAL7.2 RESPONSIBILITY OF
CONRACTOR AND COATING CONTRACTOR7.3 QUALITY PLAN7.4 TESTING OF
COATING PROPERTIES7.5 SUMMARY OF QUALITY CONTROL TESTING AND
ACCEPTANCE CRITER7.6 QUALITY RECORDS7.7 INSPECTION PERSONNEL AND
EQUIPMENT7.8 FINAL INSPECTION
8. COATING REPAIR8.1 GENERAL8.2 FIELD WELDS
9. STORAGE AND HANDLING10. REFERENCESAPPENDIX 1 INSPECTION AND
TEST PLAN THERMAL SPRAY ALUMINIUM APPENDIX 2 EXAMPLE OF INSPECTION
FORM FOR TSA APPLICATION