TABLE OF CONTENTS · 3.2 DRAWINGS Fabricator shall maintain an up to date record of all applicable drawings at all times. Piping fabrication shall take place from isometric and/or

Neptune Energy Netherlands B.V.

Specification 502 rev. 18 Page 2 of 37

TABLE OF CONTENTS

1.0 SCOPE ............................................................................................................................................... 4

2.0 CODES, STANDARDS AND SPECIFICATIONS.............................................................................. 5

3.0 PIPING FABRICATION .................................................................................................................... 7

3.1 GENERAL ........................................................................................................................................................... 7 3.2 DRAWINGS ....................................................................................................................................................... 7 3.3 PRE-FABRICATION ......................................................................................................................................... 8 3.4 WELDING CARBON STEEL .......................................................................................................................... 8 3.4.1 General .......................................................................................................................................................... 8 3.4.2 Welding Procedure Specifications WPS........................................................................................... 8 3.4.3 Welding Procedure Qualification ....................................................................................................... 9 3.4.4 Welders Competence ............................................................................................................................ 10 3.4.5 Welding preparation ............................................................................................................................. 10 3.4.6 Earthing ....................................................................................................................................................... 10 3.4.7 Welding Consumables .......................................................................................................................... 10 3.4.6 Weld numbering ..................................................................................................................................... 11 3.4.7 Production welding ................................................................................................................................ 11 3.4.8 Repairs ......................................................................................................................................................... 12 3.4.9 Post Weld Heat Treatment (PWHT) ................................................................................................. 12 3.4.10 Golden Weld ............................................................................................................................................. 12 3.5 PIPE SUPPORT FABRICATION AND INSTALLATION ....................................................................... 12

4.0 PIPING INSTALLATION ................................................................................................................ 13

4.1 REMARKS FOR PIPING INSTALLATION ............................................................................................... 13 4.2 FLANGE JOINTING AND BOLTING ........................................................................................................ 15 4.2.1 Scope ........................................................................................................................................................... 16 4.2.2 Codes ........................................................................................................................................................... 16 4.2.3 Bolting-up Requirements and selection of tools ....................................................................... 16 4.2.4 Flange Inspection and Preparation .................................................................................................. 18 4.2.5 Gasket / ring Inspection and Preparation ..................................................................................... 18 4.2.6 Stud / nut inspection and preparation ........................................................................................... 20 4.2.7 Installation Procedure - Tensioning ................................................................................................ 20 4.2.8 Tools ............................................................................................................................................................. 21 4.2.9 Bolt-up Sequence ................................................................................................................................... 22 4.3 THREADED CONNECTIONS ..................................................................................................................... 23 4.3.1 Guidelines for the making of small-bore NPT connections ................................................... 23 4.3.2 Material problems in making threaded connections ............................................................... 24 4.3.3 Galvanic corrosion and threaded connections ........................................................................... 25

5.0 REQUIREMENTS FOR NON CARBON STEEL AND GALVANISED PIPING .............................. 25

5.1 REQUIREMENTS FOR DUPLEX STEEL, SUPER DUPLEX STEEL (CLASS … DS) AND

STAINLESS (S) .............................................................................................................................................................. 25 5.1.1 Handling Duplex steel (See Attachment I to this specification) and Stainless Steel. ... 25 5.1.2 Welding of Duplex steel and Stainless (316L) ............................................................................. 25 5.1.3 Pickling and passivating of Duplex steel and Stainless (316L).............................................. 25 5.2 REQUIREMENTS FOR CUNIFER PIPING (CLASS 15UK) .................................................................. 25 5.2.1 General ........................................................................................................................................................ 26 5.2.2 Handling ..................................................................................................................................................... 26 5.2.3 Welding ...................................................................................................................................................... 26



5.3 REQUIREMENTS FOR POLY ETHYLENE PIPING (CLASS 15UP) ................................................... 26 5.4 REQUIREMENTS FOR HOT DIP GALVANISED PIPING (CLASS 15U) ......................................... 27 5.5 CLASS U2 ......................................................................................................................................................... 27 5.5 SYSTEMS THAT REQUIRE EXTRA GRADE OF CLEANING .............................................................. 28

6.0 FLUSHING AND PRESSURE TESTING ......................................................................................... 29

6.1 SCOPE ............................................................................................................................................................... 29 6.2 FLUSHING ....................................................................................................................................................... 29 6.2.1 Systems that require extra grade of cleaning. ............................................................................ 29 6.2.2 Systems to be cleaned as hydraulic control piping................................................................. 29 6.3 TESTING AND TEST SYSTEMS ................................................................................................................. 30 6.3.1 Procedure Onshore ................................................................................................................................ 30 6.3.2 Medium ...................................................................................................................................................... 32 6.3.3 Testing and recording ........................................................................................................................... 33 6.3.4 Preparation system after testing ...................................................................................................... 34 6.3.5 Alternative methods .............................................................................................................................. 34 6.3.6 Inspection and witnessing ................................................................................................................... 34 6.4 SAFETY DURING PRESSURE TESTING .................................................................................................. 34

7.0 QC PIPING FABRICATION ............................................................................................................ 35

7.1 GENERAL ......................................................................................................................................................... 35 7.2 INSPECTION PIPING PREFABRICATION .............................................................................................. 35 7.2.1 Preparation for coating ........................................................................................................................ 35 7.3 INSPECTION PIPING INSTALLATION .................................................................................................... 35 7.4 NON DESTRUCTIVE TESTING .................................................................................................................. 36 7.4.1 Quantities ................................................................................................................................................... 36 7.4.2 Types and standards for NDT ............................................................................................................ 36

8.0 DOCUMENTATION ....................................................................................................................... 37

9.0 DELIVERY AND TRANSPORT ....................................................................................................... 37

10.0 ATTACHMENTS ............................................................................................................................. 37



1.0 SCOPE

This specification is intended to supplement and confirm good working practice during

fabrication, assembly and erection of piping onshore and offshore.

The fabrication and assembly shall be in accordance with industry codes, specifications and

"Approved for Construction Drawings".

All piping shall be designed, fabricated and inspected per subject General Specifications and

according to PED and NEN-EN 13480 for platform piping and in accordance with NEN 3650

for transport pipelines (requirements for pipeline systems) and NEN 3656 Requirements for

submarine pipeline systems in steel).



2.0 CODES, STANDARDS AND SPECIFICATIONS

All piping shall be designed, fabricated and inspected per subject General Specifications and

according to Pressure Equipment Directive (PED) and/or NEN 3650 & NEN 3656.

If piping is actually subject to authorisation per PED:

this will be clearly indicated on the "Approved for Construction drawings",

all required fabrication and testing approvals for subject piping shall be obtained.

If piping is actually subject to authorisation per NEN 3650 or NEN 3656:

this will be clearly indicated on the "Approved for Construction drawings",

All piping shall be fabricated per this specification and as specified by the latest revision of:

ANSI B31.3 : Petroleum Refinery Piping,

ANSI B.1-20.1 : Pipe Threads, General Purpose

ANSI B.1.1 : Unified Inch Screw Threads

NEN-EN 13480 : Metallic Industrial Piping – All parts.

NEN 3650 : Requirements for onshore pipeline systems

NEN 3656 : Requirements for submarine pipeline systems in steel.

NEN-EN-ISO 3834-2 : Quality requirements for fusion welding of metallic materials.

All materials shall be in accordance with the latest revision of Company Specification 503 - General

Specification for Pipe, Fittings and Valves.

All surfaces shall be coated in accordance with the latest revision of Company Specification 525 -

General Painting and Coating Specification.

All welding of duplex steel shall be per subject attachment to this specification.

All pipe supporting shall be in accordance with the latest revision of the drawings for Pipe

Supporting and applicable General Specifications.

Terms and Definitions

The following terms and definitions apply in this Specification:

COMPANY shall mean ENGIE E&P Nederland or its appointed representative

CONTRACTOR shall mean the organisation providing the materials and/or as defined by

COMPANY

SUB-CONTRACTOR the COMPANY approved SUB-CONTRACTOR(s) of

the CONTRACTOR

NOTIFIED BODY Notified Body, as described by the Official Journal of

the European Communities.

Shall indicates a mandatory requirement.

Should indicates a preferred method.



Abbreviations

The following abbreviations have been used and apply in this Specification:

AFC Approved For Construction

CBI Conformiteits Beoordelings Instantie (was AKI, Aangewezen Keurings Instantie)

CS Carbon Steel

DAD Design Appraisal Document

DS Duplex Steel

FP Full Pen

GA General Arrangement

HAZ Heat Affected Zone

LR Latest Revision

LG Level Gauge

MDR Manufacturing Data Record

MIG Metal Inert Gas

MTO Material Take Off

NDT Non Destructive Testing

NoBo Notified Body

NPT National Pipe Tread

N2 Nitrogen

N2He Nitrogen wit Helium

PED Pressure Equipment Directive

PI Pressure Indicator

PWHT Post Weld Hetreatment

QC Quality Control

Scf Standard cubic feet

SS Stainless Steel

TIG Tungsten Inert Gas

UK Cunifer, Bronze, Messing

UP Polyethylene

WPS Welding Procedure Specification

WT Wall Thickness



3.0 PIPING FABRICATION

3.1 GENERAL

Fabrication shall take place according to a QC-plan and a test & inspection plan prepared by

Contractor. This plan is to be approved by Company and CBI (EU, if applicable) before start of

fabrication. As a minimum, the test & inspection plan shall include the applicable items indicated

in this specification.

Personnel shall be capable and experienced for all applicable trades.

During all stages of the work all materials used, shall be traceable and shall comply with all relevant

documents and certificates.

Appropriate fabrication/shop/material administration will be prepared and followed, system

subject to approval by Company.

If pipes are to be cut into shorter lengths the identification marks shall be re-stamped on the outer

surface of the pipe witnessed by Notified Body (NoBo) where applicable, or fabricator’s QC-

department prior to cutting.

All material shall be visually inspected upon arrival on the construction site for damage, corrosion,

proper protection, weld requirements for weldolets and marking, and certification.

Any deviations shall be reported to Company. All material shall be stored according to the

recommendations of the Supplier, until required for use.

Piping under fabrication for Company shall be fabricated and stored at all times separate from

other piping under fabrication. Detailed records of required, delivered, used, Surplus and abortive

materials will be kept at all times.

Fabrication shall take place under suitable conditions (shop), at all times spools/piping shall be kept

clean (inside mainly for debris/dirt, outside especially for metallic contamination of other (piping)

metal contamination.

If any construction is to be carried out in the vicinity of piping or equipment already installed then,

before such construction work commences adequate protection shall be provided to prevent any

damage from weld spatter, arc cutting droplets etc.

Care shall be taken to avoid overstressing, damage or deformation in any of the piping components

at all stages of the work. Shrinking or hot bending is not allowed in any case.

No field or other welding or other hot work shall be carried out before, where applicable, a hot

work permit has been obtained.

3.2 DRAWINGS

Fabricator shall maintain an up to date record of all applicable drawings at all times.

Piping fabrication shall take place from isometric and/or other drawings containing all required

information for material identification, fabrication, testing, coating, etc.

Piping installation shall take place from isometric and/or GA’s, support and penetration drawings,

and other drawings containing all required information.



Information for piping fabrication and installation shall be subject to approval by Company. Based

on all drawings the exact as built situation shall be recorded and made available to Company. within

the specified time frame as agreed upon.

3.3 PRE-FABRICATION

During all stages of the prefabrication, all used materials shall be traceable and shall comply with

all relevant documents and certificates.

During all stages of the fabrication, all pipe spools shall be properly tagged with their unique spool

number. Labels shall remain on the spool up to the installation. Labels shall be selected and

attached so that during and after blasting and painting the spool number remains readable.

All piping shall be identified using stickers, clearly readable marking indicating the unique line

number.

Contractor shall apply one sticker per isometric.

This is not applicable for exhaust piping and cunifer piping.

Blomsma stickers (Offshore Signage Standard North Sea Sector) to be used.

Piping spool dimensions shall be selected such that they can be handled in all stages of the work

without damages or overstressing and that tension free installation is ensured.

Piping spools shall be fabricated such that dimensional inaccuracies due to welding are minimised.

All measures shall be taken to ensure correct positioning and fit-up of the components to be

welded.

Before lining-up, the weld ends shall be cleaned to remove all foreign particles.

Fit -up and tackwelding shall comply with the welding procedures.

Bullets from the pipematerial shall be used for tackwelding.

Removal of bullets shall be done by grinding only.

Doubler plates and re-inforcement pads shall be fabricated from the main material (pipe, plate)

unless otherwise approved. Doubler plates and re-inforcement pads shall have a 1/4" NPT hole

and shall be tested (1 bar air) before pressure test pipe, tank or vessel.

3.4 WELDING CARBON STEEL

(For additional remarks on welding of duplex steel, see Attachment I to this specification.)

3.4.1 General

Fit-up and welding for piping shall be per applicable codes and specifications, and shall further

fulfil all requirements as described in the welding procedures.

Further to obtain a clean piping system the welding process for the root and first following layer

shall be TIG- or MIG-based (to exclude the chance on slag on the inside of the weld).

3.4.2 Welding Procedure Specifications WPS

A written welding procedure specification together with test certificates indicating mechanical

properties and chemical analyses of both base materials and welding consumables shall be

submitted to the Company representative for preliminary approval.



No procedure qualification tests shall be performed until the procedure specification has been

granted preliminary approval by the Company representative.

Welding procedure specifications shall contain the following "applicable parameters" with all

explanatory details necessary see also : ISO 15609

Material specification of base metals.

Welding process.

Wall thickness and diameter range used for procedure qualification (chemical analyses and

mechanical properties of the base material and welding consumables used for the procedure

tests shall be included in the welding procedure qualification record).

Geometry of welding groove showing allowable tolerances.

Root gap showing allowable tolerances.

Welding position and direction.

Filler metal classification.

Specification of flux.

Gas shielding - flow, mixture, composition (to include back purging).

Number and sequence of the important passes (indicate stringer or weave beads).

Welding current range, voltage range and polarity.

Travel speed or electrode runout length for each pass and range.

Heat input range.

Preheat and interpass temperatures.

Method of cleaning, cutting and machining if applicable.

When any changes in these parameters are made, the welding procedure qualification shall be set

up as a new WPS, and shall be completely re-qualified.

3.4.3 Welding Procedure Qualification

Contractor shall demonstrate to Company and if applicable to NoBo, that welding procedures and

repair welding procedures that will be applied have been qualified in accordance with the

applicable PED, NEN-EN 13480 – Prescriptions for Platform Piping or NEN 3650 – Transport

Pipelines Pipelines and NEN3656 - Requirements for submarine pipeline systems in steel.

All welding shall be multiple pass.

All weld caps shall be multiple pass for WT of 8mm and above.

No welding shall be carried out before the Welding Procedure Specifications and the procedure

qualification records are completed and approved by Company.



3.4.4 Welders Competence

Contractor shall demonstrate that the welders have been rated adequate in accordance with the

applicable PED, NEN-EN 13480 – Prescriptions for Platform Piping and NEN 3650 – Transport

Pipelines or NEN3656 Requirements for submarine pipeline systems in steel.

Each welder shall carry evidence of his qualification with him.

Each welder shall stamp each weld directly adjacent to the weld metal made by him with his

identification mark (low stress stamps).

3.4.5 Welding preparation

Internal and External surfaces to be welded shall be clean and free from paint, slag, spatter, oil,

rust, scale, salt or other material that would be detrimental to either the weld or the base metal

under welding conditions.

Butt weld end preparation is acceptable only if the surface is reasonably smooth, true and all slag

from oxygen or arc cutting is cleaned from flame cut surfaces. Discoloration (for carbon steel only)

which remain on a flame cut surface is not considered to be detrimental oxidation.

When material subject to "NoBo / AKI approval" is (thermally) removed, the place of attachment,

after grinding, must be subjected to a complete surface examination. (This consists of welded-on-

parts accessories, surplus material, etc. cut or gouged away.)

Complete weld preparation (inside diameter, alignment on inside diameter, root-opening, wall

thickness etc.) shall be as defined in the procedure qualification.

If the external surfaces of the two components are not aligned, the weld shall be tapered between

the two surfaces. (Tapering 1: 4)

When bevelling on a weld, after Company approval, (for instance to reduce misalignment) is

obtained by weld reinforcement, this reinforcement must be subjected to a complete non-

destructive examination.

3.4.6 Earthing

All welding work shall be properly earthed with the earthing point as close as possible to the joint

to be welded. The earthing point for field welds shall not be beyond any valves or other installed

equipment. Earthing marks shall be ground smooth and 100% MPI / DPI tested.

3.4.7 Welding Consumables

Only welding consumables in accordance with NEN-EN 13479 "Welding Consumables" latest

edition shall be used.

Electrodes shall be supplied in fully sealed packages and stored in a dry storage room and handled

according to the manufacturer's recommendations. All manual type electrodes shall be properly

identifiable up to the time of usage, each electrode being distinguished by proper coding. If the

coding is destroyed by baking, handling, or other causes, the electrodes shall not be used.



Electrodes used for stainless steel shall not be stored in heating cabinets containing electrodes of

other types.

Wire spools for automatic and semi-automatic processes shall be stored in cabinets with supplier

wrapping not removed and remain clearly identifiable up to the time of usage. Unidentifiable wire

shall not be used.

Each batch of wire shall be labelled with the information from the supply container. The labels with

batch number shall be recorded for reference in relation to the actual welding work.

Manual electrodes and wire shall be of the same type as those used in the procedure qualification

tests. Welding approved currents and voltage shall be within the range specified in the welding

procedure.

All unidentifiable, damaged, wet, rusty or otherwise contaminated consumables shall not be used.

Electrodes with visible stains as well as partially used electrodes (once melted) shall not be used.

All bottles containing shielding or backing gas shall have clear identification labels.

3.4.6 Weld numbering

The weld numbering shall clearly show the history of a weld, including any repairs and/or re-welds

For every weld the following information shall be gathered and maintained up to date in summary

sheets, which shall be made available at regular intervals and of which the final version shall become

part of the as built fabrication package.

a. Weld number and type (Shop, Field or Offshore Hook-up)

b. Isometric drawing number

c. Pipe spool number

d. Line number

e. Size of weld (Nominal Bore and Wall Thickness)

f. Weld procedure(s) and filler type and brand name if not on procedure(s)

g. Welders name(s) and registration number(s)

h. Date welding

i. Base material type

j. NDT type(s) and results and report number(s)

k. Status (based on QC-plan)

A weld is considered complete after visual inspection and approval by Company and completed

and approved NDT examination, for NoBo classified systems also after the approval from NoBo.

Weld numbering is done per iso and starts at “weld 1“ every time.

Prefabrication summary sheets shall reserve a weld number for ( offshore) field welds).

3.4.7 Production welding

Welding shall be performed according to Company and NoBo / AKI approved Welding Procedures.

Procedures shall be available at actual work location at all times.

Each bead shall be thoroughly cleaned of all scale, slag and other foreign matter by chipping,

grinding and wire brushing prior to application of succeeding bead.



Any piping material which is burned during welding shall be cut out and re-welded.

If lamination or split ends occurs during welding the joint shall be trimmed to remove the defect.

Any bevelled edge that has been damaged shall be repaired and (where required by the applicable

rules for welding) NDT-tested.

Welds which do not meet the requirements of the welding procedure, which are burned or oxidised

or otherwise found to be defective, shall be repaired or cut out at the discretion of Company's

representative.

Immediately after welding the weld shall be thoroughly cleaned by removing all scale, slag weld-

spatter, etc..

At each welding location, at least one electronic backing gas detector and electronic temperature

meter shall be present. If the welding procedure requires backing gas and/or controlled pre-heat

and interpass temperatures, no welding shall be performed without the presence and use of these

devices

3.4.8 Repairs

If the results of the examination are not acceptable, the weld in question may be repaired once

according to a dedicated and approved repair procedure. Each repair performed on the strength

of the above must be non-destructively re-examined, and the final result shall satisfy the same

requirements.

3.4.9 Post Weld Heat Treatment (PWHT)

If according to the NEN-EN codes "Heattreatment of Unalloyed and Low Alloy Steel/Pipes", PWHT

is required, the temperature time chart shall show that the heat treatment has been performed in

accordance with the relevant codes.

3.4.10 Golden Weld

Golden welds shall primarily be avoided however when this is not possible the number of golden

welds shall be kept as low as possible. Company and NoBo approval is required for all golden

welds.

Instruction “golden weld procedure” will be provided by Company.

3.5 PIPE SUPPORT FABRICATION AND INSTALLATION

During pre-fabrication small branches/flanges/attachment (<1 1/2") from main lines (≥ 2") shall be

supported by suitable braces in minimal 2 directions, 90° braces shall be from material equivalent

to the piping material and welded per piping WPS’s. Sharp edges shall be rounded to minimum

radius of 2 mm. Typicals to be submitted for approval. Welding to be done before testing and/or

coating.

Pipe supports shall be fabricated (Sharp edges shall be rounded to minimum radius of 2 mm) and

installed per drawings and specifications (Specification 504 for materials and fabrication techniques

and General Specification 525 for coating) and the drawings for (typical) descriptions of pipe

supports.



Pipe support number (SPS) to be welded on support by contractor.

Fabrication shall take place according to a QC-plan and test & inspection plan prepared by

Contractor. This plan is to be approved by Company and NoBo / Certifying Authority (if applicable)

before start of fabrication. As a minimum, the test & inspection plan shall include the applicable

items indicated in this specification. Pipe support drawings supplied by Company shall be checked

for dimensions and completed for construction details.

Additional pipe supports shall be detailed similar to the submitted supports and have the next

support number in sequence.

Pipe support detail drawings shall be on A4 format and shall have not more than one type of

support and shall show as a minimum:

a. Pipe support number

b. Line number and size

c. Isometric number

d. Deck name and elevation, location key-plan with distance to grid-lines

e. Structural steel beam where support is attached

f. M.T.O.

g. Indication of field welds required on the pipe support

h. All field installed items such as clamps, bolting, spring supports etc. with clear identification

to avoid mistakes

i. Special installation instructions

Location for (field) supports for lines smaller than 1½ inch and drain tubing shall be designed by

Contractor and approved by Company unless provided by Company.

All supports shall be installed such that piping system is fully and properly supported. Each support

shall be capable to and actually carry the load for which it is designed. Pipe supports welded to

main steel (beams type I, II and III ≥ 400 mm) and structural tubulars (type I, II and III ≥ 10") shall

have doubler plates, whether indicated on the drawings or not.

Painting on supports shall be the same as for the adjacent structural steel. Painting shall not affect

piping.

Security locks and tabs for spring supports shall not be removed.

Stainless steel or duplex piping shall never be in direct contact with the Carbon Steel supports;

during installation, the correct measures shall be taken.

Contractor shall prefabricate and supply deck penetrations for piping where this is indicated on

isometric.

Fabrication of penetrations are in accordance with structural specification 201.

4.0 PIPING INSTALLATION

4.1 REMARKS FOR PIPING INSTALLATION

Prior to installation all spools and piping components shall be checked for damage and absence

of any dirt inside.

Valves and in-line items shall be checked for loose internals or foreign matters.

All components shall be identifiable, pipe spools shall be clearly labelled and piping items shall be

tagged.

All flange facings, especially gasket areas, shall be checked for damage.

All piping and pipe spools shall be installed without imposing excessive stresses.



Where flanges do not meet, additional field welds shall be made.

No excessive pulling or jacking to force a system in position is allowed.

In general, the sum of structural and equipment fabrication tolerances in dimensions is more than

what can be absorbed during piping installation. Therefore field welds are required for a correct

installation.

Company shall have the right to check potential stress in piping by unbolting or otherwise.

Flange connections to equipment shall be individually checked for stress-free assembly and

alignment. Supplier’s instructions shall be adhered to.

Pipe supports shall be installed together with the piping system. Where required temporary

supports shall be used. Pipe supports shall be designed, fabricated and installed per the applicable

general specifications or otherwise indicated requirements.

Piping penetrations/sleeves (see also specification 201)

General

Pipe shall be in the middle of the applicable penetration and shall at no time be in contact with

the sleeve

Penetrations/sleeves for piping penetrations shall be included on the structural (fabrication)

drawings.

Where practical piping penetrations can be combined, tailor-made (oblong) sleeves can be

drawn and used.

Diameter of sleeves shall be according to specification 201, Attachment A-2076.

Sleeves in decks:

Penetrations shall not affect structural integrity of the deck.

Sleeves 130mm above deck, 10mm in deck plate and 10mm under deck (see table).

Sleeves to be prefabricated and installed in deck during fabrication of deck and coated with

deck where possible.

Sleeves in deck to be welded above and below deck with fillet weld = WT sleeve to the deck.

Material comparable to deck plate material.



Sleeves in grating:

Penetrations shall not affect structural integrity of the grating.

In removable grating penetrations to be avoided, possibly half-sleeves with opening to side of

grating can be used.

Sleeves 75mm above grating, 30mm (or 50mm) in grating (see table).

Sleeves to be welded in grating during grating fabrication and to be Hot-dip-galvanised with

grating. Material as material for grating

Sleeves/penetrations in beams:

Penetrations shall not affect structural integrity of the beam, calculation for each typical

application required, in general penetrations near the middle of the web

For reinforcement rings made from plate, fillet-welded to the web, on one or both sides shall

be used.

Sleeves to be prefabricated and installed in beam during fabrication of deck and coated with

deck where possible. Material as material for beams.

Where the penetration is not indicated on an "AFC" drawing from Company, approval from

Company must be given before work commences.

Penetrations through rated walls:

For penetrations through gas-tight or firerated walls the rating shall not be affected by the

construction or materials used for the penetration. Dedicated design to be made and approved

for each application. Penetrations to be closed by certified A60 material. Penetration through

rated walls shall be avoided where possible, and combined where possible.

Penetrations through sheeting shall be avoided.

Field welds shall be made after insuring that piping is installed in the correct position. Shrinking as

result of field weld shall be calculated for. Special care shall be taken not to damage already

installed piping and equipment or affect their surfaces by grinding or weld spatter. Proper cover

shall be applied.

Installed piping shall comply with the construction drawings.

Vents and drains shall be installed on high and low points where appropriate (all vents and drains

shall be indicated on the isometric drawings.) Location to be approved by Company before start of

fabrication.

Instruments, drain tubing, valve controls etc. shall be installed after piping installation.

Thread nipples shall be fabricated by Contractor of stock lengths of pipe. The ends of all field

threaded pipe shall be reamed to remove any burrs. If indicated on the drawings nipples shall be

hexagon type.

Threaded connections shall not be seal welded unless specified or approved by Company.

A sealing compound or tape approved by Company shall be used on all threaded connections.

(See applicable section of this specification.)

After completion of branch welds, the header shall be cleaned before the final weld or flange

connection eliminates access to the inside of the fabricated section.

4.2 FLANGE JOINTING AND BOLTING



4.2.1 Scope

This section covers the bolt tension and bolting-up requirements for pipe and pressure vessel

flange joints in all ratings as specified in ANSI-B16.5 and or API-6A (5000, 10000 rating), for raised

flat face and ring type joint flanges.

For bolting-up, requirements for non-standard large bore flange-type connections (pipelines,

vessel heads, etc.) in all cases the applicable drawings must be checked and followed.

Bolting materials shall consist of materials as defined in specification 503 (General Piping Material

Specification).

4.2.2 Codes

The following codes are applicable:

American Society of Mechanical Engineers (ASME)

Boiler and Pressure Vessel Code - Section VIII. Div. 1 Appendix 2.

Rules for Bolted Flange Connections.

NEN-EN 13480

API-6A

4.2.3 Bolting-up Requirements and selection of tools

Tightening of bolts in flange connections is possible by means of spanners and torque wrenches.

This may result in uneven stress distribution in bolting and uneven gasket seating pressure.

Especially when applied in higher pressure classes and larger diameters, this method may lead to

flange leakage. When flange joints are leaking additional force is often applied to the bolts in the

area where the leak occurs. This may result in more deformation of the flange and its facing, thus

increasing the tendency to leak.

An improved method of tightening is the application of hydraulic bolt-tension equipment.

For the selection of the correct tool for bolt tightening the tables 4.2.3.A, 4.2.3.B in this section shall

be used.

For the bolt tension and torque see table 4.2.7.A, in all cases pay attention to the restricting notes

at the bottom of the table, and carefully check the tables and/or graphs for this purpose that should

at all times be present with the selected tools.

Flange management system including the use of labels is required.

The contractor shall maintain currently updated records of all torqued and / or tensioned

connections and include these in the MDR. OR AS BUILT PACKAGE.

Flange management system to be approved by Company.

Table 4.2.3.A

The following flange joints shall be made up by hand using ring spanners of appropriate

dimensions. Lengthening of spanners by means of pipe, crowbars or similar is prohibited.

ANSI – B16.5 CLASS NOMINAL PIPE SIZE

150 LB (PN20) 1/2" up to and including 24"





900 LB (PN150) 1/2" up to and including 1-1/2"

1500 LB (PN250) 1/2" up to and including 1-1/2"

2500 LB 1/2" up to and including 1-1/2"

Table 4.2.3.B

The following flange joints shall be made up by hand using torque wrenches of appropriate

dimensions.


600 LB (PN100) 4" up to and including 6"




API - 6A RATING NOMINAL PIPE SIZE

5000 PSI up to and incl. 4"

10000 PSI 1/2" up to and including 2"

Table 4.2.3.C

The following flange joints shall be made up by means of a hydraulic bolt-tension

(torque) device.


600 LB (PN100) 8" and larger




API - 6A RATING NOMINAL PIPE SIZE

5000 PSI 6" and larger

10000 PSI 3" and larger



Table 4.2.3.D

The following flange joints shall be made up by means of a hydraulic bolt - tension (stretch,

e.g. "Hydratight", etc.) device.

CLASS NOMINAL PIPE SIZE APPLICATION

ANSI 900 & 1500 LB 2" and larger under water

API 5000 & 10000 2" and larger under water

ANSI 900 20" and larger critical connections

ALL If required per drawing

4.2.4 Flange Inspection and Preparation

Check the condition of the flange faces for smoothness, scratches, dirt, scale, and weld spatter

protrusions. Wire brush clean as necessary. Severe scratches, dents or combinations of defects will

require re-facing with a flange-facing machine.

All sharp edges (including bolt holes) shall be rounded to a minimum radius of 2 mm by contractor.

Check alignment of mating flanges. Use of force to achieve alignment is prohibited.

All threads and bearing surfaces shall be free from sand, chips or any other foreign material which

may influence the torque during tightening.

Check coating on flanges, all face-surface including inside bolt holes shall be coated to specification

525.

4.2.5 Gasket / ring Inspection and Preparation

The type and material for the gaskets is defined in General Specification 503 and also mentioned

on the isometric drawings/MTO’s. For clarity table 3.6.5.A, indicating the type of gasket to be used

for classes and class-combinations, is also included in this General Specification.

Once a gasket is installed, it is difficult to positively identify this gasket. A wrong gasket in a

connection is considered a serious hazardous situation. Although the connection can be perfectly

closed during pressure testing, flange facings can be damaged and gaskets can corrode, resulting

in leakages later during operation of the platform (i.e. due to galvanic corrosion between non-

matching materials).

It is therefore forbidden to use non-spec gaskets in any piping system at any time. Revealing

of any non-spec gasket in any piping system shall be followed by a 100% check (and therefore

replacement, gaskets shall not be re-used) of all gaskets involved in the project, all at cost of the

responsible party.

Only new gaskets shall be used. Damaged gaskets (including loose spiral windings) shall be

rejected. Gasket dimensions, gasket material and type, shall be checked to be per specification.

Non-specification situations, unless specifically defined on the drawings, are not acceptable.



Table 4.2.5.A

Table gaskets CS DS SS UK UP

Matl Class

15 non asb flat non asb flat non asb flat non asb flat x

CS 30 & 60 spiralw CS spiralw SS spiralw SS x x

90 and > Soft iron R SS316L R SS316L R x x

15

non asb flat non asb flat non asb flat x

DS 30 & 60 spiralw SS spiralw SS x x

90 and > SS316L R SS316L R x x

15

non asb flat non asb flat neoprene

SS 30 & 60 spiralw SS x x

90 and > SS316L R x x

15

non asb flat x

UK 30 & 60 x x

90 and > x x

15

neoprene

UP 30 & 60 x

90 and > x

Abbreviations:

CS Carbon Steel incl CS castings and Hot Dipped Galvanised

DS Duplex Steel incl DS castings

SS Stainless Steel incl SS castings

UK Cunifer, bronze, messing

UP Polyethylene

Detailed descriptions various gaskets:

see Neptune Energy General Specification 503 latest revision

"x" not expected connections, materials per drawing or ask.

Dedicated (electrical) insulation set: only if indicated on the drawings !!

In case of doubt please ask !!

Table 4.2.5.A-1

Care shall be taken to install the correct gaskets and rings as specified in the various piping

systems (specification 503).

Use of used-, wrong material-, wrong class-, wrong coated-, temporary self made-, or other non-

spec-gaskets or rings is prohibited at all times. Reason for this (and for the harsh measures in case

of failure to comply with this instruction) is the risk that an incorrect gasket or ring remains in the

system and becomes a possible reason for leakage in the future.

Table 4.2.5.A-2

In case of material change at a flange connection, the following shall apply and be adhered to

(both on the isometrics and in actual installation):

CS flange to CS flange > soft iron ring, standard gasket

CS flange to SS flange > SS316L ring, SS-class gasket

CS flange to DS flange > SS316L ring, SS-class gasket

CS meterrun flanges with SS insert type ring/ringhouse > SS316L ring, SS-class gasket

CS flanges with temporary SS strainer > Strainer has SS316L ring



4.2.6 Stud / nut inspection and preparation

Check thread on stud and nut. Minor damage of tread on stud well in between the nuts may be

repaired, including coating.

Complete coating must be intact.

Nut to flange contact surface shall be clean and smooth, avoid damage to coating in consultation

with Company.

Studs area for nuts to be lubricated with approved lubricant. The same lubricant should be used

consistently on all joints especially when controlled bolt tightening is required (see tables 3.6.3).

The lubricant for alu-coated studbolts shall be "Molyslip Alumslip".

4.2.7 Installation Procedure - Tensioning

Install gasket and all bolts and nuts before any tensioning.

Note: It is recognized that applied torque to a nut member is only one of several ways to

approximate tension and unit stress in a studbolt. Tabulated values (table 3.6.7A) are

presented for convenience and guidance only. Some factors which affect the

relationship between nut torque and boltstress are:

Tread pitch, pitch diameter, and tread form.

Surface finish of thread faces and nut bearing surface area.

Degree of parallelism of nut bearing area with flange face.

Type of lubrication and coating of the treads and nut bearing surface area.

Table can be used as a guideline for general purpose application (shaded area). For

non-standard applications dedicated calculation based on found materials,

geometries and circumstances can be made.

Develop the required bolt stress as per table 3.6.7.A "Bolt torque values" in a minimum of three

steps, following a tightening-up procedure as outlined per figure 3.6.7.B "Bolt-up sequence

description".

Note: if more than 30 % of the final bolt stress is applied during the first step, serious damage

will be done to the spiral-wound gasket and subsequent tightening cannot offset this

damage. Gasket shall be rejected.

Requirements are based on bolts with UNC/8UN Thread; friction coefficient of 0.12 or 0.13.

Lubricant with another coefficient of friction will require interpretation of table or recalculation of

bolt torque.



4.2.8 Tools

All tools used for tightening shall fit the hexagon of bolts and nuts without damaging the width

across flats and be suitable for matching nuts in accordance with ANSI B 18.2.2.

Hydraulic Torque Wrench Device

The torque wrench device, including adapters, shall be suitable for matching bolt size. Each Torque

Wrench Device shall be accompanied with a clear manual (in language of personnel involved),

indicating clearly the relationship between read-out hydraulic pressure and moment applied on

nut.

Table 4.2.7.A

Recommended bolt tension and bolt torque for ANSI B 16.5 flange connections

Bolt size and

thread inch

Bolt

tension

kN

Min.

yield

Mpa

Torque required Nm

Molycote

{0.067}

Copperb.

{0.100}

API-5A

{0.117}

Pract. fig.

{0.13}

Mach. oil

{0.150}

Dry {0.2}

1/2 UNC 33 725 80

5/8 UNC 53 725 153

3/4 UNC 78 725 142 194 222 266 274 344

7/8 UNC 108 725 230 318 363 424 451 557

1 8UN 141 725 347 484 555 643 692 831

1 1/8 8UN 185 725 496 699 803 930 1004 1220

1 1/4 8UN 233 725 688 970 1116 1292 1398 1715

1 3/8 8UN 288 725 920 1302 1501 1737 1883 2329

1 1/2 8UN 348 725 1198 1703 1964 2272 2470 3073

1 5/8 8UN 414 725 1527 2178 2515 2910 3166 3985

1 3/4 8UN 486 725 1911 2734 3158 3654 3983 5029

1 7/8 8UN 564 725 2354 3377 3905 4516 4928 6256

2 8UN 650 725 2861 4113 4759 5505 6012 7653

2 1/4 8UN 834 725 4081 5892 6824 7892 8635 11027

2 1/2 8UN 1041 725 5606 8120 9413 10884 15282

2 3/4 8UN 1267 725 6760 9824 11386 14549 18596

Notes: - Tensioning to be done in (min.) 3 steps of 0.30, 0.65 and 1.00 * indicated bolt torque

- Calculation based on API spec. 6A - Appendix D

- Stress basis is 362 MPa (being 50% yield of ASTM A320M - L7 bolting)

- Friction factor as indicated depends on numerous aspects.

- For non-standard and very critical connections dedicated calculations must be made.



4.2.9 Bolt-up Sequence

The bolt-up sequence indicated in the figure is as an example applicable for all types of fastening

tools, orientation can be changed to suit very minor differences in distance between flange facings

(resulting from fabrication tolerances, not out-of-angle welded flanges).

Important: hand tighten; then pre-tighten bolts to 10/20 ft-lbs torque, but DO NOT exceed 20% of

target torque.

Check gap for uniformity.

Use the appropriate cross-pattern tightening sequence in the sketch below for rounds 1, 2 and 3

and/or round 4 (each sequence constitutes a "round").

Figure 4.2.7.B

Final Torque _______________ ft-lbs

Lubricate, hand tighten, pre-tighten bolts.

Round 1 – Tighten to __________ ft-lbs – 1st torque value in torque chart (30% of final torque)

Round 2 – Tighten to __________ ft-lbs – 2nd torque value in torque chart (60% of final torque)

Round 3 – Tighten to __________ ft-lbs – final torque value in torque chart (100% of final torque)

Check gap around the circumference between each of these rounds, measured at every other bolt.

If the gap is not reasonably uniform around the circumference, make the appropriate adjustments

by selective bolt tightening before proceeding.

Rotational Round – 100% of final torque (same as round 3 or 4 above). Use rotational, clockwise

tightening sequence, starting with bolt number 1, for one complete round and continue until no

further nut rotation occurs at 100% of the final torque value for any nut.

If possible, retorque after twenty-four hours.



4.3 THREADED CONNECTIONS

4.3.1 Guidelines for the making of small-bore NPT connections

Threaded (NPT) piping connections and the application of various types of PTFE tape and thread

sealant.

General rules to check NPT thread connections (ANSI B1.20.1).

correct selection of materials for services, pressure and temperature (specification!),

check state and installation of cutting blocks (direction and following sequence) if male tread

is cut on pipe, use cutting oil

use of proper and undamaged thread on both male and female thread side,

the proper use of suitable sealant or tape,

correct installation and supporting of pipe,

both male and female thread must be smooth, no burrs, cuts or other irregularities can be

accepted,

minor corrosion can be removed from the thread, actually corroded thread can not be

accepted,

without tape or sealant the parts to be connected should allow 4 to 5 rotations, at least 4

threads should be engaged,

with tape or sealant it should be possible to make up the parts 3 to 4 rotations without

excessive force.

DO NOT:

unscrew an already made up thread connection after application of sealant, not even a little,

use extra sealant or tape to fix a doubtful thread,

use excessive force to make up of (non-fitting) threads.

Special care is required for the mounting/installing of plugs.

Plugs are often used numerous times on the same or a new location and therefore the threads can

be worn.

Threaded connections used for instrumentation (actual instrument, instrument air, and others) are

considered to be made per piping specifications.

For SS tubing connections, as widely in use within instrumentation and otherwise, the piping

specifications are not to be used.

All instrument tubing systems to be made according to specifications and manufacturers

recommendations.

The Use of PTFE Tape

Although PTFE tape can be applied without problems for numerous applications, it should be

realised that the application is limited by the physical properties of PTFE tape. The table (4.3.1.A) in

this section gives a summary of the possibilities for various types of tape and sealant. This table is

based on the manufacturer recommendations and practical experience.

At this moment no "tailor made" code is available for all situations.

Most commercially available tapes are of "Giveg class 0.2".



Based on experience it can be said that the use of PTFE tape can give acceptable results. The "Giveg

keurmerk" indicates that subjected tapes are fabricated controlled and the chemical properties are

checked. Therefore this must be checked before use.

PTFE tape shall be applied as follows:

In the diameter range up to 1" the PTFE tape (thickness 0.1 mm) can be used (See table.)

Tape to be applied to male thread, starting away from and working towards the pipe end, with a

tape overlap of 50%, wrap under slight tension to ensure that tape conforms to thread contours.

Only 3 to 4 layers can be applied, not more.

Do not use this tape for connections in pipe with a diameter above 1".

Alternative Thread Compounds

As alternative or addition to PTFE tape, numerous more or less liquid sealing materials are available.

At all times the manufacturers recommendations for these materials must be checked and

followed. Some (widely used) examples are included in table 3.7.1.A.

Any other brand, not listed, shall be submitted to company for approval.

4.3.2 Material problems in making threaded connections

The available piping specifications often leave the question for a practical solution for connecting

or matching two different materials un-answered. Especially on equipment with various materials

used, problems can occur.

Examples: - SS and duplex are very difficult materials to cut tread "in the field",

- Installation of threaded connections in duplex steel are very difficult, duplex-

duplex connections must be avoided completely (the male tread will cut

into the female side, far before the required number of treads is installed,

"galling").

- Tools (cutting blocks and others) for SS must be used for SS only.

Described problems should be identified and eliminated.

Table 4.3.1.A, Table Thread Joining Components

Thread Sealant

Services

Nominal

Pipe Size

(Inch) *

Working

Temp.

(C)

Remarks

PTFE tape 0.1 mm

Giveg Class 0.2

All ex. Breather

Air

up to 1 inch -20 to +150

PermaBond A131

anaerobic sealant

All ex. low temp.

cyclic duties

up to 1 inch -55 to +150

Loctite 577 For small diam.,

clean systems

up to 3/4 inch -60 to +150

SWAK (Swagelok) All "general

sealant"

up to 1 inch high press,

2 inch low press.

-50 to +175

Loctite 542 For small diam.

systems

up to 3/4 inch -60 to +150

* See specification 503 for maximum sizes threaded connections various pipe classes.



4.3.3 Galvanic corrosion and threaded connections

A possible problem with threaded connections is galvanic corrosion. Screwed connections made

up with different materials can result in a difference in electrical potential with the right (wrong)

medium this can cause galvanic corrosion. The sharp edges of the (usually male) thread can be

affected very quickly (without the possibility to detect this from the outside). This will result in a

complete collapse of the connection without warning.

Risk for galvanic corrosion can and must be identified during piping design, however, could still

cause problems during offshore use. This should be considered during piping installation and day-

to-day offshore maintenance as well.

5.0 REQUIREMENTS FOR NON CARBON STEEL AND GALVANISED PIPING

5.1 REQUIREMENTS FOR DUPLEX STEEL, SUPER DUPLEX STEEL (CLASS … DS) AND STAINLESS (S)

(Duplex = Ferritic/austenitic stainless steel from material type "Werkstoff Nr 1.4462").

(Super Duplex = Ferritic/austenitic stainless steel from material type "Werkstoff Nr 1.4501"

Welding of Super Duplex requires a different specification and will be provided by Company).

Duplex and Stainless Steel piping in general to be coated per General Specification 525 (note:

different end colours).

5.1.1 Handling Duplex steel (See Attachment I to this specification) and Stainless Steel.

Duplex and/or Stainless steel shall never be in direct contact with CS pipe supports. During

installation the correct measures shall be taken to ensure this.

5.1.2 Welding of Duplex steel and Stainless (316L)

For the requirements of welding of Duplex steel reference is made to the applicable attachment to

this specification.

Any welding of / to Duplex steel shall be performed in strict accordance with this document

(Attachment I).

5.1.3 Pickling and passivating of Duplex steel and Stainless (316L)

After welding and before coating all duplex pipe spools shall be pickled and passivated by method

of bath emersion (specification to be submitted by Fabricator and approved by Company).

Field welds shall be avoided; in case field welds can not be avoided completely, a dedicated

procedure for welding and treatment after welding shall be prepared by Contractor and submitted

to Company for approval.

After welding the outside weld area, Stainless Steel shall be pickled and passivated before blasting

and coating.

5.2 REQUIREMENTS FOR CUNIFER PIPING (CLASS 15UK)



5.2.1 General

Cunifer as per ASTM B466, is often referred to as "Cunifer 10" or "offshore quality Cunifer". Cunifer

material can deviate from standard material specifications for dimensions and shape of specially

tee's and flanges.

Cunifer is used with wt's far less than wt for comparable CS piping. For this reason the spools are

rather vulnerable, therefor extra attention in handling and supporting is required.

Cunifer piping shall not be coated, CS parts (flange backing-rings, valves, studbolts & nuts etc. and

obviously supporting) are to be coated or HD galvanized.

(Note : only possible method to coat CS backing-rings to spec. is to coat these before assembling

spools, backing rings are also delivered HD-galvanised, this is in general also acceptable.)

For systems that are normally drained/empty (dry sections deluge systems normally fabricated

from cunifer/class 15UK), after installation, pressure testing and commissioning, drainholes shall be

drilled, locations subject to approval by Company.

5.2.2 Handling

Any direct contact between Cunifer and carbon steel components shall be avoided.

Dedicated tools that have not been used on any other material shall be used.

Earthing clamps for welding and cutting shall be made of bronze.

Handling equipment, such as slings, hooks and lift truck forks shall be protected by clean

wood, cloth or plastic buffers to avoid contact with the surface.

Cunifer shall be stored indoors, it shall be protected from moisture, dust, salt, iron particles

and other matters that may initiate corrosion.

Cunifer shall never be in direct contact with CS pipe supports. During installation the correct

measures shall be taken to ensure this.

Supporting of Cunifer shall be based on (rubber) lined U-bolts with lining pieces in

accordance with General Specification 504.

5.2.3 Welding

Welding of Cunifer will be performed to requirements as laid down in the general welding

requirements description in this specification, with the following additional remarks:

welding process will be a non-slag process (in general considering the small wallthickness a

TIG process will be used), welding process and consumables will suit the Cunifer and welding

material producers guidelines for processing same.

weld material and HAZ will have mechanical and corrosion qualities at least comparable to

original material.

welding with 70/30 welding consumables.

small diameter fittings may require brazing; proper procedure to be issued for approval. Silver

brazing alloys to be used as consumable.

5.3 REQUIREMENTS FOR POLY ETHYLENE PIPING (CLASS 15UP)



PE-piping in general requires specialists to fabricate and install. In general material to be processed

to piping system to manufacturers recommendation for design, welding (fusing) supporting (entire

length), etc..

PE-piping not to be coated.

5.4 REQUIREMENTS FOR HOT DIP GALVANISED PIPING (CLASS 15U)

Spools class 15U shall be HD-Galvanised (per specification 525) after fabrication of spools. Field

welds are not allowed. Where required additional flange connections to be installed. After

galvanising and before installation flange facings and threaded connections to be checked for and

if necessary cleaned from excessive zinc.

5.5 CLASS U2

Class 2 shall be installed by personnel trained and certified by supplier Geberit.



5.5 SYSTEMS THAT REQUIRE EXTRA GRADE OF CLEANING

Some systems require extra cleaning by means of pickling and flushing because of their process

function. This is always the case for the systems indicated below, and further as indicated on the

drawings and further documents. Procedure to be prepared by Contractor and approved by

Company.

Systems to be pickled and passivated as a system for process reasons:

Hydraulical- and lube-oil systems

Piping upstream gas-compressors downstream last filter (note: possible bypass loops to be

included).

See also remarks with “testing” and “medium”.

Systems to be cleaned as hydraulic control piping.

Cleaning shall be carried out on hydraulic systems, with exception of the hydraulic cabinets and

wellhead control panels since they have been cleaned by the panel Supplier. All hydraulic lines

shall be cleaned to a minimum cleanliness level to ISO 4406 class 15/12 (equal to NAS 1638

class 6).

Prior to commencement a cleaning procedure shall be issued for review to Company (cleaning

procedure can be part of the system test procedure).

Cleaning reports and records of samples shall be available for review during FAT.

Items that could be damaged due to cleaning shall be removed or by-passed during cleaning.

Items which create high restrictions due to orifice dimensions shall be removed or by-passed.

Cleaning procedure must include as minimum

- method of cleaning

- define the extent of cleaning

- method of sampling and examination

- description of the cleaning unit (flow rate, pressure, velocity. filter mesh size)

Flushing shall be performed with:

- fluid as used in the system is preferred.

- flow shall be turbulent at all points

- temperature shall be as high as possible

When the cleaning is completed, the tubes remain filled and all connection shall be plugged

with metal plugs. In case s different cleaning fluid is used, this shall be removed and tubes

shall be blown out with dry nitrogen.

Important note :

All installed components such as valves; regulators shall be suitable to operate without

problems with oil cleanliness to ISO 4406 class 19/16 (equal to NAS 1638 class 10)

1

6



6.0 FLUSHING AND PRESSURE TESTING

6.1 SCOPE

In this specification described method of flushing and testing is applicable for piping systems on

platforms and installations. For (subsea) transportlines dedicated procedures per applicable codes

(NEN 3560) are required.

6.2 FLUSHING

After installation and before pressure testing piping systems shall be thoroughly flushed. Result

shall be a clean piping system. At least all debris and contamination of the piping system shall be

removed. Depending on the use of the piping system, further requirements shall be applicable

(hydraulic systems, fuel systems, etc.).

Flushing in general shall take place with fresh water ; if water in the system is a problem, alternatives

shall be used (air for air-system, oil for hydraulic system, etc.) Flush procedure(s) to be issued for

approval to Company.

Flushing water used for CS shall not be used for SS or DS.

Water for SS or DS shall not contain more than 20 ppm chlorides.

Where in-line items can be expected to become any obstruction to flush-out debris, or where the

possibility of damage to system or in-line items exists, these items shall be removed before flushing

(all types of valves, instruments, filters, etc.).

Finished prefabbed galvanised pipe spools to be flushed with potable water to detect extreme

layer thickness or blockage of the pipespool. (witnessed by Company).

Alternative methods to be approved by Company.

Systems shall be delivered dry and closed. This can be done with clean hot air, vacuum drying, etc.

Proposal is to be submitted to Company for approval before start erection.

6.2.1 Systems that require extra grade of cleaning.

Some systems require extra cleaning by means of pickling and flushing because of their

process function.This is always the case for the systems indicated below, and further as

indicated on the drawings and further documents. Procedure to be prepared by Contractor

and approved by Company.

Systems to be pickled and passivated as a system for process reasons:

Hydraulical- and lube-oil systems

Piping upstream gas-compressors downstream last filter (note: possible bypass loops to be

included).

See also remarks with “testing” and “medium”.

6.2.2 Systems to be cleaned as hydraulic control piping.

Cleaning shall be carried out on hydraulic systems, with exception of the hydraulic cabinets

and wellhead control panels since they have been cleaned by the panel Supplier. All hydraulic

lines shall be cleaned to a minimum cleanliness level to ISO 4406 class 15/12 (equal to NAS

1638 class 6).



Prior to commencement a cleaning procedure shall be issued for review to Company (cleaning

procedure can be part of the system test procedure).

Cleaning reports and records of samples shall be available for review during FAT.

Items that could be damaged due to cleaning shall be removed or by-passed during cleaning.

Items which create high restrictions due to orifice dimensions shall be removed or by-passed.

Cleaning procedure must include as minimum

method of cleaning

define the extent of cleaning

method of sampling and examination

description of the cleaning unit (flow rate, pressure, velocity. filter mesh size)

6.3 TESTING AND TEST SYSTEMS

6.3.1 Procedure Onshore

Note: EPI guideline: DOP-PD-15-0037 (for offshore application) will be included in the

Offshore Management System.

Prior to initial operation, each installed piping system shall be pressure and leak tested in

accordance with PED and Company standard practice to assure mechanical strength and

tightness. Table 6.3.1.A is for information only. DAD’s prepared per PED give required test

pressure. All Pressure testing shall be done in accordance with a Contractor prepared and

Company approved hydro test procedure. A test diagram shall be made for determining the

test systems.

Test pressure will be indicated on the AFC-drawings, this shall be checked versus pressure on

DAD’s.

Contractor to check allowed test pressure for all components that are included

Pressure test procedures shall be made in accordance with NEN-EN 13480 and Company

standard practice.

For new platforms, modules or skids complete systems shall be tested with all pipe supports

fitted. Nitrogen shall be used. Spring supports shall remain in the locked position. This testing

shall be done after fabrication and before leaving the fabrication yard as part of the

fabrication scope (pre-commissioning).



Table 6.3.1.A.

INDICATIVE Hydrostatic Test Pressures

Pipe

Class.

Max.design

(Barg) at

max. temp.

Temp.

rangeC

Approx.

Test press..

(Barg)

Remarks

15 17.9 -20/+95 25.0

15C 17.9 -70/+95 25.0

15H 13.2 -20/+220 25.0

15U 17.9 -20/+95 25.0

15UK 19.3 -20/+50 25.0

15UP 10.0 -10/+50 15.0

30 46.9 -20/+95 65.0

30W 43.9 -20/+200 65.0

30H 37.9 -20/+315 65.0

30U 46.9 -20/+95 65.0

60 93.0 -20/+95 130.0

60H 87.6 -20/+200 130.0

90 139.5 -20/+95 185.0

90H 133.1 -20/+180 185.0

150 219.2 -20/+200 315.0

250 387.5 -20/+95 510.0

15DS 17.7 -20/+100 25.0

15DSH 12.9 -20/+225 25.0

30DS 49.5 -20/+95 75.0

90DS 148.6 -20/+95 195.0

90DSH 131.8 -20/+180 195.0

150DS 213.0 -20/+200 300.0

250DS 381.5 -20/+150 550.0

15S 16.2 -20/+95 25.0

15SH 12.9 -20/+225 25.0

500S 345.0 -20/+95 450.0

Notes: - test medium at ambient; temperature "ambient" Ta defined as 12 Ta 25 C.

For exact test pressure, see isometrics and line list.

Where practical, appurtenances (valves, small vessels etc.) can be left in place as part of the

system.

In general, instruments can be left in place, if necessary instruments can be blocked off at

design pressure and monitored with a PI (applicable for i.e. LG's). Alternatively process

instrument connections can be disconnected, system to be tested can be blinded off (plug or

cap).



At all times the following items shall be considered:

the extra weight of vessel system contents (deck structure, supporting)

check for all items on maximum allowable pressure or possibly vacuum,

check for all valves to allowable pressure in open position and if applicable in closed position,

check required position ball / internals,

check for the absolute absence of risk on damage of internals appurtenances or vessels

either by pressure, by weight or by medium as result of pressure testing or presence. Filters

and filter type vessel internals shall not be part of pressure test with water.

Operation and/or maintenance instructions on items involved shall be carefully checked for

required position before, during and after pressure test.

Relief- and check valves shall be removed. Temporary spools may be used to avoid splitting

the test system.

No test systems shall be coupled by tubing unless agreed otherwise.

6.3.2 Medium

Medium for testing shall be clearly indicated in the testing procedure.

In general for piping nitrogen with Helium shall be used. Only in case where such test is not

practical, water will be permitted subject to approval from Company. Corrosion inhibitors shall be

added (200 ppm of a suitable and Company approved make, all to be clearly indicated in pressure

test procedure).

Maximum leakage rates (N2He) for individual joint and system averaged can be found below:

Toxic gas (in particular H2S) 5 Scf/yr

Sweet Gas 10 Scf/yr

Gas condensates 10 Scf/yr

Flammable liquids (with flash point < 55°C) 10 Scf/yr

Non flammable / Non toxic gas 40 Scf/yr

Fuel and instrument air piping shall be tested with dry air or nitrogen.

Drain systems can be tested with air in combination with a soap solution.

Lube and seal oil systems which could be impaired by the presence of water shall be alternatively

tested in accordance with manufacturer's/company's recommendation.

Test and flushing water that has been used for carbon steel systems shall not be used for stainless

steel or duplex piping. Water for stainless steel or duplex shall not contain more than 20 ppm

chlorides.



6.3.3 Testing and recording

Piping systems shall be thoroughly flushed and filled with medium selected for testing (see above).

The medium shall have ample time for setting and to allow the entrapped air to be vented.

For system tests each pressure test shall be monitored by one recorder, a thermometer and two

pressure gauges one of which is connected to the highest point of the test system.

Recorders and gauges shall be calibrated and certified in accordance with the NoBo requirements

and approved and accepted by Company.

The certificates shall be kept ready for inspection on site.

No testing shall be performed when ambient temperature is below 10 degrees C.

The minimum test pressure shall be measured at the highest point of the system.

If tested with water the test system shall be kept under pressure for settling until all entrapped air

is dissolved into the water. After approval of NoBo or Company the testing period starts and shall

be recorded. The pressure shall be maintained for the period mentioned in the pressure test

procedure or as long is required by NoBo or Company.

If pads or saddles have been installed at branch connections, ventholes shall be carefully inspected

to reveal any leakage during testing.

Ventholes shall be left open or plugged with a soft material not being able to sustain any pressure.

Each weld, flange connection and piece of equipment shall be carefully checked for leaks during

the test. Any leaks found shall be corrected after de-pressurising the system.

After correction of leaks or defects, Contractor shall retest the system.

If, during the test period, the pressure changes due to temperature variations of the test medium

a correction calculation shall be part of the test report.

If the ambient temperature is considerably higher than the test medium, care shall be taken that,

due to expansion in case of liquid test medium, the pressure does not exceed the maximum test

pressure.



6.3.4 Preparation system after testing

After successful completion of the pressure test, the system shall be drained promptly and be

dried according to a Company approved procedure. The system shall be filled with nitrogen if

Company requires so.

Care shall be taken that each high point is vented and each low point is drained.

Draining shall be slow enough not to create a vacuum that possibly can be detrimental to the

system. Prior to blowing all bottom plugs shall be removed.

All duplex systems shall, after completion, prior to load out, be cleaned and flushed with an

approved solvent, dried with hot air or by vacuum and filled with nitrogen at 1 Bar min. and

sealed off.

System(s) shall be closed with blind-plates and spades, fabricated from plate / supplied by

Contractor. For duplex flanges stainless steel liners and spades shall be used. Spades shall be

painted pink and clearly visible, all studs / nuts shall be installed, the original gaskets etc. shall be

attached to the spade. A checklist showing all spades shall be made to enable off shore re-

installation of the joints.

After pressure testing and reinstatement of the complete system, extra attention shall be paid to

obtaining a completely closed and leak-free system onshore. This shall be done by a complete test

at design pressure with nitrogen with Helium. Before startup offshore, this shall be done in line with

commissioning plan. This shall be done with a complete service test at operating pressure.

6.3.5 Alternative methods

If no pressure testing is possible, alternative/additional testing might be acceptable but only after

consultation of and approval from Company- and if applicable NoBo representative.

6.3.6 Inspection and witnessing

All test shall be witnessed and approved by Company, and where applicable by NoBo"

representative. During the test the system shall be accessible for proper and safe inspection.

6.4 SAFETY DURING PRESSURE TESTING

Precautions shall be taken to ensure that the pressure test is done in a safe manner. It should be

kept in mind that a considerable amount of energy is present in the test medium under high

pressure.

Only personnel directly involved in the test shall be permitted in the vicinity.

Further if applicable the use of N2 to fill systems after pressure testing and draining the system,

shall be reason for extra attention, note N2 if inhaled in larger quantities is lethal.

Systems filled with N2 shall at all times be clearly marked with appropriate warning signs.



7.0 QC PIPING FABRICATION

7.1 GENERAL

The nature and extend of supervision and inspection during fabrication, installation and testing

shall be agreed between Company, NoBo (if applicable) and Contractor.

The general contents agreed shall be laid down by Contractor in a quality control plan / test and

inspection plan.

7.2 INSPECTION PIPING PREFABRICATION

Inspection on prefabrication shall guarantee as a minimum the following items:

check on use correct materials and adherence to material control procedures,

visual examination materials before use,

visual examination fit-up before welding,

inspection on working (incl. welding) per specifications

visual examination after welding

inspection on dimensions (both dimensions from drawing as fabrication-results (square,

straddled, straight, etc.),

Non Destructive Testing

Heat treatment

Coating

Dimensional inspection to drawings

Inspection as required for Class. Authority for piping where applicable

Documentation including As Built.

7.2.1 Preparation for coating

Before blasting / coating can commence, to avoid damage to vulnerable parts ( i.e. treads),

and contamination of insides of pipe spools etc. with blasting material, parts shall be

protected ( closed or alternative).

For this purpose dedicated materials shall be used ( plastic caps, tubes on treaded rods,

neoprene sheets, tape)

No screwed plugs, caps that contain any pressure, shall be used!

7.3 INSPECTION PIPING INSTALLATION

Inspection on installation shall guarantee as a minimum the following items:

inspections as indicated for prefabrication where applicable

handling, transport and storage of spools

strain-free installation of piping

extra attention of closing system to avoid contamination of piping systems and equipment to

be connected

Non Destructive Testing field welds

Coating inspection

Supporting

Documentation including As Built.



7.4 NON DESTRUCTIVE TESTING

7.4.1 Quantities

Welds in piping shall be tested with NDT techniques.

In general the following scheme shall be adhered to.

Welds on piping subject to NoBo approval must be 100 % NDT tested.

Any weld in class 30 and up must be 100 % NDT tested.

Welds on piping not subject to NoBo approval and not in class 30 and up must be as, a

minimum, 10 % NDT tested. (all welders on the project must be included in this 10%).

Company reserves the right to select the welds or require additional radiographs.

7.4.2 Types and standards for NDT

NDT shall be done per approved procedures and standards and by qualified personnel (Level II).

Procedures and qualifications shall be based on EN 473, EN 13480, NEN 3650 and NEN 3656, and

shall as a minimum fulfil the NoBo requirements as laid down in the subject sheets. The locations

of the weld examined shall be indicated on a drawing in such detail, that the precise location of

each checked weld can be traced. NDT on a weld will include type of check per table included.

Radiographic: The most stringent technique and acceptance criteria shall be used.

All indications shall be reported.

NDT on welds CS and Duplex

Radiographic Ultrasonic +

Magnetic Particle

Magnetic Particle

FP butt-weld* *

FP K-weld *

Non FP-weld *

Scars / burns *

Notes:

- In all applications NDT-results must give clear view on the quality of the weld to be examined.

If necessary NDT-technique will be adapted to suit this goal.

- For SS-types (including Duplex) MPI will be replaced by Dye-Penetrant Inspection.

- Radiography implies the use of only X-ray tests. Gamma-ray tests may, in specific cases, be

accepted by an approved procedure. Cobalt-60 isotopes shall not be used.

* Weldolets one exposure supported with 100% magnetic particle / dye penetrant

examination.



8.0 DOCUMENTATION

During fabrication and installation all relevant information shall be tabulated on the "Weld History

Sheet" attached to this specification or on an approved similar Quality Control Document, and shall

be issued to Company.

The extent of further documentation to be issued shall be agreed between Company and

Contractor.

9.0 DELIVERY AND TRANSPORT

If (pre-)fabricated spools are to be delivered to Neptune Energy for offshore installation (by

Contractor or by others), these spools will be:

clean and openings and ends closed, facings protected, properly stored to avoid damage.

transported in (open top) containers suitable for offshore transport and lifting or for larger

spools equipped with rigging for single point lifting. Lifting spools shall not contain tackwelded

items.

installation materials and/or supports shall be packed per spool and shipped with the subject

spools unless agreed otherwise.

have correct and clear marking (project/drawing/spool/platform/weight).

be accompanied by clear and complete paperwork and packing lists.

Release note prepared by contractor, for signature Company representative.

10.0 ATTACHMENTS

Attachment I - Welding of ferritic/austenitic stainless steel

Attachment II - Weld history sheet


Attachment I to Specification 502 rev. 18 Page 2 of 20

TABLE OF CONTENTS

1.0 GENERAL ......................................................................................................................................... 4

1.1 SCOPE ................................................................................................................................................................. 4 1.2 REFERENCES ..................................................................................................................................................... 4 1.3 ABBREVIATIONS ............................................................................................................................................. 4 1.4 TRANSPORT, STORAGE HANDLING AND PREPARATION ............................................................. 5 1.5 DOCUMENTATION ........................................................................................................................................ 5

2.0 WELDING CONSUMABLES ........................................................................................................... 6

2.1 ELECTRODES, WIRE AND FLUX ................................................................................................................. 6 2.2 CONDITION OF STORAGE .......................................................................................................................... 6

3.0 WELDING PROCEDURES ............................................................................................................... 7

3.1 GENERAL ........................................................................................................................................................... 7 3.2 WELDING PROCEDURE SPECIFICATIONS WPS .................................................................................. 7 3.3 WELDING PROCEDURE QUALIFICATION WPQ .................................................................................. 8 3.4 PROCEDURE QUALIFICATION RECORD PQR ...................................................................................... 8 3.5 INSPECTION OF PROCEDURE QUALIFICATION TEST WELDS ...................................................... 8 3.6 QUALITY REQUIREMENTS .......................................................................................................................... 9

4.0 WELDERS'S COMPETENCE CERTIFICATES ............................................................................... 10

4.1 GENERAL ......................................................................................................................................................... 10 4.2 MARKING OF WELDS ................................................................................................................................. 10 4.3 APPLICABILITY OF WELDER AND WELDING OPERATOR QUALIFICATION ........................... 10 4.4 RETESTS ........................................................................................................................................................... 10 4.5 WELDER QUALIFICATION RECORD ...................................................................................................... 10

5.0 PRODUCTION WELDING ............................................................................................................ 11

5.1 GENERAL ......................................................................................................................................................... 11 5.2 WEATHER PROTECTION ............................................................................................................................ 11 5.3 HANDLING AND USAGE OF WELDING CONSUMABLES ............................................................. 12 5.4 WELDING END PREPARATION ............................................................................................................... 12 5.5 BACKING STRIPS .......................................................................................................................................... 12 5.6 WELDING PROCESS, POSITION AND PROGRESSION ................................................................... 12 5.6.1 Gas Tungsten Arc Welding GTAW (TIG) ........................................................................................ 12 5.6.2 Submerged-Arc Welding SAW .......................................................................................................... 13 5.6.3 Shielded Metal Arc Welding SMAW ............................................................................................... 13 5.7 ARGON GAS PURGING INSIDE PIPES .................................................................................................. 13 5.8 HEAT INPUT, PREHEATING AND INTERPASS TEMPERATURES.................................................. 13 5.9 WELD INTERRUPTION ................................................................................................................................ 13 5.10 CLEANING ....................................................................................................................................................... 14 5.11 SIZE OF WELDS ............................................................................................................................................. 14 5.12 DISTANCE BETWEEN WELDS ................................................................................................................... 14 5.13 SOCKET WELDS............................................................................................................................................. 14 5.14 WELD FINISH ................................................................................................................................................. 14 5.15 POST WELD HEAT TREATMENT ............................................................................................................. 14

6.0 FABRICATION ............................................................................................................................... 15

6.1 GENERAL ......................................................................................................................................................... 15 6.2 BENDING ......................................................................................................................................................... 15



6.3 ALIGNMENT AND FIT-UPS ....................................................................................................................... 15 6.4 FINISHING OF SURFACES ......................................................................................................................... 16 6.5 PROTECTION OF PIPE ENDS .................................................................................................................... 16 6.6 REPAIR AND REMOVAL PROCEDURES ................................................................................................ 16

7.0 INSPECTION AND TESTING REQUIREMENTS ......................................................................... 18

7.1 GENERAL ......................................................................................................................................................... 18 7.2 METHODS OF INSPECTION, TESTING AND QUALITY REQUIREMENTS ................................. 18 7.2.1 Radiographic Examination (as noted or NoBo approved equivalent) ............................... 18 7.2.2 Ultrasonic Examination ......................................................................................................................... 18 7.2.3 Dye Penetrant Examination ................................................................................................................ 18 7.2.4 Pre-Welding Inspection ........................................................................................................................ 19 7.2.5 Inspection After Welding ..................................................................................................................... 19 7.2.6 Standards on Inspection ...................................................................................................................... 19 7.2.7 Weld Rejection Report .......................................................................................................................... 19 7.2.8 Right of Rejection ................................................................................................................................... 19 7.2.9 Assessment of Indications on Radiographs in the Pipe Material Adjacent to Welds

Being Inspected .......................................................................................................................................................... 19 7.2.10 Retests of Mechanical Properties ..................................................................................................... 19



1.0 GENERAL

1.1 SCOPE

This document as part of Specification 502 covers the requirements of welding and inspection

of duplex stainless steel shop and field fabricated piping.

Duplex stainless steel shall refer ferritic/austenitic stainless steel with a chemical composition

and mechanical properties as defined in VdTüV Werkstoffblatt Nr. 418, DIN Werkstoff Nr.

1.4462. For Transport Pipelines see NEN 3650 and offshore pipelines NEN 3656.

1.2 REFERENCES

The following specifications, codes and standards are to be considered where applicable. All

conflicts between the requirements of these relevant shall be referred to Company for

resolution. In case of conflicts between the documents listed and this document, the most

stringent requirement shall govern. The latest editions of the following standards and codes

shall apply:

"Pressure Equipment Directive" hereafter indicated as PED.

NEN-EN 13480.

Specification 503, Specification for pipe, fittings and valves.

EN 3834-2 Quality requirements for fusion welding of metallic materials.

1.3 ABBREVIATIONS

BM : Base Metal

EFN : Extended Ferrite Number

GMAW : Gas Metal Arc Welding

HAZ : Heat Affected Zone

IIW : International Institute of Welding

NDT : None Destructive Test

PQR : Procedure Qualification Record

QA : Quality Assurance

QC : Quality Control

SAW : Submerged Arc Welding

SMAW : Shielded Metal Arc Welding

WM : Weld Metal

WPS : Welding Procedure Specifications

WPQ : Welding Procedure Qualifications



1.4 TRANSPORT, STORAGE HANDLING AND PREPARATION

The following recommendations shall be adopted in every step in the manufacturing process

to reduce the risk of surface contamination of this type of stainless steel.

a) Any contact between stainless steel and carbon steel components shall be avoided.

Fabrication and storage of pipe spool shall be carried out in a separate area.

b) Before transportation and field installation each pipe spool shall be protected with tape.

c) Only stainless steel wire brushes that have not been used on any other material shall be used.

Grinding wheels used for stainless steel shall not have been used for other purposes. Tools

shall be clearly marked (i.e. colour coded) to indicate their designated use. Earthing clamps for

welding and cutting should be made of stainless steel.

d) Moisture shall be removed by carefully and controlled heating with a torch. Skin temperature

shall not exceed 150 °C.

e) Acetone (or approved equivalent) may be used for cleaning stainless steel surfaces. Caution:

Acetone is extremely flammable.

f) Arc cutting shall be done by using only plasma arc process.

g) Contamination of Duplex stainless steel with zinc, etc. will not be permitted.

h) Handling equipment, such as slings, hooks, and lift truck forks, shall be covered with clean

wood, cloth, or plastic buffers to exclude contact with the stainless steel surface. These

protection means shall be immediately replaced after any contact with carbon steel.

i) Stainless steel shall be stored indoors, or otherwise protected from moisture, dust, salt, iron

particles, and other matter that may initiate or cause corrosion.

j) If any construction activity is to be carried out in the vicinity of installed duplex or stainless

steel piping and/or equipment, adequate protection shall be provided to prevent any damage

before such construction work commences.

1.5 DOCUMENTATION

The following documentation shall be supplied by the Contractor and issued for approval

when applicable:

Mill certificates of materials used if the material is supplied by the Contractor (See

specification 503 and "PED")

Welding Procedure Specifications, Procedure qualification records and welders certificates

Procedures and methods for assembly, fabrication and handling

Procedures for repairs

Inspection and QC procedures

Non destructive testing records and radiograph films

Drawings indicating material and NDT locations

Hydrotest records, including instruments calibration data

Test & Inspection Plan



2.0 WELDING CONSUMABLES

2.1 ELECTRODES, WIRE AND FLUX

Consumables from Company approved suppliers only shall be used (see Appendix to this

attachment). Consumables shall have a similar chemical analysis to that of the base material,

however, the nickel content shall at least be 7,7%.

The weld metal should have a corrosion resistance equal to, or better than, the base metal.

2.2 CONDITION OF STORAGE

Electrodes, wire and flux shall be supplied in fully sealed packages and stored in a dry storage

room. All manual type electrodes shall be properly identifiable up to the time of usage, each

electrode being distinguished by proper coding. In case the coding is destroyed by baking,

handling, or other causes, the electrodes shall not be used.

Consumables used for welding duplex stainless steel shall not be stored in heated cabinets

containing electrodes of other types, such as rutile or organic type electrodes or consumables

for welding other types of stainless steel e.g. AISI Type 316L.

Wire spool for automatic and semi-automatic processes shall be stored in cabinets with

supplier wrapping not removed and remain clearly identifiable up to the time of usage.

Unidentifiable wire shall not be used.

Flux shall be supplied and stored, in accordance with manufacturer’s instructions.

Each batch of flux and wire shall be labelled with the information from the supply container.

The labels with batch number shall be recorded by reference in relation to the actual welding

work.

All non-identified, damaged, wet, rusty or otherwise contaminated consumables are to be

scrapped. Electrodes (once melted) or with white spots on the flux shall not be used.

All bottles containing shielding gases shall have clear identification labels.



3.0 WELDING PROCEDURES

3.1 GENERAL

Detailed welding procedure shall be established and qualified in accordance with NoBo as per

PED, NEN-EN 13480 and as further required in this Specification

No production welding shall commence until the appropriate procedure tests have been

completed and approved.

Repair welding procedures are to be established and, where necessary, qualified.

3.2 WELDING PROCEDURE SPECIFICATIONS WPS

A written welding procedure specification together with test certificates indicating mechanical

properties and chemical analyses of both base materials and welding consumables shall be

submitted to the Company representative for preliminary approval.

No procedure qualification tests shall be performed until the procedure specification has been

granted preliminary approval by the Company representative.

Welding procedure specifications shall contain the following "applicable parameters" with all

explanatory details necessary (see also: ISO 15609):

Material specification of base metals.

Welding process.

Wall thickness and diameter range used for procedure qualification (chemical analyses and

mechanical properties of the base material and welding consumables used for the procedure

tests shall be included in the welding procedure qualification record).

Geometry of welding groove showing allowable tolerances.

Root gap showing allowable tolerances.

Welding position and direction.

Filler metal classification.

Specification of flux.

Gas shielding - flow, mixture, composition (to include back purging).

Number and sequence of the important passes (indicate stringer or weave beads).

Welding current range, voltage range and polarity.

Travel speed or electrode runout length for each pass and range.

Heat input range.

Preheat and interpass temperatures.

Method of cleaning, cutting and machining if applicable.

When any changes in these parameters are made, the welding procedure qualification shall be

set up as a new WPS, and shall be completely re-qualified.



3.3 WELDING PROCEDURE QUALIFICATION WPQ

A qualified welding procedure specification is one which is tested to and has achieved the

requirements of this Specification, and has been witnessed and approved by the Company's

representative and the Certifying Authority.

The Contractor shall conduct the tests required to qualify each procedure and tests shall be

witnessed by the Company representative and the Certifying Authority. The results of previous

welding procedure qualification tests may be accepted by the Company's representative and

the Certifying Authority providing:

a) Welding specifications and resulting test certificates are authenticated by the original

documentation, or by certified copies.

b) The Contractor submits documentation, for the approval of the Company representative, to

demonstrate that all the appropriate test requirements, applicable parameters, welding

conditions, equipment and materials as used in the original welding procedure qualification

tests, comply with and fulfil all the appropriate test requirements of this Specification.

All services in connection with the establishment of welding procedures, welders performance

qualifications, related tests and additional corrosion tests shall be by the Contractor.

Qualification of a welding procedure is restricted to the Contractor or Subcontractor where

the test weld was produced.

Welding procedure and welders performance qualification shall be new and subject to

approval by Company's representative.

Welding procedure qualification tests shall be conducted to verify the WPS's, and shall

simulate, as far as practical the conditions and materials to be used for production welding.

A qualified procedure is valid only for diameters and thickness in accordance with PED and

NEN-EN 13480.

3.4 PROCEDURE QUALIFICATION RECORD PQR

The specific parameters of the WPS and test results of the WPQ shall be recorded in the

procedure qualification record PQR, signed by the responsible welding engineer, QA engineer

and NoBo.

3.5 INSPECTION OF PROCEDURE QUALIFICATION TEST WELDS

The base material, welding consumables and welding process shall be equal to those as

specified in the welding procedure specification WPS.

Dimensions of the weld samples shall be sufficient to provide for the required test pieces as

defined in the PED and NEN-EN 13480.

During welding, the welder's name and all data listed in the WPS shall be recorded.



3.6 QUALITY REQUIREMENTS

All weld samples for the procedure qualification shall be subject to NDT (radiographic,

ultrasonic testing and surface examination) and acceptance in accordance with this

Specification prior to mechanical testing. The acceptance criteria for mechanical testing shall

be in accordance with PED and NEN-EN 13480.

A cross-section of the weld shall be made for microscopic and a macroscopic investigation.

The cross-section shall clearly show the weld metal, fusion line and heat affected zone. The

ferrite content shall be measured using a magna-gage equipment or an alternative tool

approved by the Company. At least 5 measurements shall be made. The ferrite content shall

be expressed in a extended ferrite number EFN and the average value shall be between 30

and 65 for the weld metal and heat affected zone. Any single value shall not exceed a 10% of

these values.

Hardness tests shall be carried out at one line 2 mm away from both surfaces of weld cross-

section and halfway between these surfaces. Zones of indentations should give three values in

the base material BM on both sides of the weld in addition to those in the weld metal WM

and heat affected zone HAZ.

The minimum distance between the indentations should be two and half times the width of

the previous indentation. The maximum allowable hardness measured is 305 HV 10 (305

Vickers hardness measured on 10 kg load). Maximum allowable hardness variation between

any point indicated may be 100 HV 10.

Charpy-V notch impact test shall be carried out when the wall thickness of pipe or fitting

exceeds 5 mm.

Three notch impact test pieces (standard specimen 10 x 10 mm) shall be taken in transverse

direction on the weld and shall be tested at Vt-test temperature in accordance with EN 13480

requirements for an Vc-assessment temperature of minus 20 degrees centigrade. The average

impact value shall not be less than 52 Joule with only one value lower, but not below 39 Joule.

The dimensions, preparation and testing of the impact test specimens shall be in accordance

with NEN-EN 875.

Subsized specimen may be used when standard specimen cannot be prepared. In this case

the required values may be lowered accordingly.

Pitting corrosion test to ASTM G48 ( method A ) test method at 22 degrees centigrade.

Exposure time 24 hours ( no pitting at 20x magnification and weight loss less than 5.0 g/m²).



4.0 WELDERS'S COMPETENCE CERTIFICATES

4.1 GENERAL

Welders and welding operators shall be qualified in accordance with the requirements of the

PED in accordance with the applicable requirements and of this Specification. Where

radiography is specified only X-ray shall be used. Mechanical testing as required by PED and

NEN 13480.

4.2 MARKING OF WELDS

The welder shall clearly mark the pipe adjacent to his weld with the identification mark

assigned to him in his qualification certificate prior to starting the root pass.

Tack welding of components does not require marking.

Marking shall be done with a white paint marker (chloride-free).

The use of stamps for marking the welds is not allowed.

The welder/operator who makes the root pass shall write his code at the top of the pipe; if,

however, two welder/operators weld the root pass, each welder/operator shall mark the top of

the pipe with his identification code on the side on which has worked. Subsequent

welders/operators shall write their identification codes below the first code in the sequence in

which they work. The identification marks may not be removed until after the welds have been

inspected both visually and non-destructively.

4.3 APPLICABILITY OF WELDER AND WELDING OPERATOR QUALIFICATION

The Contractor shall ensure that qualified welders and welding operators are employed

during fabrication only on welding the type, process and position of weld for which their

qualification test so qualifies them. Proven previous qualifications can be submitted to

Company for acceptance. A welder or welding operator may also be required to re-qualify if

inspection during fabrication reveals that repairs are necessary due to unacceptable defects.

The Contractor shall maintain an accurate record of the performance of each welder which

should show the repair rate.

The repair rate shall be indicated as a percentage of the total length of weld produced.

4.4 RETESTS

Retests are not accepted and only considered after consulting Company's representative.

4.5 WELDER QUALIFICATION RECORD

A Welder's qualification record, which includes references or the corresponding WPS nr., the

applicable parameters and the test results, shall be issued for each welder or welding operator

and for each test.



5.0 PRODUCTION WELDING

5.1 GENERAL

No welding shall be carried out before the welding procedures and procedure qualification

records are completed and approved and the welders have been qualified.

Preparation and welding of pipe components shall be in accordance with the appropriate

qualified welding procedure specifications. Manual electrodes, wire and flux shall be of the same

type and manufacture as those used in the procedure.

No welding shall be done until as much of the pipeline or piping system as will be stiffened

thereby has been properly aligned.

Every buttweld preparation, before welding, will be inspected and approved by Company's

representative.

Test & inspection Plan must contain a column for this inspection.

The Company will have the right to carry out any concurrent test deemed necessary when any

deviation from this specification is made.

Attention is to be given to the necessity of achieving adequate firm support of the pipe

components in both the vertical and horizontal plane.

Alignment and fit-ups for two pipe components shall be in accordance with para. 6.3.

Current return cables of welding equipment shall be connected directly to the pipe on which

welding work is to be done using stainless steel clamps.

The earthing point for field welds shall not be beyond any valves or other installed equipment.

Earthing marks shall be ground smooth and 100% dye penetrant tested.

Marking of welds shall be in accordance with para. 4.2.

5.2 WEATHER PROTECTION

Shelters giving adequate protection at all times to the weld area from wind, rain and moisture

shall be provided.

No welding shall be carried out when the weld surfaces are wet, moist or when the work area

is exposed to winds.

Following is required:

Weld surfaces to be thoroughly dried by heating. High metal skin temperature shall be

avoided and shall not exceed 150 deg. C.

Provisions to be made for maintaining a satisfactory surrounding temperature and protection

for the effects of wind.

Provisions to be made to reduce distortion as could occur due to differences in temperature

between components.



5.3 HANDLING AND USAGE OF WELDING CONSUMABLES

Welding rods, electrodes, filter metals and fluxes shall be handled and used in accordance

with the manufactures recommendations (see chapter 2.0).

5.4 WELDING END PREPARATION

The equipment used for edge preparation and cleaning (e.g. plasma cutting, grinding,

machining, emery cloth, grit blasting using alumina shot, wire brushing using a stainless steel

wire brush, etc.) shall cause no detrimental metallurgical effects upon the edges to be welded.

Edge preparations may be made by shearing machining or hand grinding to an accurate form.

Preparation of weld edges by plasma cutting shall, wherever practical, be done with a

mechanically guided torch. Edges shall be left free of slag, spatter, scale, dirt, grease, salt,

protective coating or other foreign matter which might effect the quality of the weld and the

cut surface shall be ground to a smooth bright uniform surface by removing approximately

0.5 mm of metal. After grinding the weld edges shall be visually examined to ensure freedom

from defects.

Any bevelled edge that has been damaged shall be restored within the tolerances required by

the welding procedure to be applied.

Restoration involving welding shall not be permitted.

The welding end preparation shall be carried out in accordance with minimum requirements

stipulated in Appendix II and shall be subjected to Company approval.

5.5 BACKING STRIPS

The use of backing strips will not be allowed.

5.6 WELDING PROCESS, POSITION AND PROGRESSION

The welding process, procedures and specifications shall be subjected to Company approval.

5.6.1 Gas Tungsten Arc Welding GTAW (TIG)

To ensure a high-quality weld with a smooth surface inside the pipe, GTAW-welding is

required for the root-bead.

Manual and automatic GTAW process in the uphill progression only.

Special care shall be taken to protect the weld area from any draught, both externally and

internally.

99.998 percent argon backing and shielding gas is always required throughout welding.

Oxidation caused by the welding procedure and/or process shall not be allowed. Flushing with

argon before welding will be required. The oxygen content of the backing gas directly before

welding shall be determined with oxygen measuring equipment and shall be less than 0.05

percent.



Between welding passes, the metal should be allowed to cool to approximately 150 deg. C.

For a high quality of welding, ferritic austenitic stainless steel material should be at a

temperature of at least 15 deg. C before welding.

Overheating may also cause cracks, and these too must be removed and repaired

(see paragraph 6.6).

When welding pipe, for best results weld short passes on alternate sides of the pipe. On pipe

less than 6 inch in diameter, each pass should be not over 2 inch in length for pipe 6 inch, or

over in diameter, each pass may be 3 inch in length.

5.6.2 Submerged-Arc Welding SAW

This shall be done in a flat position and the pipe shall be rotated. This process shall only be

used for filling and capping. Wire and flux shall be from the same manufacturer.

5.6.3 Shielded Metal Arc Welding SMAW

Electrodes shall only be used for filling and capping and only in the position recommended by

the manufacturer.

5.7 ARGON GAS PURGING INSIDE PIPES

In order to avoid surface oxidation during welding process ferritic/austenitic stainless steel

pipes must be purged with 99.998 percent argon backing gas sufficiently to remove all oxygen

inside the pipe in the weld area. The usual way to achieve this is to seal off a small length of

the pipe on each side of the weld groove. This restricted volume is then purged with a suitable

inert gas, sufficient to remove all oxygen.

Devices and procedures shall be subjected to Company approval.

5.8 HEAT INPUT, PREHEATING AND INTERPASS TEMPERATURES

Heat input during welding should be kept low to reduce the danger of unwanted structures

and precipitates.

For this reason the degree of dilution must be kept low. Two layers with little weld metal

deposited are better than one layer with higher heat input and more deposited weld metal.

Preheating is usually not required. A limited preheating may be required in highly constraint

conditions and only considered after consulting Company's representative.

The maximum interpass temperature shall not exceed 150 deg. C.

Production welding parameter monitoring is required. Minimum frequency of testing shall be

one record per process per shift and schedule shall ensure that each welder is tested at least

once per calendar month.

5.9 WELD INTERRUPTION

Welding of each weld shall be a continuous operation unless the maximum interpass

temperature is reached.



Line up clamps shall not be removed nor shall the pipe be moved until the root and the

second pass have been completed.

5.10 CLEANING

During welding any part of the weld metal of parent plate exposed to the air at elevated

temperature will become oxidised, the oxidation is ranging from light tinting to a black scale.

Oxide shall be removed after each welding root, otherwise preferential corrosion may result,

either from its difference in electrochemical properties or from its crevice action.

Upon completion of each welding pass, the weld shall be cleaned of spatter, slag and flux

deposits. After welding is completed, adjacent surfaces shall be thoroughly cleaned of all

spatter and deposits, pickled and passivated in accordance with an approved procedure by

Company's representative.

To ensure the corrosion resistance of pipelines and piping systems and the passage of

pipeline scrappers and other similar devices through the completed lines it is of particular

importance that the internal surface of pipes be as smooth as possible and free from all

internal welding beads, slag particles, weld spatter etc.

Special care shall be given to the selection of the cleaning equipment and the rules defined in

para. 1.4 shall be followed.

5.11 SIZE OF WELDS

All welds shall be continuous and multipass. They shall be properly sized to develop the full

strength of the thinner of the two pipe components joined.

5.12 DISTANCE BETWEEN WELDS

The number of welds shall be as small as possible. In general the minimum allowable distance

between circumferential welds is 3 times the external diameter of the pipe.

If any 3 m a maximum of 2 welds is allowed unless otherwise specified on the drawings.

5.13 SOCKET WELDS

Socket weld fittings shall only be used in special cases only with preliminary written approval

by Company's representative.

Where socket weld fittings or valves are used pipe sections shall be spaced approx. 1.5 mm

apart to avoid "bottoming" which can result in excessive weld stress. Approved welding

procedures are to be adhered to.

5.14 WELD FINISH

Welds shall be left as welded and not be treated with a torch or by any mechanical means

outside the allowances of the welding procedure specification to change their appearance.

5.15 POST WELD HEAT TREATMENT



Post weld heat treatment is not permitted. Any uncontrolled heating of the pipe may impede

the corrosion resistance of the material and shall be reported to the Company.

6.0 FABRICATION

6.1 GENERAL

All measures shall be taken to ensure correct positioning and sizing of the components to be

welded.

Work shall not be performed when the weather and/or lack of sufficient protection does not

permit satisfactory workmanship or when conditions prevent adequate inspection.

If any fabrication is to be carried out in the vicinity of equipment already installed, than before

such fabrication work commences, adequate protection shall be provided to prevent any

damage from weld spatter, cutting droplets etc.

Care shall be taken to avoid overloading, damage or undue deformation in any of the pipe

components at all stages of the work.

Care shall be taken to avoid any zinc contamination of the stainless steel e.g. by overspray of

zinc containing coatings.

Handling of the stainless steel pipe components shall be done with great care and the

measures outlined in para. 1.4 shall be followed.

6.2 BENDING

Bending of duplex stainless steel pipe requires great care and procedures shall be approved

by the Company before any bending commences. It is usually required to heat treat the

material after bending (1050 deg. C/water quench).

6.3 ALIGNMENT AND FIT-UPS

Internal line-up clamps of appropriate material shall be used where possible

Only for tie-in welds such as riser tie-ins and for special welds e.g. joints connecting valves,

flanges and fittings external line-up clamps may be used.

When the internal diameter is 100 mm or less an external line-up clamp may be used.

Inside diameter misalignment of the adjoining welding ends shall not exceed 1/8 of the wall

thickness with a maximum of 1 mm. If the misalignment exceeds the above value trimming at

the internal diameter of the thicker joint to a taper of 1 : 4 should be properly corrected.

Stainless steel spacing tools shall be used in conjunction with the line-up clamp to assure the

proper joint spacing which shall be in line with the applicable welding procedure.



Any longitudinal welds in pipes shall be so positioned that the weld is at the top 120 of the

pipe and any two adjacent longitudinal welds shall be at least 45 apart.

6.4 FINISHING OF SURFACES

When fabrication is completed, all welds shall be ground as indicated in the welding

procedures or on the drawings to allow proper radiographic or ultrasonic inspection, and to

remove all detrimental spatter, burrs, tack welds and other marks. Where so required the

damage shall be rectified in accordance with an agreed procedure.

6.5 PROTECTION OF PIPE ENDS

A circular tight cap, of a design which will not damage pipe ends shall be used to cover the

open ends of the pipe and shall be placed on the line at the end of each day's work to prevent

entry of foreign material. Caps shall not be removed until commencement of the following

day's work. The requirements to protect the stainless steel as defined in para. 1.4 shall be

adhered to.

All open ends of pipe ate to be capped off and sealed once installation in completed. This

protection shall be in line with para. 1.4.

6.6 REPAIR AND REMOVAL PROCEDURES

Defective welds shall not be repaired before approval of Company in obtained.

All repairs shall be executed by qualified welders according to approved procedures and all

requirements of this Specification shall be met.

The removal of weld metal or portions of the base metal may be done by machining or

grinding. High metal skin temperature shall be avoided and shall not exceed 150 deg. C. The

unacceptable portions of the weld shall be removed including the relevant heat affected zone

without substantial removal of the base metal and shall be done in such a manner that the

remaining weld metal or base metal is not nicked or undercut. The grooves are to be free

from scale and to have acceptable contours, and shall be visually and dye penetrant inspected

prior to re-welding to ensure the defect has been completely removed.

Additional weld metal to compensate for any deficiency in size shall be deposited using

procedures as required in the making of the original weld. The surfaces shall be thoroughly

cleaned before depositing the additional weld metal.

Local repairs shall normally be inspected 100% by the method prescribed for the original weld

with due regard to confirming that the original defect has been removed.

Every possible care shall be taken with repairs to minimise welding stresses.

If planar defects (cracks, lamellar tears, etc.) have to be repaired, every effort shall be made to

prevent propagation of the defect during its removal. Dye penetrant inspection shall be

carried out to check for the complete removal of the defect.



A weld with unacceptable defects may only be repaired once by Company approved repair

procedure. If the repair is not acceptable the complete weld shall be removed.

Second attempts at repairing the same weld area SHALL only be made by permission of the

Company.

In the event that it is required to cut out a weld, this may be carried out by plasma cutting,

after which all material in the relevant heat affected zones shall be removed prior to

rewelding.

All costs including new materials shall be at the CONTRACTOR’s expense.

An unacceptable weld shall be repaired or replaced in accordance with all above clauses.

Where repair is selected, the following measures are required:

- Overlap or excessive convexity - remove excessive weld metal.

- Excessive concavity of weld or craters, undersized welds, undercutting - prepare surfaces

and deposit additional weld metal.

- Excessive weld porosity, excessive slag inclusions, heavy metal inclusions, incomplete

fusion or planar defects - remove unacceptable portions and re-weld.



7.0 INSPECTION AND TESTING REQUIREMENTS

7.1 GENERAL

Written NDT procedures approved by the Company shall be prepared. All operations shall be

performed in accordance with these procedures.

All personnel performing welding inspection or non-destructive testing shall be qualified, as

required by EN 473 (level 2) in the technique to be applied, or to a Company approved

equivalent qualification.

7.2 METHODS OF INSPECTION, TESTING AND QUALITY REQUIREMENTS

7.2.1 Radiographic Examination (as noted or NoBo approved equivalent)

All radiography shall be carried out in accordance with the method described in NEN EN 1435

and NEN-EN 13480.

Radiography implies the use of only X-ray tests. Gamma-ray tests may, in specific cases, be

accepted by an approved procedure. Cobalt-60 isotopes shall not be used.

Radiographs shall be supplemented by ultrasonic testing accompanied by dye penetrant

testing where there is reason to suspect planar defects such as cracks or lack of fusion.

Radiographs shall be made using a film equal to ASTM E-94 Type 1.

Quality shall be as defined in NEN-EN 13480 and further applicable codes.

7.2.2 Ultrasonic Examination

Ultrasonic examination may be used in lieu of radiographic examination. The method shall be

selected such that the progress of the construction is not affected (refer to NEN-en 1714 and

NEN-EN 1712.

All ultrasonic examination work shall be carried out in accordance with the methods described

in NEN-EN13480, and per NoBo approved procedure.

Since the experience with ultrasonic examination of welds in duplex stainless steel is limited

the inspection procedure shall be qualified on a weld produced with the welding procedure to

be used for the project and with the IIW reference blocks VI and V2.

Welds shall be judged in accordance with para. 7.2.7.

Proposal for UT test and acceptance to be subject to approval by Company.

7.2.3 Dye Penetrant Examination

Dye penetrant inspection shall be carried out in accordance with NEN-EN 571 or similar as

described in NEN-EN13480, procedure to be NoBo approved.



Any weld or area which is tested by means of dye penetrant testing shall be judged

unacceptable if any crack, regardless of size, is revealed.

7.2.4 Pre-Welding Inspection

All materials shall be in accordance with NEN-EN 13480 and subject to visual inspection for

surface defects, laminations at ends, etc.

All preparations and repaired preparations shall normally be inspected.

7.2.5 Inspection After Welding

All weld surfaces shall be visually inspected and there shall be free of dents, cracks, craters,

pinholes, weld spatter, residual slag, pits, laps and other harmful surface defects.

All welds shall be fully radiographed.

When radiography is not practical or where the Company's representative requires a further

examination of a weld to assist in the evaluation of suspected defects, ultrasonic examination

and/or dye penetrant testing may be used.

7.2.6 Standards on Inspection

Inspection and standard of acceptance shall be based on NEN-EN 13480.

7.2.7 Weld Rejection Report

The report on each rejected weld shall state the identification number of the weld and the

name of the welder/operator as well as the reason for rejection of the weld.

The International Institute of Welding code shall be used for indicating the reason.

7.2.8 Right of Rejection

Since non-destructive testing methods show only dimensions of defects, Company may reject

welds if the depth of the defects effects the strength of the weld irrespective of the fact that

these welds seem to meet the standards of inspection.

7.2.9 Assessment of Indications on Radiographs in the Pipe Material Adjacent to Welds Being

Inspected

Welds and adjacent pipe material showing indications the pipe material next to the weld has

been damaged in any way whatsoever (e.g. arc burns, damage of a sharp or deep nature, weld

beads, defects in the longitudinal seam of longitudinally welded pipe, etc.) shall be

unacceptable.

7.2.10 Retests of Mechanical Properties

If a test piece does not meet the requirements, the cause should be established where

possible. The tests shall be repeated on two pipes or components taken at random from the

same product lot, to determine whether to reject or approve the whole lot. The contractor



may consider reheattreating the complete product lot. Above matters always to be performed

in consultation with Company.

PROJECT NR:

PLATFORM: REV.:

ACCEPTED BY: DATE:

APPR.: APPR.: APPR.: 1-Jan-00

NAME: NAME: NAME:

SIGN.: SIGN.: SIGN.:PAGE 1 OF 1

CHARGE

NRCERTIF. TYPE REMARKS DESCRIPTION & SIZE

WAS NRWELDER

NR

MT/PT

EXAMIN.CONTRAC-TOR COMPANY AUTHORITY

X-RAY

REPORT

NR

AUTHORITY REG. NR :

MPI / DP

REPORT

NR

US EXAM

REPORT

NR

ATTACHMENT II

WELD

NUMBER ITEM NR MATERIALCERTIFICATE

INDEX NR

CONTRACTOR COMPANY AUTHORITY

FABRICATION/INSPECTION INFORMATION

TO

SPECIFICATION 502, REV. 18

DRAWING NR:

AUTHORITY SEQ. NR :

REMARKS

ASSESSMENT/ACCEPTANCE BY :

LINE NR:

MATERIAL INFORMATION

WELD HISTORY SHEET

HYDROTEST

PRESSURE:

BARG,

COMPANY:

AUTHORITY:

CONTRACTOR:

Documents

TABLE OF CONTENTS · 3.2 DRAWINGS Fabricator shall maintain an up to date record of all applicable drawings at all times. Piping fabrication shall take place from isometric and/or