32-SAMSS-028

Previous Issue: 30 July 2003 Next Planned Update: 1 August 2008 Revised paragraphs are indicated in the right margin of 28

Materials System Specification

32-SAMSS-028 30 March 2005 Manufacture of Double Pipe Heat Exchangers

Heat Transfer Equipment Standards Committee Members Al-Anizi, S.S., Chairman Al-Anezi, M.A. Al-Bagawi, J.J. Al-Dossary, M.A. Al-Gahtani, M.S. Al-Hamam, I.H. Al-Rumaih, A.M. Fernandez, G.T. Moore, M.A. Naffa'a, M.Y.

Saudi Aramco DeskTop Standards Table of Contents 1 Scope............................................................. 2 2 Conflicts and Deviations................................ 2 3 References..................................................... 2 4 Definitions...................................................... 4 5 Responsibilities.............................................. 6 6 Proposals....................................................... 6 7 Thermal Design.............................................. 7 8 Mechanical Design......................................... 7 9 Nozzles......................................................... 11 10 Supports....................................................... 13 11 Clips and Attachments................................. 13 12 Materials....................................................... 13 13 Fabrication.................................................... 15 14 Nondestructive Testing................................. 16 15 Heat Treatment............................................ 19 16 Inspection and Pressure Tests..................... 20 17 Nameplates and Stampings......................... 23 18 Painting........................................................ 24 19 Shipping Requirements................................ 24 20 Drawings, Calculations and Data................. 26

Document Responsibility: Heat Transfer Equipment 32-SAMSS-028 Issue Date: 30 March 2005 Next Planned Update: 1 August 2008 Manufacture of Double Pipe Heat Exchangers

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1 Scope

1.1 This specification covers the minimum mandatory requirements for the mechanical design, materials, fabrication, inspection and testing of new double pipe and multitube hairpin heat exchangers (hereinafter referred to as exchangers). It does not cover exchangers that undergo repairs or alterations.

1.2 The requirements in this specification are in addition to and supplement the requirements of the ASME Boiler and Pressure Vessel Code.

1.3 Where a licensor specification requirement is more stringent than that of this specification, this licensor specific requirement shall govern.

2 Conflicts and Deviations

2.1 Any conflicts between this specification and other applicable Saudi Aramco Materials System Specifications (SAMSSs), Engineering Standards (SAESs), Standard Drawings (SASDs), or industry standards, codes, and forms shall be resolved in writing by the Company or Buyer Representative through the Manager, Consulting Services Department of Saudi Aramco, Dhahran.

2.2 Direct all requests to deviate from this specification in writing to the Company or Buyer Representative, who shall follow internal company procedure SAEP-302 and forward such requests to the Manager, Consulting Services Department of Saudi Aramco, Dhahran.

3 References

Materials or equipment supplied to this specification shall comply with the latest edition of the references listed below, unless otherwise noted.

3.1 Saudi Aramco References

Saudi Aramco Engineering Procedure

SAEP-302 Instructions for Obtaining a Waiver of a Mandatory Saudi Aramco Engineering Requirement

Saudi Aramco Engineering Standards

SAES-A-206 Positive Material Identification

SAES-A-301 Materials Resistant to Sulfide Stress Corrosion Cracking

SAES-H-001 Selection Requirement for Industrial Coating


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SAES-H-100 Painting Requirements for Industrial Facilities

SAES-H-101 Approved Protective Coating Systems

SAES-H-101V Approved Saudi Aramco Data Sheets - Paints and Coatings

SAES-W-010 Welding Requirements for Pressure Vessels

Saudi Aramco Materials System Specification

01-SAMSS-016 Qualification of Pipeline and Pressure Vessel Steels for Resistance to Hydrogen-Induced Cracking

Saudi Aramco Inspection Requirements

Form 175-323100 Manufacture of Heat Exchangers

Saudi Aramco Forms and Data Sheet

Form 2714-ENG Data Sheet

Form NMR-7922-1 Non-material Requirements for Shell and Double-Pipe Heat Exchangers

Saudi Aramco Standard Drawing

AE-036250 Ferrules for 0.75 inch Outside Diameter Tubes (Sheets 1 & 2)

3.2 Industry Codes and Standards

American Petroleum Institute

API STD 660 Shell-and-Tube Heat Exchangers for General Refinery Services

API PUBL 941 Steels for Hydrogen Service at Elevated Temperatures and Pressures in Petroleum Refineries and Petrochemical Plants

API RP 945 Avoiding Environmental Cracking in Amine Units

American Society of Civil Engineers

ASCE 7 Minimum Design Loads for Buildings and Other Structures

American Society of Mechanical Engineers (Boiler and Pressure Vessel Code)

ASME SEC II Material Specifications Parts A, B and D


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ASME SEC V Non-destructive Examination

ASME SEC VIII D1 Rules for Construction of Pressure Vessels

ASME SEC VIII D2 Rules for Construction of Pressure Vessels, Alternative Rules

ASME B2.1 National Pipe Threads

ASME B16.5 Pipe Flanges and Flanged Fittings

ASME B16.11 Forged Steel Fittings, Socket Welding and Threaded

ASME SA-688 Welded Austenitic Stainless Steel Feedwater Heater Tubes

American Society for Nondestructive Testing

ASNT CP-189 Standard for Qualification and Certification of Nondestructive Testing Personnel

ASNT SNT-TC-1A Recommended Practice for Qualification and Certification of Nondestructive Testing Personnel

U.S. Military Standards and Federal Specifications

MIL-C-16173 Corrosion Preventive Compound, Solvent Cutback, Cold-Application

National Association of Corrosion Engineers

NACE RP0472 Methods of Control to Prevent In-Service Cracking of Carbon Steel Welds in P-1 Materials in Corrosive Petrochemical Refining Environments

Tubular Exchanger Manufacturers Association

Welding Research Council

WRC 107 Welding Research Council Bulletin: Local Stresses in Spherical and Cylindrical Shells Due to External Loadings

4 Definitions

AARH: Average arithmetic roughness height, which is a measure of surface texture.


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Cyclic Service: Services that require fatigue analysis per AD-160 of ASME SEC VIII D2. This applies to Division 1 and Division 2 of ASME SEC VIII.

Design Engineer: The Engineering Company responsible for specifying on the data sheet the thermal and mechanical design requirements for heat exchangers.

Double Pipe Exchanger: Consists of a single tube enclosed within a U-shaped pipe shell.

Exchanger Manufacturer: The company responsible for the manufacture of new exchangers in accordance with this specification.

Hot Forming: Forming operations carried out at an elevated temperature such that re-crystallization occurs simultaneously with deformation.

Hydrogen Service: Process streams containing relatively pure hydrogen and component streams containing hydrogen with a partial pressure of 350 kPa abs (50 psia) and higher.

Lethal Services: Process streams containing a concentration of hydrogen sulfide in excess of 20% by volume shall be considered as lethal service. Other services as determined by the project design may also be designated as lethal services.

Low-Alloy Steels: Steels with nominal chromium contents of 5% chrome and/or nominal nickel content up to 3%.

Minimum Thickness: Thickness required for withstanding all primary loads, excluding allowance for corrosion.

Multitube Exchanger: Consists of multitubes within a U shaped shell.

MDMT: Minimum design metal temperature, determined by the Design Engineer.

Nominal Thickness: Thickness required for withstanding all primary loads, including allowance for corrosion.

Saudi Aramco Engineer: The Supervisor of the Process Equipment Unit, Consulting Services Department, Dhahran.

Saudi Aramco Inspector: The person or company authorized by the Saudi Aramco Inspection Department to inspect exchangers to the requirements of this specification.

Utility Services: Water, air and nitrogen services.

Wet Sour Services: Following process streams containing water and hydrogen sulfide:


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1) Sour water with a hydrogen sulfide concentration above 2 milligrams per liter.

2) Crude containing hydrogen sulfide when transported or processed prior to completion of stabilization.

3) Gas or hydrocarbon condensate containing hydrogen sulfide when transported or processed prior to completion of sweetening or hydrogen sulfide stripping.

4) Multiphase services when the partial pressure of hydrogen sulfide is above 0.34 kPa abs (0.05 psia) in the gas phase or a concentration of hydrogen sulfide above 2 milligrams per liter in the water phase.

Wet Sour HIC Services: All of the above wet Sour Services where the H2S concentration in the water phase is above 50 milligrams per liter.

Exception:

Lean and rich DGA services, other lean amine services, and caustic services are not included.

5 Responsibilities

5.1 The Design Engineer is responsible for specifying the thermal and mechanical design requirements and completing the Saudi Aramco data sheet in accordance with this specification. The Design Engineer must also provide out the thermal design calculations.

5.2 The Exchanger Manufacturer is responsible for the thermal design (rating) and verification of the Design Engineer's thermal design, if applicable. The Exchanger Manufacturer is also responsible for the manufacture of exchangers, which includes the complete mechanical design, Code and structural calculations, supply of all materials, fabrication, nondestructive examination, inspection, testing, surface preparation, and preparation for shipment, in accordance with the completed data sheet and the requirements of this specification.

6 Proposals

6.1 Exchanger Manufacturer's proposal shall be based on details for individual exchangers as outlined on the data sheet. A completed data sheet shall be submitted for each exchanger quoted.

6.2 The Exchanger Manufacturer may offer an alternative design, but must quote on the base inquiry documents.


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6.3 The proposal shall include a detailed description of any exception to the requirements of this specification.

7 Thermal Design

7.1 The size of each exchanger unit, if specified on the data sheet, must be verified by the Exchanger Manufacturer at time of proposal.

7.2 All data represented by the letter M on the data sheet is the responsibility of the Exchanger Manufacturer.

8 Mechanical Design

8.1 General

8.1.1 All exchangers shall be mechanically designed in accordance with the rules of ASME SEC VIII D1, (hereinafter referred to as the Code), and the requirements of this specification.

8.1.2 The edition of the Code to which exchangers are to be manufactured, shall be in accordance with the data sheet.

8.1.3 Should the Exchanger Manufacturer have any part of a stress analysis executed by a third party, the Exchanger Manufacturer shall advise the Saudi Aramco Engineer.

8.1.4 No proof testing shall be permitted unless specifically approved by the Saudi Aramco Engineer.

8.1.5 Application of ASME Code Cases to the manufacture of exchangers requires approval of the Saudi Aramco Engineer.

8.1.6 Exchangers shall be designed to withstand the combined stresses of all loads in accordance with the Code, and this specification.

8.2 Design Pressure

8.2.1 The value of design pressure(s) shall be in accordance with the data sheet.

8.2.2 The Design Engineer shall specify on the data sheet the external design pressure and corresponding temperature.

8.2.3 For exchangers subjected to steam out, the Design Engineer shall specify on the data sheet the external design pressure and corresponding temperature.


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8.3 Maximum Allowable Working Pressure

8.3.1 The Exchanger Manufacturer shall calculate the maximum allowable working pressure (MAWP) acting on both sides of the exchanger, in the hot and corroded condition in accordance with the applicable Code.

8.3.2 The calculations shall be based on the nominal as-built thicknesses excluding thicknesses required for corrosion. The MAWP of an exchanger shall not be limited by flange ratings.

8.4 Design Temperature

8.4.1 The value of the design temperature(s) shall be in accordance with the data sheet.

8.4.2 The design temperature of shell to tube closures shall be the higher of the shell-side or tube-side design temperatures.

8.4.3 The design temperature of flanges shall be the higher of the shell-side or tube-side design temperatures.

8.5 Minimum Design Metal Temperature

8.5.1 The value of the minimum design metal temperature (MDMT) shall be as specified on the data sheet.

8.5.2 The MDMT shall be used to determine the requirements for impact testing in accordance with this specification.

8.6 Joint Efficiency

8.6.1 The joint efficiency shall be specified on the data sheet.

8.6.2 A joint efficiency of 85% or higher shall be used for the design of all pressure containing components of ASME SEC VIII D1 exchangers.

8.7 Corrosion Allowances

The amount of corrosion allowance shall be as specified on the data sheet.

8.8 Loads

8.8.1 Wind and Earthquake Loads

1) The Exchanger Manufacturer shall calculate the static effects of loads due to wind and the effects due to earthquake loads acting


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on an exchanger in the operating position in accordance with the requirements of this specification.

2) The wind speed, earthquake zone, and soil coefficient corresponding to the site location shall be as specified on the data sheet.

3) Exchangers shall be designed for wind and earthquake loads in accordance with ASCE 7.

4) With reference to ASCE 7, the wind Category Classification to be used in the calculations of wind loads shall be Category III, and the Seismic Hazard Exposure Group to be used in calculations of earthquake loads shall be Group III.

5) Wind pressures shall be assumed to act on the projected surface area of the exchanger.

8.8.2 Piping, Equipment and External Loads

1) The Exchanger Manufacturer shall ensure that local stresses imposed on the exchanger due to piping and equipment, lifting, supports and other external loads do not exceed the allowable in accordance with the applicable Code. The stress analysis shall be completed in accordance with the procedures as detailed in WRC 107 or a finite element analysis.

2) Piping and equipment loads imposed on the exchanger shall be as specified on the data sheet.

8.9 Load Combinations

8.9.1 All components of the exchanger, including their supports, shall be designed to withstand the combined stresses resulting from the following:

1) Internal and/or external design pressures

2) All other loads exerted on the component and specified in Section 8.8.

3) All exchanger components shall be designed to withstand a full hydrostatic test in the erected position. Allowable stresses to be used shall be in accordance with the Code (90% of yield at test temperature). However, forces produced due to design, wind or earthquake loads may be reduced by 40% for this short time field hydrostatic test.


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8.9.2 Moments or forces acting on the exchanger due to external piping are to be added to those moments and forces due to other external primary loads.

8.10 Stress Analysis

Stress analysis shall be carried out as specified on the data sheet.

8.11 Tubes and Tube Bundles

8.11.1 Unless otherwise specified on the data sheet, the tube outside diameters and tube wall thicknesses shall be in accordance with API STD 660.

8.11.2 The minimum tube outside diameter shall be 19.05 mm (0.75 inch).

8.11.3 Unless otherwise approved by the Saudi Aramco Engineer, the length of U tubes measured to their tangent lines shall not exceed 6 m.

8.11.4 Where more than one exchanger of identical mechanical design, pressure rating and materials is required for the same service, tube bundles shall be inter-changeable.

8.11.5 Tubeside elements shall be removable without cutting.

8.11.6 The inner tube shall be without intermediate weld.

8.11.7 The exchangers with sea water flowing through the tubes shall be fitted with ferrules (tube end protectors) at the inlet end of the tubes. For tube materials other than those given in this specification, the requirement for ferrules shall be confirmed with the Saudi Aramco Engineer.

Commentary Note:

Saudi Aramco Standard Drawing AE-036250 gives ferrules details for 0.75 inch outside diameter tubes. For larger tube diameters, Exchanger Manufacturer shall propose ferrule details for the consideration of Saudi Aramco Engineer.

8.12 Closures

8.12.1 Elements shall be designed to be removable through the use of bolted closure joints.

8.12.2 Packed closures may be used only when the shell side fluid is a utility service.


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8.13 Interconnecting Piping

Interconnecting piping connecting exchangers in series/parallel arrangements, for the same exchanger unit, shall be designed and furnished by the Exchanger Manufacturer.

9 Nozzles

9.1 General

9.1.1 The sizes, ratings (ASME pressure classes), and facings of exchanger inlet and outlet nozzles shall be as specified on the data sheet.

9.1.2 Flange bolt holes shall straddle the normal horizontal and vertical centerlines of the exchanger.

9.1.3 Projections measured from the outside of shells to the face of flanges shall be sized so that studs may be removed from the back of a flange without interference with insulation.

9.1.4 Flanged connections shall be one of the following types:

1) Forged steel long welding neck

2) Forged steel welding neck flange with seamless pipe, or rolled plate with 100% radiography. The bores of nozzle flanges shall match the nozzle neck bore.

3) Studded nozzles and proprietary designs may be offered as alternatives provided their designs are in accordance with the Code and with prior approval of the Saudi Aramco Engineer.

4) However, for utility services up to and including 120°C (250°F) design temperature and 1.7 MPa ga (200 psig) design pressure, nozzles may be slip-on type flanges with seamless pipe nozzle necks or rolled plate with 100% radiography.

9.1.5 Threaded or socket-welded connections are prohibited in hydrogen, lethal, wet sour and caustic services. However, for other services, smaller than NPS 1½ threaded or socket-welded connections with 6000-lb rating conforming to ASME B16.11 may be used.

Commentary Note:

This requirement is intended for vents, drains and instrument connections that may be attached to shell or nozzles

9.1.6 Threaded connections shall conform to ASME B2.1.


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9.2 Reinforcement of Openings

9.2.1 Reinforcement of exchanger openings shall be in accordance with the applicable Code and this specification.

9.2.2 The thickness of reinforcing pads shall not exceed the shell thickness of the exchanger.

9.3 Integrally reinforced openings (with no reinforcing pads) shall be provided under the following services and design conditions:

1) Cyclic services

2) Carbon steel with shell thickness 50 mm and greater

3) Low-alloy steels with shell thickness 25 mm and greater

4) Exchangers with design metal temperatures greater than 425°C

5) Hydrogen service

9.4 Ratings (ASME Pressure Classes) and Facings

9.4.1 The ASME pressure classes and facings shall be as specified on the data sheet.

9.4.2 Pressure ratings shall be in accordance with ASME B16.5.

9.4.3 Gasket seating surfaces shall comply with the following:

1) For spiral wound gaskets, 125 to 250 AARH, in all services, except hydrogen

2) For spiral wound gaskets in hydrogen service, 125 to 150 AARH

3) The side-walls of ring joint flanges in all services, 63 AARH

4) For non-metallic gaskets, 250 to 500 AARH

9.4.4 The surface roughness of machined surfaces, other than gasket contact faces, shall not exceed 500 AARH.

9.5 Weld Attachment Details

9.5.1 All nozzle necks for exchangers in hydrocarbon, hydrogen, caustic, amine, wet sour, and steam services shall be attached by welding completely through the total thickness of the exchanger shell, including any reinforcement.


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9.5.2 Permissible types of nozzle weld-attachments shall be in accordance with Figure UW-16.1 (c), backing rings are to be removed, (d), (e), (f-1), (f-2), (f-3), (f-4) and (g).

10 Supports

Exchangers shall be supported by two movable type supports.

11 Clips and Attachments

11.1 All exchangers shall be provided with a grounding lug connection welded to a support.

11.2 Exchangers with component weight up to and including 27 kg (60 lb.) shall be provided with at least one lifting lug per component.

11.3 Components in excess of 27 kg (60 lb.) require two lifting lugs per component.

11.4 Shells shall be provided with lifting lugs in suitable locations to permit lifting of the complete exchanger. The lugs shall be designed such that the lifted parts hang vertically when suspended from the lugs. Lugs on insulated exchangers shall be of sufficient standout to clear insulation.

The Exchanger Manufacturer shall supply and install supports required for fireproofing materials.

12 Materials

12.1 General

12.1.1 All materials required for pressure and non-pressure components shall be specified on the data sheet in accordance with Table 1, Acceptable Materials for Carbon and Low-Alloy Steels and the requirements of this specification.

12.1.2 The Exchanger Manufacturer may propose alternative materials at time of proposal, but the alternative materials must comply with all the requirements of the Code and this specification.

12.1.3 Materials other than those listed in Table 1 of this specification shall not be permitted without the prior approval of the Saudi Aramco Engineer.


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12.1.4 All materials must be clearly identified and provided with Mill Test Certificates. Lack of adequate identification and certification shall be cause for rejection.

12.1.5 Suitability of low alloy steels for use for exchangers in hydrogen services above 205°C (400°F) shall be qualified through chemical analysis, mechanical testing including but not limited to tensile, hardness, microhardness, temper embrittlement tests and nondestructive examinations (ultrasonic, wet fluorescent magnetic particle, etc.). Materials specifications and tests procedures for base and weldments materials shall be submitted to Saudi Aramco Engineer for review and approval prior to ordering the materials from the mill.

12.1.6 All materials, except carbon steels, shall be alloy verified by the Exchanger Manufacturer in accordance with SAES-A-206.

12.1.7 The use of C-½ Mo steels in hydrogen services is prohibited.

12.1.8 Materials with properties enhanced by heat treatment cycles such as tempering, intermediate stress relief (ISR) and the final post weld heat treatment shall be tested to verify that their mechanical properties have been retained after all heat treatment cycles. These tests shall also include two additional postweld heat treatment cycles to account for future repairs or alteration.

12.1.9 HIC Resistant Materials

For exchangers designated for wet sour services HIC (hydrogen induced cracking) as defined in this specification with design temperatures between 0°C and 200°C, all plates for shells and heads shall be made of HIC resistant steel. HIC resistant steel shall be qualified in accordance with 01-SAMSS-016.

12.2 Impact Testing

12.2.1 The Exchanger Manufacturer shall determine impact testing requirements of materials for pressure components based on the values of the minimum design metal temperature (MDMT), unless lower test temperature is specified on the data sheet.

12.2.2 Baffle plates, bars, tie-rods, spacers, and support plates, are exempt from impact testing requirements.

12.2.3 Impact testing requirements for materials not listed in Table 1, shall be obtained from the Saudi Aramco Engineer.


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12.2.4 The minimum acceptable Charpy impact energy values for steels listed in Table 3 shall be per Table-2 unless larger values are specified on the data sheet. Materials that are not listed in Table 3 shall be referred to Saudi Aramco Engineer for classification.

12.2.5 Unless otherwise specified in the design Code, materials of components, including welding consumables, shall be impact tested, at the MDMT.

12.2.6 The exemptions of UG-20 (f), CS-66(b)(1) and (3), UCS-68(c), UG-84(b)(2) and by reference Table UG-84.4 are not permitted for exchangers within the scope of this specification.

12.2.7 Certified Mill Test Certificates may be used to verify the base materials impact testing results.

12.3 Gaskets

Gaskets shall be non-asbestos. The materials of construction for spiral wound gaskets shall be as follows:

1) For exchangers with design temperatures from -100°C to 0°C:

Type 304 or 316 stainless steel (SS) windings with solid Type 304 or 316 stainless steel outer centering rings

2) For exchangers with design temperatures from 1°C to 425°C:

Type 304 or 316 SS windings with solid carbon steel outer centering rings.

3) For exchangers with design temperatures above 425°C:

Type 321 or 347 SS windings with solid; Type 304 or 316 outer centering rings.

4) For exchangers in vacuum service, inner ring shall be either Type 304 or 316 SS.

13 Fabrication

13.1 General

13.1.1 Welds attaching nozzles and their reinforcement pads and other attachments to pressure components shall not be closer than 20 mm from any pressure retaining welds.

13.1.2 All nozzles shall be ground flush to the inside curvature of the shell and inside diameters shall be radiused smooth.


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13.1.3 Where a split reinforcing pad is required, the weld joining the pad sections shall be oriented with the circumferential direction of the shell. Tapped tell-tale holes 0.25" NPT shall be provided as follows:

1) One hole in all single piece reinforcing pads

2) Where a pad is split, each segment shall have at least one tapped hole.

13.1.4 All internal and external welded attachment pads shall have their corners rounded to a minimum radius of 50 mm radius and shall be fully seal welded.

13.1.5 All external non-pressure attachments shall be vented through a 0.25" NPT telltale hole.

13.2 Welding

All welding shall be in accordance with the requirements of SAES-W-010.

14 Nondestructive Testing

14.1 General

14.1.1 All Nondestructive Testing (NDT) shall be performed in accordance with the Exchanger Manufacturer's written procedure prepared in accordance with ASME SEC V with the scope of NDT and acceptance/rejection criteria as defined by the referencing Code section and this specification.

14.1.2 All NDT shall be performed by personnel certified in accordance with the Exchanger Manufacturer's written practice prepared in accordance with ASNT SNT-TC-1A, or at the option of the Exchanger Manufacturer ASNT CP-189. Other schemes of personnel certification shall be at the sole discretion and approval of the Saudi Aramco Inspector. Personnel responsible for interpretation of NDT results shall be certified by the Saudi Aramco Inspection Department.

14.1.3 All NDT on exchangers which are to be postweld heat treated shall be made after postweld heat treatment.

14.1.4 All pressure and non-pressure welds shall be visually inspected where accessible. All segments of longitudinal, circumferential or built-up head pressure weld seams covered or rendered inaccessible by internals, lifting lugs or other attachments shall be fully radiographed


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the entire affected length plus 10 inches either side prior to installation of the attachment.

14.2 Radiographic Testing

14.2.1 Joint efficiencies shall be in accordance with the data sheet.

14.2.2 100% radiography is required for exchangers for the following services and design conditions:

1) Lethal services

2) Hydrogen services

3) Cyclic services

4) Weld joints where any of the pressure retaining materials requires impact testing per the applicable Code or this specification.

5) Exchanger weld joints requiring full radiography per the applicable Code (see UW-11 for Division 1 exchangers and AF-220 for Division 2 exchangers).

14.2.3 All radiography shall be performed with intensifying screens. Only lead or lead foil (fluoro-metallic) screens shall be permitted unless otherwise approved by the Saudi Aramco Inspection Department.

14.2.4 Tungsten inclusions in Gas Tungsten Arc welds shall be evaluated as individual rounded indications. Clustered or aligned tungsten inclusions shall be removed and repaired.

14.2.5 Radiographic film interpretation shall be done by personnel certified in accordance with ASNT CP-189 to ASNT Level II Film Interpreter or approved equivalent by the Saudi Aramco Inspection Department.

14.2.6 Where it is not possible to meet the spacing requirement in paragraph 13.1.1 of this specification such that a nozzle or an attachment weld of a reinforcing pad or a structural component will either intersect or encroach on a butt weld the following shall be performed:

14.2.6.1 If the nozzle is installed onto or encroaching on a butt weld in the exchanger wall:

1) radiograph of the butt weld in the exchanger wall for a length equal to three times the diameter of the opening with the center of the opening at mid-length.


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2) Where a reinforcing pad is required, the butt weld shall be ground flush and radiographed, prior to the installation of the reinforcing pad.

14.2.6.2 Where an attachment weld of a reinforcing pad or a structural component will either intersect or encroach on a butt-weld in the exchanger wall:

1) the butt weld shall be radiographed for a length equal to the projection of the intersecting or encroaching segment of the attachment weld plus a minimum of 50 mm on either side.

2) Perform magnetic particle examination on the exchanger side of the joint attaching the reinforcing pad or structural component.

14.3 Ultrasonic Testing

Where radiography as required by the applicable Code, approved drawings or special instructions is deemed inaccessible or inconclusive, ultrasonic testing may be substituted with approval of the Saudi Aramco Engineer.

14.4 Magnetic Particle Testing

14.4.1 Permanent magnetic yokes are not permitted.

14.4.2 Prods are not permitted for use on air-hardenable materials, materials which require impact testing, and on the fluid side of pressured components for exchangers in wet sour service.

14.4.3 Magnetic particle examination shall be performed on hot formed surfaces and for parts that undergo reheat treatment as per the applicable Code.

14.4.4 Except for non-ferro-magnetic materials, wet fluorescent magnetic particle examination using an AC yoke is required for the following:

1) All internal welds, including temporary internal welds for exchangers in wet sour, caustic, amine and hydrogen services.

2) All internal and external welds for all services made using the SMAW welding process when the nominal thickness of pressured components is 25 mm and thicker.

3) Exchanger support attachment welds.


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14.5 Hardness Testing

Weld hardness testing shall be in accordance with the requirements of SAES-W-010.

14.6 Liquid Penetrant Testing

Liquid penetrant testing shall be conducted on all structural attachment welds on pressured components of non-ferrous materials and which are attached after the hydrotesting of the exchanger.

15 Heat Treatment

15.1 Postweld Heat Treatment

15.1.1 Postweld heat treatment (PWHT) shall be done when required by the Code or when specified on the data sheet.

15.1.2 Code exemptions for PWHT of ferritic materials based on the use of austenitic or nickel-based electrodes are not permitted.

15.1.3 Code exemptions for PWHT of P4 and P5 materials are not permitted for applications involving either wet sour or hydrogen service or for materials exceeding 2.5% nominal chromium content.

15.1.4 The maximum PWHT soaking temperature for carbon steel and C-0.5 Mo materials shall not exceed the temperature at which the test pieces were heat treated as shown on the Mill Test Certificates, or 650°C for carbon steel and 690°C for C-0.5 Mo.

15.1.5 The maximum PWHT soaking temperature for low alloy steels shall not exceed the tempering temperature at which test pieces and components were heat treated as shown on Mill Test Certificates, but shall be not less than 700°C.

15.1.6 PWHT shall follow all welding and repairs but shall be performed prior to any hydrotest or other load test.

15.1.7 The following sign shall be painted on the postweld heat treated exchanger:

CAUTION-EXCHANGER HAS BEEN POSTWELD HEAT TREATED-DO NOT WELD

15.1.8 The sign shall be located such that it is clearly visible from the ground.


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15.1.9 PWHT shall be in accordance with the requirements of SAES-W-010.

15.2 Heat Treatment of Tubes

15.2.1 The following tubes shall be heat treated after cold forming and bending:

1) U bends, including 300 mm of straight portions measured from the tangent lines of all carbon steel tubes for exchangers in caustic, wet sour and amine services

2) Monel, brass and all chrome alloy tubes in all services

15.2.2 The following tubes shall be solution annealed:

1) Entire tubes manufactured of unstabilized stainless steels in accordance with ASME SA-688. The solution annealing temperature shall be 1070°C.

2) U bends, including 300 mm of straight portions measured from the tangent lines of all stabilized stainless steels.

16 Inspection and Pressure Tests

16.1 Inspection

16.1.1 The responsibility for inspection rests with the Exchanger Manufacturer in accordance with the applicable Code and the requirements of this specification.

16.1.2 Exchangers manufactured in accordance with this specification are subject to verification by the Saudi Aramco Inspector in accordance with Saudi Aramco Inspection Requirements Form 175-323100.

16.1.3 Inspection procedures shall be established in accordance with ASME SEC V. A written procedure for each inspection method and technique, including acceptance criteria, to be used shall be submitted to the Saudi Aramco Inspector for approval. Qualification of the procedure by the Exchanger Manufacturer may be required, as determined by the Saudi Aramco Inspector. Inspection procedures in conformance with other standards are acceptable only with the approval of the Saudi Aramco Inspector.

16.1.4 Written reports and evaluations of all inspections performed by the Exchanger Manufacturer shall be made and submitted to the Saudi Aramco Inspector, at a frequency to be determined by the Saudi Aramco Inspector.


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16.1.5 Additional inspection of any weld joint at any stage of the fabrication may be requested by the Saudi Aramco Inspector, including re-inspection of previously inspected joints. The Saudi Aramco Inspector also has the right to request or conduct independent NDT of any joint. If such testing should disclose gross non-conformance to the requirements of the Code or this specification, all repair and NDT costs shall be done at the Exchanger Manufacturer's expense.

16.1.6 Prior to final inspection and pressure testing, the inside and outside of exchangers shall be thoroughly cleaned of all slag, scale, dirt, grit, weld spatter, paint, oil, etc.

16.1.7 Inspection at the mill, shop, or fabrication yard shall not release the Exchanger Manufacturer from responsibility for repairing or replacing any defective material or workmanship that may be subsequently discovered in the field.

16.1.8 All appropriate safety precautions shall be taken for each inspection method.

16.1.9 All NDT shall be done by or under the supervision of personnel certified to ASNT CP-189 or approved equivalent for the particular method or technique to be used.

16.1.10 Surface irregularities, including weld reinforcement, inhibiting accurate interpretation of the specified method of NDT shall be ground smooth.

16.1.11 Inspection of all welds shall include a band of base metal at least one inch wide on each side of the weld.

16.2 Inspection Access

16.2.1 The Saudi Aramco Inspector shall have free access to the work at all times.

16.2.2 Saudi Aramco shall have the right to inspect the fabrication at any state and to reject material or workmanship which does not conform to the specified requirements.

16.2.3 Saudi Aramco reserves the right to inspect, photograph, and/or videotape all material, fabrication, coating, and workmanship and any materials, equipment, or tools used or to be used for any part of the work to be performed.


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16.2.4 Saudi Aramco may reject the use of any materials, equipment, or tools that do not conform to the specification requirements, jeopardize safety of personnel, or impose hazard of damage to Saudi Aramco property.

16.2.5 All of the rights of Saudi Aramco and their designated representatives for access, documentation, inspection, and rejection shall include any work done by sub-contractors or sub-vendors.

16.2.6 The Exchanger Manufacturer shall provide the Saudi Aramco Inspector all reasonable facilities to satisfy him that the work is being performed as specified.

16.2.7 The Exchanger Manufacturer shall furnish, install, and maintain in a safe operating condition all necessary scaffolding, ladders, walkways, and lighting for a safe and thorough inspection.

16.3 Pressure Tests

16.3.1 After completion of all external and internal welding and heat treatment and prior to any painting, exchangers shall be pressure tested using water as the testing media in accordance with the applicable Code and this specification. Pneumatic testing in lieu of hydrostatic testing requires the approval of the Saudi Aramco Engineer.

16.3.2 No preliminary pressure testing shall be made prior to postweld heat treatment.

16.3.3 The use of shellacs, glues, lead, etc. on gaskets during testing is prohibited. No paint or primer shall be applied to an exchanger prior to hydrostatic testing.

16.3.4 The Exchanger Manufacturer shall furnish all test materials and facilities, including blinds, bolting, and gaskets.

16.3.5 After testing, the exchanger shall be completely drained and thoroughly dried including around the internals.

16.3.6 Test pressure for the tube side shall be 1.5 times its calculated MAWP in the new and cold (ambient temperature) condition multiplied by the lowest ratio (for the materials of which the tube is constructed) of the allowable stress for the test temperature to the allowable stress for the design temperature. Test pressure for the shell side is calculated similarly.


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16.3.7 Water used for pressure testing shall be potable. For exchangers manufactured from stainless steel, the water shall not contain more than 50 ppm chlorides.

16.3.8 The temperature of the water during hydrostatic testing shall be maintained at not less than 17°C throughout the testing cycle.

16.3.9 It is the responsibility of the Exchanger Manufacturer to ensure that the temperature of the water is a minimum of 17°C above the ductile to brittle transition temperature of the material.

16.3.10 All welded attachments provided with telltale holes shall be pneumatically tested at 30 kPa (5 psig) prior to heat treatment and pressure testing. Telltale holes must not be plugged during pressure testing.

16.3.11 Exchangers designed for stacking shall be hydrotested in the stacked position.

16.3.12 Hydrostatic test pressure shall be held for a minimum of one hour per 25 mm of exchanger shell thickness and in no case less than one hour.

17 Nameplates and Stampings

17.1 Each exchanger shall be identified by a nameplate and marked with the information required by the applicable Code and the requirements of this specification.

17.2 Exchangers manufactured inside and outside Saudi Arabia shall be Code stamped for all services, in accordance with the applicable Code.

17.3 The nameplate and its mounting bracket shall be located such that the nameplate is easily readable from grade or platform. Brackets shall extend from the outside of exchanger to clear insulation, and with sufficient access for surface preparation, and painting. The nameplate markings as required by UG-116 of the Code shall be stamped or engraved such that the nameplate material is permanently deformed with the symbols.

17.4 Nameplates shall be 3 mm minimum thickness and manufactured from type 304 stainless steel or Monel and welded to the mounting bracket.

17.5 The mounting bracket material shall conform to Table 1, General Note (F) and shall be continuously welded to the exchanger.


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18 Painting

18.1 The type of painting system to be used shall be in accordance with the SAES-H-001 and SAES-H-101V attached to the purchase order.

18.2 Prior to painting, surfaces shall be cleaned to remove all scale, rust, grease, dirt, weld spatter and foreign objects.

18.3 Gasket contact surfaces shall not be painted.

19 Shipping Requirements

19.1 General

19.1.1 Prior to shipping, exchangers are to be dried and then cleaned from all loose scales, weld slags, dirt and debris to the satisfaction of the Saudi Aramco Inspector.

19.1.2 The Exchanger Manufacturer is responsible for ensuring that the exchangers being shipped are adequately braced and shall provide temporary supports where appropriate to ensure adequate supporting of the exchanger during shipment.

19.1.3 Marking shall be done with water-insoluble material that contains no harmful substances that would attack or harmfully affect the exchanger at ambient and operating temperatures.

19.1.4 The marking material shall be free of lead, sulfur, zinc, cadmium, mercury, chlorine, or other halogens.

19.1.5 Export packaging, marking and shipping shall be in accordance with the purchase order.

19.2 Internal Protection

19.2.1 The internal surfaces of the exchangers shall be protected from corrosion by use of a non-toxic vapor phase corrosion inhibitor such as CORTEC VCI-309 or 307 or equivalent, applied at a rate of 0.3 kg/m³.

19.2.2 The inhibitor selected must be appropriate for the metallurgy of the exchanger. Desiccants may only be used with approval of the Saudi Aramco Engineer.

19.2.3 Exchangers must be sealed vapor tight using metallic covers, for the inhibitor to be effective.


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19.2.4 Nitrogen blanketing, temporary rust preventive in accordance with MIL-C-16173 Grade IV (example: Tectyl 846) or a vapor proof bag with moisture control may be used.

19.2.5 Temporary coatings for use on exchangers with corrosion resistant linings (stainless steel and monel clad) must be chloride free, suitable for its intended use and not result in crevice corrosion.

19.3 External Protection

19.3.1 The protection of external surfaces shall be obtained by using one of the following and as directed in the Purchase Order:

1) A hard temporary preservative in accordance with MIL-C-16173, Grade I, which can be removed at site prior to surface preparation and application of the Saudi Aramco coating and painting system in the shop.

2) Prepare the surface and apply the complete (primer and final coatings) Saudi Aramco surface preparation, and coating and painting system in the shop.

3) Solid stainless steel exchangers, which are to be shipped via ocean freight, shall be protected using a temporary protective system compatible with stainless steel and suitable outdoor exposure in accordance with MIL-C-16173 Grade IV.

19.3.2 Threaded nozzle connections shall be protected with threaded plugs. However, tell-tale holes in reinforcing pads shall be protected with wooden plugs or packed with a rust preventative grease such as Denso paste.

19.3.3 Flanged connections and all other machined surfaces shall be protected by a coating such as MIL-C-16173 Grade IV, which is easily removed in the field and fitted with a steel or wood cover, 3 mm thick and neoprene gaskets.

19.3.4 Covers shall be securely attached by a minimum of four bolts equally spaced. For ocean shipment, flanged connections shall also be covered with heavy duty plastic bags securely taped to the nozzles.

19.3.5 Flanges with permanent blind flanges or covers shall be secured with the gaskets and bolting required for service.


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20 Drawings, Calculations and Data

20.1 The Exchanger Manufacturer shall prepare drawings, calculations, and data in accordance with Form NMR-7922-1, Non-material Requirements.

20.2 Drawings and calculations which are approved by the Design Engineer shall not relieve the Exchanger Manufacturer of the responsibility to comply with the Code, and this specification.

Revision Summary 30 July 2003 Major revision. 30 March 2005 Editorial revision to replace NACE MR0175 with newly approved SAES-A-301.


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Table 1 – Acceptable Materials for Carbon and Low-Alloy Steels

Exchanger Design Metal Temperature Component -100 to -47°C -46 to 0°C 1 to 425°C 426 to 645°C

SA-203 Grade D or E

SA-516 Grade 70N or SA-537 Class 1

SA-516 Grade 70, or SA-537 Class 1 or SA-285 Grade C (1)

SA-387 Grade 11, 12 or 22

Shell pipe SA-333 SA-333 SA-106 SA-335 Nozzle pipe Grade 3 Grade 6 Grade B or SA-53

Grade B (1) P11, 12 or 22

Tubes, (Baffles, tube supports) (2)(4)

SA-249 Type 304

SA-334 or SA-249 Type 304

SA-179 or SA-214

SA-179 or SA-214 or SA-213 Type 304

Forged flanges and forged fittings

SA-350 LF3 SA-350 LF2 SA-105 SA-182 F11, 12 or 22

Wrought fittings SA-420 WPL3 SA-420 WPL6 SA-234 WPB SA-234 WP 11, 12 or 22

Studs/nuts for pressure connection

SA-320 L43/ SA-194 Grades 4 or 7

SA-320 L7/SA-194 Grade 2H

SA-193B7/ SA-194 Grade 2H

SA-193 B5, or B16/SA-194 2H or 2

General Notes: (A) Materials for hydrogen service shall be selected in accordance with API PUBL 941 using a value for the hydrogen partial

pressure 10% above the design partial pressure and a temperature of 30°C above the design temperature. (B) Materials for exchangers in amine service shall be selected in accordance with Table 1 and API RP 945. (C) Materials for exchangers in wet sour service, with design temperature up to 200°C, shall be in accordance with Table 1, with

the following revisions: (1) Forged flanges and forged fittings are restricted to: SA-350 LF1 or LF2 or SA-266, Class 4, S2.1. (2) Studs and nuts are restricted to: SA-193 B7M or L7M and SA-194 Grade 2HM. (3) Satisfy the requirements of SAES-A-301 and NACE RP0472. (4) For exchangers under the service conditions specified in paragraph 12.1.9.1, shells and heads formed from plate shall be

manufactured from HIC resistant steel. (D) Materials for pressure components in sea water service shall be in accordance with Table 1 with the following revisions:

(1) Carbon steel pressure components in contact with sea water shall be clad or weld overlayed with Monel. (2) Tube material shall be either Cu/Ni SB-111 (Alloy Number C71500) or Titanium SB-338 Grade 2. (E) Low alloy material shall be specified in the normalized and tempered heat treated condition. (F) The material for nameplate mounting brackets shall be of the same type and material grade as the shell material. (G) Impact testing of materials and welding procedures are required when MDMT is lower than -28°C. (H) Impact testing of materials is only required when MDMT is -27 to -18°C. Impact testing of welding procedures is not

required for this temperature range, (unless otherwise required by the applicable Codes), if the consumable classifications per ASME SEC IIC has impact property requirements at -46°C or lower.

Specific Notes: (1) SA-53 and SA-285 materials shall only be used for utility services. (2) Tubes in hydrogen, wet sour, amine and caustic services shall be seamless. (3) Movable shell support plates shall be of the same ASME material as the shell material. (4) Baffles, tube supports, and impingement protection shall be of the same basic material as the tubes except for high alloy

steel tubes when these components may be of carbon steel provided shell side fluid does not require more corrosion resistant material. For titanium tubes, the materials for these components shall be subject to approval from Saudi Aramco Engineer.


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Table 2 – Charpy-V Impact Test Requirements

Minimum Required Impact Value for Full Size Specimen at MDMT, Joules

Reference Thickness, t, inch

Material Class t < ½ ½ < t < 1 1 < t < 2 t > 2 1a 34/27 34/27 34/27 34/27 1b 34/27 34/27 34/27 34/27 2a 34/27 34/27 34/27 34/27 2b 34/27 34/27 34/27 47/38 2c 34/27 34/27 47/38 61/48 3 34/27 34/27 34/27 34/27

Notes: (1) In the notation such as 34/27, the first number is the minimum average energy of three specimens and the

second number is the minimum for one specimen impact test results. (2) See Table 3 for material specification.

Table 3 – Material Classes

Class Material Specification 1a SA 53 Gr. B 2b SA 105 2a SA106 Gr. B 2b SA 182 Gr. F11 and F12 2c SA 182 Gr. F22 3 SA 203 Gr. D and E 2b SA 204 Gr. A, B and C 2b SA 266 Cl. 1 2c SA 266 Cl. 2 and 4 1a SA 333 Gr. 1 3 SA 333 Gr. 3 2a SA 333 Gr. 6 2b SA 335 Gr. P11, P12 and P22 2b SA 336 Gr. F12 2c SA 336 Gr. F11 and F22 2b SA 350 Gr. LF2 3 SA 350 Gr. LF3 2b SA 387 Cl. 1, Gr. 11, 12 and 22; Cl. 2, Gr. 12 2c SA 387 Cl. 2, Gr. 11 and 22 2a SA 442 Gr. 55 and 60 2b SA 516 Gr. 70 2c SA 533 Cl. 1 2b SA 537 Cl. 1 2c SA 420 Gr. WPP3 and WPL6 2c SA 234 Gr. WPB 2c SA 234 Gr. WP11, WP12 and WP22

32-SAMSS-028

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