Standard Practice

Format, Content, and Guidelines for Developing a

Materials Selection Diagram

This NACE International standard represents a consensus of those individual members who have reviewed this document, its scope, and provisions. Its acceptance does not in any respect preclude anyone, whether he or she has adopted the standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not in conformance with this standard. Nothing contained in this NACE International standard is to be construed as granting any right, by implication or otherwise, to manufacture, sell, or use in connection with any method, apparatus, or product covered by Letters Patent, or as indemnifying or protecting anyone against liability for infringement of Letters Patent. This standard represents minimum requirements and should in no way be interpreted as a restriction on the use of better procedures or materials. Neither is this standard intended to apply in all cases relating to the subject. Unpredictable circumstances may negate the usefulness of this standard in specific instances. NACE International assumes no responsibility for the interpretation or use of this standard by other parties and accepts responsibility for only those official NACE International interpretations issued by NACE International in accordance with its governing procedures and policies which preclude the issuance of interpretations by individual volunteers. Users of this NACE International standard are responsible for reviewing appropriate health, safety, environmental, and regulatory documents and for determining their applicability in relation to this standard prior to its use. This NACE International standard may not necessarily address all potential health and safety problems or environmental hazards associated with the use of materials, equipment, and/or operations detailed or referred to within this standard. Users of this NACE International standard are also responsible for establishing appropriate health, safety, and environmental protection practices, in consultation with appropriate regulatory authorities if necessary, to achieve compliance with any existing applicable regulatory requirements prior to the use of this standard. CAUTIONARY NOTICE: NACE International standards are subject to periodic review, and may be revised or withdrawn at any time in accordance with NACE technical committee procedures. NACE International requires that action be taken to reaffirm, revise, or withdraw this standard no later than five years from the date of initial publication. The user is cautioned to obtain the latest edition. Purchasers of NACE International standards may receive current information on all standards and other NACE International publications by contacting the NACE International FirstService Department, 1440 South Creek Drive, Houston, Texas 77084-4906 (telephone +1 [281] 228-6200).

Approved 2007-06-22 NACE International

1440 South Creek Drive Houston, Texas 77084-4906

+1 (281) 228-6200

ISBN 1-57590-212-5 ©2007, NACE International

NACE SP0407-2007

Item No. 21123

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NACE International 1

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Foreword

This standard practice provides format, content, and guidelines for developing a materials selection diagram (MSD). A MSD documents the materials selection of new equipment and piping for the refinery, process chemical, power, and other industries. This standard is intended for use by the owner/operators, licensors, and the contractor/fabricators of petroleum refineries, process chemical plants, power plants, and other industrial processing plants as a reference guide for developing a MSD to identify the materials of construction and the process conditions and other key technical issues that influence the selection of materials for use during the development and construction phases of projects. This standard was prepared by Task Group (TG) 302 on Refining and Chemicals Material Selection Diagrams: Standard. TG 302 is administered by Specific Technology Group (STG) 34 on Petroleum Refining and Gas Processing and is sponsored by STG 36 on Process Industry: Materials Performance in Chemicals. This standard is issued by NACE under the auspices of STG 34.

In NACE standards, the terms shall, must, should, and may are used in accordance with the definitions of these terms in the NACE Publications Style Manual, 4th ed., Paragraph 7.4.1.9. Shall and must are used to state mandatory requirements. Should is used to state something considered good and is recommended but is not mandatory. The term may is used to state something

considered optional.

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NACE International Standard Practice

Format, Content, and Guidelines for Developing a Materials

Selection Diagram Contents

1. General ........................................................................................................................... 1 2. Equipment and Materials Information to Be Shown on MSD ......................................... 1 3. Process Data to Be Shown on MSD ............................................................................... 5 4. Guidelines on Completing the MSD ................................................................................ 6 5. References ...................................................................................................................... 7 6. Appendix A: Sample Materials Selection Diagrams ....................................................... 8 7. Table 1 ............................................................................................................................ 2 8. Table 2 ............................................................................................................................ 3 9. Table 3 ............................................................................................................................ 4 10. Figure A1 ....................................................................................................................... 8 11. Figure A2 ....................................................................................................................... 9 12. Figure A3 ..................................................................................................................... 10

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Section 1: General

1.1 A MSD summarizes material requirements for process equipment and piping in the refining, process chemical, power, and other industries, and provides information needed for the development of piping and instrumentation diagrams (P&IDs) and equipment mechanical data sheets.

1.1.1 Generally, the process and design data used to select the materials are also shown on the MSD. In its simplest form, a typical MSD consists of a marked-up or overlaid version of a simplified process flow diagram (PFD), showing relevant operating conditions, materials selection information, and application(s) of other material degradation preventative measures.

1.2 The scope of this standard is to define the minimum and optional information to be included on the MSD, provide recommended formats, and give guidance on key issues that arise when materials are selected. This standard does not define how to evaluate specific corrosion and materials degradation mechanisms or how to select materials for specific processes. Sample MSDs are included in Appendix A of this standard to show nonmandatory format and content examples. 1.3 It is intended that the primary use of the MSD is associated with new capital projects, retrofits, and expansions (especially in cases in which process conditions

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may have changed). Because the information stated on the MSD may change during project execution, the MSD may require revisions as issues surface during the project engineering and equipment fabrication stages of the project. Some projects use the MSD throughout the project, updating it as changes occur and making it “as-built” to be deliverable to the owner/operator, while other projects use the MSD only in the initial project stages. This standard covers primarily the initial MSD preparation. 1.4 The format and content of the initial MSD, its use, and its update philosophy should be agreed on by the owner/operator and the contractor/fabricator/licensor in the initial phases of the project.

1.5 The person specifying materials of construction must be familiar with corrosion and materials degradation mechanisms particular to the type of unit being designed.

1.6 Suitable tools (e.g., NACE standards, API

(1) standards

including API RP 571,1 public domain isocorrosion curves,

company proprietary corrosion data, company standards, prior operating experience) shall be employed as necessary In selecting materials.

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Section 2: Equipment and Materials Information to Be Shown on MSD

2.1 Equipment and Piping Components 2.1.1 The following information shall be shown on the MSD:

2.1.1.1 Materials of construction (minimum alloy requirement) for equipment components and piping (using a materials legend), normally identified by name or tag number (see Table 1); 2.1.1.2 Injection, mix, and chemical addition points; 2.1.1.3 Design corrosion allowances; 2.1.1.4 Corrosion-resistant alloy cladding or weld overlay with required minimum thickness and on which side for components such as tubesheets; 2.1.1.5 Coatings/linings for special internal corrosion considerations (external coatings are typically covered by other specifications);

2.1.1.6. Special materials selection, corrosion prevention, inspection, or testing requirements in the form of notes (e.g., stress-relief [SR] requirements, thermal stabilization, velocity limits, maximum hardness requirements, references to industry standards, special owner/user standards, special cleaning requirements, alternate materials selection); and 2.1.1.7 Prefabricated equipment (e.g., compressors, skid-mounted equipment) may be specified “Manufacturer’s Standard” or “Mfr. Std.” under the material heading. Manufacturer’s standard materials selection shall be reviewed for conformance to design life and safety requirements for the intended service, if/when used.

2.1.2 Materials of construction for equipment components to be shown on the MSD:

____________________________ (1)

American Petroleum Institute (API), 1220 L St. NW, Washington, DC 20005.

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Table 1: Information to Be Shown on MSD

TYPE OF EQUIPMENT OR PIPING

COMPONENTS (AS APPLICABLE)

Mandatory/Optional (M/O)

Heat Exchanger (Shell and Tube) Shell Channels Baffles/Cages Tubes Tubesheets

M M O M M

Heat Exchanger (Plate and Frame) Plates Frame Gaskets

M O O

Air Cooler Headers Tubes Plugs (if different)

M M O

Centrifugal Pump API material class (if applicable) Case Impeller

O O O

Tank Shell (includes fixed roof and bottom) Floating roof Linings Seals

M

O M O

Towers Shell Trays/Packing Distributors

M M O

Drums Shell Boot (when present) Internals

M M O

Reactors Shell Internals

M O

Piping Pipe Control valves Valve trim

M O O

Heater Radiant tubes Convection tubes Hangers

M M O

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2.1.2.1 Materials of construction for supplementary equipment components should be identified on the MSD if the standard materials of construction are not adequate for the process service (e.g., special gaskets and seals).

2.1.2.2 Additional components, (e.g., bolting, impingement plates, vessel trim) may be included as needed, based on factors such as whether the materials are covered in other project, site, or industry specifications, or company work practices.

2.1.2.2.1 Any chemical treatment requirements, including:

2.1.2.2.1.1 Corrosion monitoring probe(s) and method(s); 2.1.2.2.1.2 Sampling point(s); 2.1.2.2.2 Cathodic protection;

2.1.2.2.3 Charpy or impact test requirements; and 2.1.2.2.4 External environmental issues (underground, marine, etc.)

2.2 Material Designations

2.2.1 Engineering materials should be designated by “generic” formats (e.g., carbon steel [CS] or UNS

(2)

S31600 [316 stainless steel {SS}]). Other specifications such as ASTM

(3) (e.g., A 516

2 or A 351

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gr. CF8M), DIN(4)

(e.g., 174454),

or trade names should

not be used unless some aspects of the product forms are considered critical. Using specific material specifications in lieu of generic designations would limit product forms, availability, supplier sources, etc. Requirements for specific product forms may be covered by use of a specific note.

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2.2.1.1 Using specific material specifications (e.g., ASTM, ASME, DIN) is acceptable when agreed to by the owner and contractor.

2.2.2 UNS numbers may be shown, provided that they are not the sole materials designator, because UNS numbers may not be immediately recognized.

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2.2.3 A legend of the material designations should be included on each MSD. An example of some typical material designations that have been used are listed in Table 2, along with examples of the UNS designations for materials that may fit that category.

Table 2: Typical Material Designations

MSD Format Example UNS Designations

(A)

Full Designation

CI Cast iron

DI Ductile iron

CS K02504, K02401, K03006 Carbon steel

LTCS Low-temperature carbon steel

1 ¼ Cr K11562, K11756 1 ¼ Cr- ½ Mo

2 ¼ Cr K21590 2 ¼ Cr-1 Mo

5 Cr K41545 5 Cr- ½ Mo

9 Cr K81590 9 Cr-1 Mo

12 Cr S40500 (405 SS), S41000 (410 SS), or S41008 (410S SS)

12-13 Cr steel

304L S30403 304L SS

316L S31603 316L SS

321 S32100 321 SS

347 S34700 347 SS

310 S31000 310 SS

2205 S32205/S31803 22% Cr Duplex SS

Alloy 20 N08020 Alloy 20

6% Mo S31254, N08367, N08926 Superaustenitic SS with 6% Mo

800 N08800 (alloy 800), N08810 (alloy 800H), or

N08811 (800HT)

Alloy 800

825 N08825 Alloy 825

625 N06625 Alloy 625

276 N10276 Alloy 276

400 N04400 Alloy 400

Adm C44300, C44400, C44500 Admiralty brass

NRB C46400, C46500, C46700 Naval rolled brass

70/30 C71500 70/30 Cu-Ni

90/10 C70600 90/10 Cu-Ni

Ti-2 R50400 Titanium grade 2

Ti-12 R53400 Titanium grade 12 (A)

During the early stages of design, the actual method of fabrication of components is not necessarily known; therefore, specifying anything more than the generic material category is not common during the initial stage of a project’s life (see Paragraph 2.2.1).

____________________________ (2)

Metals and Alloys in the Unified Numbering System (latest revision), a joint publication of ASTM International (ASTM) and SAE International (SAE), 400 Commonwealth Drive, Warrendale, PA 15096-0001. (3)

ASTM International (ASTM), 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959 (4)

Deutches Institut fur Normung (DIN), Burggrafenstrasse 6, 10787 Berlin, Germany.

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2.2.4 In some cases, specific trade names have been used when a material with specific properties is required (see Paragraph 2.2.1). 2.2.5 Cladding, lining, or overlay shall be indicated using a material designation such as “CS with 2.54-mm (0.100-in.) minimum 304L cladding.” For internal coatings and linings, specific types (e.g., epoxy phenolic, vulcanized natural rubber, and vinyl ester fiber-reinforced plastic [FRP]) should be indicated.

2.3 Content and Format of Notes

2.3.1 General notes are notes applicable to the entire process unit and should be labeled with a unique identifier (typically a letter) on all MSDs. General notes that are applicable to a process unit shall be repeated

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in the same order using the same identifier on all MSDs. 2.3.2 Specific notes are unique to specific pieces of equipment, piping, or locations on the MSD, and should be cited appropriately. Specific notes should be labeled with a unique identifier (typically a number) and generally follow the general notes on the associated MSD page (if the MSD is continued on more than one page). 2.3.3 All nomenclature used on the MSD should be defined in a general note or legend. These definitions shall include, but are not limited to, the material nomenclature listed in Paragraph 2.2.3 that has been used on the MSD. Table 3 lists examples of other commonly used nomenclature. Others may be used as agreed on by the owner/operator and the contractor/fabricator.

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Table 3: Other Commonly Used Nomenclature

Nomenclature Meaning

B Baffles

C Case

CA Corrosion allowance

CH Channel

H Header

IMP Impeller

INJ Injection point (e.g., water wash, chemicals)

INT Internals

PWHT Postweld heat treatment for service or material. (Design code requirements for PWHT based on thickness must also be met, but are not

typically identified on the MSD.)

SH Shell

SR Stress relief

T Tubes

TS Tubesheets

2.3.4 All special materials requirements shall be listed on the MSD, usually in the specific notes. Examples of special requirements that have been used on MSDs in the past include:

2.3.4.1 Alloy 20 or alloy 825 drains in SS reactor inlet and outlet lines; 2.3.4.2 Maximum strength limit on CS for a liquefied petroleum gas (LPG) sphere; 2.3.4.3 Higher molybdenum content (e.g., 2.5% min.) for type 316L SS in cold, flowing seawater or naphthenic acid service;

2.3.4.4 Thermal stabilization of base materials and welds for type 321 SS or 347 SS operating above 427°C (800°F); 2.3.4.5 Special gaskets and seals for methyl tertiary-butyl ether (MTBE) service; 2.3.4.6 No substitution of vanadium-grade Cr-Mo steels, in which straight grades are listed; and 2.3.4.7 Autorefrigeration expected.

2.4 Corrosion Allowance

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2.4.1 Corrosion allowance (CA) is a critical parameter in the selection of materials of construction for pressure-containing components in a unit. Because of this, specifying a CA is required. 2.4.2 A specific minimum acceptable CA shall be indicated on the MSD for each pressure-containing component excluding pump cases, and except as noted in Paragraph 2.4.3. Example formats that have been used successfully include (see Appendix A for examples):

2.4.2.1 CS with X CA, where X represents the thickness in the appropriate unit of measure.

2.4.2.2 Showing the materials reference above the line and showing the CA directly below it. 2.4.2.3 CS-X, where a legend is created to represent the specific CA being used on the unit.

2.4.3 When the owner/operator specifies only a minimum CA for a specific material, it should be noted as a general note in accordance with Paragraph 2.3.1.

2.5 Additional Information

2.5.1 Additional materials-related information or operational requirements for corrosion control may be shown on the MSD. Examples of additional materials-related information include corrosion inhibitors, internal cathodic protection (CP), water wash injections, sampling locations, and corrosion probes. Examples of operational requirements include velocity limits, minimum design metal temperature (MDMT), and minimum pressurizing temperatures. 2.5.2 The injection point location for chemical injections (corrosion inhibitors, dispersants, antifoulants, etc.) along with the generic chemical type (i.e., neutralizing amine, ammonium hydroxide, etc.) should be shown on the MSD. Requirements for quills or spray nozzles should be indicated at each location.

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2.5.3 Corrosion probes may be uniquely numbered. Additionally, details on the type of probes may be provided. 2.5.4 Injection and mix points may be uniquely numbered. 2.5.5 Equipment and piping design service life may be shown on the MSD. For example, vessels: 30-year service life; bundles: 10-year service life; piping: 10-year service life; heater tubes: 12-year service life. At a minimum, the design service life should be defined in the transmittal information with the MSDs. 2.5.6 The MSD should schematically show changes in piping material, CA, or both that occur in the piping and not at the inlet/outlet flanges on stationary and rotating equipment. These changes (material specification breaks) typically occur at main control valves or at valves in bypass loops. Because of the high level of detail required to describe piping materials, typically, piping material is indicated generically on the MSD, leaving the actual specifics of the materials change for tools such as P&IDs or piping line designations to address. 2.5.7 If the pump materials of construction are shown on the MSD, the pump material class should be shown in accordance with API Standard 610,

5 PIP

(5) Practice

RESP73H6 (chemical services), or PIP Practice

RESP003H7 (water services) for centrifugal pumps or

generically as separate materials of construction for the case and impeller. For other types of pumps, the materials of construction for the case, impellers, and other applicable major components should be shown. If pump materials are modified from those shown for the reference standard’s class, the material changes should be clearly explained in the specific MSD notes.

2.6 Consistency

2.6.1 The nomenclature and formatting shall remain consistent throughout all of the MSDs associated with a process unit or project.

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Section 3: Process Data to Be Shown on MSD

3.1 Process Data

3.1.1 The process data used for materials selection should be shown on the MSD. The pertinent data may vary from unit to unit, and predicted damage mechanisms may vary. Example of typical data (as applicable), including corrosive agents and

contaminants that have the potential to affect materials selection, include:

3.1.1.1 Operating temperature; 3.1.1.2 Operating pressure; 3.1.1.3 Hydrogen partial pressure;

____________________________ (5)

Process Industry Practices (PIP), 3925 West Braker Lane (R4500), Austin, TX 78759.

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3.1.1.4 MDMT (especially for low-temperature processes or areas subject to autorefrigeration); 3.1.1.5 H2S concentration; 3.1.1.6 Sulfur concentration; 3.1.1.7 Free water concentration; 3.1.1.8 Ammonia concentration (e.g., in hydroprocessing unit effluent streams) 3.1.1.9 Total acid number (TAN) or neutralization number; 3.1.1.10 Chloride concentration; 3.1.1.11 pH; 3.1.1.12 Critical corrosion velocity limits; 3.1.1.13 Significant contaminants; and 3.1.1.14 Short-term operating conditions that could affect materials selection (e.g., presulfiding).

3.1.2 This information may be shown for all piping streams or may be selectively shown for piping streams when the data are applicable to the materials choice (i.e., hydrogen partial pressure would not typically be

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shown on piping streams operating below 204 C

[400 F]). Units of measure (e.g., ppm, psia) shall be clearly indicated for each data point or be globally defined in the general notes.

3.2 Process Data Formats

3.2.1 Process data may be provided in a heat and material balance (H&MB) or a subset of the H&MB on the MSD. Often additional information relevant to materials selection is placed on the H&MB subset (e.g., pH, hydrogen partial pressure, H2S concentration [pH2S or wt%]). These process data may be located on the MSD or as a separate sheet. If a separate sheet is used, the page number and revision of the information shall be indicated on the MSD. 3.2.2 Another format that may be used identifies operating temperature in one geometric form (e.g., rectangles, trapezoids) and the pressure in other shapes (e.g., ovals, elongated hexagons) with lines attaching each to the applicable piping. The remaining process data (as applicable) may then be shown in a separate geometric form also with a line attached to the applicable piping. 3.2.3 Other process data presentation may be used as agreed on by the owner/operator and contractor/fabricator.

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Section 4: Guidelines on Completing the MSD

4.1 Unless indicated otherwise, materials of construction and CA shall be selected on the basis of anticipated corrosion rate or rate of material degradation under the combination of all process variables (e.g., stream composition, velocity, temperature, pressure) and the specified component design life.

4.1.1 In most cases, maximum normal operating conditions are used to select materials. Design temperatures and pressures are not typically used to evaluate predicted corrosion and degradation mechanisms, and are typically used for code strength/thickness calculations. 4.1.2 In some process environments, severe corrosion or material degradation can occur when normal operating conditions are exceeded. Therefore, the effect of all short-term conditions on the materials of construction should be considered. Examples of short-term conditions are:

4.1.2.1 Alternate operations (e.g., presulfiding, catalyst regeneration);

4.1.2.2 No flow (power outage, steam-out, cleaning, etc.); 4.1.2.3 Startup and shutdown; 4.1.2.4 Upset and emergency conditions;.

4.1.2.4.1 Exposure to short-term conditions outside the operating window is of particular concern for equipment and piping in corrosive environments in which either the corrosion rate is temperature-influenced (e.g., acid services, oxygenated water), or a corrosion mechanism is highly temperature-dependent (e.g., caustic stress corrosion cracking [SCC]).

4.1.2.5 Start of run (SOR) and end-of-run (EOR) conditions.

4.1.3 When it is highly impractical to achieve the design service life for a specific component (e.g., heater tubes), the most practical material should be selected and notes regarding expected life should be added to the MSD.

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4.2 If PWHT or SR is required for reasons other than satisfying the fabrication code, notes regarding this shall be included on the MSD. Heat treating is typically used to mitigate the potential for failure when “as-welded” materials are exposed to conditions that promote environmental cracking. Examples of applications that have been used by some owner/operators in the past include:

4.2.1 CS equipment in severe wet H2S services; 4.2.2 CS equipment and piping in amine service at all operating temperatures (except storage tanks); 4.2.3 CS equipment and piping in caustic service at operating conditions above the NACE caustic cracking curve;

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4.2.4 Cr-Mo steel materials; 4.2.5 CS equipment in HF service; and

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4.2.6 CS deaerator storage sections.

4.3 The effect of all low-temperature conditions on materials of construction shall be evaluated when the possibility of exposure to low temperatures exists. Examples of low-temperature conditions that are typically used to set the MDMT include:

4.3.1 Lowest operating temperature; 4.3.2 Atmospheric temperature; 4.3.3 Shop and field hydrostatic or pneumatic test temperature; 4.3.4 Upset and emergency conditions; and 4.3.5 Autorefrigeration and other sources of cooling.

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References

1. API RP 571 (latest revision), “Damage Mechanisms Affecting Fixed Equipment in the Refining Industry” (Washington, DC: API). 2. ASTM A 516/A 516M (latest revision), “Standard Specification for Pressure Vessel Plates, Carbon Steel, for Moderate- and Lower-Temperature Service” (West Conshohocken, PA: ASTM). 3. ASTM A 351/A 351M (latest revision), “Standard Specification for Castings, Austenitic, for Pressure-Containing Parts” (West Conshohocken, PA: ASTM). 4. DIN 17445 (latest revision), “Stainless Steel Casing; Technical Delivery Conditions” (Berlin, Germany: DIN).

5. API Standard 610 (latest revision), “Centrifugal Pumps for Petroleum, Petrochemical, and Natural Gas Industries” (Washington, DC: API). 6. PIP Practice RESP73H (latest revision), “Application of ASME B73. 1 - 2001 Specification for Horizontal End Suction Centrifugal Pumps for Chemical Process” (Austin, TX: PIP). 7. PIP Practice RESP003H (latest revision), “Specification for Horizontal Centrifugal Pumps for Water Service” (Austin, TX: PIP).

8. NACE Standard RP0403 (latest revision), “Avoiding Caustic Stress Corrosion Cracking of Carbon Steel Refinery Equipment and Piping” (Houston, TX: NACE).

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Appendix A: Sample Materials Selection Diagrams (nonmandatory)

FIGURE A1: Sample 1

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FIGURE A2: Sample 2, Part 1

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FIGURE A3: Sample 2, Part 2

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