Piping Material Selection

Engineering Encyclopedia Saudi Aramco DeskTop Standards

Material Selection

Note: The source of the technical material in this volume is the Professional Engineering Development Program (PEDP) of Engineering Services. Warning: The material contained in this document was developed for Saudi Aramco and is intended for the exclusive use of Saudi Aramco’s employees. Any material contained in in this document which is not already in the public domain may not be copied, reproduced, sold, given, or disclosed to third parties, or otherwise used in whole, or in part, without the written permission of the Vice President, Engineering Services, Saudi Aramco.

Chapter : Pi P iping & Valves File Reference: M EX 10102

For additional information on this subject, contact K.S. Chu on 873-2648 or R. Hingoraney on 873-2649

Engineering Encyclopedia

Piping & Valves Material Selection

C ON TE NTS

P AGE

Factors That Affect Affect Material Selection................................................................................ 1 Material Strength ................................................................................................................. 2 Corrosion Resistance ........................................................................................................... 6 Material Toughness ............................................................................................................. 8 Fabricability....................................................................................................................... 11 Suitability for Wet, Sour Service....................................................................................... 12 Primary Pipe Manufacturing Processes ............................................................................. 13 Seamless Pipe .................................................................................................................... 13 Electric Resistance-Welded Pipe ....................................................................................... 14 Submerged Arc-Welded Pipe ............................................................................................ 16 Furnace-Welded Furnace-Weld ed Pipe ........................................................................................................ 16 Spiral-Welded Pipe............................................................................................................ 17 Saudi Aramco Limitations on Metallic Pipe...................................................................... 17 Determining Determining Applicable Standards for Pipe and Piping Components................ Components...................... ............ ......... ... 19 Standards for Pipe and Piping Components Componen ts ...................................................................... 19 Standards for Pipe ............................................................................................................. 21 Standards for Fittings ........................................................................................................ 23 Standards for Flanges ........................................................................................................ 25 Standards for Valves.......................................................................................................... 27 Standards for Gaskets and Bolting .................................................................................... 28 Selecting Materials ............................................................................................................ 29 Material Selection Process................................................................................................. 29 General Selection............................................................................................................... 30 Sample Problem 1 ............................................................................................................. 30 Sample Problem 3 ............................................................................................................. 32 Sample Problem 4 ............................................................................................................. 32 SAMSS Requirements ....................................................................................................... 36 Material Selection for Low-Temperature Service ............................................................. 36

Saudi Aramco DeskTop Standards



Material Selection for Transportation Pipelines ................................................................ 39 Material Selection for Lined, Coated, and Nonmetallic Piping ......................................... 41 Piping Specification........................................................................................................... 43 WORK AID 1: Procedures for Determining Applicable Industry and Saudi Aramco Standards for Pipe and Piping Components ............. ................... ............ ............ ........... ........... .......... .... 46 Descriptions of Applicable SAES and SAMSS Requirements.......................................... 50 WORK AID 2: Procedures for Selecting Materials........................................................... 56 GLOSSARY ...................................................................................................................... 59




Factors That Affect Material Selection The Saudi Aramco engineer must recognize the factors that determine the applicable SAMSS's, and the concerns associated with particular services and the use of certain materials. Identifying factors that affect material selection helps the engineer make an optimal choice if more than one material is suitable. It also helps the engineer to specify appropriate SAMSS requirements based on fluid characteristics and additional information that is required in material selection (i.e., chemistry, produ ct form). Several factors influence the selection of a material for a particular piping service. The most important factors include the following: •

Strength.

•

Corrosion resistance.

•

Toughness.

•

Fabricability.

•

Suitability for wet, sour service.

•

Availability.

•

Cost.

A discussion of the first five of these factors appears below. The remaining two factors, availability and cost, are outside the scope of this course. The assessment of these factors will prepare the Saudi Aramco engineer for the materials selection process. This process is governed by service environment and design conditions. Selecting material consists of the following: 1.

Picking a basic material chemistry from SAES-L-032, Materials Selection for Piping Systems.

2.

Using industry standards to determine material designations for piping components.

3.

Specifying the applicable SAMSS's.

This process will be discussed in detail in the last section of this module.


1



Material Strength A material's strength is defined by the following four values: •

Yield strength.

•

Tensile strength.

•

Creep strength.

•

Fatigue strength.

Alloy content and material grain size are factors that affect material strength. Yield and Tensile Strength

Most engineers are familiar with the first two of these, yield strength and tensile strength. A stress-strain diagram that is produced from a standard tensile test shows these two values. Figure 1 illustrates such a stress-strain diagram. As the stress in a material increases, its deformation also increases. Eventually a value known as the yield strength, Point A in Figure 1, is reached. This value is the stress that is required to produce permanent deformation in the material. If the stress is further increased, the permanent deformation continues to increase until the material fails. The maximum stress that the material attains is known as the tensile strength and is shown by Point B in Figure 1. If a large amount of strain occurs in going from Point A to Point C, the rupture point, the material is called a ductile material. Steel is an example of a ductile material. If the strain in going from Point A to Point C is small, the material is classified as brittle. Gray cast iron is an example of a brittle material.

TYPICAL STRESS-STRAIN DIAGRAM FOR STEEL

FIGURE 1


2



Both the yield and tensile strengths decrease as temperature increases and these strengths control the allowable stress that is used for piping component design at temperatures below the creep range. Allowable stress will be discussed in MEX 101.03. Figure 2 shows the variation of allowable stress with temperature for a typical carbon steel pipe material, based on ASME/ANSI B31.3. Note that below about 400°C (750°F), the allowable stress is governed by the material yield and tensile strengths.

VARIATION OF ALLOWABLE STRESS, WITH TEMPERATURE

FIGURE 2 Creep Strength

Below about 400°C (750°F) for a given stress, the strain in most materials remains constant with time. Above this temperature, even with constant stress, the strain in the material will increase with time. This behavior is known as creep. The temperatures above 400°C (750°F) are known as the creep range. The creep strength, like the yield and tensile strengths, varies with temperature. For a particular temperature, the creep strength of a material is the minimum stress that will rupture the material during a specified period of time. A 100,000 hour design life is typically used to determine the allowable stress for piping system materials at temperatures that are in the creep range.


3



Figure 3 is a typical curve that illustrates the three stages of creep. The creep rate will vary during primary creep, will reduce to a smaller but relatively constant rate during secondary creep, and then will increase during tertiary creep until material rupture occurs. Allowable stresses for piping materials that operate at temperatures that are in the creep range are typically based on the material strength in the secondary creep stage where the creep rate is constant, and also on the stress at rupture.

TYPICAL CURVE SHOWING THREE STAGES OF CREEP

FIGURE 3


4



Fatigue Strength

The fatigue strength is the fourth strength factor that influences material selection. The fatigue strength is important for piping systems that experience either mechanical or thermal cyclic loading. A piping system that contains a reciprocating pump or reciprocating compressor is an example of a piping system that experiences cyclic loading. Figure 4 shows the allowable fatigue stress versus the number of loading cycles for materials that would include ASTM A106, Gr. B carbon steel seamless pipe. The allowable fatigue stress decreases as the number of cycles increases. Piping systems must be designed such that a fatigue failure will not occur during their design life.

DESIGN FATIGUE CURVE

Source: ASME Section VIII, Division 2, 1986. With permission from the American Society of Mechanical Engineers.

FIGURE 4


5



Corrosion Resistance

Corrosion of materials involves the destruction of the metal by chemical or electrochemical attack. Corrosion of materials takes many forms. Figure 5 briefly describes some of the most common forms of corrosion that may affect all piping systems. Figure 6 describes the forms of corrosion that are present mainly in plant piping systems, which are usually associated with the higher temperatures and greater concentrations of corrosive substances that occur in plant piping. The methods that are used to protect piping systems from the effects of corrosion depend on the type of piping system.

CORROSION THAT MAY OCCUR IN ALL PIPING SYSTEMS Characterized by a uniform metal loss over the entire surface General or of the material. May be combined with erosion if the Uniform materials are exposed to high-velocity fluids, or moving fluids Corrosion that contain abrasive materials, that depend on a layer of oxidation to protect them. Pitting A form of localized metal loss randomly located on the Corrosion material surface. Occurs most often in stagnant areas or areas of low-flow velocity. Occurs when two dissimilar metals contact each other in a Galvanic corrosive electrolytic environment. One of the two metals, Corrosion known as the anodic metal, develops deep pits or grooves as a current flows from it to the other metal, known as the cathodic metal. A localized corrosion that is similar to pitting. Crevice Crevice corrosion occurs at places such as gaskets, lap joints, and Corrosion bolts, where a crevice can exist. This type of corrosion affects materials that are generally noted for resistance to uniform corrosion. Occurs when a different concentration of either a corrosive Concentration fluid or dissolved oxygen contacts areas of the same metal. Cell Corrosion This type of corrosion is usually associated with stagnation of the fluid. Occurs in cast iron that is exposed to salt water or weak acids. Graphitic This corrosion reduces the iron in the cast iron, and leaves the Corrosion graphite in place. The result is a material that is extremely soft but shows no metal loss. FIGURE 5


6



Liquid and gas transportation piping systems usually have cathodic protection systems installed to prevent external corrosion. Coatings are sometimes used to protect against internal corrosion. In liquid-transportation piping systems, corrosion inhibitors may also be used to protect against internal corrosion.

CORROSION THAT OCCURS MAINLY IN PLANT PIPING

Carburization

Corrosion Fatigue

Decarburizatio n

Graphitization

Hydrogen Embrittlement

Hydrogen Blistering

A high-temperature reaction that occurs between certain material alloys in an environment that contains compounds such as carbon dioxide or methane. The carbon is absorbed on the surface of the metal and diffuses inward. This results in loss in ductility, weldability, and creep strength. Occurs when the material experiences high cyclic stresses in the presence of a corrosive environment. The cyclic stresses initiate small cracks in the metal surface. Corrosion occurs at the crack tip as a result of a strong anodic/cathodic relationship with the crack sides. Occurs in an oxidizing or reducing environment in the absence of carbon in the atmosphere. In decarburization, carbon in the steel combines with oxygen or hydrogen to form carbon monoxide or hydrocarbons. The diffusion of the carbon out of the steel leaves the steel softer and weaker. A metallurgical behavior that occurs in carbon and low-alloy steels at temperatures above 450°C (800°F). When this occurs, the carbon that is normally present in steel as Fe3C is gradually converted to graphite. Occurs when hydrogen at a high temperature and pressure diffuses into steel and reacts with iron ca rbides to form methane. The methane then collects at grain boundaries, causes high intergranular stresses, and ultimately leads to fissuring of the metal at the grain boundary. Occurs when atomic hydrogen at a high temperature and pressure diffuses into steel and collects at discontinuities. The atomic hydrogen then forms molecular hydrogen. Since molecular hydrogen will not diffuse through steel, pressure builds up inside the voided area and causes rupture of the metal in a local area. The ruptured area appears as a blister on the surface of the metal. FIGURE 6


7



Stress Corrosion

Temper Embrittlement

Occurs when the material contains high applied or residual tensile stresses in the presence of a corrosive environment. Stress corrosion results in small localized cracks tha t have little, if any, ductility. The crack tip undergoes corrosion as a result of a strong anodic/cathodic relationship with the sides of the crack. A reduction in the toughness of low-chrome alloys (below 3% chrome) that are exposed to temperatures above 400°C (750°F). Generally attributed to a weakening effect caused by segregation at grain boundaries of elements that are present in trace quantities.

FIGURE 6, CONT'D For plant piping systems that are in corrosive service, the protection against corrosion usually comes by using alloys that resist corrosion. The most common alloys that are used for this purpose are chromium and nickel. Low-alloy steels, with a chromium content of 1-1/4% to 9%, and stainless steels, increase corrosion resistance for a large number of environments. A notable exception is austenitic stainless steel in an environment that contains chlorides or polythionic acid. Stress-corrosion cracking may occur in such a case unless precautions are taken to prevent it. Such precautions involve selecting a resistant alloy or preventing the formation of an acid by excluding air or water.

Material Toughness Fracture of common carbon and low-alloy steels occurs in either shear or cleavage, which depends on the state of stress, the temperature, and the strain rate. The primary characteristics of these fracture types are as follows: •

A shear fracture, or ductile fracture, exhibits yielding and deformation and will occur at some point well beyond Point A in Figure 1.

•

A cleavage fracture, or brittle fracture, lacks the yielding and deformation that is found in a shear fracture. A cleavage fracture often occurs soon after first yielding of the material. Because brittle fracture occurs with little or no prior deformation, there is little warning before it occurs. Brittle fracture of materials must be avoided.


8



One way to characterize the fracture behavior of a material is the amount of energy that is necessary to initiate and propagate a crack in the material at a given temperature. This is known as the material's toughness. Tough materials require a relatively large amount of energy to initiate and propagate a crack. Brittle materials require less energy to initiate and propagate a crack. The amount of energy is usually specified in joules or ft-lbs. The energy can be measured by standard Charpy V-notch tests. Toughness is of particular concern for piping systems that are subject to temperatures below 0°C (32°F). For piping systems that are subject to low temperatures, ensure that the material has adequate toughness for the service temperatures. To ensure adequate toughness, each ASME/ANSI B31 Code states requirements for material toughness. In addition, 01-SAMSS-036 and 02SAMSS-001 specify manufacturing, material standards and chemistry, heat treatment, and impact testing requirements for low-temperature pipe and piping components, respectively. For cross-country pipelines, 01-SAMSS-022 and SAES-L-031 define mandatory fracture control testing requirements. Also, SAES-L-030 covers impact testing requirements for piping in low-temperature service.

ABSORBED ENERGY VERSUS TEMPERATURE Brittle Fracture Zone

Transition Zone

Ductile Fracture Zone

Mixed Mode Behavior

Clevage

Upper Shelf

Shear

Difficult Crack Initiation and Propagation

Easy Crack Initiation 20 joules (15 ft.-lbs)

Lower Shelf TEMPERATURE

FIGURE 7


9



As Figure 7 shows, a material's temperature affects the amount of energy that is required to initiate and propagate a crack. The lower the temperature, the easier it is to have a brittle fracture in a material. The energy versus temperature curve that is shown in Figure 7 has three zones: a brittle fracture zone, a transition zone, and a ductile fracture zone. The transition zone defines the temperature at which the material behavior changes from brittle to ductile. The beginning of the transition zone is normally taken at about 20 joules (15 ft-lb) of absorbed energy. Various other factors affect the toughness of a material. These include the following: •

Chemical composition or alloying elements.

•

Heat treatment.

•

Grain size.

The major chemical elements that affect a material's toughness and their effect are as follows: •

Carbon. High carbon content has two detrimental effects on toughness. It raises the transition temperature, and lowers the maximum absorbed energy.

•

Manganese. This element improves the material's toughness when used in concentrations of up to 1.4%. 01-SAMSS-036 contains requirements for carbon-manganese steel pipe in lowtemperature service.

•

Nickel. This element significantly increases the toughness of a material. Up to 3% nickel is allowed by 01-SAMSS-036 for pipe.

•

Oxygen, Sulfur, Molybdenum. These elements have a detrimental effect on a material's toughness. The amount of each of these elements is controlled in steels that require good toughness qualities. Fully deoxidized steel is required for pipe based on 01-SAMSS-036.


10



Heat treatment affects both strength and toughness. Heat treatment will improve the toughness properties of steel. However, as the yield strength increases, the effectiveness of heat treatment on toughness decreases. Normalized steel and heat treatment after welding are required by 01-SAMSS-036. Steels with a small grain size (fine-grained) must be used for low-temperature pipe, as required by 01-SAMSS-036.

Fabricability For a material to be useful in the construction of a piping system, it must be available in the shapes or forms that are required. In piping systems, some common shapes and forms include the following: •

Seamless pipe.

•

Plate that is used for welded pipe.

•

Wrought elbows, tees, reducers, and crosses.

•

Forged flanges, couplings, and valves.

•

Cast valves.

For welded pipe, the plate that is used must be ductile enough to permit rolling. For crosscountry pipelines, the material must be ductile to allow bending during construction to conform to moderate changes in elevation or lateral end points. The weldability of materials includes consideration of the effect of welding on the following material properties: •

Reduction in strength.

•

Reduction in toughness or ductility.

•

Increase in hardness of the weld and the heat affected zone (HAZ).

•

Inducement of residual stresses.

•

Risk of stress-corrosion cracking in plant piping.


11



Suitability for Wet, Sour Service Cross-country welded pipelines in a wet, sour environment may suffer from Hydrogen Induced Cracking (HIC) unless special precautions are taken in material selection. HIC is a form of hydrogen attack on welded carbon steel in environments that contain wet H2S. HIC can occur in piping when the partial pressure of H2S in a wet gas or multiphase service exceeds 345 Pa (absolute) (0.05 psia) and the total pressure is at least 450 kPa (absolute) (65 psia). In wet crude or product piping, HIC can occur if the partial pressure of H2S exceeds 345 Pa (absolute) (0.05 psia) and the total pressure is at least 1,830 kPa (absolute) (265 psia). Seamless pipe is inherently resistant to HIC and thus is exempt from the special requirements that are necessary to prevent HIC. Wet, sour services include the following: •

Wet, sour gas.

•

Dry, sour gas, where a process upset could result in water entering into or forming in the pipe.

•

Wet, sour, multiphase service.

•

Wet, sour crude or product.

•

Sour water.

SAES-L-033 contains general corrosion protection requirements for pipelines and plant piping systems and provides the specific requirements for welded line pipe in wet, sour service. SAES-L-033 requires the use of steel that conforms to the requirements of 01-SAMSS-016. SAES-L-033 provides that, with the concurrence of the applicable operating department, non01-SAMSS-016 steel may be used if the maximum possible hoop stress is below 25% of the minimum specified yield strength of the material. Paragraph 5 of 01-SAMSS-016 provides acceptance criteria for the following: •

Material Composition.

•

Hydrogen Induced Cracking (HIC) Sensitivity Tests.

•

Nondestructive Testing.


12



Primary Pipe Manufacturing Processes

A description of pipe should include the manufacturing process. When the engineer is selecting material, the pipe manufacturing process will help him determine the potential overall quality of the pipe. As noted in MEX 101.03, the required pipe thickness decreases as the pipe quality increases; therefore, less total material weight is required when higher quality pipe is used. Seamless pipe is the strongest and will last the longest, but is the most expensive. Also, because of the hazards with some fluids, certain manufacturing processes are prohibited. Prohibited manufacturing processes are specified in SAES-L-006. The Saudi Aramco engineer needs to determine the most suitable pipe manufacturing process for a piping system. Pipe is usually manufactured using one of the following five processes: •

Seamless pipe.

•

Electric resistance-welded pipe.

•

Submerged arc-welded pipe.

•

Furnace-welded pipe.

•

Spiral-welded pipe.

The quality of the manufacturing processes varies, with seamless pipe being the best and furnace-welded pipe the worst. A brief description of each process follows.

Seamless Pipe The hot, rotary piercing process is usually used to produce seamless pipe. The pipe starts as a round billet of high-quality, killed steel. The billet is heated to a forging temperature of 1,200-1,315°C (2,200-2,400°F), and forced over the rounded nose of a hardened piercing mandrel. This gives a thick-walled tube. A plug or ball is inserted in the pierced hole. The tube then passes through a series of rollers that shape the billet to the final outside diameter of the pipe and reduce its wall thickness to the desired value. Because there is no seam in the pipe, the joint quality factor, as defined by the piping codes, is 1.0, the highest possible. The joint quality factor is a parameter that is used to determine the required pipewall thickness for specific design conditions. Pipewall thickness calculations are discussed in MEX 101.03.


13



Electric Resistance-Welded Pipe Electric resistance-welded pipe typically is used when the diameter and/or thickness makes seamless pipe impractical or too expensive. The welded pipe usually begins as a plate. The flat plate becomes a pipe through several steps that may include rolling or forming, tack welding, final welding, cold expanding, end beveling, and external and/or internal coating. Inspection of the product usually occurs at various steps throughout the process of changing a plate into a pipe. A typical operation for a large-diameter pipe would include the following steps: •

A plate of the proper thickness is sheared to the desired width and shot-blasted or pickled.

•

A set of dies is used to first form the plate into a "U" shape. The U-shaped plate is then formed into a circular shape with a second set of dies.

•

Alternatively, the plate is rolled into the circular shape.

•

The circular shape is then welded into a pipe.

•

The pipe is cold-expanded to its final outside diameter and wall thickness.

•

The ends of the pipe are beveled as required, and the pipe is externally coated or internally lined, if required.

Pipe that is made using the electric resistance-welding (ERW) process goes through a welding machine. Figure 8 shows conceptually what happens in the welding machine. The welding machine has adjustable rollers that force the open edges of the formed plate together. It also has two circular electrodes to place a current across the gap between the open edges of the plate. The current across the edges heats the metal while the rolls force the edges together to complete the weld under pressure. While the weld is still hot, the pipe passes between rollers and over a mandrel to smooth the weld area. SAES-L-006 prohibits the use of ERW pipe for hazardous service, unless it is manufactured and tested in accordance with an applicable SAMSS.

ELECTRIC RESISTANCE-WELDING PROCESS

FIGURE 8 Saudi Aramco DeskTop Standards

14




15



Submerged Arc-Welded Pipe

The submerged arc-welding process is the most common for manufacturing carbon steel pipe. Pipe that is made through the use of the submerged arc-welding (SAW) process also goes through a welding machine. Figure 9 illustrates the process. With this process, the open ends of the formed plate have either a single (single-submerged arc, SSAW) or double (doublesubmerged arc, DSAW) bevel. While rollers force the beveled edges together, a consumable electrode adds metal to the weld. A blanket of granulated flux covers the arc and the molten metal. The flux creates a protective atmosphere and a slag that shields the weld metal until it solidifies. If required, the internal bead is ground flush with the inside surface of the pipe. Electric resistance-welded pipe and submerged arc-welded pipe are high-quality pipe that are suitable for most services. Most cross-country pipelines consist of one of these two types of pipe. Since they contain a longitudinal seam, however, they may not be as high a quality as seamless pipe. The joint quality factor for these two processes is usually taken between 0.8 and 1.0, depending on the piping design code, the material specification, and the degree of inspection.

SUBMERGED ARC-WELDING PROCESS

FIGURE 9

Furnace-Welded Pipe Furnace-welded pipe is generally the lowest cost (and lowest quality) pipe. The process that is used to make furnace-welded pipe is similar to that used for ERW pipe. The free edges of formed plate are forced together and heated in a furnace. The heat causes the free edges to fuse together. The quality of the welded joint is not as high as in the ERW or SAW processes. The joint quality factor for this type of pipe is usually around 0.6. SAES-L-006 prohibits the use of furnace-welded pipe for hazardous services.


16



Spiral-Welded Pipe

Spiral-welded pipe is made by winding narrow coils of steel into cylinders with the edges forming a helix. Electric resistance or double-submerged arc-welds join the edges together. Spiral-welded pipe that is used in ASME/ANSI B31.3 piping systems has a joint quality factor of between 0.75 and 1.0, which depends on the material specification and welded joint detail. Spiral-welded pipe is used primarily for cross-country pipeline services, where the specifications and weld details that are used result in a joint quality factor of 1.0. SAES-L006 prohibits the use of spiral-welded pipe for hazardous services, unless it is manufactured and tested in accordance with an applicable SAMSS.

Saudi Aramco Limitations on Metallic Pipe In addition to the limitations noted under each manufacturing process, SAES-L-006 specifies limitations on metallic pipe sizes, wall thicknesses, minimum yield strength, and other specification or application-specific limitations.

Pipe Size

SAES-L-006 states that pipe outside diameters must be in accordance with API Specification 5L. Intermediate sizes and the sizes 1/8, 1/4, 3/8, 1-1/4, 2-1/2, 3-1/2, and 5 in. shall not be used except when necessary to match vendor equipment connections. Pipe sizes smaller than 3/4 in. shall not be used for hazardous services (including vents and drains) except for instrument connections and on vendor-supplied, skid-mounted equipment, or other applications when the pipe is protected against mechanical damage.

Other Pipe Specification Requirements

SAES-L-006 also states the following limitations. •

Iron pipe specifications shall not be used for hazardous services.

•

Only steel pipe specifications shall be used to handle flammable fluids.

•

Carbon steel pipe for hazardous services shall have a specified minimum yield strength (SMYS) of not less than 241 MPa (35,000 psi).

•

Pipe manufactured per API Specification 5L, Gr. X65 and X70, shall be derated to X60 when used in applications that are within the scope of ASME/ANSI B31.3.


17



•

Pipe in accordance with 01-SAMSS-033 or 01-SAMSS-035 shall be used when the design minimum temperature (as defined in SAES-L-002) is at -18°C (0°F) and above.

•

Pipe in accordance with 01-SAMSS-036 shall be used when the design minimum temperature is between -45°C and -18°C (-50°F and 0°F). 01-SAMSS-033 imposes additional requirements that are aimed at improving the toughness properties of pipe in low-temperature services.

•

Pipe in accordance with specifications listed in ASME/ANSI B31.3, with a minimum temperature of -45°C (-50°F), may be used when the design minimum temperature is between -29°C and -18°C (-20°F and 0°F). This requirement forces the pipe material to have better toughness properties than would otherwise be needed at temperatures between -29°C and -18°C (-20°F and 0°F).

•

Impact testing is not required when the design minimum temperature is below -18°C (0°F) but at or above -29°C (-20°F), and if: -

The maximum operating pressure of the pipe will not exceed 25% of the maximum design pressure allowed by ASME/ANSI B31.3 at ambient temperature, and,

-

The combined longitudinal stress due to pressure, dead weight, and displacement strain does not exceed 41.4 MPa (6,000 psi) for any temperature within this range.

Industry experience has found that brittle fracture is not a concern unless the stress levels in the pipe are above these values. Therefore, impact testing is not necessary. The mechanical design of the piping system would have to be very conservative in order to meet these requirements. •

The requirements of 01-SAMSS-016 shall be applied for welded line pipe in wet, sour services. Seamless pipe may be used as an alternative, as long as it meets the hardness requirements of 01-SAMSS-035.

•

The requirements of 01-SAMSS-022 shall be applied for fracture control of transportation pipelines in gas, liquefied gas, and multiphase services.

•

Schedule 40 carbon steel pipe in nominal sizes of 50 mm (2 in.) and smaller shall be permitted only for nonhazardous service.


18



Determining Applicable Standards for Pipe and Piping Components Saudi Aramco and industry standards specify material requirements for pipe and piping components. A complete material specification needs to include the applicable industry standard. The Saudi Aramco engineer must determine the standard that governs the design of the particular component. This determination will allow him to designate the industry standard that is applicable to a component for a particular service, and specify the SAES's and SAMSS's that give additional requirements. Work Aid 1 summarizes the Saudi Aramco SAES's and SAMSS's that apply to pipe and piping components. The paragraphs that follow summarize the application of industry and Saudi Aramco standards to pipe and piping components.

Standards for Pipe and Piping Components The ASME/ANSI B31 piping codes each provide a list of acceptable industry standards that cover the materials and design for piping and piping components. Some of the common organizations that issue industry standards are as follows: •

American National Standards Institute (ANSI).

•

American Society of Mechanical Engineers (ASME).

•

American Petroleum Institute (API).

•

American Society for Testing and Materials (ASTM).

•

American Welding Society (AWS).

•

American Water Works Association (AWWA).

•

Manufacturers Standardization Society of the Valve and Fittings Industry (MSS).

•

National Association of Corrosion Engineers (NACE).


19



The ASME/ANSI B31 piping codes contain tables that list acceptable industry standards for pipe components as follows: •

ASME/ANSI B31.3 - Table 326.1, Component Standards (for metallic components). Table A326.1, components).

Component

•

ASME/ANSI B31.4 - Table 423.1, Material Dimensional Standards.

•

ASME/ANSI B31.8 - Appendix B.

Standards

Standards

(for

and

nonmetallic

Table

426.1,

In addition to the industry standards, Saudi Aramco specifies materials requirements in the Saudi Aramco Engineering Standards (SAES's), the Saudi Aramco Materials System Specifications (SAMSS's), and in Mandatory Saudi Aramco Standard Drawings. In order to discuss the application of industry standards to Saudi Aramco piping systems, the additional requirements given in the SAES's, SAMSS's, and Mandatory Drawings, standards for the following piping and common piping components will be examined. •

Pipe.

•

Fittings.

•

Flanges.

•

Valves.

•

Bolting (includes gaskets and bolts).


20



Standards for Pipe Industry Standards

ASTM and API materials standards cover most of the metallic pipe that is used by Saudi Aramco. The most often used metallic pipe materials include the following designations: •

ASTM A106, Seamless Carbon Steel Pipe for High-Temperature Service .

•

ASTM A53, Pipe, Steel, Black and Hot-Dipped, Zinc Coated, Welded and Seamless .

•

API 5L, Specification for Line Pipe .

•

ASTM A333, Seamless and Welded Steel P ipe for Low-Temperature Service .

•

ASTM A335, Seamless Ferritic Alloy Steel Pipe for High-Temperature Service .

•

ASTM A312, Seamless and Welded Austenitic Stainless Steel Pipe .

Nonmetallic pipe for utility piping within Saudi Aramco usually consists of either PolyVinyl Chloride (PVC) or Reinforced Thermosetting Resin (RTR) pipe. PVC pipe is covered by industry standard ASTM D1785, PVC Plastic Pipe, Sch 40, 80 and 120 . Several ASTM standards exist for RTR pipe. These include the following: •

ASTM D2996, Filament-Wound Fiberglass RTR Pipe .

•

ASTM D2997, Centrifugally Cast RTR Pipe .

•

ASTM D3517, Fiberglass RTR Pressure Pipe .

•

ASTM D3754, Fiberglass RTR Sewer and Industrial Pressure Pipe .


21



SAES and SAMSS Requirements

Saudi Aramco gives requirements and limitations that supplement the industry standards for pipe in the SAES's and SAMSS's. Work Aid 1 contains a chart titled "SAES and SAMSS Requirements" that includes identification of the Saudi Aramco documents that include additional requirements with respect to pipe. For example, 01-SAMSS-010, Fabricated Carbon Steel Piping , specifies acceptable carbon steel pipe specifications as follows (unless otherwise specified in the specific purchase order): •

API 5L, Grade B through X60.

•

ASTM, Grade B, seamless, black.

•

ASTM A106, Grade B.

The pipe specification that is actually used depends on detailed design considerations, cost, availability, and standardization requirements. API 5L is often used for pipeline applications, while the other specifications are used for plant applications. It should be noted that Saudi Aramco currently does not have pipe specification requirements for material other than carbon steel. Therefore, applications that require low-alloy or stainless steel pipe materials are handled on an individual basis. A chart that is contained in Work Aid 2 summarizes typical pipe specifications that are used for low-alloy and stainless steel applications.


22



Standards for Fittings Industry Standards

The fittings include elbows, miters, laps, tees, crosses, reducers, unions, integrally reinforced connections, and pipe caps. Fittings will be discussed in MEX 101.04. The major industry standards tha t are used for metallic piping fittings are as follows: •

ASME/ANSI B16.9, Factory-Made Wrought Steel Butt-Welded Fittings .

•

ASME/ANSI B16.11, Forged Steel Fittings, Socket-Welded and Threaded .

•

ASME/ANSI B16.12, Cast Iron Threaded Drainage Fittings .

•

ASTM A74, Cast Iron Soil Pipe and Fittings .

The primary industry standards that cover nonmetallic (PVC) fittings are as follows: •

ASTM D2665, Polyvinyl Chloride Plastic Drain, Waste, and Vent Pipe and Fittings .

•

ASTM D3311, Drain, Waste, and Vent (DWV) Plastic Fittings .

•

ASTM F439, Socket-Type CPVC Plastic Pipe Fittings, Schedule 80 .

•

DIN 8063.


23




Saudi Aramco gives requirements and limitations that supplement the industry standards for pipe fittings in the SAES's and SAMSS's. Work Aid 1 identifies the Saudi Aramco documents that include additional requirements with respect to pipe fittings. For example: •

01-SAMSS-010 requires that carbon steel forged, steel threaded or socket-welded fittings conform to ANSI B16.11, and be ASTM A105 material.

•

02-SAMSS-005 requires that carbon steel butt-welded fittings conform to ANSI B16.9. The material shall conform to the requirements of ASTM A234/A234M, Grade WPB, when the fittings are welded to Grade B pipe. The material must conform to MSS SP-75 when the fittings are welded to API 5L, Grade X42 through X65 pipe. The two fitting specifications are used so that the material strength of the fitting is comparable to the strength of the pipe to which it is welded. 02-SAMSS-005 also contains additional material chemistry, manufacture and testing requirements that are beyond what are contained in the industry standards. Here again, Saudi Aramco does not currently have explicit fitting specification requirements for materials other than carbon steel. However, 02-SAMSS-005 states that the mechanical and chemical properties of the fitting material should be similar to those of the matching pipe. Therefore, applications that require low-alloy or stainless steel pipe materials are handled on an individual basis. Work Aid 2 summarizes typical fitting specifications that are used for low-alloy and stainless steel applications.

Standard Drawings

Saudi Aramco has standard drawings that apply to metallic fittings that are used in several services. For example, Drawing AE-036175 provides details of a heavy welding boss that is used for making threaded connections to vessels and lines. Several SAMSS's require the use of Saudi Aramco Standard Drawings for specific components and assemblies.


24



Standards for Flanges Industry Standards

Each of the piping codes lists acceptable industry standards for piping flanges in the tables cited in the introduction to this topic. These include the following: •

ASME/ANSI B16.1, Cast Iron Pipe Flanges and Flanged Fittings , Class 25, 125, 250 and 800.

•

ASME/ANSI B16.5, Pipe Flanges and Flanged Fittings.

•

ASME B16.47, Large-Diameter Steel Flanges , NPS 26 through NPS 60.

•

API 605, Large-Diameter Carbon Steel Flanges.

•

MSS SP-44, Steel Pipe Line Flanges.

•

API 6A, Wellhead Equipment.

These standards contain information that concerns acceptable flange materials. Flange material specifications are selected to match the chemistry of the pipe material. Most flanges are made from forgings. Nonmetallic flanges use the same standards that apply to fittings. See "Standards for Fittings" for more information.


25




Saudi Aramco gives requirements and limitations in the SAES's and SAMSS's that supplement the industry standards for flanges. Work Aid 1 identifies the Saudi Aramco documents that include additional requirements with respect to pipe flanges. For example, SAES-L-009, Metallic Flanges, Gasket, and Bolts , specifies requirements for carbon steel flanges, which includes reference to the appropriate industry standards and material specification requirements. 02-SAMSS-011, Forged Steel Weld-Neck Flanges for Low- and Intermediate-Temperature Service , specifies additional material specification and testing requirements. Generally speaking, selection of an appropriate carbon steel flange material specification is governed by design temperature and the Specified Minimum Yield Strength (SMYS) of the connected pipe. The SMYS of the flange material will be comparable to that of the connected pipe. For most plant piping systems, flange material will be either ASTM A105N, A350, Grade LF2, or A266 C14. A350, Grade LF2 is now the dominant flange material that is used in Saudi Aramco applications. Flanges for pipeline applications will typically be higher strength material specifications, as required in 02SAMSS-011.

Standard Drawings

Some Saudi Aramco transportation piping systems, 650 mm (26 in.) and above in diameter, have nonstandard flanges. The nonstandard flanges were used for these piping systems because at the time the piping systems were built, no standards existed for flanges over 600 mm (24 in.) in size. Mandatory Saudi Aramco drawings are required where these flanges are used. Also, mandatory standard drawings exist for spectacle blinds used by Saudi Aramco.


26



Standards for Valves Industry Standards

A large number of industry standards exist for valves because many different types of valves are used in piping systems. Like pipe fittings and pipe flanges, the ASME/ANSI B31 piping codes list acceptable valve standards in the tables cited in the introduction to this section on piping standards. These include the following: •

ASME/ANSI B16.34, Valves - Flanged, Threaded, and Welding End .

•

API 599, Steel and Ductile Iron Plug Valves .

•

API 600, Steel Gate Valves - F langed and Butt-Welding Ends .

•

API 602, Compact Steel Gate Valves.

•

API 606, Compact Steel Gate Valves-Extended Body .

•

API 608, Metal Ball Valves - Flanged and Butt-Welding Ends .

•

API 609, Lug- and Wafer-Type Butterfly Valves .


Saudi Aramco SAES's and SAMSS's reference many of the industry standards that cover valve materials, design, inspection, and testing. Each of the major valve types that is used by Saudi Aramco has a SAMSS that lists the necessary industry standards for the particular valve type, plus additional Saudi Aramco requirements. In addition, two SAMSS's cover general requirements for valves as follows: •

04-SAMSS-003, Additional Requirements for Low-Temperature Valves .

•

04-SAMSS-048, Valve Inspection and Testing R equirements .

Work Aid 1 identifies the Saudi Aramco documents that include additional requirements with respect to valves.


27



Standards for Gaskets and Bolting Industry Standards

The industry standards that cover materials for most gaskets used by Saudi Aramco are as follows: •

ASME/ANSI B16.20, Ring Joint Gaskets and Grooves for Steel Pipe Flanges : Soft iron gaskets in this standard are used by Saudi Aramco for flanged joints requiring an octagonal ring-type gasket.

•

ASME/ANSI B16.21, Nonmetallic Flat Gaskets for Pipe Flanges : Gaskets in this standard are used by Saudi Aramco for nonhazardous services where sheet gaskets are acceptable.

•

API 601, Metallic Gaskets for Piping, Double-Jacketed Corrugated and Spiral Wound : Gaskets in this standard are used for flanged joints in most Saudi Aramco services.

•

API 6A Type RX: Gaskets for flanges per API 6A.

•

ASTM D1418: Gasket materials for flanges in acid and other corrosive services.

Saudi Aramco uses bolting materials covered by the following standards: •

ASTM A193, Stud Bolts with A194 Nuts : Used for most services.

•

ASTM A320, Stud Bolts : Used for low-temperature services.

•

ASTM A307, Machine Bolts : Used for flat-faced cast iron or nonmetallic flanges in noncorrosive service.


Gasket and bolting materials are covered by the same SAES and SAMSS documents that cover flanges. See "Standards for Flanges" for a listing of these standards and specifications.


28



Selecting Materials

Selection of material is governed by the service environment and specified design conditions. Selecting material consists of the following: 1.

Selecting a basic material chemistry from the applicable SAES-L-032 or -L-008 table.

2.

Using industry and Saudi Aramco standards to designate a material specification.

3.

Specifying the applicable SAMSS's.

Material Selection Process The material selection process that uses the Saudi Aramco SAES’s and SAMSS’s begins with selection of the basic material chemistry that is based on the service environment and specified design conditions. A specific material standard is then designated for the pipe and piping components. If necessary, special requirements that are associated with a particular type of piping, or particular service conditions, can then be addressed by specifying particular SAES's or SAMSS's. This section of the module will discuss the following: •

General Material Selection.

•

Materials Selection for Low-Temperature Service.

•

Materials Selection for Transportation Line Pipe.

•

Materials Selection for Lined, Coated, and Nonmetallic Piping.

The overall material selection procedure is contained in Work Aid 2.


29



General Selection Basic Material for Pipe, Fittings, and Flanges

Selection of the basic material chemistry is governed by the service environment and the design conditions. Table 1 of SAES-L-032 contains a list of service environments, design conditions, and basic material chemistry. This table is used to select the basic material chemistry for the piping system. The required service environment and design conditions will be known information that is based on the specified process design requirements. This information will consist of the primary service fluid and its concentration, design temperature, whether air is present or not, and the fluid flow velocity. Table 1 of SAES-L-032 is then entered with this information, and the basic material that is required for the pipe and piping components other than valves is selected. An equivalent or better material may also be used, subject to the approval of the assigned engineering specialist in the Consulting Services Department. For service conditions which differ from those that are listed, the assigned engineering specialist must be consulted. As examples of how to use this table, consider the following two sample problems.

Sample Problem 1 A pipeline will transport crude oil cross-country at a temperature of 80°C (176°F). No air will be present in the crude oil. To select the basic chemistry of the piping material: •

Go to the line "Crude Oil or Products" under the first column of SAES-L-032, Table 1. This column has the heading "ENVIRONMENT".

•

Next, move to the right to the column headed "TEMP DEGREES C" and check that the fluid temperature is below the maximum permitted. Because this is the case, move to the right to the column headed "BASIC MATERIAL".

•

The basic material is carbon steel.

•

The "REMARKS" column references Paragraph 2.4. Paragraph 2.4 of SAES-L-032 requires that all material for wet, sour service must also meet the requirements of NACE Standard MR-01-75. It also indicates that other standards might contain additional requirements for Hydrogen Induced Cracking (HIC) resistance.


30



Sample Problem 2

Piping in a refinery will contain process steam at a temperature of 500°C (932°F). No air will be present with the steam. To select the basic chemistry of the piping material: •

Go to the line "Steam" under the first column of SAES-L-032, Table 1. Move to the right. There are three temperature ranges listed. The steam in this case is in the third temperature range, 480-560°C (896-1,040°F).

•

Move across to the right on the line that contains this temperature range. Under the heading "BASIC MATERIAL," the basic piping material is 2-1/4 Cr - 1 Mo alloy steel.

•

There are no additional considerations in the "REMARKS" column in this case.

Basic Materials for Valve Body and Trim

The selection of basic materials for valves is similar to that for pipe, fittings, and flanges. The basic materials for valves are governed by the service environment and the specified design conditions. Table 1 in SAES-L-008, Selection of Valves , contains a list of service environments, conditions, and valve body and trim materials. The valve trim refers to those parts of the valve internals that are in contact with the service fluid. Valve trim will be discussed further in MEX 101.06. Table 1 of SAES-L-008 is used in the same manner as Table 1 in SAES-L-032. The following sample problems select the basic valve materials for the piping systems described in Sample Problems 1 and 2.


31



Sample Problem 3 For the crude oil pipeline at 80°C (176°F) in Sample Problem 1: •

Look for the line "Crude Oil or Products" under the heading "ENVIRONMENT." Under the heading "CONDITIONS," look for the line under the column "Temp. deg C" that has a temperature greater than or equal to 80°C (176°F).

•

Move to the right under the heading "VALVE MATERIALS." The basic valve materials are a "CS" body and "410" trim. The alloy designations are shown in Table IV of SAES-L-008. The alloy designation "CS" stands for carbon steel and the alloy designation "410" stands for AISI 410 stainless steel.

•

Note that there is a reference to Note 15 of Table 1 for the environment "Crude Oil or Products." Note 15 states that materials for valves in wet, sour service must meet the requirements of NACE Standard MR-01-75.

Sample Problem 4 For the steam piping in Sample 2: •

Repeat the process. The basic valve materials are a "CrMo22" body and "410" trim. Table IV of SAES-L-008 shows that the alloy "CrMo22" stands for 2-1/4 Cr - 1 Mo Steel.

•

Note that the "REMARKS" column indicates that the disk or gate seating area must be overlaid with Stellite No. 6 or 12, or equivalent. Stellite is a hard alloy that is used to harden the surface of valve parts in order to provide them with better wear resistance. The valve seating area will be discussed further in MEX 101.06.


32



Nelson Chart

Before discussing the next topic, Materials Standards Designation, the environments that contain hydrocarbon gas plus hydrogen or 100% hydrogen must be reviewed. Table 1 of SAES-L-032 states that the basic material must be per the Nelson Chart. The Nelson Chart, shown in Figure 10, contains curves for various material chemistries. These curves show the maximum combination of temperature and hydrogen partial-pressure permissible. Use of a material at conditions that are above its curve could result in hydrogen embrittlement and eventual failure. To use the Nelson Chart, the design temperature and hydrogen partial-pressure must both be known. After plotting the two values on the Nelson Chart, the basic material to use is the one associated with the curve above the plotted point. For example, the point for an environment that contains hydrogen at a temperature of 371°C (700°F) and a hydrogen partial-pressure of 10.34 MPa (absolute) (1,500 psia) is shown plotted as Point A in Figure 10. The line above Point A is the one for 2.25 Cr - 1.0 Mo Steel. Thus, this would be the basic material chemistry needed to prevent material damage due to hydrogen attack.

NELSON CHART

A

FIGURE 10


33



Several items should be noted with respect to the material chemistries that are shown on the Nelson Chart. •

Material chemistries C-0.25 Mo, C-0.5 Mo, and 1.0 Cr-0.5 Mo are shown. Neither C0.25 Mo nor C-0.5 Mo materials would be used in a hydrogen environment since there is concern about their long-term reliability even at conditions that are within their Nelson Chart limits. The 1.0 Cr-0.5 Mo material is often not readily available. Therefore, from a practical standpoint, if carbon steel is not acceptable for the specified conditions, the first higher alloy material that would be considered is 1.25 Cr-0.5 Mo.

•

A 2.0 Cr-0.5 Mo material is shown above the 1.25 Cr-0.5 Mo curve. This material would not be specified for the same reason that the 1.0 Cr-0.5 Mo material is not used. Therefore, if 1.25 Cr-0.5 Mo material is not adequate for the specified design conditions, the 2.25 Cr-1.0 Mo material would be the next alloy considered.

•

The material cost on a per pound basis increases as the alloy content increases. Therefore, the lowest alloy material that is acceptable for the specified design conditions should be used. The 2.25 Cr-1.0 Mo material would be the highest alloy that is typically needed for the most severe Saudi Aramco applications.

Material Standards Designation

Once the basic material chemistry is selected, the specific material standards designations for the pipe, fittings, flanges, valves, and bolting must be determined. The material standard designation will usually include an ASTM, API, or BS material designation and a material grade. A few useful industry references that contain materials designations versus chemistry are as follows: •

Appendix A (Allowable Stress Tables) in ASME/ANSI B31.3.

•

Table 1A, "List of Materials Specifications" in ASME/ANSI B16.5.

•

Table 1, "List of Materials Specifications" in ASME/ANSI B16.34.


34



There will often be more than one material standard, or grade within a standard, that is available for a particular general material chemistry. This is especially true for carbon steel. These material standards and grades will typically have different relative strengths, or different alloying elements, that are associated with them. The specific material standard and grade that is to be used is determined from among the alternatives during detailed engineering of the piping system, and considers specific Saudi Aramco requirements. As noted earlier, Saudi Aramco requires that carbon steel piping material be selected from among three specific material standards, but does not mandate the use of one over another. Conversely, Saudi Aramco has more specific requirements with respect to permissible materials for carbon steel flanges. Several of the other specific Saudi Aramco material standards requirements were noted earlier. Work Aid 2 contains a summary table that gives material chemistry versus product forms for some of the metallic materials that are used by Saudi Aramco. If the basic material and product form have both been determined, this table can be used to find the applicable material specification. For some of the more exotic or proprietary materials, it is usually sufficient to specify the alloy type and the piping component, such as "Hastelloy C-276 Seamless Pipe." Examples of such materials are: •

Hastelloy B-2.

•

Hastelloy C-22.

•

Hastelloy C-276.

•

Monel 400.

•

Alloy 20.

•

Alloy 600.

•

254 SMO Stainless Steel.

SAES-L-009 contains the material designation or description for gaskets and bolting materials that apply to various services. Later modules of MEX 101 will discuss Saudi Aramco materials standards requirements further when specific piping component and fabrication requirements are discussed.


35



SAMSS Requirements To complete the materials selection process for general piping and piping components, the applicable SAMSS's should be referenced. This is especially important if the specification is being used as part of a request for bids or for a purchase requisition. For example, if a carbon steel piping system is involved, 01-SAMSS-010, Fabricated Carbon Steel Pipe , must be specified to ensure that the erection contractor has the appropriate fabrication requirements.

Material Selection for Low-Temperature Service Pressurized piping systems with a minimum service temperature of -18°C to -45°C (0°F to 50°F) have special material requirements. Normally, these piping systems are used for refrigerated natural gas liquids (NGL), such as butane and propane. The concern with these systems is to ensure that the material has adequate toughness such that brittle fracture will not occur. SAES-L-030, Material for Low-Temperature Service , gives the toughness requirements for materials in any low-temperature service. This standard states the testing methods and the minimum acceptance criteria. Materials in low-temperature service require impact testing unless the minimum design temperature is below -18°C (0°F), but at or above -29°C (-20°F), and the following: •

The maximum operating pressure will not exceed 25% of the maximum pressure allowed by ASME/ANSI B31.3 at ambient temperature, and,

•

The combined longitudinal stresses due to pressure, dead weight, and displacement strain do not exceed 41.4 MPa (6,000 psi) for any temperature within the specified range.

SAES-L-030 also allows the use of carbon steels with an ASTM product specification for low-temperature service, if the material has been impact tested and found acceptable in a test temperature of at least 11°C (20°F) below the minimum design temperature.


36



Basic Material

Carbon steel is the basic material that is used for low-temperature systems in Saudi Aramco applications. Piping components must also comply with requirements of the applicable SAMSS. The SAMSS's that cover low-temperature piping are as follows: •

01-SAMSS-036 for Pipe.

•

02-SAMSS-001 for Fittings and Flanges.

•

04-SAMSS-003 for Valve Materials.

Material Designations

The material designations allowed for pipe by 01-SAMSS-036 are as follows: •

API 5L, Gr. B.

•

ASTM A333, seamless, Gr. 6 or Gr. 7.

•

ASTM A671, Gr. CC65 or Gr. CF65, Class 22, or Gr. S2.

SAES-L-006 also requires that pipe that is used for low-temperature systems must meet the requirements of 01-SAMSS-036, or be listed in ASME/ANSI B31.3 as adequate for a minimum temperature of -46°C (-50°F). The material designation that is allowed for pipe fittings and flanges by 02-SAMSS-001 is ASTM A420, Gr. WPL3. Materials to ASTM A420, Gr. WPL 6 and other standard materials may be used if they meet the additional requirements of 02-SAMSS-001.


37



The SAMSS for low-temperature valves, 04-SAMSS-003, allows the following component materials to be used without additional impact testing: •

Materials manufactured of austenitic stainless steel or copper-, nickel-, and aluminum based alloys.

•

Materials that comply with one of the following specifications, or those with superior impact properties:

•

-

Castings:

ASTM A352, Gr. LC2.

-

Forgings:

ASTM A350, Gr. LF3.

-

Pipe:

ASTM A333, Gr. 3.

-

Plate:

ASTM A203, Gr. B, D, or E.

-

Bolts:

ASTM A320, Gr. L7.

-

Nuts:

ASTM A194, Gr. 4

Materials manufactured to fine-grain practice and normalized, for use in services with a minimum design temperature of -12.2°C (10°F) or higher.

04-SAMSS-003 prohibits the use of NBR and other nitrile rubbers. The specification also requires that stem packing be PTFE-lubricated inhibitor-impregnated braided-asbestos packing, or a specified graphite-type packing system. Gaskets for flanges in low-temperature service shall be spiral-wound stainless steel nonasbestos-filled, such as Flexitallic Type CG. Bolting shall be ASTM A193, Gr. B7 or B7M with ASTM A194, Gr. 2HM nuts, or A320, Gr. 7 with A194, Gr. 4 or 7 nuts (depending on the specified temperatures). See SAES-L-009 for details on gasket and bolting requirements. In addition to giving the material standards designation, the SAMSS's that cover materials for low-temperature service present the detailed impact test requirements and acceptance criteria for the components.


38



Material Selection for Transportation Pipelines Transportation line pipe for either liquid, gas, or multiphase fluids follows the general selection process given above. In addition to the general selection process, there are several SAES's standards and SAMSS's specifications that apply to transportation piping components. Basic Material

SAES-L-032 gives the basic material as carbon steel for crude oil or products. For hydrocarbon gas, this standard specifies that the basic material shall be per the Nelson Chart. Since transportation piping that contains hydrocarbon gas will usually be below 200°C (392°F), the basic material for the piping components will be carbon steel. SAES-L-008 for valves also gives carbon steel as the basic material for the valve body in crude oil and hydrocarbon gas service. SAES-L-008 also specifies the basic material for the valve trim. Material Designation

The major material designation for transportation line pipe used by Saudi Aramco is API 5L. Acceptable grades are Gr. B and Gr. X-42 or higher. The numerical value in the "X-Grades" of the API 5L specification indicated the yield strength of the specific grade. For example, X-42 has a 42,000 psi Specified Minimum Yield Strength, X-52 has a 52,000 psi Specified Minimum Yield Strength, etc. The line pipe may be manufactured through the use of either a seamless or a welded process. In addition to the requirements of API 5L, the pipe may also need to satisfy the requirements of several Saudi Aramco standards as follows: •

SAES-L-031, Fracture Control of Line Pipe and 01-SAMSS-022, Fracture Control Testing Procedures for Line Pipe : Line pipe with a wall thickness of 6.3 to 38 mm (0.25 to 1.5 in.) must satisfy the fracture testing and Charpy impact energy acceptance levels stated in these documents.

•

01-SAMSS-033, API 5L, Electric Welded Line Pipe : Line pipe, 100 mm (4 in.) and above in diameter, manufactured using the ERW or electric induction process must satisfy the requirements of this standard.

•

01-SAMSS-016, Sour, Wet Service Line Pipe : Line pipe in sour, wet service, as defined by SAES-L-033 must meet the requirements of this specification.

•

01-SAMSS-035 , API Line Pipe : All API 5L line pipe must satisfy the requirements of this specification.


39



Material Designation for Components Butt-Welded Fittings — ASTM A234, Gr. WPB.

The requirements of 02-SAMSS-005 must also be met by the fittings for transportation piping. Flanges and Other Forged Components Used in Transportation Piping — Flanges for transportation

piping systems are also selected in accordance with SAES-L-009 and 02-SAMSS-011 requirements. Flange material is selected to be of comparable strength to that of the higher strength steels that are typically used in transportation pipeline systems. Refer to SAES-L009 and 02-SAMSS-011 for specific requirements. Bolting for Transportation Piping — ASTM A193, Gr. B7 stud bolts with ASTM A194, Gr. 2H

nuts should be used. Sour, Wet Service or Services Where the Bolting Will Be Deprived of Atmospheric Exposure — Gr.

B7M stud bolts and Gr. 2HM nuts should be used. Gaskets — Type 316 stainless steel, spiral wound, nonasbestos-filled gaskets are typically

used. Flanges, gaskets, and bolting materials must meet the requirements of SAES-L-009. Valve Bodies Used in Transportation Piping — API 6D, ASTM A316 Gr. WCB or WCC, or

ASTM A105 if forged. Trim will be AISI Type 410 with hardfacing on one of the seating surfaces. Additional materials requirements for valves in transportation piping are given in the following SAMSSs: •

04-SAMSS-001, Gate Valves.

•

04-SAMSS-005, Check Valves, Swing-Type.

•

04-SAMSS-035, General Requirements for Valves.

•

04-SAMSS-050, Gate Valves, Through-Conduit-Type, API 6D.

•

04-SAMSS-051, Ball Valves, API 6D.

•

04-SAMSS-052, Ball Valves, API 6A.


40



Material Selection for Lined, Coated, and Nonmetallic Piping In many instances, it is necessary to use internal linings or external coatings on metallic pipe. Some Saudi Aramco water piping systems use an internal cement lining for protection from erosion. Submarine transportation piping may need to be coated externally with cement to provide additional mass to compensate for buoyancy. Transportation line pipe may be externally coated with fusion-bonded epoxy (FBE) or extruded polyethylene for corrosion protection. Piping in some services may be made of nonmetallic materials. nonmetallic piping systems are as follows:

Examples of such

•

Asbestos-cement piping in water services.

•

Reinforced thermosetting resin (RTR) piping for use in unpressurized sewers.

•

RTR piping used for pressure services.

•

PVC, CPVC, and RTRP piping for use in acidic or caustic services.

In most cases, the materials selection for linings and coatings will be determined in an applicable SAMSS. Nonmetallic pipe material selection will be determined using SAES-L060 and applicable SAMSS's.

Basic Material and Material Designation Internal Cement Lining — The material for the cement lining in cement-lined water pipe is given

in 01-SAMSS-005 as Portland Cement, conforming to the requirements of ASTM C150 Type V. The metallic pipe will be carbon steel, conforming to either API 5L or ASTM A120. External Coating for Submarine Piping — Specific materials requirements for the external coating

that is used to provide additional mass to submarine piping are given in 01-SAMSS-012. This document states that the coal tar coating applied to the shop-cleaned carbon steel pipe shall conform to standard AWWA C-203. The cement that is used for the external coating shall be Portland Cement conforming to the requirements of ASTM C150 Type V as modified by 09-SAMSS-064. The wire that is used to reinforce the cement coating shall conform to ASTM A641.


41



External Fusion-Bonded Coating — The material requirements for fusion-bonded epoxy external

coating on line pipe is given in 09-SAMSS-089. This specification states that the external coating material shall be a powdered resin for application by the fusion-bond process. It also states that the vendor coating the pipe may select any of the buyer-approved products or an equal alternative agreed upon by the buyer in writing. Any proposed alternative materials must meet/pass the qualification tests given in Appendix A of 09-SAMSS-089. External Polyethylene Coating — The materials requirements for extruded polyethylene external

coating on line pipe is given in 09-SAMSS-090. This specification states that the external coating material shall consist of an epoxy primer, an extruded ethylene copolymer adhesive, and extruded polyethylene outer layers. It also states that the vendor coating the pipe may select any of the buyer- approved products or equal alternative agreed upon by the buyer in writing. Any proposed alternative materials must meet/pass the qualification tests given in Appendix A of 09-SAMSS-090. Cement-Asbestos Piping — The materials requirements for cement-asbestos piping are provided in

01-SAMSS-001, Paragraphs 5 and 6 and Tables I - VIII. Note that use of this type of piping is limited to repair of existing systems and is n o longer allowed in new installations. PVC and CPVC Piping — Saudi Aramco Standards SAES-L-032 and SAES-L-008 specify this

nonmetallic material for piping in certain acidic or caustic services and for certain water services. SAES-L-060 provides limitations on the use of these materials. The material designation of these materials are generally covered by ASTM standards such as ASTM D1785, Polyvinyl Chloride Plastic Pipe or SASO standards such as SSA-14, Pipes for Potable Water of Unplasticized Plastic . RTR Piping — Reinforced thermosetting resin piping material is specified in SAES-L-032 for a

hypochlorite sodium or calcium environment and for several types of water service. There are two SAMSS specifications that cover this type of material, 01-SAMSS-029 and 01SAMSS-034. Each of these specifications define the requirements for the piping materials. The requirements specify a series of ASTM tests that the materials must pass to be acceptable.


42



Piping Specification It should be clear from the previous discussions that a piping system will consist of several different types of components (such as the pipe, valves, flanges, and fittings). Selection of the basic material chemistry that is required for these components is relatively straightforward, as previously discussed. However, the specific material standards and other engineering requirements that each of these components are to meet must also be specified in order to correctly design, fabricate, and erect the system. These additional requirements come from a variety of industry and Saudi Aramco documents. In many cases, there will also be more than one technically acceptable option from which to choose. The final selection will also include considerations such as cost, availability, and the desire to standardize. Standardization is desirable in order to simplify future field maintenance and repair activities, to reduce the likelihood of incorrect material being used in the field, and to minimize the number of different types of items that must be stored in Saudi Aramco warehouses. It is possible to go directly to each industry and Saudi Aramco document every time that it is necessary to determine the detailed requirements for a specific component in a particular situation, but this approach is neither practical nor economical. Therefore, standard "piping specifications" are developed for specific projects or locations. A piping specification will typically specify the following items for each particular fluid service and set of design conditions: •

Pipe: Material standard and required wall thicknesses.

•

Fittings: Type, design standard, material specification.

•

Valves: Type, design standard, material specification.

•

Flanges: Type, design standard, type of face, material specification.

•

Gaskets: Type, design standard, material specification.

•

Bolting: Material specification.

•

Any special fabrication and testing requirements that are associated with the particular service application.


43



The requirements that are specified in a piping specification are selected to meet all applicable industry and Owner Company requirements for a specific fluid service and set of design conditions. The overall piping specification for a project or location will contain many individual piping specifications. Each individual piping specification will be for only one general material chemistry, may include more than one service fluid (as long as each fluid would have the same technical requirements), will encompass an appropriate range of design temperature and design pressure conditions, and will be valid for one specified corrosion allowance. SAES-L-005, Limitations on Piping Components , is an example of a piping specification. Each individual piping specification within SAES-L-005 is assigned a unique Code Number. The Code Number is formed of four parts as follows: •

Prefix Number. This number designates the primary pressure rating of the flanges in the system. For example, a "1" indicates Class 150 flanges, and a "3" indicates Class 300 flanges. Flange pressure rating defines acceptable combinations of pressure and temperature in accordance with ASME/ANSI B16.5 requirements. Pressure rating will be discussed in detail in MEX 101.04.

•

Service Group Letter. This letter designates the particular type of fluid service for which the piping specification is suitable. The Service Groups that are included in SAES-L005 are as shown in Figure 11.

•

Suffix Number. This number indicates the type of flange face that will be used. For example, a "raised-face" flange is the most commonly used type, and is designated by "1". Flange faces will also be discussed in MEX 101.04.

•

Terminal Letter. This letter is used if it is necessary to distinguish among different piping specifications that have the same first three symbols.

As an example, refer to piping specification 1A1 in SAES-L-005. The "1" covers Class 150 flanges, the "A" means that the pipe may be used in general pressure service (including hazardous fluids), and the final "1" means that the pipe uses raised-face-type flanges. Material and design details are specified for the pipe (based on size), valves (based on valve type and size), flanges, threaded- and butt-welded-type fittings, gaskets, and bolting. Notes are also provided that specify appropriate additional design and fabrication requirements. All of the details that are specified will meet Saudi Aramco SAES and SAMSS requirements. Therefore, adhering to all the detailed requirements that are contained in this piping specification will help ensure that Saudi Aramco requirements will be met.


44



The piping specifications that are contained in SAES-L-005 are used to the extent that is possible possib le in Saudi Saud i Aramco A ramco facilities facilitie s in order to maximize maxim ize standardizatio standa rdization. n. However, Howe ver, they will not cover all potential service requirements that may be encountered. Therefore, a contractor will develop additional piping specifications, as necessary, to cover other services or pipe materials. These additional piping piping specifications will have the same overall structure and content as the ones that are in SAES-L-005, but the specific details will differ. The piping specifications that are contained in SAES-L-005 also indicate the appropriate Saudi Aramco stock stock number for for each of the the specified piping components. The piping components that are associated with these stock numbers will meet Saudi Aramco requirements. The Saudi Aramco Materials Supply Organization (MSO) has developed a system that identifies all standard piping components, contains appropriate purchase descriptions that encompass appropriate Saudi Aramco requirements, and identifies acceptable vendors who can supply these components. This system is is available to all Saudi Aramco personnel who need to specify or purchase piping components, and it has also been computerized. Saudi Aramco also makes this system available for use by its contractors in order to help achieve consistency and to increase the probability of their meeting Saudi Aramco requirements.

SAES-L-005 SERVICE GROUPS Service Group A C D E F G H L N

Service Gen General eral pres presssure se service, incl ncluding ding hazar azardo dous us fluids uids Corr Corros osiv ivee and and spec specia iall ser servi vice ces, s, rese reserv rved ed for for pip pipin ing g spe speci cifi fica cati tion onss tha thatt are not covered in Categories A through N Low-pressure utilities, noncorrosive Low-pressure utilities, corrosive Nonpressure sewers Smal Smalll-diamet meter pipi piping ng around und pum pump ps an and com compr pres esssors ors Low-pressure hy hydrocarbon se service Low-temperature service Plumbing Plum bing drain and vent systems system s in buildin b uildings gs FIGURE 11


45



WORK WORK AID AID 1: 1: Proc Proced edur ures es for for Det Deter ermi mini ning ng Appl Applic icab able le Indu Indust stry ry and and Sau Saudi di Aramco Standards for Pipe and Piping Components There are many industry and Saudi Aramco standards standards that may apply to piping systems. This Work Aid lists the the industry standards that apply to to steel pipe and piping components. It also lists and briefly describes the Saudi Aramco SAES's and SAMSS's that apply to pipe and piping pipin g compo co mponents nents.. When it is necessary to specify material requirements for a piping system, the first step is to determine the industry and Saudi Aramco standards that apply to the the system. This determination is based on the available design information and the scopes of the specific standards. The Saudi Aramco documents will narrow down the material selection process to standards that are acceptable to Saudi Aramco, and it will also supplement the industry standard requirements. 1.

2.

Indus Industr try y Standa Standard rdss Appli Applicab cable le to to Steel Steel Pip Pipee are as as foll follows ows:: •

ASTM A106, Seamless Carbon Steel Pipe for High-Temperature Service Service

•

ASTM A53, Pipe, Steel, Black and Hot-Dipped, Hot-Dip ped, Zinc-Coated, Zinc-Coa ted, Welded and Seamless.

•

API 5L, Specification Specification for Line Pipe.

•

ASTM A333, Seamless and Welded Steel P ipe for Low-Temperature Service.

•

ASTM A335, Seamless Ferritic Alloy Steel Pipe for High-Temperature Service.

•

ASTM A312, Seamless and Welded Austenitic Stainless Steel Pipe.

Indust Industry ry Standar Standards ds Applica Applicable ble to Steel Steel Fittin Fittings gs are as follow follows: s: •

ASME/ANSI B16.9, Factory-Made Factory-M ade Wrought Wro ught Steel Butt-Welded Butt-Weld ed Fittings. Fitting s.

•

ASM E/ANSI B16.11, Forged Steel Fittings, Fi ttings, Socket-Weld So cket-Welded ed and Threaded. T hreaded.


46



3.

4.

Indus Industr try y Standa Standard rdss Appli Applicab cable le to to Steel Steel Flang Flanges es are are as foll follows ows:: •

ASME/ANSI B16.5, Pipe Flanges F langes and Flanged Fittings. F ittings.

•

API 605, Large Diameter D iameter Carbon C arbon Steel Ste el Flanges. Flange s.

•

API 6A, Wellhead Equipment.

•

ASM E B16.47, Large-Diameter Large-Di ameter Steel S teel Flanges, Flan ges, NPS NP S 26 Through Thr ough NPS NP S 60.

•

M SS SP-44, Steel Pipe Line Flanges.

Indus Industr try y Stand Standar ards ds Appl Applic icabl ablee to Val Valves ves are are as fol follo lows ws:: •

ASM E/ANSI B16.34, Valves - Flanged, Threaded, and Welding End.

•

API 599, Steel and Ductile Iron Plug Valves.

•

API 600, Steel Gate Valves - F langed and Butt-Welding Ends.

•

API 602, Compact Steel Gate Valves.

•

API 606, Compact Steel Gate Valves-Extended Body.

•

API 608, Metal Ball B all Valves - Flanged Flange d and Butt-Welding Bu tt-Welding Ends.

•

API 609, Lug- and Wafer-Type Wafer-Typ e Butterfly Butterf ly Valves. Valves .


47



5.

Industry Standards Applicable to Gaskets and Bolting are as follows: •

ASME/ANSI B16.20, Ring Joint Gaskets and Grooves for Steel Pipe Flanges.

•

ASME/ANSI B16.21, Nonmetallic Flat Gaskets for Pipe Flanges.

•

API 601, Metallic Gaskets for Piping, Double-Jacketed Corrugated and Spiral Wound.

•

ASTM A193, Specifications for Alloy-Steel and Stainless Steel Bolting Materials for High-Temperature Service.

•

ASTM A194, Specification for Carbon and Alloy-Steel Nuts for Bolts for High Pressure and High-Temperature Service.

•

ASTM A320, Specification for Alloy-Steel Bolting Materials for Low-Temperature Service.

6.

Use Figure 12 and subsequent summaries of the Saudi Aramco SAES's and SAMSS's that are contained at the end of this Work Aid to determine which Saudi Aramco documents apply to the particular piping system.

7.

Use requirements that are contained in the applicable Saudi Aramco documents to finalize the material standards requirements.


48



SAES AND SAMSS REQUIREMENTS Standard SAES-L-005 SAES-L-006 SAES-L-007 SAES-L-008 SAES-L-009 SAES-L-030 SAES-L-031 SAES-L-032 SAES-L-060 SAES-L-061 01-SAMSS-001 01-SAMSS-005 01-SAMSS-010 01-SAMSS-016 01-SAMSS-017 01-SAMSS-022 01-SAMSS-029 01-SAMSS-033 01-SAMSS-034 01-SAMSS-035 01-SAMSS-036 02-SAMSS-001 02-SAMSS-005 02-SAMSS-010 02-SAMSS-011 04-SAMSS-001 04-SAMSS-002 04-SAMSS-003 04-SAMSS-041 04-SAMSS-042 04-SAMSS-048 04-SAMSS-050 04-SAMSS-051 04-SAMSS-052

Pipe

Fittings

Flanges

Valves

Bolting

X X

X

X

X

X

X X X X X X X X X X X X X X X X X X

X X

X X

X X X X X X

X X X X X X

X

X

X

X

X

X

X X

X

X

X X

X

X X X X X X X

X X X X X X X X X

FIGURE 12


49



Descriptions of Applicable SAES and SAMSS Requirements SAES-L-005, L imitations on Pipin g Components

Covers the selection of compatible pipe material items that are used together in a specific system or service and that are listed in a Piping Specification under a code number.

SAES-L-006, M etall ic Pi pe Selection

Covers limitations on the selection of metallic pipe and tubing for pressure services in plant piping and transportation piping.

SAES-L-007, Selection of M etalli c Pipe F ittin gs

Covers limitations on the selection of metallic pipe fittings for pressure services in plant piping and transportation piping.

SAES-L-008, Selection of Val ves

Covers limitations on the selection of all valves that are normally classified under Saudi Aramco Materials System Class 04. This standard contains tables of applicable materials for valves and valve components. It also contains a section on materials limitations.

SAES-L-009, M etall ic F langes, Gaskets, and Bol ts

Covers limitations on the selection of metallic pipe flanges, gaskets, and bolting for pressure services in plant piping and transportation piping. This standard references ASTM material standards for specific applications.


50



SAES-L-030, M ateri al f or L ow-Temperatur e Service

Covers toughness requirements for carbon steels that are used in refrigerated fluid service at a minimum design temperature that is within the range -18°C to -45°C (0°F to -50°F). These requirements, which are more restrictive than the requirements in ASME/ANSI B31.3, supplement that standard.

SAES-L-031, F racture Control of L ine Pipe

Covers supplementary material toughness requirements to control crack propagation at temperatures above 0°F (32°F) in carbon steel pipe that is used for cross-country and submarine pipelines. Applies to line pipe, 150 mm (6 in.) or larger NPS, with wall thicknesses of 6.35 to 38.1 mm (0.25 to 1.5 in.).

SAES-L-032, M ater ial Selection f or Pi pin g Systems

Specifies, based on the fluid to be transported, the basic pipe material chemistry for piping systems. Contains a table that lists service fluid (environment), concentration of the fluid transported, service temperature, and whether air is present.

SAES-L-060, Nonmetall ic Piping

Covers requirements and limitations for the design, installation, and testing of nonmetallic piping, except for plumbing.

SAES-L-061, Techn icall y Acceptable RTR Pipi ng

Lists specific RTR pipe and fittings, in accordance with 01-SAMSS-029 or 01-SAMSS-034 that have undergone and passed an evaluation by Saudi Aramco and are acceptable for use in Saudi Aramco installations.

01-SAMSS-001, Asbestos-Cement Pi pe, Fi tti ngs, and Gaskets

Covers the requirements for the manufacture, classification, dimensions, and testing of asbestos-cement pipe, pipe fittings, and gaskets for pressure and nonpressure service. Asbestos-cement-lined pipe is used only in the repair of existing systems. It is no longer allowed in new installations.


51



01-SAMSS-005, Pipe, Cement-L in ed, Shop Appli ed

Provides references, including material specifications, covering the manufacture, inspection, and testing of cement-lined pipe.

01-SAMSS-010, F abri cated Carbon Steel Pi ping

Covers applicable material standards and the minimum requirements for the fabrication of carbon steel pipe spools.

01-SAMSS-016, Sour , Wet Service Li ne Pipe

Defines additional requirements that are necessary to obtain welded line pipe that is resistant to Hydrogen Induced Cracking (HIC) in wet, sour environments.

01-SAMSS-017, Auxi li ary Pipin g for M echanical Equipment

Defines the minimum requirements that govern the design, fabrication, installation, and inspection of auxiliary piping that is associated with compressors, pumps, fans, turbines, engines, and gears.

01-SAMSS-022, F racture Control Testing Pr ocedures for L ine Pipe

Defines the mandatory fracture control testing procedures that are applicable to line pipe with wall thicknesses of 6.3 to 38 mm (0.25 to 1.5 in.) and that are intended for use in crosscountry and offshore pipelines at temperatures between 0°C and 120°C (32°F and 250°F).

01-SAMSS-029, Un r estrai ned Gasketed Join t RTR Sewer Pipe and Fi ttin gs

Covers the requirements for Reinforced Thermosetting Resin (RTR) pipe, couplings, and fittings that use polyester or epoxy resin and unrestrained gasketed joints for 300-1,200 mm (12- 8 in.) nominal size.

01-SAMSS-033, API 5L E lectri c-Welded Li ne Pipe

Defines requirements that supplement API specification 5L for plain-end electric-resistance or electric induction-welded steel pipe 100 mm (4 in.) and above in nominal diameter.


52



01-SAMSS-034, RTR Pr essur e Pipe and F itti ngs

Defines the requirements for RTR pipe, couplings, fittings, flanges and spools that use polyester, vinyl ester, or epoxy resin with restrained adhesive-bonded joints, restrained or unrestrained gasketed joints, or butt joints with reinforced laminated overlays.

01-SAMSS-035, API L ine Pipe

Defines requirements that supplement API specification 5L for beveled end, seamless, or submerged arc-welded (straight seam or spiral seam) carbon steel pipe.

01-SAMSS-036, Low-T emperatu re Pipe

Covers the requirements for seamless pipe, 25 mm (1 in.) nominal size or larger, and for straight seam, submerged arc-welded pipe, 400 mm (16 in.) nominal size and larger, for service with minimum design temperatures between 0°C and -46°C (32°F and -50°F).

02-SAMSS-001, Pipi ng Components for L ow-Temperatu re Service

Covers the requirements that apply to piping components for use in refrigerated natural gas liquid (NGL) service with minimum design temperatures between 0°C and -46°C (32°F and 50°F). This specification supplements ASME/ANSI B16.11 and ASME/ANSI B16.14.

02-SAMSS-005, Butt-Welded Pipe Fi ttings

Supplements the requirements of ASME/ANSI B16.9 and ASTM A234 Gr. WPB for wrought carbon steel pipe fittings. Also supplements the requirements of MSS SP-75 for high-strength fittings. In addition, it covers fittings suitable for wet, sour service. Does not include cast fittings or corrosion-alloy steel pipe fittings.

02-SAMSS-010, F lan ged In sul atin g Joints/Spools for Cathodic Protection

Describes the requirements for insulating joints and spools with bolted flanges and any standard pressure rating and pipe diameter.


53



02-SAMSS-011, F orged Steel W eld-Neck Fl anges for L ow- and I ntermediate- Temper atur e Service

Covers requirements for forged steel weld-neck flanges for low- and intermediatetemperature services. Included are certain lapped joint and swivel ring assemblies. Also included are special forgings such as anchor flanges, long weld-neck flanges, contour-forged (integrally reinforced) and out-size flanges. High-temperature flanges, such as ASTM A182 F5 and F11, and extra-low-temperature flanges, such as ASTM A350 LF3 and LF9, are not covered. This standard supersedes Saudi Aramco Drawing AB-036028.

04-SAMSS-003, Additi onal Requi r ements for L ow-Temperatu re Valves

Contains specific information concerning material requirements for valves in lowtemperature service.

04-SAMSS-035, General Requi r ements for Val ves

Defines general requirements for valves that are normally classified under Saudi Aramco Materials System (SAMS) Class 04.

04-SAMSS-048, Val ve I nspection an d Testin g Requi rements

Covers the minimum requirements for inspection and testing of metallic and nonmetallic valves that are normally classified under Saudi Aramco Materials System (SAMS) Class 04. Such valves include gate, globe, angle, check, needle, ball, plug, piston, butterfly, choke, diaphragm, etc., that are used for on/off, manual control service or for prevention of reverse flow, as appropriate. Specifically excluded from the scope are: control, safety-relief, relief, surge relief, solenoid, pilot, and other valves that are classified under SAMS Class 34; and wellhead valves that are classified under SAMS Class 45.


54



04-SAMSS-049, I nspection an d Testin g Requi rements

Establishes the minimum quality control and testing requirements for API 6A 10,000 psi valves and chokes, 1-13/16 inch and larger, which may be used in sour, wet services downstream of the wellhead and tree assembly. In addition, each of the major valve types used by Saudi Aramco has an SAMSS that lists the necessary industry standards for the particular valve type. •

04-SAMSS-001, Gate Valves.

•

04-SAMSS-002, Globe Valves.

•

04-SAMSS-005, Check Valves, Swing-Type.

•

04-SAMSS-041, Expanding Plug Valve.

•

04-SAMSS-042, 4-Way Diverter Valve.

•

04-SAMSS-050, Gate Valves, Through-Conduit Type, API 6D.

•

04-SAMSS-051, Ball Valves, API 6D.

•

04-SAMSS-052, Ball Valves, API 6A.


55



WORK AID 2:

Procedures for Selecting Materials

1.

Given the piping system service environment and design conditions, select a basic material chemistry using Table 1 of SAES-L-032. However, for environments that contain Hydrocarbon Gas plus Hydrogen or 100% Hydrogen, use the Nelson Chart in Figure 13 to select basic material chemistry. Do not use C-0.25 Mo, C-0.5 Mo materials at all, and only use 1.0 Cr-0.5 Mo material if its availability is confirmed.

2.

Select the basic material designation for valve body and trim using Tables 1 and IV-A in SAES-L-008.

3

Determine applicable material standards designation for piping components using the "Material Chemistries for Various Product Forms" chart in Figure 14, and SAES-L-009. Refer to other applicable SAES and SAMSS requirements using the "SAES and SAMSS Requirements" chart in Work Aid 1. Also note the following:

4.

•

Socket-welded and threaded fittings and valves will typically be forged.

•

Butt-welded fittings will typically be wrought.

•

Flanged or welded-end valves will typically be castings.

Specify applicable SAMSS's for the purchase order using Work Aid 1.


56



NELSON CHART

FIGURE 13


57



MATERIAL CHEMISTRIES FOR VARIOUS PRODUCT FORMS Basic Material Chemistry Carbon Steel

Pipe

Forged Fittings A105

Wrought Fittings A234, Gr. WPB

API 5L, Gr. B; A333 (seamless), Gr. 6 or 7; A671, Gr. CC 65 or CF 65 C1.22, or Gr. S2 API 5L, Gr. X42 (Pipeline applications only)

A350, Gr. LF 3

A420, Gr. WPL3 or WPL6

A352 Gr. LC2

A105

A216 Gr. WCB

API 5L, Gr. X52 (Pipeline applications only)

—

API 5L, Gr. X60 (Pipeline applications only)

—

MSS SP75. See 02SAMSS005. MSS SP7 5. See 02SAMSS005. MSS SP7 5. See 02SAMSS005. A234, Gr. WP1 A234, Gr. WP11b C1.1 or WP11 C1.2 A234, Gr. WP22 C1.1

A217, Gr. WC9

A182, Gr. F11 C1.1 or C1.2 A182, Gr. F22 C1.2 or C1.3

A403, Gr. WP304 A403, Gr. WP316

A351, Gr. CF 8 A351, Gr. CF 8M

A403, Gr. WP304 A403, Gr. WP316

API 5L, Gr. B; A106, Gr. B; or A53 Gr. B (seamless)

C- 1/2 Mo

A335, Gr. P1

1 1/4 Cr- 1/2 Mo

A335, Gr. P11

2 1/4 Cr-1 Mo

A335, Gr. P22

18 Cr-8 Ni (Stainless Steel) 16 Cr-12 Ni-2 Mo (Stainless Steel)

A312, TP304

Note:

A312, TP316

A182, Gr. F1 A182, Gr. F11 C1.1 or C1.2 A182, Gr. F22 C1.2 or C1.3 A182, Gr. F304 A182, Gr. F316

Castings A216, Gr. WCB

Flanges A350, Gr. LF2; A105N; or A266 Cl 4. See SAES-L-009 & 02-SAMSS-011 A350, Gr. LF2 or A266 Cl 4. See SAES-L-009 & 02-SAMSS-011 A707, Gr. L3 Cl..1 See 02-SAMSS-011.

—

A350, Gr. LF 6 Cl.1. See 02-SAMSS-011.

—

A350, Gr. LF 6 Cl.6. See 02-SAMSS-011.

A217, Gr. WC1 A217, Gr. WC6

A182, Gr. F1

In cases where multiple material specifications and/or grades are shown, the final selection will be made during detailed engineering based on specific design requirements, cost, schedule, and standardization considerations.

FIGURE 14


58



GLOSSARY

alloy

A substance composed of two or more metals.

brittle material

A material that ruptures with little or no deformation.

charpy V-notch tests

Test to measure the energy absorbed by a material during rupture at a particular temperature.

corrosion

Material degradation that involves metal loss (strain).

creep

Creep is the property of material where the strain changes with time at a constant temperature and stress.

cyclic loading

Loading that repeats regularly with time.

dies

Devices for imparting a desired shape, form, or finish to a material.

ductile material

A material that undergoes large deformation before rupturing.

fabricability

The joining of piping components into integral pieces ready for assembly.

fatigue

The tendency of a material to break under repeated or cyclical loading.

fatigue strength

The stress required to fail a material after a pa rticular number of cycles.

flux

A substance applied to a surface to be joined by welding to prevent the formation of oxides.

fracture

The process of breaking.

fracture control

Requirements, including chemistry, steel manufacturing, and heat treatment, for materials to prevent fracture.

heat treatment

Treating metal at a temperature above a critical range to change its properties.


59

Piping Material Selection

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