Piping Material Specifications

This topic provides basic information and guidelines for understanding, different Piping Material Specifications used in Piping Material Engineering.

Piping specification is a document specifying each of the components. Different material specifications are segregated in different “Piping Class”. Identification of the “Piping Classes” depends on each Design Engineer.

Input Documents for Preparation of Piping Material Specification

Piping Specification Index indicating Piping classes, Service Fluids, basic material, corrosion allowance, design pressure and temperature and specific requirements like NACE compliance, statutory regulations etc. Approval on these specific requirements shall be obtained from Process department/Process Licensor or client.

Piping Material Index is provided by Process Licensor.

From the P&IDs/PEFS obtain the maximum size of lines covered by each piping class/service fluid.

Components include…

• Pipes
• Fittings
• Flanges
• Gaskets
• Bolting
• Valves
• Specialties

The selection of piping material requires knowledge of corrosion properties, strength and engineering characteristics, relative cost and availability.

Piping Elements

Classification Based on Material of Construction

Codes

A group of general rules or systematic procedures for Design, fabrication, installation and inspection prepared in such a Manner that it can be adopted by legal jurisdiction and made into Law.

Standards

Documents prepared by a professional group or committee which are believed to be good and proper engineeringpractice and which contain mandatory requirements.

American Standards

1. American Petroleum Institute (API)
2. American Iron and Steel Institute (AISI)
3. American National Standard Institute (ANSI)
4. American Society of Mechanical Engineers (ASME)
5. American Society of Testing Materials (ASTM)
6. American Welding Society (AWS)
7. American Water Works Association (AWWA)
8. Manufacturers Standardization Society of Valves and Fitting Industry-Standard Practises (MSS-SP)

For the Codes and Standards to be used, refer to the Bid document/Basic engineering package and year of issue to be adhered to for the Project.

Commonly used piping system design codes are:

1) ASMEB 31.1- Power Piping

2) ASMEB 31.3- Process Piping

Year of Issue of the Code must be specified in the Bid Package/Basic Engineering Packages. If not specified, clarification/confirmation shall be obtained from Client or latest edition shall be adhered to at the time of contract.

Specifications and Standards Accepted by ASME B 31.3

1 ANSI-American National Standard Institute

2 API-American Petroleum Institute

3 ASCE-American Society of Civil Engineers

4 ASME-American Society of Mechanical Engineers

5 ASNT-American Society for Non-destructive Testing

6 ASTM-American Society for Testing Materials

7 AWS-American Welding Society

8 CDA-Copper Development Association

9 CGA-Compressed Gas Association

10 EJMA-Expansion Joint Manufactures Association

11 ICBO-International Conference of Building Officials (Earlier known as UBC–Uniform Building Code)

12 MSS-Manufacturers Standardization Society of the Valve and fitting Industry

13 NACE-National Association of Corrosion Engineers

14 NFPA-National Fire Protection Association

15 NIST-National Institute of Standards and Technology (Earlier known as NBS –National Bureau of Standards)

16 PFI-Pipe Fabrication Institute

17 PPI-Plastic Pipe Institute

18 SAE-Society of Automotive Engineers

ASME Dimensional Standards

Major ASME standards referred for the piping engineers are:

1) ANSIB1.1-Unified Inch Screw Threads

2) ASMEB1.20.1-Pipe Threads general purpose–(ExANSIB2.1)

3) ASMEB16.1-Cast Iron Pipe Flanges and Flanged Fittings

4) ASMEB16.3-Malleable Iron Threaded Fittings.

5) ASMEB16.4-Cast Iron Threaded Fittings

6) ASMEB16.5-Steel Pipe flanges and Flanged Fittings

7) ASME B 16.9-Steel Butt welding Fittings

8) ASME B 16.10-Face to face and end to end dimensions of Valves

9) ASME B 16.11-Forged steel Socket welding and Threaded fittings

10) ANSI B 16.20-Metallic Gaskets for pipe flanges –ring joint, spiral wound and jacketed flanges

11) ASME B 16.21-Non Metallic Gasket for pipe flanges

12) ASME B 16.25-Butt Welding Ends

13) ASME B 16.28-Short Radius Elbows and Returns

14) ASME B 16.34-Steel Valves, flanged and butt welding ends.

15) ASME B 16.42-Ductile Iron Pipe Flanges & Flanged Fittings –Class 150 and 300

16) ASME B 16.47-Large Diameter Steel Flanges –NPS 26-60

17) ASME B 18.2 1 & 2 -Square and hexagonal head Bolts and Nuts–(in & mm)

18) ASME B 36.10-Welded and seamless Wrought Steel Pipes

19) ASME B 36.19-Welded and Seamless Austenitic Stainless Steel Pipes.

ASTM Standards

ASTM has 16 sections 71 Volumes

Section0- Index

Section1- Iron & Steel Products-7 Volumes-736 Standards

Section2- Non Ferrous Metal& Products-5 Volumes-678 Standards

Section3- Metal Test Methods & Analytical Procedures-6 Volumes-651 standards

Section4- Construction-10Volumes-1601standards

Section5– Petroleum Products Lubricants etc-5 Volumes-577 standards

Section6-Paints,RelatedCoatings& Aromatics-4Volumes-795Standards

Section 7- Textiles-2 Volumes-325 Standards

Section 8- Plastics-4 Volumes-556 Standards

Section 9- Rubber-2 Volumes-287 Standards

Section 10- Electric Insulation & Electronics-5 Volumes-487 Standards

Section 11- Water &Environmental Technology-2 Volumes-763 Standards

Section 12- Nuclear, Solar & Geothermal energy-2 Volumes-248 Standards

Section 13- Medical Device & Services-1 Volume.

Section 14- General Methods & Instrumentation-3 Volumes-336 Standards

Section 15- General Products, Chemical Specialties & end use products-9 Volumes-1498 Standards

Unified Numbering System (UNS)

The UNS number itself is not a specification, since it establishes no requirements for form, condition, quality etc. It is a unified identification of metal sand alloys for which controlling limits have been established in specifications elsewhere.

The UNS provides means of correlating many naturally used numbering systems currently administered by Societies, trade associations, individual users and producers of metal sand alloys, thereby avoiding confusion caused by use of more than one identification number for the same material and by the opposite situation of having the same number assigned to two different materials.

UNS establishes 18 Series numbers of metals and alloys. Each UNS number consists of a single letter prefix followed by five digits. In most cases the alphabet is suggestive of the formula of metal identified.

1. A00001 –A99999 –Aluminium & Al. Alloys.
2. C00001 –C99999 –Copper & Copper alloys.
3. E00001 –E99999 –Rare earth & rare earth like metal & Alloys.
4. L00001 –L99999 –Low methug metals & alloys
5. M00001 –M99999 –Miscellaneous non-ferrous metals & alloys.
6. N00001 –N99999 -Nickel & nickel alloys
7. P00001 –P99999 -Precious Metals & alloys
8. R00001 –R99999 -Reactive & refractory metal & alloys.
9. Z- Zinc & Zinc alloys
10. D – Specified Mech. Properties of Steels.
11. F – Cast Iron & Cast Steels.
12. G – AISI & SAE Carbon & alloys Steels.
13. H—AISIH Steels.
14. J –Cast Steels.
15. K –Misc steels & Ferrous alloys.
16. S –Stainless Steels.
17. T –Tool Steels.
18. W –Welding Filler Metals & Electrodes

The basic material or the generic material of construction is specified by the Process Licensor for the process fluids. The Piping Engineer is expected to detail out the same based on the Codes and Standards.

The Piping Design Criteria originates from the Line List which specifies design conditions with respect to pressure and temperature

In absence of this data, the Piping Engineer considers the following for strength calculations

• Design Pressure as 10% higher than the maximum anticipated operating pressure.
• Design Temperature as 25° above the maximum anticipated operating temperature.
• When operating temperature is 15° C and below, the design temperature astheanticipatedminimumoperatingtemperature

The design should meet the requirements of the relevant code.

The material used shall be in accordance with latest revision of standards.

If ASTM materials are used, then the materials adapted by ASME/ANSI should be preferred.

The basic criteria for selection of material:

• Suitability of material for service fluid from corrosion point of view.
• Suitability of material for given design conditions (Design pressure & design temperature
• Life cycle cost

The selection of materials in general shall follow the norms below: (ref. ASME B31.3)

1. Carbon steel shall be used up to 800 ^oF (425 ^oC).
2. Low temperature steel shall be used below -20 ^oF (-29 ^oC)
3. Alloy carbon steel shall be used above 800 ⁰F (425 ^oC).
4. For corrosive fluids, recommendations from the Process Licensor to be followed.

Pipes

In American standard, the pipes are covered under

36. a) ASME B 36.10 -Welded and Seamless Wrought Steel Pipe
37. b) ASME B 36.19 -Stainless Steel Pipe

Stainless steel pipes are available in schedule 5S, 10S, 40S and 80S whereas carbon steel pipes are available in schedule 10, 20, 30, 40, 60, 80, 100, 120, 140, 160, STD,XS, XXS.

The figures indicated in these standards are the nominal thickness and mill tolerance of 12.5% is applicable to those values.

Generally the thicknesses are specified by schedule numbers. B36.10 covers pipe sizes upto 80 inch (2000mm) NB and B36.19 covers pipe sizes upto 24 inch(600mm)NB. The thickness specified in these standards match except for the following:

10″ SCH80 / SCH80S

12″ SCH40 / SCH40S

12″ SCH80 / SCH80S

14″ SCH10 / SCH10S

16″ SCH10 / SCH10S

18″ SCH10 / SCH10S

20″ SCH10 / SCH10S

22″ SCH10 / SCH10S

Pipe Ends

Based on the material of construction and the pipe to pipe joint, the ends of the pipes are specified as follows.

Bevelled ends, Plain ends, Screwed ends, Flanged ends, Spigot/Socket ends

Butt Weld Pipe Joints

Advantages

1. Most practical way of joining big bore piping
2. Reliable leak proof joint
3. Joint can be radiographed

Disadvantages

1. Weld intrusion will affect flow
2. End preparation is necessary

 

Socket Weld Pipe Joints

Advantages

1. Easier Alignment than butt welding
2. No weld metal intrusion into bore

Disadvantages

1. The 1/16″(1.5 mm) recess pockets liquid
2. Use not permitted by code if Severe Erosion or Crevice Corrosion is anticipated.

 

Screwed Pipe Joints

 

Advantages

1. Easily made at site
2. Can be used where welding is not permitted due to fire hazard

Disadvantages

1. Joint may leak when not properly sealed
2. Use not permitted by code if severe erosion, crevice corrosion, shock or vibration are anticipated.
3. Strength of pipe is reduced as threads reduce wall thickness
4. Seal welding may be required
5. Code specifies that seal welding shall not be considered to contribute for strength of joint

 

Flanged Pipe Joints

 

Advantages

1. Can be easily made at site
2. Can be used where welding is not permitted due to material properties or fire hazard.
3. Dismantling is very easy

Disadvantages

1. It is a point of potential leakage
2. Cannot be used when piping is subjected to high bending moment.

Spigot Socket Pipe Joints

Advantages

1. Can be easily made at site.
2. Can accept misalignment upto 10^oat pipe joints.

Disadvantages

1. Suitable for low pressure application.
2. Special configuration at pipe ends required.

Types of Pipes

Based on the method of manufacture pipes could be classified as;

• Seamless
• Welded
• Electric Resistance Welded (ERW)
• Electric Fusion Welded (EFW)
• Spiral Welded
• Furnace Butt welded
• Double Submerged Arc Welded
• Forged and Bored

 

Pipe Materials

1. ASTM A53: Welded and Seamless Steel Pipe Black and Galvanized
2. ASTM A106: Seamless CS Pipe for High Temp. Services
3. ASTM A120: Black and Hot Dipped Zinc coated (Galvanized) welded and seamless pipe for ordinary use
4. ASTM A134: Electric fusion welded steel plate pipe (Sizes ≥ 16”NB)
5. ASTM A135: Electric resistance welded pipe
6. ASTM A155: Electric fusion welded steel pipe for high temperature service
7. ASTM A312: Seamless and welded Austenitic stainless steel pipes
8. ASTM A333: Seamless and welded steel pipe for low temperature service
9. ASTM A335: Seamless ferric alloy steel pipe for high temperature service
10. ASTM A358: Electric fusion welded Austenitic chrome-nickel steel pipe for high temperature service
11. ASTM A369: Carbon and ferric alloy steel forged and bored for high temperature service
12. ASTM A376: Seamless austenitic steel pipe for high temperature central station service
13. ASTM A409: Welded large diameter Austenitic steel pipe for corrosive or high temperature service
14. ASTM A426: Centrifugally cast ferric alloy steel pipe for high temperature service
15. ASTM A430: Austenitic steel forged and bored pipe for high temperature service
16. ASTM A451: Centrifugally cast austenitic steel pipe for high temperature service
17. ASTM A452: Centrifugally cast austenitic steel cold wrought pipe for high temperature service
18. ASTM A524: Seamless carbon steel pipe for atmospheric and low temperature services
19. ASTM A587: Electric welded low carbon steel pipe for the chemical industry
20. ASTM A660: Centrifugally cast carbon steel pipe for high temperature service
21. ASTM A671: Electric fusion welded steel pipe for atmospheric and low temperature service (Sizes ≥ 16” NB)
22. ASTM A672: Electric fusion welded steel pipe for high pressure service at moderate temperature services (Sizes ≥ 16″NB)
23. ASTM A691: Carbon and alloy steel pipe, electric fusion welded for high pressure service at high temperatures (Sizes ≥ 16″ NB)
24. ASTM A731: Seamless and welded ferritic stainless steel pipe
25. ASTM A790: Seamless and welded ferritic/austenitic stainless steel pipe
26. ASTM A813: Single or double welded austenitic stainless steel pipe
27. ASTM A814: Cold worked welded austenitic stainless steel pipe
28. ASTM F1545: Plastic Lined Ferrous Pipe
29. API 5L: Line pipe

Thickness of Straight Pipe under Internal Pressure

ASME B 31.3, the Process Piping Code, in clause 304.1.1 gives minimum thickness as follows:

tm = t + c

c = sum of the mechanical allowances (thread or groove depth) plus corrosion and erosion allowances. For threaded components, the nominal thread depth (dimension h of ASME B1.20.1, or equivalent) shall apply. For machined surfaces or grooves where the tolerance is not specified, the tolerance shall be assumed to be 0.5 mm (0.02 in.) in addition to the specified depth of the cut.

D = outside diameter of pipe as listed in tables of standards or specifications or as measured

d = inside diameter of pipe. For pressure design calculation, the inside diameter of the pipe is the maximum value allowable under the purchase specification.

E = quality factor from Table A-1A or Table A-1B from B31.3

P = internal design gage pressure

S = stress value for material from Table A-1 or Table A-1M from B31.3

T = pipe wall thickness (measured or minimum in accordance with the purchase specification)

t = pressure design thickness, as calculated in accordance with para. 304.1.2 of B31.3 for internal pressure or as determined in accordance with para. 304.1.3 of B31.3 for external pressure

tm = minimum required thickness, including mechanical, corrosion, and erosion allowances

W = weld joint strength reduction factor in accordance with para. 302.3.5(e) of B31.3

Y = coefficient from Table 304.1.1 (B31.3), valid for t < D/6 and for materials shown. The value of Y may be interpolated for intermediate temperatures.

For t ≥ D/6,

Y = (d + 2c) / (D + d + 2c)

For t < D/6,

the internal pressure design thickness for straight pipe shall be not less than that calculated in accordance with below equations.

t = PD / 2 (SEW + PY)

t = P (d + 2c) / 2 [SEW – P(1 – Y)]

For t ≥ D/6 or for P/SE > 0.385, calculation of pressure design thickness for straight pipe requires special consideration of factors such as theory of failure, effects of fatigue, and thermal stress.

 

Thickness of Straight Pipe under External Pressure.

To calculate wall thickness and reinforcement or stiffening requirements for straight pipe under external pressure, the procedure outlined in the BPV Code, Section VIII, Division 1, UG-28 using UG-30 shall be followed, using as the design length, L, the running centre line length between any two sections stiffened in accordance with UG-29. As an exception, for pipe with Do/t < 10, the value of S to be used in determining Pa2 shall be the lesser of the following values for pipe material at design temperature:

(a) 1.5 times the stress value from Table A-1 or Table A-1M of B31.3 Code, or

(b) 0.9 times the yield strength tabulated in Section II, Part D, Table Y-1 (B 31.3) for materials listed therein

(The symbol Do in Section VIII is equivalent to D in B31.3 Code.)

Standard Pipe Fittings

 

Dimensional Standards for Pipe Fittings

1. ASME B 16.1 -Cast Iron Pipe Flanges and Flanged Fittings
2. ASME B 16.3 -Malleable-Iron Threaded Fittings
3. ASME B 16.4 -Grey Iron Threaded fittings
4. ASME B 16.5 -Pipe Flanges and Flanged Fittings
5. ASME B 16.9 -Factory-Made Wrought Steel Butt welding Fittings
6. ASME B 16.11 -Forged Fittings, Socket welding and Threaded
7. ASME B 16.28 -Wrought Steel Butt welding Short Radius Elbows and Returns
8. ASME B 16.42 -Ductile Iron Pipe Flanges and Flanged Fittings
9. BS 1640 -Butt weld Fittings
10. BS 3799 -Socket weld and Screwed end fittings
11. BS 2598 -Glass Pipelines and Fittings
12. MSS-SP-43 -Stainless Steel Fittings

 

Socket Weld /Screwed Fitting Materials

1 ASTM A105 -Forged Carbon Steel

2 ASTM A181 -Forged Carbon Steel for General Purposes

3 ASTM A182 -Forged Alloy Steel and Stainless Steel

4 ASTM A234 -Wrought Carbon Steel and Alloy Steel pipe fittings for moderate and elevated temperatures

5 ASTM A350 -Forged Alloy Steel for Low Temperature Services

Bevelled end fittings are covered under ASME B 16.9, B16-28 and BS 1640. Thickness to suit pipe thickness.

 

Butt Weld Fitting Materials

1. ASTMA234-Carbon Steel and Alloy steel pipe fittings
2. ASTMA403-Austenitic Stainless Steel fittings
3. ASTMA420-Alloy Steel for low temperature Services

Flanged fittings are covered under ASME B 16.5 and BS 1650 for carbon and alloy steel piping and ASME B 16.1 for cast iron fittings.

Flanged End Fitting Materials

1.ASTM A 216 -Carbon Steel Castings

2.ASTM A 351 -Stainless Steel Castings

3.ASTM A 352 -Alloy Steel Castings

4.ASTM F 1545 -Plastic Lined Fittings

Elbows

45 Deg. Elbow   

45 Deg. Miter Bend

90 Deg. Elbow (Long Radius R=1.5D)

90 Deg. Elbow (Short Radius R=1D)

90 Deg. Elbow (Socket Weld)

90 Deg.Miter Bend

180 Deg. Returns

 

Tees

Equal Tees & Reducing Tees

Butt Weld Tees

Socket Weld Tees

 

Cross

Equal & Reducing Cross

 

Reducers

Concentric Reducer

Eccentric Reducer

 

Stub Ends

Long Stub Ends &Short Stub Ends with class A & B

Class A

Class B

Couplings

Half Coupling

Full Coupling

Reducing Coupling 

Swage Nipple

Eccentric  & Concentric

 

Special Fittings

Weldolet

Sockolet

Threadolet

Elbowlet

Sweepolet

Nipolet

Latrolet

 

Flanges

Classification -Based On

Based On Attachment to Pipe

• Slip-On
• Socket Weld
• Screwed On
• Lap Joint
• Welding Neck
• Blind

Slip-On Raised Face Flange

Socket Welded Raise Face Flange

Threaded Raise Face Flange

Lap Joint Flange with Stub End

Weld Neck Raised Face Flange

Reducing Slip On Flange

Expander or Reducer Flange

 

Based On Pressure-temperature Rating

The flanges are also classified by the pressure temperature rating in ASME B 16.5 as below :

150 #, 300 #, 400 #, 600 #, 900 #, 1500 #, 2500 #

Based On Facing

• Flat face
• Raised face
• Ring type joint
• Tongue and groove
• Male and female

Flat Face

Raised Face

Ring Joint

Tongue and Groove Joint

Male and Female Joint

 

Based On Face Finish

• Smooth finish
• Serrated finish.

The serrations are specified by the number which is the Arithmetic Average Roughness Height (AARH).

Based On Material Of Construction

Flange Materials:

• ASTM A105 -Forged Carbon Steel
• ASTM A181 -Forged Carbon Steel forGeneral Purpose
• ASTM A182 -Forged Alloy Steel andStainless Steel
• ASTM A350 -Forged Alloy Steel for low temperature services

Spectacle Blinds, Spade & Spacers

These are used for positive isolation whereby physical separation between the systems is achieved. The need for positive isolation is dictated by special safety and process requirements.

Positive isolation shall be provided when:

• Hot work has to be done or
• Equipment has be to hydrostatically tested
• Entry by personal is required for inspection or maintenance or
• Equipment has to be opened or removed whilst remainder of unit is still in operation.

If the weight of the spectacle blind exceeds 250 N, then spades and spaces shall be used.

Gaskets

Proper selection of gasket depends upon following factors.

• Compatibility of the gasket material with the fluid.
• Ability to withstand the pressure-temperature ofthe system.

 Based on the type of construction, gaskets are classified as:

• Full Face
• Inside bolt circle
• Spiral wound metallic
• Ring type
• Metal jacketed

For high temperature and high pressure applications, spiral wound metallic gaskets are used.

ASME B 16.5 does not recommend the use of 150# rating gaskets on flanges other than welding neck and lapped joint type.

The spiral wound gasket will perform when the flange face is 125-250 AARH finish.

Dimensional Standards for Gaskets

• API 601 -Metallic Gasket for Refinery Piping
• BS 3381 -Metallic Spiral Wound Gaskets
• ASME B16.20 -Metallic Gaskets for pipe flanges
• ASME B16.21 -Non-metallic Gaskets for pipe flanges

 Insulating Gasket kits

Insulating gasket kits are used between dissimilar metals to avoid galvanic corrosion.

 

Bolting

For low pressure, low temperature services, machine bolts are used and studs are used otherwise.

Flanged joints using low strength carbon steel bolts shall not be used above 200^oC or below –29^oC

Material of Construction for Bolting

Bolting materials normally used are

• ASTM A 307 -Low Carbon Steel Bolting Material
• ASTM A 320 -Alloy Steel Bolting material for low temperature service
• ASTM A 563 -Carbon and alloy steel nuts
• ASTM A 193 -Alloy Steel Bolting Material for high temperature service
• ASTM A 194 -Alloy Steel nut material for high temperature service

Non Ferrous Piping

The commonly used materials are:

• Aluminum
• Alloy-20
• Hastalloy
• Lead
• Monel
• Nickel
• Titanium

Non-Ferrous Piping Materials

• ASTM B-241 Seamless Aluminum and Aluminum Alloy Pipe
• ASTM B-42 Seamless Copper Pipe
• ASTM B-43 Seamless Red Brass Pipe
• ASTM B-315 Seamless Copper Alloy Pipe & Tube
• ASTM B-466 Seamless Copper Nickel Pipe & Tube
• ASTM B-467 Welded Copper Nickel pipe
• BS-334 Chemical Lead Pipe & Fittings
• ASTM B-161 Seamless Nickel Pipe & Tube
• ASTM B-165 Seamless Nickel Copper Alloy (Monel) Pipe
• ASTM B-337 Seamless & Welded Titanium and Titanium Alloy Pipe
• ASTM B-658 Seamless & Welded Zirconium and Zirconium Alloy Pipe.

Non-Metallic and Lined Piping

The commonly used materials are PTFE, FRP, PVC, PP, HDPE, LDPE, Glass, Cement, Ceramic, etc. To add mechanical strength with the corrosion properties of non-metallic materials, the conceptofliningofmaterialis established. The combination normally used in the industry are:

• Mild Steel Rubber Lined(MSRL),
• Mild Steel Glass Lined(MSGL),
• Mild Steel Cement Lined,
• Mild Steel PP Lined,
• FRP with PP Lining,
• Mild Steel PTFE lined

The commonly used internal pipe coating in Oil and Gas Projects:

• PE Lining or Rotolining
• FBE Coating
• Chemflake Coating
• Belzona Coating

PE Lining or Rotolining

For PE Lining for any straight pipe spool can be done up to 36 meters. Whereas 12 meters or 18 meters will be selected, on account of transportation facilities availability.

Wherever PE lining is not feasible (like short spools or spools having branch fittings) rotolining is adopted.

For both PE lining & Rotolining, the concerned vendor need to be consulted and concurrence obtained w.r.t the dimensional limitations.