Engineering Standard

SAES-L-131 23 July 2011

Fracture Control of Line Pipe
Document Responsibility: Materials and Corrosion Control Standards Committee

Saudi Aramco DeskTop Standards

Table of Contents

1 Scope............................................................. 2
2 Conflicts and Deviations................................. 2
3 References..................................................... 2
4 Classification of Line Pipe.............................. 3
5 Testing Requirements.................................... 3

Previous Issue: 8 February 2009 Next Planned Update: 8 February 2014

Revised paragraphs are indicated in the right margin Page 1 of 10
Primary contact: Buraiki, Iyad Abdulrazzak on 966-3-8760243

Copyright©Saudi Aramco 2011. All rights reserved.

Document Responsibility: Materials and Corrosion Control Standards Committee SAES-L-131
Issue Date: 23 July 2011
Next Planned Update: 8 February 2014 Fracture Control of Line Pipe

1 Scope

This standard covers line pipe supplementary fracture toughness requirements to control
crack propagation at temperatures above 0°C in carbon steel pipe used for off-plot
transportation piping, such as cross-country pipelines, flowlines, trunklines, and
testlines, as defined in SAES-L-100. The requirements apply to line pipe with wall
thicknesses of 6.35 mm to 38.1 mm (0.25 to 1.5 inch), in accordance with
API SPEC 5L, 01-SAMSS-035 and 01-SAMSS-333.

2 Conflicts and Deviations

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

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

3 References

The selection of material and equipment, and the design, construction, maintenance, and
repair of equipment and facilities covered by this standard shall comply with the latest
edition of the references listed below, unless otherwise noted or modified by specific
provisions of this standard.

3.1 Saudi Aramco References

Saudi Aramco Engineering Procedure

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

Saudi Aramco Engineering Standard

SAES-L-100 Applicable Codes and Standards for Pressure
Piping Systems

Saudi Aramco Materials System Specifications

01-SAMSS-035 API Line Pipe

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Document Responsibility: Materials and Corrosion Control Standards Committee SAES-L-131
Issue Date: 23 July 2011
Next Planned Update: 8 February 2014 Fracture Control of Line Pipe

01-SAMSS-333 High Frequency Welded Line Pipe

3.2 Industry Codes and Standards

American Petroleum Institute

API SPEC 5L/ISO 3183:2007 Specification for Line Pipe
(Modified)

4 Classification of Line Pipe

Line pipe, within the scope of this standard, is herein classified according to the fracture
toughness acceptance criteria required for different types of fluid service.

 Class IV Line Pipe: This class is for gas, two-phase flow, and liquid lines such as
NGL, whose vapor pressure may exceed 690 kPa (100 psia). This category also
incorporates the former Class II and Class III.
Commentary Note:

Class I was originally for liquid lines with maximum vapor pressure up to 690 kPa
(100 psia). This class has been discontinued because PSL 2 pipe ordered to
API SPEC 5L meets the toughness requirement for Class I service by default.
Class III was originally for buried gas pipelines and Class II has been used for liquids
such as NGL, whose vapor pressure may exceed 100 psia. The former Classes II, III,
and IV are now all in Class IV.

5 Testing Requirements

5.1 Class IV pipe shall be tested per 01-SAMSS-035 (parent metal, heat-affected
zone, and weld metal Charpy V-notch tests). The API SPEC 5L/ISO 3183
absorbed energy values (based on transverse specimens), from tests at 0°C, shall
meet or exceed the values determined below. In no case may the required
energy value be less than the minimum required value for PSL 2 pipe given in
Table 8 of the current version of API SPEC 5L. The energy values calculated
below are considered to be the average energy of three specimens.

5.1.1 For lean natural gas (> 90% Methane) or liquids (with vapor
pressure/MAOP < 0.35):

Cv = (0.0147) H2 (Dt/2)0.284 (1)

Cv : Required Charpy V-notch absorbed energy (average of three full

size transverse specimens) per API SPEC 5L/01-SAMSS-035.
H : Maximum allowable hoop stress, ksi
(This is normally the Design Factor x SMYS)

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Document Responsibility: Materials and Corrosion Control Standards Committee SAES-L-131
Issue Date: 23 July 2011
Next Planned Update: 8 February 2014 Fracture Control of Line Pipe

D : Outside diameter, inches

t : Nominal pipe wall thickness, inches

Toughness values listed in the attached Tables 1 through 4 are based on

the above formula, at various design factors and strength levels (valid up
to strength level X65).
Commentary Note:

The above equation is based on lean natural gas (> 90% methane,
acoustic velocity 1300 fps) and no backfill over the pipe. The equation is
conservative for the case of a buried pipeline.

5.1.2 For liquids (with vapor pressure/MAOP > 0.35), the formula in Table 5
may be used. However, it is generally advisable to modify the design to
increase the design pressure (MAOP) in order to reduce the ratio.

5.1.3 For “rich” gases containing significant amount of hydrocarbons or gases

that do not meet the definition of lean gas, contact the Materials
Engineering Unit of CSD for gas decompression and fracture velocity
calculation to define the required fracture arrest toughness. The following
information is needed:
 Gas composition
 Gas temperature and pressure
 Diameter and wall thickness of pipe
 Design factor
 Pipe strength grade (SMYS)
 Maximum allowable operating pressure (MAOP)
Commentary Note:

For rich gas service, gases other than methane and liquids with high
vapor pressure like NGL, CSD can perform calculations using the
computer programs GASDECOM and DUCTOUGH with the method
outlined in NG-18 Report No. 208 "Final Report on Fracture Control
Technology for Natural Gas Pipelines" from the Pipeline Research
Committee International.

5.2 A correction factor shall be used for Charpy V-notch energies greater than
70 ft-lb (95 J) as follows:

When Cv ≥ 70 ft-lb (95 J), Cv = Cv + (0.00269) Cv2.04 – 21.18 (2)

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Document Responsibility: Materials and Corrosion Control Standards Committee SAES-L-131
Issue Date: 23 July 2011
Next Planned Update: 8 February 2014 Fracture Control of Line Pipe

5.3 Specimen Orientation: All specimens shall be oriented transverse to the rolling
direction. The orientation specified in API SPEC 5L/ISO 3183 shall apply except
that for spiral welded (helical seam) pipe, the specimen shall be transverse to the
rolling direction of the skelp (perpendicular to the helical seam).

Revision Summary
8 February 2009 Revised the “Next Planned Update.” Reaffirmed the content of the document, and reissued
with minor changes.
23 July 2011 Editorial revision to clarify paragraph 5.1.

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Document Responsibility: Materials and Corrosion Control Standards Committee SAES-L-131
Issue Date: 23 July 2011
Next Planned Update: 8 February 2014 Fracture Control of Line Pipe

Table 1 – Required Charpy Values (ft-lbs) for Line Pipe in Lean Natural Gas
(> 90% Methane) or Liquid (Vapor Pressure/MAOP < 0.35) Service
Design Factor = 0.72
Dt (inches2) 36 ksi 42 ksi 52 ksi 60 ksi 65 ksi
2 20 20 21 27 32
3 20 20 23 31 36
4 20 20 25 33 39
5 20 20 27 36 42
6 20 20 28 37 44
7 20 20 29 39 46
8 20 20 31 41 48
9 20 21 32 42 49
10 20 21 33 43 51
11 20 22 33 45 52
12 20 22 34 46 54
13 20 23 35 47 55
14 20 23 36 48 56
15 20 24 37 49 57
16 20 24 37 50 58
17 20 25 38 50 59
18 20 25 38 51 60
19 20 25 39 52 61
20 20 26 40 53 62
21 20 26 40 53 63
22 20 27 41 54 64
23 20 27 41 55 64
24 20 27 42 56 65
25 20 28 42 56 66
26 20 28 43 57 67
27 21 28 43 57 67
28 21 28 44 58 68
29 21 29 44 59 69
30 21 29 44 59 69
32 22 30 45 60 71
34 22 30 46 61 72
36 22 31 47 62 73
38 23 31 48 63 74
40 23 31 48 64 75
42 23 32 49 65 76
44 24 32 50 66 77
46 24 33 50 67 78
48 24 33 51 68 79

Note: This table was generated for API SPEC 5L pipe from the formula in Paragraph 5.2.1.
D : Outside diameter, inches
t : Nominal pipe wall thickness, inches.

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Document Responsibility: Materials and Corrosion Control Standards Committee SAES-L-131
Issue Date: 23 July 2011
Next Planned Update: 8 February 2014 Fracture Control of Line Pipe

Table 2 – Required Charpy Values (ft-lbs) for Line Pipe in Lean Natural Gas
(> 90% Methane) or Liquid (Vapor Pressure/MAOP < 0.35) Service
Design Factor = 0.6
Dt (inches2) 36 ksi 42 ksi 52 ksi 60 ksi 65 ksi
2 20 20 20 20 22
3 20 20 20 21 25
4 20 20 20 23 27
5 20 20 20 25 29
6 20 20 20 26 31
7 20 20 20 27 32
8 20 20 21 28 33
9 20 20 22 29 34
10 20 20 23 30 35
11 20 20 23 31 36
12 20 20 24 32 37
13 20 20 24 32 38
14 20 20 25 33 39
15 20 20 25 34 40
16 20 20 26 34 40
17 20 20 26 35 41
18 20 20 27 36 42
19 20 20 27 36 42
20 20 20 28 37 43
21 20 20 28 37 44
22 20 20 28 38 44
23 20 20 29 38 45
24 20 20 29 39 45
25 20 20 29 39 46
26 20 20 30 39 46
27 20 20 30 40 47
28 20 20 30 40 47
29 20 20 31 41 48
30 20 20 31 41 48
32 20 21 31 42 49
34 20 21 32 43 50
36 20 21 33 43 51
38 20 22 33 44 52
40 20 22 34 45 52
42 20 22 34 45 53
44 20 22 34 46 54
46 20 23 35 46 54
48 20 23 35 47 55

Note: This table was generated for API SPEC 5L pipe from the formula in Paragraph 5.2.1.
D : Outside diameter, inches
t : Nominal pipe wall thickness, inches.

Page 7 of 10
Document Responsibility: Materials and Corrosion Control Standards Committee SAES-L-131
Issue Date: 23 July 2011
Next Planned Update: 8 February 2014 Fracture Control of Line Pipe

Table 3 – Required Charpy Values (ft-lbs) for Line Pipe in Lean Natural Gas
(> 90% Methane) or Liquid (Vapor Pressure/MAOP < 0.35) Service
Design Factor = 0.5
Dt (inches2) 36 ksi 42 ksi 52 ksi 60 ksi 65 ksi
2 20 20 20 20 20
3 20 20 20 20 20
4 20 20 20 20 20
5 20 20 20 20 20
6 20 20 20 20 21
7 20 20 20 20 22
8 20 20 20 20 23
9 20 20 20 20 24
10 20 20 20 21 25
11 20 20 20 21 25
12 20 20 20 22 26
13 20 20 20 23 26
14 20 20 20 23 27
15 20 20 20 23 28
16 20 20 20 24 28
17 20 20 20 24 29
18 20 20 20 25 29
19 20 20 20 25 29
20 20 20 20 25 30
21 20 20 20 26 30
22 20 20 20 26 31
23 20 20 20 26 31
24 20 20 20 27 31
25 20 20 20 27 32
26 20 20 21 27 32
27 20 20 21 28 33
28 20 20 21 28 33
29 20 20 21 28 33
30 20 20 21 29 34
32 20 20 22 29 34
34 20 20 22 30 35
36 20 20 23 30 35
38 20 20 23 31 36
40 20 20 23 31 36
42 20 20 24 31 37
44 20 20 24 32 37
46 20 20 24 32 38
48 20 20 25 33 38

Note: This table was generated for API SPEC 5L pipe from the formula in Paragraph 5.2.1.
D : Outside diameter, inches
t : Nominal pipe wall thickness, inches.

Page 8 of 10
Document Responsibility: Materials and Corrosion Control Standards Committee SAES-L-131
Issue Date: 23 July 2011
Next Planned Update: 8 February 2014 Fracture Control of Line Pipe

Table 4 – Required Charpy Values (ft-lbs) for Line Pipe in Lean Natural Gas
(> 90% Methane) or Liquid (Vapor Pressure/MAOP < 0.35) Service
Design Factor = 0.4
Dt (inches2) 36 ksi 42 ksi 52 ksi 60 ksi 65 ksi
2 20 20 20 20 20
3 20 20 20 20 20
4 20 20 20 20 20
5 20 20 20 20 20
6 20 20 20 20 20
7 20 20 20 20 20
8 20 20 20 20 20
9 20 20 20 20 20
10 20 20 20 20 20
11 20 20 20 20 20
12 20 20 20 20 20
13 20 20 20 20 20
14 20 20 20 20 20
15 20 20 20 20 20
16 20 20 20 20 20
17 20 20 20 20 20
18 20 20 20 20 20
19 20 20 20 20 20
20 20 20 20 20 20
21 20 20 20 20 20
22 20 20 20 20 20
23 20 20 20 20 20
24 20 20 20 20 20
25 20 20 20 20 20
26 20 20 20 20 21
27 20 20 20 20 21
28 20 20 20 20 21
29 20 20 20 20 21
30 20 20 20 20 21
32 20 20 20 20 22
34 20 20 20 20 22
36 20 20 20 20 23
38 20 20 20 20 23
40 20 20 20 20 23
42 20 20 20 20 24
44 20 20 20 20 24
46 20 20 20 21 24
48 20 20 20 21 25

Note: This table was generated for API SPEC 5L pipe from the formula in Paragraph 5.2.1.
D : Outside diameter, inches
t : Nominal pipe wall thickness, inches.

Page 9 of 10
Document Responsibility: Materials and Corrosion Control Standards Committee SAES-L-131
Issue Date: 23 July 2011
Next Planned Update: 8 February 2014 Fracture Control of Line Pipe

Table 5 – Required Charpy Values for Liquids if Vapor Pressure/MAOP > 0.35

Dt 1/2
((1.39 5.23 
Pv
+ n) MAOP)
Cv = 0.00263 ln sec ( 2 ) (3)

Cv : Required Charpy V-notch absorbed energy (average of three full size

transverse specimens) per API SPEC 5L/ISO 3183 and 01-SAMSS-035,
in ft-lb
Pv : Vapor pressure of pipeline liquid, psi
n : Constant with value as listed in the table below
MAOP : Maximum allowable operating pressure (design pressure), psi
  Flow stress = Y + 10 ksi = SMYS + K + 10, in ksi
(K from the table below)
Y : Estimated actual yield strength = SMYS + K, in ksi
(K from the table below)
SMYS : Specified minimum yield strength, ksi
D : Outside diameter, inches
t : Nominal pipe wall thickness, inches

Computed and Assumed Constants

API Grade K (ksi) n

Gr. B 15 0.40
X42 13 0.33
X52 9 0.27
X60 6 0.23
X65 5 0.21
X70 5 0.20

Note: The equation in this form is valid for design factor of 0.72.

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