API 579-Part 5-Level 2 Provided By :Yousef Akbari

Input

Item Abbreviation Unit QTY

Pipeline name 30in Piping -API 5L-X65

Material Carbon Steel

Allowble Stress S Mpa 177

Out Side diameter D mm 762

Minimum Thickness in
t 19
undamaged area mm
Maximum operating Pressure
5.76
(MOP) P Mpa

Maximum Allowable Working

MAWP
Pressure
Mpa

Minimum Remaining Thickness tmm mm 9

d 10
Maximum Corrosion Depth mm
Corrosion Rate CR mm/Year 0.1
next inspection Date I years 10
2
Feature Corrosion Allowence FCA mm

Weld Joint Efeciency -C Ec 1

direction

Weld Joint Efeciency -L El 1

Direction
Corrosion Length L mm 180
Corrosion width C mm 1800
Distance from MSD Lmd mm 1000
radius at the base of a Groove-
gr mm 11
Like Flaw
load F N 100
Moment M N.mm 500
Conic angle α Rad(Deg) 0
supplemental thickness tsl mm 0
Mechanical allowance MA mm 0
 CTP Data Gathering
C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 C13 C14 C15 C16 C17 C18

M1 15 14 13 13 12 11.5 14 10 11 14 14.5 12 10 14 15 14.5 14 14

10

M2 14.5 13.5 12.5 12.5 11.5 11 13.5 9.5 10.5 13.5 14 11.5 9.5 13.5 14.5 14 13.5 13.5 9.5
M3 14.9 13.9 12.9 12.9 11.9 11.4 13.9 9.9 10.9 13.9 14.4 11.9 9.9 13.9 14.9 14.4 13.9 13.9 9.9

M4 14.2 13.2 12.2 12.2 11.2 10.7 13.2 9.2 10.2 13.2 13.7 11.2 9.2 13.2 14.2 13.7 13.2 13.2 9.2

M5
14.6 13.6 12.6 12.6 11.6 11.1 13.6 9.6 10.6 13.6 14.1 11.6 9.6 13.6 14.6 14.1 13.6 13.6 9.6

M6 14.79 13.77 12.8 12.75 11.73 11.22 13.77 9.69 10.71 13.77 14.3 11.73 9.7 13.77 14.8 14.28 13.77 13.77 9.69

M7 15.25 13 13.14 13.14 12.09 11.57 14.20 9.99 11.04 14.20 14.72 12.09 9.99 14.20 15.25 14.72 14.20 12.0
9.99

11.6 10.6 9.6 9.6 12 9.5 10.6 9 11 10.6 11.1 8.6 11 10.6 11.6 11.1 10.6 10.6
M8 8.6

M9
14.75 13.75 12.8 12.75 11.75 11.25 13.75 11 10.75 13.75 14.3 11.75 9.8 13.75 14.8 14.25 13.75 13.75 9.75

11.6 10.6 9.6 9.6 11.2 9.5 10.6 9 10.2 10.6 11.1 8.6 9.2 10.6 11.6 11.1 10.6 10.6
 STEP 1 – Determine the CTP
Data Abbriviation Unit QTY Remark
Minimum
Thickness in t mm 19
undamaged area
Minimum
Remaining tmm mm 9
Thickness

Corrosion Length L mm 180

Corrosion width C mm 1800

tmm d
Location
mm mm

1 11.6
2 10.6
3 9.6
4 9.6
5 11.2
6 9.5
7 10.6
8 9
9 10.2
10 10.6
11 11.1
12 8.6
13 9.2
14 10.6
15 11.6
16 11.1
17 10.6
18 10.6
STEP 2 – Determine the wall thickness to be used in the assessment

Equation unit QTY

mm 17

STEP 3 – Determine the minimum measured thickness in the LTA, tmm and Dimensional L and C

Data Abbreviation unit QTY Remark

minimum measured thickness determined at the time of the tmm mm 9

assessment
longitudinal extent or length of the region of local metal loss
L mm 180
based on future corroded thickness

circumferential extent or length of the region of local metal

C mm 1800
loss

STEP 4 – Determine the remaining thickness ratio using and the longitudinal flaw length
parameter

Data Abbreviation QTY Remark

remaining thickness ratio Rt 0.41

longitudinal flaw length

parameter
λ 2.03
STEP 5 – Check the limiting flaw size criteria

Equation Critaria Result Remark

0.35>=0.2 Pass

3.2>=1.3 Pass

1000>=80.8 pass

STEP 6 – If the region of metal loss is categorized as an LTA (i.e., the LTA is not a groove),

Equation Critaria Result Remark

16.67>=0.5 Pass

part9 Or Table
5.3

g) STEP 7 – Determine the MAWP(Use tc for calculation)

Mpa 8.04

Mpa 16.38

Mpa 8.04
STEP 8 – Determine the Remaining Strength Factor for the longitudinal CTP .using the following procedure.
a – Rank the thickness readings in ascending order based on metal loss profile
C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 C13 C14 C15 C16 C17 C18
M1 15.00 14.00 13.00 13.00 12.00 11.50 14.00 10.00 11.00 14.00 14.50 12.00 10.00 14.00 15.00 14.50 14.00 14.00
M2 14.50 13.50 12.50 12.50 11.50 11.00 13.50 9.50 10.50 13.50 14.00 11.50 9.50 13.50 14.50 14.00 13.50 13.50
M3 14.90 13.90 12.90 12.90 11.90 11.40 13.90 9.90 10.90 13.90 14.40 11.90 9.90 13.90 14.90 14.40 13.90 13.90
M4 14.20 13.20 12.20 12.20 11.20 10.70 13.20 9.20 10.20 13.20 13.70 11.20 9.20 13.20 14.20 13.70 13.20 13.20
M5 14.60 13.60 12.60 12.60 11.60 11.10 13.60 9.60 10.60 13.60 14.10 11.60 9.60 13.60 14.60 14.10 13.60 13.60
M6 14.79 13.77 12.75 12.75 11.73 11.22 13.77 9.69 10.71 13.77 14.28 11.73 9.69 13.77 14.79 14.28 13.77 13.77
M7 15.25 13.00 13.14 13.14 12.09 11.57 14.20 9.99 11.04 14.20 14.72 12.09 9.99 14.20 15.25 14.72 14.20 12.00
M8 11.60 10.60 9.60 9.60 12.00 9.50 10.60 9.00 11.00 10.60 11.10 8.60 11.00 10.60 11.60 11.10 10.60 10.60
M9 14.75 13.75 12.75 12.75 11.75 11.25 13.75 11.00 10.75 13.75 14.25 11.75 9.75 13.75 14.75 14.25 13.75 13.75

b – Set the initial evaluation starting point as the location of maximum metal loss
tmmi 11.60 10.60 9.60 9.60 11.20 9.50 10.60 9.00 10.20 10.60 11.10 8.60 9.20 10.60 11.60 11.10 10.60 10.60
di 5.40 6.40 7.40 7.40 5.80 7.50 6.40 8.00 6.80 6.40 5.90 8.40 7.80 6.40 5.40 5.90 6.40 6.40
C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 C13 C14 C15 C16 C17 C18
C – At the current evaluation starting point, subdivide the thickness profile into a series of subsections and calculate RSF For Each section then Select Minimum
Value of RSF in Length
STEP 8.4 – For each subsection, compute the Remaining Strength Factor using Equation (5.18).
Sub-Section Li diAve Ai λi Mti A0i RSFi
C1-C18 180 6.67 1201 2.03 1.6331 3060 0.80
1.20 RSFi
1.00 1.01
C2-C17 160.00 6.7688 1083 1.81 1.5291 2720 0.81 0.97 0.94
0.91 0.88 0.86
C3-C16 140.00 6.82 955 1.58 1.429 2380 0.83 0.80 0.83 0.81 0.80

C4-C15 120.00 6.85 822 1.35 1.3341 2040 0.86 0.60

C5-C14 100.00 6.94 694 1.13 1.2459 1700 0.88 0.40
C6-C13 80.00 7.15 572 0.90 1.1667 1360 0.91
0.20
C7-C12 60.00 6.98 419 0.68 1.0989 1020 0.94
0.00
C8-C11 40.00 6.775 271 0.45 1.0459 680 0.97 0 50 100 150 200
C9-C10 6.6 20.00 132 0.07 1.0015 112.2 1.01
Min Valu of RSF 0.80
 - -------s i+3________

-- - - -
-si+_
2 ____
_

-----si+1 _____

---Si ___

tc

'------____________________, J_
Cross Hatched Area - Ai i
A 0 - Area Within Box

(a) Subdivision Process for Determining the RSF

A d max B
d v use
in Level 2
D
A=corroded Area
AO=ABCD
STEP 9: MAWPr Calculation
Equation unit QTY Result Remark

MAWPr= (RSF/RSFa)MAWP Mpa 7.15 Pass

STEP 10: Check Failure in circumferential(Axial, L) direction

Step 10.1: If Equation (5.13) is satisfied, the circumferential extent is acceptable, and no further
evaluation is required. Otherwise, proceed to STEP 9.2.

C 2L(Ec/EL) Result Remark

Equation

continue to
1800 360
10.2

STEP 10.2 – Calculate the minimum thickness required for longitudinal stresses
Equation unit QTY Remark

mm 6.12 6.12

STEP 10.3 – If Equation (5.14) is satisfied, the circumferential extent is acceptable, and no further
evaluation is required. Otherwise, proceed to STEP 9.4.

Equation unit tmm-FCAml Result

mm 7 Pass

STEP 10.4 – The MAWPr for the component can be adjusted using Equation (5.15).
unit MAWPr Result

Mpa 8.17 pass