Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. CONTENTS 1. General
3
2. Types and causes of corrosion.............. corrosion........................ ................... ................... ................... ................... .................... ................... ................... ................... ................... ................... ................................. ........................ 3 3. Bureau piping corrosion experience.............. experience....................... ................... ................... ................... .................... ................... ................... ................... ................... ................... ................... ................... .................4 ........4 4. Industry Codes and standards and other Classification Classification societies............ societies...................... .................... ................... ................... ................... ................... ................... .....................6 ............6 5. Overview of acceptance criteria Procedure................ Procedure.......................... ................... ................... ................... ................... ................... ................... ................... .........................................8 ................................8 6. Procedure for pipe corrosion assessment...............................................................................................................................9 7. Examples of applying pipe corrosion assessments.......... assessments................... ................... ................... ................... ................... ................... .................... ................... ................................. ........................ 10 8. Supplementary pipe data................ data.......................... ................... ................... ................... ................... ................... ................... .................... ................... ................... ................... ................... ............................. ................... 29
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Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. 8. Procedure...................... Procedure................................... ........................... ........................... ........................... ............................ ........................... ........................... ........................................ .......................... 9 9. Tables .......................... ........................................ ............................ ........................... ........................... ............................ ........................... ........................... ............................ ................................. ................... 9 9.1 Table – Minm. Wall Thickness for Steel Pipes................... Pipes................................. ........................... ........................... ............................ ........................... ................... ...... 10 9.2 Table – Commercial Pipe Pipe Sizes and Wall Thickness.................... Thickness.................................. ............................ ........................... ........................... ..................... .......11 11 9.3 Table – Corrosion Corrosion Allowance Allowance for Steel Steel Pipes. .......................... ........................................ ............................ ........................... ........................... .........................12 ...........12 10. ASME B 31G 31G Procedure..................... Procedure.................................. ........................... ............................ ........................... ........................... ......................................... ........................... 13 11. Flowchart .................. ............................... ........................... ............................ ........................... ........................... ........................... ........................... ..................................... ....................... .. 14 12. Table – Values of “L” for pipe sizes sizes ≥ NPS 2 and < NPS NPS 6.................... 6.................................. ............................ .............................. ................ 15 12. Table – Values of “L” for pipe sizes ≥ NPS 50.8 mm and < NPS152.4 mm
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12. Table – Values of “L” for pipe pipe sizes ≥ NPS 6 and < NPS 10....................... 10..................................... .......................................17 .........................17 12. Table – Values of “L” for pipe sizes ≥ NPS 152.4 mm and < NPS 254mm
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12. Table – Values of “L” for pipe sizes ≥ NPS 10 and < NPS 16........................... 16......................................... ........................... ................... ......
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12. Table – Values of “L” for pipe sizes ≥ NPS 254 mm and < NPS 406.4 mm........................... mm..................................................20 .......................20 12. Table – Values of “L” for pipe sizes ≥ NPS 16 and < NPS 20........................... 20........................................ ........................... ...............................22 .................22 12. Table – Values of “L” for pipe sizes ≥ NPS406.4 mm and < NPS 508mm.................................. 508mm....................................................24 ..................24 12. Table – Values of “L” for pipe sizes ≥ NPS 20 and < NPS 24........................... 24........................................ ........................... ...............................26 .................26 12. Table – Values of “L” for pipe sizes ≥ NPS 508mm and < NPS 609.6 mm........................ mm..................................... ...........................28 ..............28 13. Examples.................... Examples.................................. ........................... ........................... ............................ ........................... ........................... ............................ ........................... ................................. .................... 30
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Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. 1.
GENERAL This document provides acceptance criteria and methods for evaluation of corrosion thinning in carbon steel piping. piping. The details details are to assist the Surveyors Surveyors in determining determining the acceptable acceptable corrosion corrosion limits for piping systems in service. The ABS Steel Vessel Rules provide requirements for the design approval of new piping systems, whereas details related to acceptance criteria for corrosion of piping in service is not available. This document is divided into four sections: 1) Types and causes of corrosion 2) Rules and Industry standards available 3) Inspection and Testing methods 4) Recommended approach for Marine piping systems and Marine piping systems of MODU and Floating Production Installations. The process piping systems for MODU and Floating Production Installations have not been covered in this document because of a separate approach which will be addressed in the future.
2.
TYPES AND CAUSES OF CORROSION There are many causes of thinning of pipes pipes due to corrosion. Some of the principal causes are: 1) Pitting 2) Erosion and Erosion/Corrosion Erosion/Corrosion 3) Electrochemical process 4) Microbiologically Influenced Corrosion (MIC)
Following is a short description of the causes of corrosion in pipes: 1) Pitting: Pitting is defined as localized regions of metal loss which can be characterized by a pit diameter on the order of the plate thickness or less, and a pit depth that is less than the plate thickness. The types of pitting experienced are: Localized or confined within a Local Thin Area (LTA ). Widespread or a LTA located in a region of widely scattered pitting.
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Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. 2) Erosion and Erosion /Corrosion: This is the removal of surface material due to impact of solid or liquid particles and normally occurs in areas of turbulent flow or change in direction of flow. A combination of erosion and corrosion results in significantly greater metal loss than can be expected from corrosion or erosion alone. 3) Electrochemical Process: This is caused by an electrochemical reaction between two dissimilar metals in an electrically conductive environment. 4) Microbiologically Influenced Corrosion (MIC): This is caused by the presence of various microbiological agents under specific environmental conditions. This is very common in HVAC systems and produces large pits.
3.
BUREAU PIPING CORROSION EXPERIENCE The following data was obtained from O2K reports related to pipe failures. The systems with the most reported failures (as of June 2005) attributed to corrosion were as follows: System
Number of reports
Ballast System
22
Sea Water System
14
Fire Main System
14
Steam System
13
Cargo Fuel Oil Pipe
3
Fuel Oil
1
Air Line
1
Bilge System
1
Offshore Piping Systems
1
From these reports are listed some representative observations concerning the particular system. Ballast System: 1) Ballast piping in No. 5 center double bottom ballast tank, pitted. 2) 8 inch ballast piping on main deck starboard of Cargo Hatch # 1 was noted to be leaking. The pipe had been fitted with a temporary soft patch
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Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping.
Sea Water System: 1) Seawater crossover main manifold and several smaller lines in engine room bilges found corroded and repaired with doubler. 2) The following seawater piping pieces were found wasted over 25% of original wall thickness, and replaced at the owners discretion: 3) The 20 inch waster piece at the combined overboard located outboard. 4) The 10 inch diameter manifold penetration at the Sprinkler Pump overboard discharge. 5) The low sea chest 30 inch penetration piece and the flanged waster piece adjacent to it. 6) The 24 inch flanged waster piece. 7) The 4 inch waster piece of the Distiller Plant Condenser overboard line.
Fire Main System: 1) The 4 inch diameter fire main piping located starboard side main deck forward of house at Frame No.26 had signs of failure due to wastage and was repaired by cropping approximate two and one-half foot section of the wasted piping, installing new schedule 80 seamless steel pipe and 150# slip-on flanges and welding using approved materials, weld procedure and welders. 2) On lower level of engine room port side inboard of fire and general service pump, corroded pin holes were found in 6" fire main piping. Steam System: 1) Heating Coils in various Fuel Oil Tanks found leaking. 2) Pinhole leak observed on Boiler blow down Line (Reported in a number of cases). Cargo Fuel Oil Pipe : The original fuel oil piping in way of No. 5 centerline double bottom was soft patched due to excessive wastage. The heated fuel oil inside the piping in way of ballast tanks has caused the proliferation of fuel oil piping wastage. Fuel Oil Pipe: 1) Heating Coils in various Fuel Oil Tanks found leaking. 2) Pinhole leak observed on Boiler blow down Line (Reported in a number of cases). Service Air System: Service air pipe on Port side upper deck heavily wasted.
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Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. Bilge System: The bilge system six-inch diameter steel pipe located in the aft engine room bilge, Frame 121-128, was reportedly found with an approximate 20 foot section wasted, thinned and leaking. Upon completion of fabrication the new sections of piping was examined, shop hydro tested at 50 psig and found satisfactory Offshore Pipe Corrosion failure: The mud pipeline system mainly on the elbows and T-unions in various locations were found corroded.
4.
INDUSTRY CODES AND STANDARDS AND OTHER CLASSIFICATION SOCIETIES Industry Codes and Standards There are various industry codes and standards relating to piping systems. Some of the common standards are listed as follows: ASME B 31G - Manual for Determining Remaining Strength of Corroded Pipelines. DNV RP-F101 - Recommended practice for Corroded Pipelines. RSTRENG (Remaining Strength) – Technology for use in evaluating the remaining strength of a pipeline when exposed to corrosion. ASME B31G and RSTRENG are approved technologies by DOT. 4.1
A short description of these standards is described as follows: ASME B 31G
1) Used extensively for evaluation of Structural Integrity of Pipelines with Corrosion caused metal loss 2) Table for Corrosion Limits compares Longitudinal extent and maximum Depth of corroded area. 3) It is Conservative compared to other methods like RSTRENG and DNV RP-F101. RSTRENG (Remaining Strength) 1) Designed to evaluate remaining strength of externally corroded pipe 2) Provides more accurate assessment of corroded area compared to other methods 3) Less conservative than ASME B 31G 4) PC based Program, therefore difficult to use in the field by Surveyors. DNV RP F101 1) Uses empirical formula to calculate piping failures. 2) Unsuitable for Surveyors at locations.
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Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. 4.2
ABS Rules for “Building and Classing Steel Vessels – 2005”
Some of the survey requirements for new pipes in ABS Rules are as follows: 1) For new pipes, the wall thickness is calculated, which includes the corrosion allowance. This was added in ABS Rules in 2000 as per IACS UR. 2) Chemical cargo and Process piping are excluded from the scope. 3) Class 1 & 2 Pipes are Hydro Tested at 1.5 x P, where P is the design pressure. 4.3
ABS Rules – “Survey after Construction 2005”
The Rules for Survey after Construction has test requirements for various systems as follows: 1) Fire Main 2) Main Steam Piping 3) Cargo Piping 4) Liquefied Gas Carriers 5) Chemical Carriers Fire Main System Satisfactory pressure test at the working pressure Main Steam Piping Thickness to be measured by NDT. Alternatively, Hydro test to 1.25 times W.P Cargo Piping System – Tankers (Cargo, C.O.W, Bunker, Ballast and Tank Vent Piping System). Pressure test at working pressure, NDT or both. Liquefied Gas Carrier - Cargo Handling System Hydrostatic Test at 1.25 Maximum allowable Relief Valve setting. Chemical Carriers – ESP >10 Yrs. Cargo pipes outside cargo tanks & ballast pipes passing through cargo tanks. Thickness measured at random or selected pipe lengths to be opened for internal examination. Pressure tested to maximum working pressure.
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Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. 4.4
Some additional inspection/assessment methods in the industry are:
1) API 570 – Piping Inspection Code 2) API RP 580 – Risk - Based Inspection. 3) API 579 – Recommended Practice for Fitness - for - Service. API 570 This was developed for Petroleum, refining and chemical process industries, but may be used for any piping system. The API 570 covers inspection, repair, alteration and re-rating procedures for piping that have been inservice. API RP 580 Risk – Based Inspection in accordance with API RP 580 is a systematic evaluation of the likelihood of failure and the associated consequences of failure. API 579 Standardization of Fitness for Service assessment techniques for pressurized equipment. Best practice and not a mandatory standard or Code. If depth of all pits is less than the specified corrosion/erosion allowance and adequate thickness is available for future pitting damage, no further action is required, other than to record the data. (The specific corrosion allowance for various piping service is given in ABS Rules). If extent of pitting has reached the corrosion allowance, then local or widespread pitting is to be assessed. 4.5
Feedback from other Class Society
Based on informal discussions with various other Classification Societies regarding their Guidance or Process Instructions available relating to the degree of acceptable corrosion permissible on pipes in service we have collected the following information: 1) LRS no Rules, but Surveyors follow a general 12.5% reduction in pipe thickness. 2) BV has a general criteria of 10 % in overall reduction in thickness and 30% in localized reduction. 3) DNV follows the corrosion allowance limits as per the IACS UR. These limits are identical to those in the ABS Steel Vessel Rules.
5.
OVERVIEW OF ACCEPTANCE CRITERIA PROCEDURE 1) The traditional hammer test and hydro test. 2) Based on ABS Rules, the following procedure is proposed for pipelines.
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Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. a) Outside Diameter, minimum required pipe wall thickness and corrosion allowance of pipe details should be available to the Surveyor. The Surveyor can verify onboard in the Piping drawings, the O.D and Schedule of the pipes and obtain the corrosion allowance and the minimum required wall thickness from the Tables which can be included in the P.I. b) NDT test, like UT Gauging, Scanning techniques or Radiography of the pipe to be carried out, wherever necessary. c) Check adequacy of residual corrosion allowance. This can be verified with the Tables included in the P.I. d) If depth of pit is less than the corrosion allowance and adequate thickness is available for future pitting damage, then no further action is required, other than to record the data. 3) If extent of pitting has reached the corrosion allowance, then proceed with ASME B31 G calculations, if required.
6.
PROCEDURE FOR PIPE CORROSION ASSESSMENT 1.
Obtain the nominal pipe size (outer diameter), schedule, pipe nominal wall thickness (t),and pipe service.
2.
Obtain the minimum Rule required wall thickness and Rule corrosion allowance (see Tables 4-62/Table 4, 4-6-2/Table 3)
3.
Determine Actual Corrosion Allowance = Nominal Wall Thickness – Rule Required Wall Thickness
4.
Measure maximum depth (d) of corroded area.
5.
If (d) < Actual Corrosion Allowance, arrest further corrosion and return pipe to service.
6.
If (d) > Actual Corrosion Allowance, determine ratio (d/t).
7.
If (d/t) is < 10%, arrest further corrosion and return pipe to service.
8.
If (d/t) is > 80%, repair or replace pipe.
7.
If 10% < (d/t) < 80%, measure longitudinal extent of the corroded area “L” and apply Tables 1 through 5, (as applicable) as follows:
Select the appropriate Table based on nominal pipe size and measurement units. Table 1 2 3 4
Applicable to Nominal Pipe Sizes (US Units)
Applicable to Nominal Pipe Sizes (SI Units)
≥ NPS 2 in. AND < NPS 6 in.
≥ NPS 50.8 mm. AND < NPS 152.4 mm
≥ NPS 6 in. AND < NPS 10 in.
≥ NPS 152.4 mm AND < NPS 254 mm
≥ NPS 10 in. AND < NPS 16 in.
≥ NPS 254 mm AND < NPS 406.4 mm
≥ NPS 16 in. AND < NPS 20 in.
≥ NPS 406.4 mm AND < NPS 508 mm 9
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Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping.
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≥ NPS 20 in. AND < NPS 24 in.
≥ NPS 508 mm AND < NPS 609.6 mm
Locate the row with a depth equal to the measured maximum depth of the corroded area. If the exact measured value is not listed, choose the row showing the next greater depth. Scan across the columns indicating the wall thickness of the pipe. If the nominal wall thickness is not listed, use the column for the next thinner wall. The value “L” for the maximum allowable longitudinal extent of corrosion permitted is found at the intersection of the column for wall thickness and row for depth. If the maximum longitudinal extent of corrosion is less than that measured, repair or replace the pipe.
7.
EXAMPLES OF APPLYING PIPE CORROSION ASSESSMENTS 7.1
Service: Salt Water Pipe Example 1
1) NPS of Pipe: 3 inches. 2) O.D: 3.5 inches. 3) Nominal Wall Thickness (Schedule 40): 0.216 inches 4) Minimum Wall Thickness for Sea Water (4-6-2/Table 3): 0.165 inches 5) Rule Corrosion Allowance from 4-6-2/Table 3: 0.118 inches 6) Actual Corrosion Allowance = Nominal Wall Thickness. – Minimum Wall Thickness = 0.216 – 0.165 = 0.051 inches (rounded to 0.06) 7) Referring to Table 1, based on depth of pit of 0.06 inches and nominal wall thickness of 0.218 inches, the Allowable Length of Corrosion is 1 13/16 inches. The pipe is suitable for continued service if the measured Length of Corrosion is less than 1 13/16 inches. 7.2
Service: Salt Water Pipe Example 2
1) NPS of Pipe: 12 inches 2) O.D: 12.75 inches 3) Nominal Wall Thickness (Schedule 40): 0.406 inches 4) Minimum Wall Thickness for Sea Water (4-6-2/Table 4): 0.248 inches 5) Rule Corrosion Allowance from 4-6-2/Table 3: 0.118 inches 6) Actual Corrosion Allowance = Nominal Wall Thickness – Minimum Wall Thickness = 0.406 – 0.248 = 0.158 inches 7) Referring to Table 3, based on depth of pit of 0.118 inches (rounded to 0.12 inches) and nominal wall thickness of 0.406 inches (rounded to 0.365 inches), the Allowable Length of Corrosion is 2 5/8 inches 10 Revision 0
Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. 7.3
Service: Fuel Oil Line On Deck Example 3
1) NPS of Pipe: 8 inches 2) O.D: 8.625 inches 3) Nominal Wall Thickness (Schedule 40): 0.322 inches 4) Minimum Wall Thickness for Fuel Oil (4-6-2/Table 4): 0. 177 inches 5) Rule Corrosion Allowance from 4-6-2/Table 3: 0.039 inches 6) Actual Corrosion Allowance = Nominal Wall Thick. – Minimum Wall Thickness = 0.322 – 0.177 = 0.145 inches 7) Referring to Table 2, based on depth of pit of 0.039 inches (rounded to 0.04 inches) and nominal wall thickness of 0.322 inches, the Allowable Length of Corrosion = 6 7/16 inches 7.4
Service: Fuel Oil Line Passing Thru Fuel Tank Example 4
1) NPS of Pipe: 8 inches 2) O.D: 8.625 inches 3) Nominal Wall Thickness (Schedule 40): 0.322 inches 4) Minimum Wall Thickness for Fuel oil (4-6-2/Table 4): 0. 228 inches 5) Rule Corrosion Allowance from 4-6-2/Table 3: 0.039 inches 6) Actual Corrosion Allowance = Nominal Wall Thickness – Minimum Wall Thickness: 0.322 – 0.228 = 0.094 inches 7) Referring to Table 2, based on depth of pit of 0.039 inches (rounded to 0.04 inches) and nominal wall thickness of 0.322 inches, the Length of corrosion = 6 7/16 inches
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Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. Pipe Corrosion Assessment Procedure Diagram
Obtain:
Nominal pipe size (O.D.), Schedule, and Pipe Service. Pipe Nominal Wall Thickness (t),
From Steel Vessel Rules or Other Applicable Rules/Guides: Minimum Rule Required Wall Thickness (4-6-2/Table 4), and Rule Corrosion Allowance (4-6-2/Table 3)
Determine Actual Corrosion Allowance Measure the maximum depth (d) of corroded area. If (d) < Actual Corrosion Allow.
If (d) > Actual Corrosion Allow.
Determine ratio (d/t) If (d/t) < 10%
Return pipe to service
If (d/t) > 80%
Repair/Replace pipe
If 10% < (d/t) < 80%
Assess local and widespread pitting Measure Length of Corrosion
Refer to Tables 1 through 5 as appropriate to obtain Maximum Permissible Length of Corrosion (L). If Measured (L) < Permissible (L)
Return pipe to service
If Measured (L) > Permissible (L)
Repair/Replace pipe
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Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. The following Tables are from ASME B 31 G
TABLE 1 VALUES FOR "L" FOR PIPE SIZES ≥ NPS 2 in. AND < NPS 6 in. Example: A pipe of wall thickness of 0.218 inches and pit depth of 0.06 inches gives a Length of corrosion of 1 3/16 inches
Wall Thickness t in. Depth d in.
0.083
0.109
0.125
0.141
0.154
0.172
0.188
0.218
0.02
15/16
1 15/16
2 7/16
2 9/16
2 11/16
2 7/8
3
0.03
1/2
7/8
1 1/8
1 1/2
1 15/16
2 7/8
3
3 1/4
0.04
3/8
5/8
3/4
15/16
1 1/8
1 3/8
1 3/4
2 3/4
0.05
5/16
7/16
9/16
11/16
13/16
1
1 3/16
1 5/8
0.06
1/4
3/8
1/2
9/16
11/16
13/16
15/16
1 3/16
0.07
5/16
7/16
1/2
9/16
11/16
3/4
1
0.08
5/16
3/8
7/16
1/2
9/16
11/16
13/16
0.09
5/16
3/8
7/16
1/2
9/16
3/4
0.1
1/4
5/16
3/8
7/16
1/2
11/16
5/16
3/8
7/16
1/2
5/8
5/16
3/8
7/16
9/16
5/16
3/8
1/2
0.14
3/8
7/16
0.15
5/16
7/16
0.01
0.11 0.12 0.13
0.16
3/8
0.17
3/8
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Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping.
TABLE 1 VALUES FOR "L" FOR PIPE SIZES ≥ NPS 50.8 mm AND < NPS 152.4 mm Depth ‘d’ mm
Wall Thickness “t’ mm 2.1
0.3
50.8
0.5
2.8
3.2
3.6
3.9
4.4
4.8
23.8
49.2
61.9
65.1
68.3
73.0
76.2
0.8
12.7
22.2
28.6
38.1
49.2
73.0
76.2
82.6
1.0
9.5
15.9
19.1
23.8
28.6
34.9
44.5
69.9
1.3
7.9
11.1
14.3
17.5
20.6
25.4
30.2
41.3
1.5
6.4
9.5
12.7
14.3
17.5
20.6
23.8
30.2
1.8
7.9
11.1
12.7
14.3
17.5
19.1
25.4
2.0
7.9
9.5
11.1
12.7
14.3
17.5
20.6
2.3
7.9
9.5
11.1
12.7
14.3
19.1
2.5
6.4
7.9
9.5
11.1
12.7
17.5
7.9
9.5
11.1
12.7
15.9
7.9
9.5
11.1
14.3
7.9
9.5
12.7
3.6
9.5
11.1
3.8
7.9
11.1
2.8 3.0 3.3
5.5
4.1
9.5
4.3
9.5
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Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping.
TABLE 2 VALUES FOR "L" FOR PIPE SIZES ≥ NPS 6 in. AND < NPS 10 in. Wall Thickness t in. Depth d in.
0.083
0.01
3 5/16
0.02
0.125
0.156
0.188
0.203
0.219
0.25
1 1/2
4 1/16
4 9/16
5
0.03
7/8
1 7/8
3 3/8
0.04
5/8
1 1/4
0.05
1/2
0.06
7/16
0.312
5
5 3/16
5 3/8
5 3/4
1 7/8
2 15/16
3 5/8
4 5/8
5 3/4
6 7/16
15/16
1 3/8
1 15/16
2 5/16
2 3/4
3 7/8
6 7/16
13/16
1 1/8
1 9/16
1 3/4
2 1/16
2 11/16
4 3/4
0.07
11/16
15/16
1 5/16
1 7/16
1 11/16
2 1/8
3 3/8
0.08
9/16
13/16
1 1/8
1 1/4
1 7/16
1 3/4
2 11/16
0.09
1/2
3/4
1
1 1/8
1 1/4
1 9/16
2 1/4
0.10
7/16
11/16
7/8
1
1 1/8
1 3/8
2
0.11
9/16
13/16
7/8
1
1 1/4
1 3/4
0.12
9/16
3/4
13/16
15/16
1 1/8
1 5/8
0.13
11/16
3/4
7/8
1 1/16
1 7/16
0.14
5/8
11/16
13/16
15/16
1 3/8
0.15
9/16
5/8
3/4
7/8
1 1/4
0.16
11/16
13/16
1 3/16
0.17
5/8
3/4
1 1/8
0.18
3/4
1 1/16
0.19
11/16
1
0.20
5/8
15/16
0.21
7/8
0.22
13/16
0.23
13/16
0.24
3/4
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Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. TABLE 2 VALUES FOR "L" FOR PIPE SIZES ≥ NPS 152.4 mm AND < NPS 254 mm Depth d mm
Wall Thickness t mm 2.1
3.2
4.0
4.8
5.2
5.6
6.4
7.9
0.3
84.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.5
38.1
103.2
115.9
127.0
0.0
0.0
0.0
0.0
0.8
22.2
47.6
85.7
127.0
131.8
136.5
146.1
0.0
1.0
15.9
31.8
47.6
74.6
92.1
117.5
146.1
163.5
1.3
12.7
23.8
34.9
49.2
58.7
69.9
98.4
163.5
1.5
11.1
20.6
28.6
39.7
44.5
52.4
68.3
120.7
1.8
0.0
17.5
23.8
33.3
36.5
42.9
54.0
85.7
2.0
0.0
14.3
20.6
28.6
31.8
36.5
44.5
68.3
2.3
0.0
12.7
19.1
25.4
28.6
31.8
39.7
57.2
2.5
0.0
11.1
17.5
22.2
25.4
28.6
34.9
50.8
2.8
0.0
0.0
14.3
20.6
22.2
25.4
31.8
44.5
3.0
0.0
0.0
14.3
19.1
20.6
23.8
28.6
41.3
3.3
0.0
0.0
0.0
17.5
19.1
22.2
27.0
36.5
3.6
0.0
0.0
0.0
15.9
17.5
20.6
23.8
34.9
3.8
0.0
0.0
0.0
14.3
15.9
19.1
22.2
31.8
4.1
0.0
0.0
0.0
0.0
0.0
17.5
20.6
30.2
4.3
0.0
0.0
0.0
0.0
0.0
15.9
19.1
28.6
4.6
0.0
0.0
0.0
0.0
0.0
0.0
19.1
27.0
4.8
0.0
0.0
0.0
0.0
0.0
0.0
17.5
25.4
5.1
0.0
0.0
0.0
0.0
0.0
0.0
15.9
23.8
5.3
0.0
0.0
0.0
0.0
0.0
0.0
0.0
22.2
5.6
0.0
0.0
0.0
0.0
0.0
0.0
0.0
20.6
5.8
0.0
0.0
0.0
0.0
0.0
0.0
0.0
20.6
6.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
19.1
16 Revision 0
Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. TABLE 3 VALUES FOR "L" FOR PIPE SIZES ≥ NPS 10 in. AND < NPS 16 in. Wall Thickness t in. Depth d in.
0.156
0.02
5 13/16
0.03
0.219
0.25
0.307
0.344
0.365
0.438
0.5
4 5/16
6 7/8
7 3/8
0.04
2 7/16
5 15/16
7 3/8
8 1/8
8 5/8
8 7/8
0.05
1 3/4
3 1/2
4 15/16
8 1/8
8 5/8
8 7/8
9 3/4
10 3/8
0.06
1 7/16
2 9/16
3 3/8
5 3/4
8 5/8
8 7/8
9 3/4
10 3/8
0.07
1 3/16
2 1/8
2 11/16
4 1/8
5 1/2
6 5/8
9 3/4
10 3/8
0.08
1 1/16
1 13/16
2 1/4
3 5/16
4 3/16
4 7/8
8 3/8
10 3/8
0.09
15/16
1 9/16
1 15/16
2 13/16
3 1/2
3 15/16
6 1/8
9 3/8
0.10
13/16
1 7/16
1 3/4
2 7/16
3
3 3/8
4 15/16
6 15/16
0.11
3/4
1 3/16
1 9/16
2 3/16
2 5/8
2 15/16
4 3/8
5 5/8
0.12
11/16
1 1/16
1 7/16
2 3/8
2 5/8
3 11/16
4 13/16
0.13
1
1 5/16
1 13/16
2 3/16
2 3/8
3 5/16
4 1/4
0.14
15/16
1 1/4
1 11/16
0.15
7/8
1 1/8
1 9/16
0.16
13/16
1 1/16
0.17
3/4
2
2
2 3/16
3
3 13/16
1 5/8
2 1/16
2 3/4
3 7/16
1 7/16
1 3/4
1 15/16
2 9/16
3 3/16
1
1 3/8
1 5/8
1 13/16
2 3/8
2 15/16
0.18
15/16
1 5/16
1 9/16
1 11/16
2 1/4
2 3/4
0.19
7/8
1 1/4
1 7/16
1 5/8
2 1/8
2 5/8
0.20
3/4
1 1/8
1 3/8
1 1/2
2
2 7/16
0.21
1 1/8
1 5/16
1 7/16
1 7/8
2 5/16
0.22
1 1/16
1 1/4
1 3/8
1 13/16
2 1/4
0.23
1
1 3/16
1 5/16
1 3/4
2 1/8
0.24
15/16
1 1/8
1 1/4
1 11/16
2 1/16
TABLE 3 (cont’d) VALUES FOR "L" FOR PIPE SIZES ≥ NPS 10 in. AND < NPS 16 in. Depth d in.
Wall Thickness t in. 17 Revision 0
Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping.
0.156
0.219
0.25
0.307
0.344
0.365
0.438
0.5
0.25
1 1/16
1 3/16
1 9/16
1 15/16
0.26
1 1/16
1 1/8
1 1/2
1 7/8
0.27
1
1 1/16
1 7/16
1 13/16
0.28
1 1/16
1 7/16
1 3/4
0.29
1
1 3/8
1 11/16
0.3
1 5/16
1 5/8
0.31
1 1/4
1 9/16
0.32
1 3/16
1 1/2
0.33
1 3/16
1 7/16
0.34
1 1/8
1 3/8
0.35
1 1/16
1 3/8
0.36
1 5/16
0.37
1 1/4
0.38
1 1/4
0.39
1 3/16
0.4
1 3/16
0.41
18 Revision 0
Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. TABLE 3 VALUES FOR "L" FOR PIPE SIZES ≥ NPS 254 mm AND < NPS 406.4 mm Wall Thickness t mm Depth d mm
4.8
0.5
196.9
0.8
196.9
227.0
1.0
114.3
1.3
7.9
8.7
9.5
11.1
12.7
227.0
254.0
266.7
279.4
77.8
152.4
254.0
266.7
279.4
301.6
322.3
1.5
60.3
104.8
188.9
266.7
279.4
301.6
322.3
1.8
50.8
82.6
133.4
171.5
223.8
301.6
322.3
360.4
2.0
44.5
69.9
106.4
130.2
161.9
258.8
322.3
360.4
2.3
38.1
60.3
88.9
108.0
128.6
188.9
290.5
360.4
2.5
34.9
54.0
77.8
92.1
109.5
152.4
215.9
360.4
2.8
31.8
49.2
69.9
82.6
95.3
130.2
174.6
352.4
3.0
28.6
44.5
63.5
74.6
85.7
114.3
149.2
268.3
3.3
27.0
41.3
57.2
68.3
77.8
101.6
131.8
219.1
3.6
23.8
38.1
54.0
61.9
71.4
92.1
117.5
188.9
3.8
22.2
34.9
49.2
57.2
66.7
85.7
108.0
166.7
4.1
33.3
46.0
54.0
61.9
79.4
98.4
150.8
4.3
28.6
42.9
50.8
57.2
74.6
92.1
136.5
4.6
27.0
41.3
47.6
54.0
69.9
88.9
127.0
4.8
25.4
38.1
44.5
50.8
65.1
81.0
117.5
5.1
36.5
42.9
49.2
61.9
76.2
111.1
5.3
34.9
41.3
46.0
58.7
60.3
104.8
5.6
33.3
38.1
44.5
55.6
68.3
98.4
5.8
31.8
36.5
42.9
54.0
65.1
93.7
6.1
30.2
34.9
39.7
50.8
63.5
88.9
33.3
38.1
49.2
60.3
85.7
6.4
6.4
15.9
19 Revision 0
Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. TABLE 3 (cont’d) VALUES FOR "L" FOR PIPE SIZES ≥ NPS 254 mm AND < NPS 406.4 mm Wall Thickness t mm Depth d mm
4.8
6.4
7.9
8.7
9.5
11.1
12.7
15.9
6.6
31.8
36.5
47.6
57.2
82.6
6.9
30.2
34.9
46.0
55.6
79.4
7.1
33.3
42.9
54.0
76.2
7.4
33.3
41.3
52.4
73.0
7.6
31.8
39.7
49.2
69.9
7.9
39.7
47.6
68.3
8.1
38.1
46.0
65.1
8.4
36.5
44.5
63.5
8.6
34.9
42.9
61.9
8.9
33.3
42.9
60.3
9.1
41.3
58.7
9.4
39.7
57.2
9.7
38.1
55.6
9.9
36.5
54.0
10.2
36.5
52.4
10.4
50.8
10.7
49.2
10.9
47.6
11.2
47.6
11.4
46.0
11.7
44.5
11.9
42.9
12.2
42.9
12.4
33.3
12.7
39.7
20 Revision 0
Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. TABLE 4 VALUES FOR "L" FOR PIPE SIZES ≥ NPS 16 in. AND < NPS 20 in. Wall Thickness t in. Depth d in.
0.188
0.02
7 3/4
0.03
7 3/4
8 15/16
0.04
4 1/2
8 15/16
0.05
3 1/16
0.06
2 3/8
0.07
0.25
0.312
0.344
0.375
0.438
0.5
10
10 1/2
11
10
10 1/2
11
11 7/8
12 11/16
4 1/8
7 7/16
10 1/2
11
11 7/8
12 11/16
2
3 1/4
5 1/4
6 3/4
8 13/16
11 7/8
12 11/16
14 3/16
0.08
1 3/4
2 3/4
4 3/16
5 1/8
6 3/8
10 3/16
12 11/16
14 3/16
0.09
1 1/2
2 3/8
3 1/2
4 1/4
5 1/16
7 7/16
11 7/16
14 3/16
0.10
1 3/8
2 1/8
3 1/16
3 5/8
4 5/16
6
8 1/2
14 3/16
0.11
1 1/4
1 15/16
2 3/4
3 1/4
3 3/4
5 1/8
6 7/8
13 7/8
0.12
1 1/8
1 3/4
2 1/2
2 15/16
3 3/8
4 1/2
5 7/8
10 9/16
0.13
1 1/16
1 5/8
2 1/4
2 11/16
3 1/16
4
5 3/16
8 5/8
0.14
15/16
1 1/2
2 1/8
2 7/16
2 13/16
3 5/8
4 5/8
7 7/16
0.15
7/8
1 3/8
1 15/16
2 1/4
2 5/8
3 3/8
4 1/4
6 9/16
0.16
1 5/16
1 13/16
2 1/8
2 7/16
3 1/8
3 7/8
5 15/16
0.17
1 1/8
1 11/16
2
2 1/4
2 15/16
3 5/8
5 3/8
0.18
1 1/16
1 5/8
1 7/8
2 1/8
2 3/4
3 1/2
5
0.19
1
1 1/2
1 3/4
2
2 9/16
3 3/16
4 5/8
0.20
1 7/16
1 11/16
1 15/16
2 7/16
3
4 3/8
0.21
1 3/8
1 5/8
1 13/16
2 5/16
2 3/8
4 1/8
0.22
1 5/16
1 1/2
1 3/4
2 3/16
2 11/16
3 7/8
0.23
1 1/4
1 7/16
1 11/16
2 1/8
2 9/16
3 11/16
0.24
1 3/16
1 3/8
1 9/16
2
2 1/2
3 1/2
6
0.625
21 Revision 0
Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. TABLE 4 (cont’d) VALUES FOR "L" FOR PIPE SIZES ≥ NPS 16 in. AND < NPS 20 in. Wall Thickness t in. Depth d in.
0.188
0.25
0.312
0.344
0.375
0.438
0.5
0.625
0.25
1 5/16
1 1/2
1 15/16
2 3/8
3 3/8
0.26
1 1/4
1 7/16
1 7/8
2 1/4
3 1/4
0.27
1 3/16
1 3/8
1 13/16
2 3/16
3 1/8
0.28
1 5/16
1 11/16
2 1/8
0.29
1 5/16
1 5/8
2 1/16
2 7/8
0.30
1 1/4
1 9/16
1 15/16
2 3/4
0.31
1 9/16
1 7/8
2 11/16
0.32
1 1/2
1 13/16
2 9/16
0.33
1 7/16
1 3/4
2 1/2
0.34
1 3/8
1 11/16
2 7/16
0.35
1 5/16
1 11/16
2 3/8
0.36
1 5/8
2 5/16
0.37
1 9/16
2 1/4
0.38
1 1/2
2 3/16
0.39
1 7/16
2 1/8
0.40
1 7/16
2 1/16
3
0.41
2
0.42
1 15/16
0.43
1 7/8
0.44
1 7/8
0.45
1 13/16
0.46
1 3/4
0.47
1 11/16
0.48
1 11/16
0.49
1 5/16
0.50
1 9/16
22 Revision 0
Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. TABLE 4 VALUES FOR "L" FOR PIPE SIZES ≥ NPS 406.4 mm AND < NPS 508 mm Depth d mm
Wall Thickness t mm 4.8
6.4
7.9
8.7
9.5
11.1
12.7
15.9
0.5
196.9
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.8
196.9
227.0
0.0
0.0
0.0
0.0
0.0
0.0
1.0
114.3
227.0
254.0
266.7
279.4
0.0
0.0
0.0
1.3
77.8
152.4
254.0
266.7
279.4
301.6
322.3
0.0
1.5
60.3
104.8
188.9
266.7
279.4
301.6
322.3
0.0
1.8
50.8
82.6
133.4
171.5
223.8
301.6
322.3
360.4
2.0
44.5
69.9
106.4
130.2
161.9
258.8
322.3
360.4
2.3
38.1
60.3
88.9
108.0
128.6
188.9
290.5
360.4
2.5
34.9
54.0
77.8
92.1
109.5
152.4
215.9
360.4
2.8
31.8
49.2
69.9
82.6
95.3
130.2
174.6
352.4
3.0
28.6
44.5
63.5
74.6
85.7
114.3
149.2
268.3
3.3
27.0
41.3
57.2
68.3
77.8
101.6
131.8
219.1
3.6
23.8
38.1
54.0
61.9
71.4
92.1
117.5
188.9
3.8
22.2
34.9
49.2
57.2
66.7
85.7
108.0
166.7
4.1
33.3
46.0
54.0
61.9
79.4
98.4
150.8
4.3
28.6
42.9
50.8
57.2
74.6
92.1
136.5
4.6
27.0
41.3
47.6
54.0
69.9
88.9
127.0
4.8
25.4
38.1
44.5
50.8
65.1
81.0
117.5
5.1
36.5
42.9
49.2
61.9
76.2
111.1
5.3
34.9
41.3
46.0
58.7
60.3
104.8
5.6
33.3
38.1
44.5
55.6
68.3
98.4
5.8
31.8
36.5
42.9
54.0
65.1
93.7
6.1
30.2
34.9
39.7
50.8
63.5
88.9
6.4
33.3
38.1
49.2
60.3
85.7
6.6
31.8
36.5
47.6
57.2
82.6
6.9
30.2
34.9
46.0
55.6
79.4
7.1
33.3
42.9
54.0
76.2
7.4
33.3
41.3
52.4
73.0
23 Revision 0
Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. TABLE 4 (cont’d) VALUES FOR "L" FOR PIPE SIZES ≥ NPS 406.4 mm AND < NPS 508 mm Depth d mm
Wall Thickness t mm 4.8
6.4
7.9
9.5
11.1
12.7
15.9
31.8
39.7
49.2
69.9
7.9
39.7
47.6
68.3
8.1
38.1
46.0
65.1
8.4
36.5
44.5
63.5
8.6
34.9
42.9
61.9
8.9
33.3
42.9
60.3
9.1
41.3
58.7
9.4
39.7
57.2
9.7
38.1
55.6
9.9
36.5
54.0
10.2
36.5
52.4
7.6
8.7
10.4
50.8
10.7
49.2
10.9
47.6
11.2
47.6
11.4
46.0
11.7
44.5
11.9
42.9
12.2
42.9
12.4
33.3
12.7
39.7
24 Revision 0
Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. TABLE 5 VALUES FOR "L" FOR PIPE SIZES ≥ NPS 20 in. AND < NPS 24 in. Wall Thickness t in. Depth d in.
0.219
0.03
9 3/8
10
0.04
8 1/16
10
0.05
4 3/4
6 11/16
0.06
3 9/16
0.07
0.25
0.344
0.406
0.469
0.5
0.562
0.625
11 3/4
12 3/4
13 3/4
14 3/16
4 5/8
11 3/4
12 3/4
13 3/4
14 3/16
15
2 7/8
3 11/16
7 9/16
12 3/4
13 3/4
14 3/16
15
15 13/16
0.08
2 7/16
3 1/16
5 3/4
8 7/8
13 3/4
14 3/16
15
15 13/16
0.09
2 3/16
2 11/16
4 3/4
6 13/16
10 3/16
12 13/16
15
15 13/16
0.10
1 5/16
2 3/8
4 1/16
5 11/16
7 15/16
9 1/2
14 1/8
15 13/16
0.11
1 3/4
2 1/8
3 5/8
4 7/8
6 5/8
7 11/16
10 5/8
15 13/16
0.12
1 5/8
1 15/16
3 1/4
4 5/16
5 3/4
6 9/16
8 11/16
11 3/4
0.13
1 1/2
1 13/16
3
3 15/16
5 1/16
5 3/4
7 7/16
9 11/16
0.14
1 3/8
1 11/16
2 3/4
3 9/16
4 5/8
5 3/16
6 9/16
8 5/16
0.15
1 1/4
1 9/16
2 9/16
3 5/16
4 3/16
4 3/4
5 7/8
7 5/16
0.16
1 3/16
1 7/16
2 3/8
3 1/16
3 7/8
4 3/8
5 3/8
6 5/8
0.17
1 1/16
1 3/8
2 1/4
2 7/8
3 5/8
4 1/16
4 15/16
6 1/16
0.18
1 1/4
2 1/8
2 11/16
3 7/16
3 13/16
4 1/16
5 9/16
0.19
1 3/16
2 9/16
3 3/16
3 9/16
3 7/8
5 3/16
0.20
1 1/8
1 7/8
2 7/16
3 1/16
3 3/8
3 5/8
4 7/8
0.21
1 13/16
2 5/16
2 7/8
3 3/16
3 1/2
4 9/16
0.22
1 11/16
2 3/16
2 3/4
3 1/16
3 5/16
4 5/16
0.23
1 5/8
2 1/8
2 5/8
2 7/8
3 3/16
4 1/8
0.24
1 9/16
2
2 1/2
2 3/4
3 1/16
3 15/16
0.25
1 1/2
1 15/16
2 7/16
2 11/16
2 15/16
3 3/4
0.26
1 7/16
1 7/8
2 5/16
2 9/16
2 13/16
3 5/8
0.27
1 3/8
1 3/4
2 1/4
2 7/16
2 3/4
3 7/16
0.28
1 11/16
2 1/8
2 3/8
2 5/8
3 5/16
0.29
1 5/8
2 1/16
2 1/4
2 9/16
3 3/16
11 3/4
2
25 Revision 0
Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. TABLE 5 (cont’d) VALUES FOR "L" FOR PIPE SIZES ≥ NPS 20 in. AND < NPS 24 in. Wall Thickness t in. Depth d in.
0.219
0.25
0.344
0.30
0.406 1 9/16
0.469 2
0.5
0.562
0.625
2 3/16
2 7/16
3 1/8
0.31
1 15/16
2 1/8
2 3/8
3
0.32
1 7/8
2 1/16
2 5/16
2 7/8
0.33
1 13/16
2 1/4
2 13/16
0.34
1 3/4
1 15/16
2 3/16
2 3/4
0.35
1 11/16
1 7/8
2 1/8
2 5/8
0.36
1 5/8
1 13/16
2 1/16
2 9/16
0.37
1 9/16
1 3/4
2
2 1/2
0.38
1 11/16
1 15/16
2 7/16
0.39
1 5/8
1 7/8
2 3/8
0.40
1 9/16
1 13/16
2 5/16
0.41
1 3/4
2 1/4
0.42
1 3/4
2 3/16
2
0.43
2 1/8
0.44
2 1/16
0.45
2
0.46
1 15/16
0.47
1 15/16
0.48
1 7/8
0.49
1 13/16
0.50
1 3/4
26 Revision 0
Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. TABLE 5 VALUES FOR "L" FOR PIPE SIZES ≥ NPS 508 mm AND < NPS 609.6 mm. Wall Thickness t mm Depth d mm
5.6
6.4
0.8
238.1
254.0
1.0
204.8
254.0
298.5
1.3
120.7
169.9
1.5
90.5
1.8
8.7
10.31
11.9
12.7
14.3
15.9
298.5
323.9
349.3
360.4
117.5
298.5
323.9
349.3
360.4
381.0
73.0
93.7
192.1
323.9
349.3
360.4
381.0
401.6
2.0
61.9
77.8
146.1
225.4
349.3
360.4
381.0
401.6
2.3
55.6
68.3
120.7
173.0
258.8
325.4
381.0
401.6
2.5
33.3
60.3
103.2
144.5
201.6
241.3
358.8
401.6
2.8
44.5
54.0
92.1
123.8
168.3
195.3
269.9
401.6
3.1
41.3
49.2
82.6
109.5
146.1
166.7
220.7
298.5
3.3
38.1
46.0
76.2
100.0
128.6
146.1
188.9
246.1
3.6
34.9
42.9
69.9
90.5
117.5
131.8
166.7
211.1
3.8
31.8
39.7
65.1
84.1
106.4
120.7
149.2
185.7
4.1
30.2
36.5
60.3
77.8
98.4
111.1
136.5
168.3
4.3
27.0
34.9
57.2
73.0
92.1
103.2
125.4
154.0
4.6
31.8
54.0
68.3
87.3
96.8
103.2
141.3
4.8
30.2
50.8
65.1
81.0
90.5
98.4
131.8
5.1
28.6
47.6
61.9
77.8
85.7
92.1
123.8
5.3
46.0
58.7
73.0
81.0
88.9
115.9
5.6
42.9
55.6
69.9
77.8
84.1
109.5
5.8
41.3
54.0
66.7
73.0
81.0
104.8
6.1
39.7
50.8
63.5
69.9
77.8
100.0
6.4
38.1
49.2
61.9
68.3
74.6
95.3
6.6
36.5
47.6
58.7
65.1
71.4
92.1
6.9
34.9
44.5
57.2
61.9
69.9
87.3
7.1
42.9
54.0
60.3
66.7
84.1
7.4
41.3
52.4
57.2
65.1
81.0
7.6
39.7
50.8
55.6
61.9
79.4
TABLE 5 (cont’d) VALUES FOR "L" FOR PIPE SIZES ≥ NPS 508 mm AND < NPS 609.6 mm. 27 Revision 0
Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. Wall Thickness t mm Depth d mm
5.6
6.4
8.7
10.3
11.9
12.7
14.3
15.9
7.9
49.2
54.0
60.3
76.2
8.1
47.6
52.4
58.7
73.0
8.4
46.0
50.8
57.2
71.4
8.6
44.5
49.2
55.6
69.9
8.9
42.9
47.6
54.0
66.7
9.1
41.3
46.0
52.4
65.1
9.4
39.7
44.5
50.8
63.5
9.7
42.9
49.2
61.9
9.9
41.3
47.6
60.3
10.2
39.7
46.0
58.7
10.4
44.5
57.2
10.7
44.5
55.6
10.9
54.0
11.2
52.4
11.4
50.8
11.7
49.2
11.9
49.2
12.2
47.6
12.5
46.0
12.7
44.5
28 Revision 0
Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. 8.
SUPPLEMENTARY PIPE DATA The following Tables are from the ABS Rules for Building and Classing Steel Vessels 2005 and listed for convenience. Refer to the latest edition of the Rules when applying this data. 1) Commercial pipe sizes and wall thickness. 4-6-2/Table 8 2) Corrosion allowance for Steel Pipes. 4-6-2/Table 3 3) Minimum wall thickness of Steel Pipes.
4-6-2/Table 4
29 Revision 0
Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. TABLE 8 Commercial Pipe Sizes and Wall Thicknesses Nominal pipe size
Outside diameter (in., mm)
Nominal wall thickness (in., mm) Standard
Sch.40
1/8 in.
0.405
0.068
0.068
6 mm
10.287
1.727
1.727
1/4 in.
0.540
0.088
8 mm
13.716
3/8 in. 10 mm
Extra strong
Sch.80
Sch.160
Double extra strong
0.095
0.095
--
--
2.413
2.413
0.088
0.119
0.119
--
--
2.235
2.235
3.023
3.023
0.675
0.091
0.091
0.126
0.126
--
--
17.145
2.311
2.311
3.200
3.200
1/2 in.
0.840
0.109
0.109
0.147
0.147
0.188
0.294
15 mm
21.336
2.769
2.769
3.734
3.734
4.775
7.468
3/4 in.
1.050
0.113
0.113
0.154
0.154
0.219
0.308
20 mm
26.670
2.870
2.870
3.912
3.912
5.563
7.823
1 in.
1.315
0.133
0.133
0.179
0.179
0.250
0.358
25 mm
33.401
3.378
3.378
4.547
4.547
6.350
9.903
1 1/4 in.
1.660
0.140
0.140
0.191
0.191
0.250
0.382
32 mm
42.164
3.556
3.556
4.851
4.851
6.350
9.703
1 1/2 in.
1.900
0.145
0.145
0.200
0.200
0.281
0.400
40 mm
48.260
3.683
3.683
5.080
5.080
7.137
10.160
2 in.
2.375
0.154
0.154
0.218
0.218
0.344
0.436
50 mm
60.325
3.912
3.912
5.537
5.537
8.738
11.074
2 1/2 in.
2.875
0.203
0.203
0.276
0.276
0.375
0.552
65 mm
73.025
5.156
5.156
7.010
7.010
9.525
14.021
3 in.
3.500
0.216
0.216
0.300
0.300
0.438
0.600
80 mm
88.900
5.486
5.486
7.620
7.620
11.125
15.240
3 1/2 in.
4.000
0.226
0.226
0.318
0.318
--
--
90 mm
101.600
5.740
5.740
8.077
8.077
4 in.
4.500
0.237
0.237
0.337
0.337
0.531
0.674
100 mm
114.300
6.020
6.020
8.560
8.560
13.487
17.120
5 in.
5.5.63
0.258
0.258
0.375
0.375
0.625
0.750
125 mm
141.300
6.553
6.553
9.525
9.525
15.875
19.050
6 in.
6.625
0.280
0.280
0.432
0.432
0.719
0.864
150 mm
168.275
7.112
7.112
10.973
10.973
18.263
21.946
8 in.
8.625
0.322
0.322
0.500
0.500
0.906
0.875
200 mm
219.075
8.179
8.179
12.700
12.700
23.012
22.225
10 in.
10.750
0.365
0.365
0.500
0.594
1.125
1.000
250 mm
273.050
9.271
9.271
12.700
15.088
28.575
25.400
12 in.
12.750
0.375
0.406
0.500
0.688
1.312
1.000
300 mm
323.850
9.525
10.312
12.700
17.475
33.325
25.400
14 in.
14.000
0.375
0.438
0.500
0.750
1.406
--
350 mm
355.600
9.525
11.125
12.700
19.050
35.712
16 in.
16.000
0.375
0.500
0.500
0.844
1.594
400 mm
406.400
9.525
12.700
12.700
21.438
40.488
18 in.
18.000
0.375
0.562
0.500
0.938
1.781
450 mm
457.200
9.525
14.275
12.700
23.825
45.231
20 in.
20.000
0.375
0.594
0.500
1.031
1.969
500 mm
508.000
9.525
15.088
12.700
26.187
50.013
22 in.
22.000
0.375
--
0.500
1.125
2.125
550 mm
558.800
9.525
12.700
28.575
53.975
-----
30 Revision 0
Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. Nominal pipe size 24 in. 600 mm
Outside diameter (in., mm)
Nominal wall thickness (in., mm) Standard
Sch.40
24.000
0.375
0.688
609.600
9.525
17.475
Extra strong
Sch.80
Sch.160
Double extra strong
0.500
1.219
2.344
--
12.700
30.963
59.538
These pipe sizes and wall thicknesses are according to ANSI B36.10.
TABLE 3 Corrosion Allowance c for Steel Pipes (see 4-6-2/5.1.1) Piping Service
Corrosion allowance, c mm
in.
Superheated steam
0.3
0.012
Saturated steam
0.8
0.032
Steam heating coils in cargo tanks
2.0
0.079
Feed water for boilers in open circuits
1.5
0.059
Feed water for boilers in closed circuits
0.5
0.02
Blowdown for boilers
1.5
0.059
Compressed air
1.0
0.039
Hydraulic oil
0.3
0.012
Lubricating oil
0.3
0.012
Fuel oil
1.0
0.039
Cargo oil
2.0
0.079
Refrigerant
0.3
0.012
Fresh water
0.8
0.032
Sea water
3.0
0.118
Notes For pipes passing through tanks, the proper additional corrosion allowance is to be taken into account for the external medium. For special alloy steels which are considered to be corrosion resistant, the corrosion allowance can be reduced to zero.
31 Revision 0
Acceptance criteria and methods for evaluation of corrosion thinning in Carbon Steel Piping. TABLE 4 Minimum Wall Thickness for Steel Pipes (See 4-6-2/5.1.3) Nom.
Wall thickness, mm
Outside dia. mm
A
6
10.2
1.6
8
13.5
10
Wall thickness, in.
Outside dia. in.
A
1/8
0.405
0.063
1.8
1/4
0.540
0.071
17.2
1.8
3/8
0.675
0.071
15
21.3
2.0
2.8
1/2
0.840
0.079
0.110
20
26.9
2.0
2.8
3/4
1.050
0.079
0.110
25
33.7
2.0
3.2
4.2
6.3
6.3
1
1.315
0.079
32
42.4
2.3
3.5
4.2
6.3
6.3
1 1/4
1.660
40
48.3
2.3
3.5
4.2
6.3
6.3
1 1/2
50
60.3
2.3
3.8
4.2
6.3
6.3
65
76.1
2.6
4.2
4.2
6.3
80
88.9
2.9
4.2
4.2
90
101.6
2.9
4.5
100
114.3
3.2
125
139.7
150
C
D
E
0.126
0.165
0.248
0.248
0.091
0.138
0.165
0.248
0.248
1.900
0.091
0.138
0.165
0.248
0.248
2
2.375
0.091
0.150
0.165
0.248
0.248
7.0
2 1/2
2.875
0.102
0.165
0.165
0.248
0.276
7.1
7.6
3
3.500
0.114
0.165
0.165
0.280
0.300
4.5
7.1
8.1
3 1/2
4.000
0.114
0.177
0.177
0.315
0.318
4.5
4.5
8.0
8.6
4
4.500
0.126
0.177
0.177
0.315
0.337
3.6
4.5
4.5
8.0
9.5
5
5.563
0.142
0.177
0.177
0.346
0.375
168.3
4.0
4.5
4.5
8.8
11.0
6
6.625
0.157
0.177
0.177
0.346
0.432
200
219.1
4.5
5.8
5.8
8.8
12.5
8
8.625
0.177
0.228
0.228
0.346
0.5
250
273.0
5.0
6.3
6.3
8.8
12.5
10
10.750
0.197
0.248
0.248
0.346
0.5
300
323.9
5.6
6.3
6.3
8.8
12.5
12
12.750
0.220
0.248
0.248
0.346
0.5
350
355.6
5.6
6.3
6.3
8.8
12.5
14
14.000
0.220
0.248
0.248
0.346
0.5
400
406.4
6.3
6.3
6.3
8.8
12.5
16
16.000
0.248
0.248
0.248
0.346
0.5
450
457.0
6.3
6.3
6.3
8.8
12.5
18
18.000
0.248
0.248
0.248
0.346
0.5
size mm
Columns: A B C D E
B
C
D
E
Nom. size in.
B
(2003) Pipes in general, except where Columns B, C, D or E are applicable Bilge, ballast and sea water pipes except those covered by column D (2003) Vent, overflow and sounding pipes for integral tanks except those covered by column D (see Note 6 and 7) and fuel oil pipes passing through fuel oil tanks. Bilge, ballast, vent, overflow and sounding pipes passing through fuel tanks (see Notes 6, 7 and 8). Bilge, vent, overflow, sounding and fuel pipes passing through ballast tanks (see Note 6, 7 and 8). Ballast pipes passing through cargo oil tanks (see Note 9). Cargo pipes passing through ballast tanks (see Note 9).
Notes: 1 2 3 4 5 6 7 8 9 10
(2002) The minimum thicknesses are the smallest thicknesses selected from those thicknesses specified in ISO 4200 Series 1, JIS, or ASTM Standards. Notwithstanding the requirements of this Table, diameters and thicknesses specified in other recognized standards will also be acceptable. For threaded pipes, where approved, the thickness is to be measured to the bottom of the thread. For pipes protected against corrosion, a reduction of thickness not exceeding 1 mm (0.039 in.) may be considered. For minimum wall thicknesses of copper, copper alloy and austenitic stainless steel pipes, see 4-6-2/Table 5A and 4-6-2/Table 5B. This table is not applicable to exhaust gas pipes. For that part of a vent pipe exposed to weather, pipe wall is to be as specified in 4-6-4/9.3.2(a). The thickness indicated for sounding pipes is for the portions outside the tanks to which the pipe is opened. Within bilge well, to which the pipe is not opened, the thickness is to be extra-heavy; see 4-6-4/11.3.3iv). For bilge pipes, column D thickness applies only where required by 4-6-4/5.5.4(c). Where permitted by 5-1-7/3.3.3 and 5-1-7/5.3.2. (2002) For nominal sizes larger than 450 mm (18 in.), the minimum wall thickness specified for 450 mm (18 in.) nominal size pipe is applicable. 32 Revision 0
