Ballot ID:

Title: HIC/SOHIC Damage Factor Corrections: H2S, HF

Purpose: To improve the granularity of the damage factor calculations for H2S and HF HIC/SOHIC damage mechanisms.

Impact: Will minimize recurring required inspections for very low susceptible applications

Rationale: Even for low susceptible applications, 581 will often require inspections every turn around. The goal is to minimize repeated inspections for very low susceptibility applications

Technical Reference(s):

API 571

Primary Sponsor:

Name: Phil Henry/ Mike Matrona

Company: The Equity Engineering Group

Phone: (216)283-6012

E-mail: phenry@e2g.com

Tracking Status

Submitted to Task Group Submitted to SCI Submitted to Master Editor

Date Resolution Date Resolution Date Added

Proposed Changes and/or Wording

Committee Draft

Proposed Change to Table 6.3 Rationale: The changes being recommended to chapters 9 and 14 require a new row to be added to table 6.3 for an SVI of 0.5.

Table 6.3 – SCC Damage Factors – All SCC Mechanisms

VIS

Inspection Effectiveness

E 1 Inspection 2 Inspections 3 Inspections

D C B A D C B A D C B A

0 0 0 0 0 0 0 0 0 0 0 0 0 0

0.5 0.5 0.5 0.3 0.2 0.13 0.3 0.2 0.15 0.1 0.2 0.13 0.1 0.05

1 1 1 0.7 0.5 0.3 0.7 0.5 0.3 0.2 0.5 0.3 0.2 0.1

10 10 8 3 1 0.5 6 2 0.5 0.3 4 1 0.5 0.2

50 50 40 17 5 3 30 10 2 0.5 20 5 1 0.3

100 100 80 33 10 5 60 20 4 1 40 10 2 0.5

500 500 400 170 50 25 300 100 20 5 200 50 8 1

1,000 1,000 800 330 100 50 600 200 40 10 400 100 16 2

5,000 5,000 4,000 1,670 500 250 3,000 1,000 250 50 2,000 500 80 10

VIS

Inspection Effectiveness

E 4 Inspections 5 Inspections 6 Inspections

D C B A D C B A D C B A

0 0 0 0 0 0 0 0 0 0 0 0 0 0

0.5 0.5 0.18 0.1 0.05 0.005 0.15 0.05 0.005 0.005 0.05 0.005 0.005 0.005

1 1 0.4 0.2 0.1 0.01 0.3 0.1 0.01 0.01 0.1 0.01 0.01 0.01

10 10 2 1 0.3 0.1 1 0.5 0.1 0.01 0.5 0.1 0.01 0.01

50 50 10 2 0.7 0.2 5 1 0.5 0.1 1 .5 0.1 0.01

100 100 20 5 1 0.3 10 2 0.7 0.2 5 1 0.3 0.1

500 500 100 25 2 0.7 50 10 1 0.5 25 5 0.5 0.3

1,000 1,000 200 50 5 1 100 25 2 0.7 50 10 1 0.5

5,000 5,000 1,000 250 25 2 500 125 5 1 250 50 2 1

Committee Draft

Proposed change to Chapter 9 Rationale: Proposal is to add a VERY LOW susceptibility for HIC/SOHIC – H2S cracking. We are also recommending the removal of the asterisks from the high category in table 9.2 because a “very high” category does not exist in the method. The goal is to minimize repeated inspections for very low susceptibility applications. For Table 9.2, the defined pH ranges were changed. API 571 states hydrogen diffusion through steel is minimal at pH 7, while noting the rate of diffusion increases at both higher and lower pH levels. The table was reconstructed in a manner that illustrated these claims.

The <50 ppm column was separated into two columns: <5, and 5-50 ppm. API 571 provides the following

justification:

“An arbitrary value of 50 wppm H2S in the water phase is often used as the defining concentration

where wet H2S damage becomes a problem. However, there are cases where cracking has occurred at

lower concentrations or during upset conditions where wet H2S was not ordinarily anticipated. The

presence of as little as 1 wppm of H2S in the water has been found to be sufficient to cause hydrogen

charging of the steel.”

This resolution increases the granularity of the method while providing more conservative values for H2S concentrations near 50 ppm.

Table 9.1 – Data Required for Determination of the DF – HIC/SOHIC-H2S Cracking

Required Data Comments

Susceptibility

(Very Low, Low, Medium, High)

The susceptibility is determined by expert advice or using the

procedures in this paragraph.

Presence of Water

(Yes or No)

Determine whether free water is present in the component.

Consider not only normal operating conditions, but also start-up,

shutdown, process upsets, etc.

H2S Content of Water Determine the H2S content of the water phase. If analytical results

are not readily available, it can be estimated using the approach of

Petrie & Moore (see Reference 31).

pH of Water Determine the pH of the water phase. If analytical results are not

readily available, it should be estimated by a knowledgeable

process engineer.

Presence of Cyanides

(Yes or No)

Determine the presence of cyanide through sampling and/or field

analysis. Consider primarily normal and upset operations but also

start-up and shutdown conditions.

Sulfur Content of Plate Steel Determine the sulfur content of the steel used to fabricate the

component. This information should be available on MTRs in

equipment files. If not available, it can be estimated from the

ASTM or ASME specification of the steel listed on the U-1 form in

consultation with materials engineer.

Committee Draft

Steel Product Form

(Plate or Pipe)

Determine what product form of steel was used to fabricate the

component. Most components are fabricated from rolled and

welded steel plates (e.g., A285, A515, A516), but some small-

diameter components are fabricated from steel pipe and piping

components. Most small-diameter piping is fabricated from steel

pipe (e.g., A106, A53, API 5L) and piping components (e.g., A105,

A234), but most large diameter piping (above approximately NPS

16 diameter) is fabricated from rolled and welded plate steel.

Age

(years)

Use inspection history to determine the time since the last SCC

inspection.

Inspection Effectiveness Category The effectiveness category that has been performed on the

component.

On-Line Monitoring

(Hydrogen Probes, Process

Variables, or Combination)

The type of proactive corrosion monitoring methods or tools

employed, such as hydrogen probes and/or process variable

monitoring.

Number of Inspections The number of inspections in each effectiveness category that have

been performed.

Committee Draft

Table 9.2 – Environmental Severity – HIC/SOHIC-H2S Cracking

pH of Water Environmental Severity as a Function of H2S content of Water

< 50 ppm 5 to 50 ppm 50 to 1,000 ppm 1,000 to 10,000 ppm > 10,000 ppm

< 45.5 Low Moderate Moderate High High

4 to 6.5 Very Low Low Low Moderate Moderate

5.5 6.6 to 7.5 Low Very Low Very Low Low Low Moderate

7.6 to 8.3 Low Very Low Low Moderate Moderate* Moderate*

8.4 to 8.9 Low Very Low Low Moderate Moderate* High*

> 9 Low Low Moderate High* High* Note: *If cyanides are present, increase the susceptibility to HIC/SOHIC-H2S one category for pH > 7.6 8.3 and H2S concentrations greater than 1,000 ppm.

Committee Draft

Table 9.3 – Susceptibility to Cracking – HIC/SOHIC-H2S Cracking

Table 9.4 – Determination of Severity Index – HIC/SOHIC-H2S Cracking

Susceptibility Severity Index – VIS

High 100

Medium 10

Low 1

Very Low 0.5

None1 0 Notes:

1. A susceptibility level of “none” is indicative of the damage mechanism being inactive.

Environmental Severity

Susceptibility to Cracking as a Function of Steel Sulfur Content High-Sulfur Steel(1)

> 0.01% S Low Sulfur Steel

≤ 0.01% Product Form –

Seamless/Extruded Pipe

As-Welded PWHT As-Welded PWHT As-Welded PWHT

High High High High Medium Medium Low

Moderate High Medium Medium Low Low Low Very Low

Low Medium Low Low Low Very Low Low Low Very Low

Very Low Low Low Very Low Very Low Very Low Very Low Notes:

1. Typically includes A 70, A 201, A 212, A 285, A 515, and most A 516 before about 1990.

Committee Draft

Proposed change to Chapter 14 Rationale: Proposal is to add a VERY LOW susceptibility for HIC/SOHIC – HF cracking. The goal is to minimize repeated inspections for very low susceptibility applications.

Table 14.1 – Data Required for Determination of the DF – HIC/SOHIC-HF Required Data Comments

Susceptibility

(Very Low, Low, Medium, High)

The susceptibility is determined by expert advice or using the

procedures in this paragraph.

Presence of HF

(Yes of No)

Determine whether HF may be present in the component.

Consider not only normal operating conditions but also upset

conditions that may allow carryover of HF from other components.

Sulfur Content of Plate Steel Determine the sulfur content of the plate steel used to fabricate

the component. This information should be available on the

material test report (MTR) in the equipment files. If not available,

it can be estimated from the ASTM or ASME specification of the

steel listed on the U-1 form in consultation with a materials

engineer.

Steel Product Form

(Plate or Pipe)

Determine what product form of steel was used to fabricate the

component. Most components are fabricated from rolled and

welded steel plates (e.g., A285, A515, A516), but some small-

diameter components are fabricated from steel pipe and piping

components. Most small-diameter piping is fabricated from steel

pipe (e.g., A106, A53, API 5L) and piping components (e.g., A105,

A234), but most large-diameter piping (above approximately NPS

16 diameter) is fabricated from rolled and welded plate steel.

Age

(years)

Use inspection history to determine the time since the last SCC

inspection.

Inspection Effectiveness Category The effectiveness category that has been performed on the

component

Number of Inspections The number of inspections in each effectiveness category that have

been performed

Committee Draft

Table 14.2 – Susceptibility to Cracking – HIC/SOHIC-HF

Table 14.3 – Determination of Severity Index – HIC/SOHIC-HF

Susceptibility Severity Index – VIS

High 100

Medium 10

Low 1

Very Low 0.5

None1 0 Notes:

1. A susceptibility level of “none” is indicative of the damage mechanism being inactive.

Weld Construction

Susceptibility to Cracking as a Function of Steel Sulfur Content

High-Sulfur Steel Plate(1) > 0.01% S

Low-Sulfur Steel ≤ 0.01% S

Product Form – Seamless/Extruded Pipe(2)

Non-PWHT High High Low

PWHT High Medium Low Notes:

1. Typically includes A 70, A 201, A 212, A 285, A 515, and most A 516 before about 1990.

1.2. A Very Low susceptibility can be assigned to Seamless/Extruded Pipe under guidance of expert opinion.

Committee Draft