Inspection of In-Service Corridor Piping

1. SCOPE

………………………………………………………………………………….

1. REFERENCES
2. DEFINITIONS
3. GENERAL

………………………………………………………………………………

1. INSPECTION PERSONNEL QUALIFICATION
2. SAFETY

7.

INSPECTION REQUIREMENTS And PROCEDURES …………………

1. ESTABLISHING LOCATIONS for TML and CUI
2. TYPES Of INSPECTION and SURVEILLANCE
3. INSPECTION FREQUENCY …………………………………………………….11. EXTENT OF INSPECTION
4. CORROSION RATE DETERMINATION
5. CONCRETE PIPE SLEEPERS, SUPPORT

FOUNDATIONS & CULVERTS…………………………………………………..14. BURIED SECTIONS OF PIPELINES UNDER ROAD CROSSINGS 15. REPORTING and DOCUMENTATION

FIGURE

1. Piping Classification Matrix ……………………………………………………….2.

Inspection Frequency Matrix

1. Attachment I : Determination of the number of TMLs

on corridor line ……………………………………………………………………….. 4. Attachment II : Corridor Piping Inspection Report Form

TABLE

I. Piping Classification of Sabic Products………………………………………..

1. Scope

This standard is to be used in conjunction with API 570 for inspection of above ground metallic piping

systems that have been in-service in the Royal Commission pipeline corridor in Jubail and Yanbu Industrial

Cities.

Note: Inspection and monitoring of Cathodic Protection (CP) systems for buried sections of pipelines

is applicable to only Yanbu corridor pipelines.

1. References

Reference is made in this standard to the following documents. The latest issues, amendments, and

supplements to these documents shall apply unless otherwise indicated.

API-570- Inspection, Repair, Alteration, and Rerating of In-Service Piping Systems

API RP 574 – Inspection of Piping System Components

API RP 750 – Management of Process Hazards

ASNT SNT-TC-1A / CP-189 – Qualification and Certification of Nondestructive Testing Personnel

NFPA 704 – Identification for the Fire Hazards of Materials

Royal Commission Engineering Manual, Section 1140

1. Definitions

For the purpose of understanding this standard, the following and other applicable definitions listed in

API 570 apply.

SABIC. All SABIC affiliates.

Authorized Piping Inspector. A qualified inspection personnel authorized by Sabic inspection

department.

CUI. Corrosion under insulation, including stress corrosion cracking under insulation.

Deadlegs. Components of a piping system that normally have no significant flow. Examples include the

following: blanked branches, lines with closed block valves, pressurized dummy support legs, stagnant

control valve by-pass piping, spare pump piping, relief valve inlet and outlet header piping, high point vents,

sample points, drains, bleeders, and instrument connections.

In service. Piping containing any amount of process fluid.

Piping systems. An assembly of interconnected piping that is subject to the same set of design conditions.

Piping system also includes pipe-supporting elements but does not include support structures, such as

structural frames and foundations.

Thickness measurement locations (TML). Designated areas on piping systems where periodic

inspections and thickness measurements are conducted.

1. General

4.1 SABIC shall determine the inspection program and inspection frequencies for the piping systems based

on the criteria specified in this standard. The minimum requirements and recommendations of API 570

shall also be adhered to Piping systems that are susceptible, but not limited, to the following specific types

and areas of deterioration, shall be considered for inspection.

a. Injection points

b. Deadlegs

c. Corrosion under insulation (CUI)

d. Soil-to-air (S/A) interfaces

e. Service specific and localized corrosion

f. Erosion and corrosion/erosion

g. Environmental cracking

h. Corrosion beneath linings and deposits

i. Fatigue cracking

j. Creep cracking

k. Brittle fracture

l. Freeze damage

4.2 The inspection shall ensure that all pipelines are appropriately labelled in accordance with Royal

Commission Engineering Manual Section 1140.

1. Inspection Personnel Qualification

5.1 Approving Authority shall ensure that the Piping inspection personnel has at least one of the following

qualifications.

a. API 570 certified piping inspector

b. Engineering graduate with one year experience in piping inspection with proven competence.

c. High school certificate with three years experience in piping inspection with proven competence.

5.2 Approving Authority shall ensure that NDT personnel are certified to minimum of NDT Level II in UT as

per ASNT SNT-TC-1A / CP.189.

1. Safety

Preparation for inspection of in-service piping systems shall be in accordance with SABIC’s in-house

safety procedures and API 570, paragraph 5.2 and section 8 of API 574.

1. Inspection Requirements and Procedures

7.1 SABIC approved inspector shall carry out inspection of Sabic piping systems.

7.2 SABIC or SABIC approved contractor shall be responsible for developing, documenting, approving,

implementing, executing, and assessing piping inspection systems and inspection procedures that will

meet the requirements of this standard. The inspection department shall create the necessary documents

for inspecting requirements.

1. Establishing Locations for TML and CUI

8.1 The selection of Thickness Measurement Locations (TMLs) shall be in accordance with the

Attachment II. For further details refer to API 570, Paragraph 5.5.

8.2 Certain areas and types of piping systems are potentially more susceptible to CUI, including the

following

a. Areas subject to process spills, ingress of moisture, or acid vapors

b. Carbon steel piping systems, including those insulated for personnel protection, operating

between –4 °C to120 °C. CUI is particularly aggressive where operating temperatures cause frequent

or continuous condensation and re-evaporation of atmospheric moisture

c. Carbon steel piping systems that normally operate in-service above 120 °C but are in

intermittent service

d. Deadlegs and attachments that protrude from insulated piping and operate at a different

temperature than the operating temperature of the active line

e. Austenitic stainless steel piping systems operating between 65 °C-204 °C. (These systems are

susceptible to chloride stress corrosion cracking.)

f. Vibrating piping systems that have a tendency to inflict damage to insulation jacketing providing a

path for water ingress

g. Piping systems with deteriorated coatings and/or wrappings

8.3 The areas of piping systems listed in 8.2 may have specific locations within it that are more susceptible

to CUI, including the following

a. All penetrations or breaches in the insulation jacketing systems, such as

(i) Deadlegs (vents, drains, and other similar items)

(ii) Pipe hangers and other supports

(iii) Valves and fittings (irregular insulation surfaces)

(iv) Bolted-on pipe shoes

b. Termination of insulation at flanges and other piping components

c. Damaged or missing insulation jacketing

d. Insulation jacketing seams located on the top of horizontal piping or improperly lapped or sealed

insulation jacketing

e. Termination of insulation in a vertical pipe

f. Caulking that has hardened, has separated, or is missing

g. Bulges or staining of the insulation or jacketing system or missing bands. (Bulges may indicate

corrosion product buildup.)

h. Low points in piping systems that have a known breach in the insulation system, including low

points in long unsupported piping runs. During external inspection particular attention shall be paid in

checking the corrosion of drain nozzles and valves and condition of piping at sliding supports and pipe

movements at loops due to expansion.

i. Carbon or low-alloy steel flanges, bolting, and other components under insulation. Locations

where insulation plugs have been removed to permit piping thickness measurements on insulated

piping should receive particular attention. These plugs should be promptly replaced and sealed.

1. Types of Inspection and Surveillance

After identifying the locations for inspection, SABIC’s inspection department shall determine what type of

inspection and surveillance is required to determine the physical state of the in-service piping. Inspection

and surveillance can be any one or a combination of the following

a. Internal visual inspection.

b. Thickness measurement inspection.

c. External visual inspection.

d. Vibrating piping inspection.

e. Supplemental inspection.

1. Inspection Frequency

10.1 The inspection frequency shall be based on the classification of the piping systems and the rate of

deterioration of the pipeline due to corrosion/erosion.

10.2 The inspection frequency of metallic piping systems shall be determined using the following

methodology

STEP 1: Establish the piping class of the product using the matrix given in Figure 1. (Classification of
some SABIC products is given in Table 1 for guidance. This matrix is developed from API RP 570 and
NFPA 704 that provide potential hazards for different process fluids.)
STEP 2: Identify which Failure/Deterioration category of the following three is applicable to your
in-service pipeline:
Category A:No internal / external corrosion
Category B:Externally coated / Insulated (CUI), No internal corrosion
Category C:External / Internal corrosion, erosion and other degradation suspected.
STEP 3: Determine the Inspection frequency by plotting the piping class versus failure/deterioration
category (established in step 1 & 2 respectively) in matrix given in Figure 2.
10.3 Once the inspection frequency is established, the inspection interval can be increased only after two
consecutive inspections. The increase in inspection interval for any given pipeline shall be based on the
actual inspection data gathered during the two consecutive inspections. However, decrease in inspection
interval can be made whenever the extent of corrosion and corrosion rate is found to increase than
previously envisaged or established.
11. Extent of Inspection
11.1 The visual inspection shall include (but not limited to) the items listed in Attachment II.
11.2 The extent of inspection for corrosion under insulation (CUI) shall be as follows:

11.3 The extent of thickness monitoring shall be in accordance with Attachment I.

11.4 TML’s have been identified on the loop sketch in Attachment II as typical. For different piping

configurations, TML’s shall be identified on the sketch.

1. Corrosion Rate Determination

12.1 Once the thickness measurements are tabulated, the corrosion rate and remaining life shall be

determined in accordance with API 570 Paragraph 7.1. The remaining life shall set the requirements for

subsequent inspections based on corrosion rates. However, the inspection frequency shall not exceed as

specified in clause 10 above and given in Figure 2.

1. Concrete Pipe Sleepers, Support Foundations & Culverts

All reinforced concrete pipe sleepers, support foundations and culverts shall be visually inspected for any

signs of concrete deterioration (i.e. delamination, cracking and spalling of concrete) and immediately

reported to the “Industrial Coordinator” of Royal Commission for their repair works.

1. Buried Sections of Pipelines Under Road-Crossings (Yanbu Corridor Only)

14.1 All buried sections of the pipelines that are under-passing the road crossings in Yanbu Corridor only,

shall be appropriately coated and cathodically protected.

14.2 For all new pipelines cathodic protection shall be achieved within one week of pipeline burial.

14.3 The minimum design life of cathodic protection systems shall be 20 years.

14.4 The anode spacing shall not be in excess of 10 m.

14.5 The cathodic protection (CP) system type shall preferably be sacrificial (Galvanic) and comprise

magnesium anodes. In case of impressed current CP system, all pipelines from all different companies at

each common buried location shall be bonded to each other.

14.6 The CP system shall preferably have the provision and/or facility to interrupt the applied cathodic

current and measure ‘instant-off’ pipe-to-soil steel potentials.

14.7 Each CP system shall be monitored and in case of ICCP system be appropriately adjusted as well if

required, on annual basis minimum.

14.8 Each pipeline shall have at least 2-3 fixed locations for measuring pipe-to-soil steel potentials using

hand-held reference electrodes.

14.9 The afforded cathodic protection of pipelines shall be considered sufficient only, if either of the

following two criterions is met

a. Achieving an Instant-off pipe-to-soil steel potential of negative (-) 850 mV Cu/CuSO4 or a

current-on pipe-to-soil steel potential of negative (-)1000 mV Cu/CuCuSo4 (minimum).

b. A depolarization of minimum 100 mV from instant-off pipe-to-soil steel potential after interrupting

the applied cathodic current.

1. Reporting and Documentation

15.1 Inspection report shall be produced for each inspection and the attachment II shall be used as

minimum for reporting the inspection.

15.2 The inspection report shall include the following as minimum

a) Actual measured thickness

b) Remaining life

c) Condition assessment

d) Any repairs carried out

e) Next recommended inspection date

15.3 All inspection records / report shall be retained for two consecutive inspections.

FIGURE 1
PIPING CLASSIFICATION MATRIX

FIGURE 2
INSPECTION FREQUENCY MATRIX

KEY:
A = No corrosion internal / external
B = Externally coated / Insulated (CUI), no internal corrosion
C = External / Internal corrosion, erosion degradation suspected

Table I
PIPING CLASSIFICATION OF SABIC PRODUCTS.

Figure 3
ATTACHMENT I:DETERMINATION OF THE NUMBER OF TMLs ON CORRIDOR LINE
The attachment is a guide for establishing the minimum number of TMLs for each circuit in a Class 1, 2 or
3 (on-site) piping systems. This method takes into account the classification of the piping system as well
as the length of the line, number of fittings, and assumed circuit corrosion rate.
The general formula is:
Number of TMLs = (L + F) * (C)
The factors for this equation are defined in the following table.

X = Number of Fittings

CR = Assume Circuit Corrosion Rate

Notes

1. Assume one complete length of pipeline as “One Circuit”.
2. Minimum no. of TMLs at each “Loop” shall be 9 as shown in sketch on attachment II.
3. Selection of loops on one circuit shall be evenly distributed to cover the entire length of the line.
4. Minimum no. of the loops to be inspected shall not be less than 10% of the total no. of the loops.

Example Calculation

Typical length of pipeline

=

14500m

Length Factor

(L)

=

3.0

Typical no. of Loops on One Circuit

=

40 nos.

No. of fittings on each loop (typically)

=

4 nos.

Therefore total no. of fittings

=

40 * 4 = 160 nos.

Piping Class

=

Class I

Therefore calculated fitting factor (F)

=

0.375 * 160 = 60

Corrosion rate factor (C)

=

2.0

Number of TMLs

=

(3 + 60) * 2 = 126 nos.

Min. no. of TMLs at each loop (see note 2)

=

9 nos.

Therefore no. of loops to be inspected

=

126/9 = 14 nos.

For even distribution, every 3rd loop can be selected for inspection.

Figure 4
ATTACHMENT II : Corridor Piping Inspection Report Form