Best Practice SABP-H-092 01 JUN 2017
Inspection and Root Cause Analysis of FBE External Coating Failures
Document Responsibility: Coatings Standards Committee
Primary contact: Mana Mansour Page 1 of 26
CopyrightSaudi Aramco 2017. All rights reserved.
Saudi Aramco DeskTop Standards Table of Contents
1 Scope ................................................................... 2
2 Purpose ................................................................ 2
3 Definitions ............................................................ 2
4 References ........................................................... 4
5 Responsibilities ................................................... 6
6 Introduction ......................................................... 6
7 Field Investigation ............................................... 7
8 Lab Investigation ............................................... 12
9 Bibliography ...................................................... 15
Document Responsibility: Paints and Coatings Standards Committee SAEP-H-092
Issue Date: 01 JUN 2017 Shop Application of FBE to the External Surfaces of Line Pipes
Saudi Aramco: Company General Use
Previous Issue: 01 JUN 2017 Next Planned Update: 01 JUN 2020 Page 2 of 26
Primary contact: Mana Mansour
1 Scope
The scope of this document is FBE failures on externally coated buried pipelines.
Premature external FBE coating failures have been observed on buried Saudi Aramco
Oil and Gas transmission lines. A reasonable expectation of service life for FBE is
around 30 years, but failures within less than 10yrs of installation have been observed.
Given the inspection, remediation costs and in particular the safety impacts of
premature failures, a more structured and comprehensive approach towards field
investigations is felt warranted to better understand and prevent such occurrences in the
future. It is hoped that this best practice will detect chronic quality and contractor errors
that only a long term study of this nature is capable of exposing.
2 Purpose
The purpose of this document is to act as a guide to both field and lab personnel when
assessing the cause of external coating failures on FBE coated buried pipelines. It
details the methodology, accepted practices and decision making to be followed when
confronted with a coating failure or potential failure. This practice has been developed
with Coating, CP, Piping and Corrosion specialists to assist in correctly assigning the
mode of failure and most probable failure root cause and the most appropriate corrective
actions.
3 Definitions
CIPS Close-Interval Potential Survey. Used for detecting areas with low CP
potential
CNS Chlorides, Nitrates and Sulphates the usual anions that drive
corrosion.
CD Cathodic Disbondment. Coating delamination driven by excessive CP
current.
CP Cathodic Protection (impressed current or sacrificial anodes).
EDS Energy-Dispersive (X-ray) Spectroscopy or EDX. Used to determine
elements present.
DCVG Direct Current Voltage Gradient. Used for detecting coating defects and
anomalies.
DFT Dry Film Thickness of FBE film usually in microns (m)
Document Responsibility: Paints and Coatings Standards Committee SAEP-H-092
Issue Date: 01 JUN 2017 Shop Application of FBE to the External Surfaces of Line Pipes
Saudi Aramco: Company General Use
Previous Issue: 01 JUN 2017 Next Planned Update: 01 JUN 2020 Page 3 of 26
Primary contact: Mana Mansour
DJ Single pipes (12m) are commonly welded at the plant into a 24m length
called a Double Joint. The DJ weld is usually shop coated. Multiple
DJs are welded in the field to form a Pipe String.
DSC Differential Scanning Calorimetry. Used to determine Tg and % cure of a
resin.
ECDA External Corrosion Direct Assessment. Inspection methodology for
external pipeline corrosion.
EIS Electrochemical Impedance Spectroscopy technique used to measure
film permeability and behaviour with respect to moisture penetration.
FBE Fusion Bonded Epoxy.
FJ Field Joint. Weld between 2 pipe strings. Compare with GW or DJ.
FTIR Fourier Transform Infrared Spectroscopy. Used to determine chemical
structure of organic materials.
GW Girth Weld. Another designation for Field Joint (FJ).
Holiday Exposed bare steel on a coated pipe (due to damage etc)
HSS Heat Shrink Sleeve. Commonly used on girth welds (Field Joints)
ID Internal Diameter refers to location of coating on pipe.
ILI In-Line Inspection using intelligent internal scraper to detect pipe wall
thinning.
KM Kilometer. Usually refers to a location along the pipe. Eg; KM71.
MIC Microbiologically Influenced Corrosion.
MPN Most Probable Number. Measure of Bacteria Numbers.
qPCR Quantitive Polymerase chain reaction. Method to measure live and dead
bacteria numbers
ML Metal Loss. In the case of piping, the reduction in wall thickness.
OD Outer diameter of a pipe
Pipe String Pipeline, welded together in preparation for burial.
SEM Scanning Electron Microscope. Used for high magnification imaging and
analysis.
TGA Thermal Gravimetric Analysis. Alternate method for determining thermal
stability and chemical composition of compounds
Document Responsibility: Paints and Coatings Standards Committee SAEP-H-092
Issue Date: 01 JUN 2017 Shop Application of FBE to the External Surfaces of Line Pipes
Saudi Aramco: Company General Use
Previous Issue: 01 JUN 2017 Next Planned Update: 01 JUN 2020 Page 4 of 26
Primary contact: Mana Mansour
TMA Thermo-Mechanical Analysis. Alternate method for determining Tg.
Tg Glass Transition Temperature. Transition point between rubber like and
solid like behaviour.
XRD X-ray diffraction. Method for determining crystallographic structure of
inorganic compounds (oxides, soil, etc)
XRF X-ray fluorescence. Method for determining elemental composition of
inorganic materials (soils, oxides, etc)
4 References
4.1 Saudi Aramco References
Saudi Aramco Engineering Standards
SAES-H-002 Internal and External Coatings for Steel Pipelines and
Piping
SAES-H-002V Approved Saudi Aramco Data Sheets for the Pipeline and
Piping Coatings
Saudi Aramco Materials System Specification
01-SAMSS-024 Pipe Handling and Nesting
09-SAMSS-089 Shop Applied External FBE for Steel Line Pipes
09-SAMSS-200 Storage, Handling and Installation of Externally Coated
Pipe
Saudi Aramco Inspection Requirements
Form 175-091300 Shop-Applied External FBE Coating
4.2 Industry Codes and Standards
American Society for Testing and Materials
ASTM D4417 Field Measurement of Surface Profile for Blast Cleaned
Pipe.
ASTM D4959-16 Determination of Water Content of Soil by Direct Heating
ASTM D5162-08 Discontinuity (Holiday) Testing of Nonconductive
Protective Coating on Metallic Substrates
ASTM G14 Test for Impact Resistance of Pipeline Coatings
ASTM G51 95 Measuring pH of Soil for Use in Corrosion Testing.
ASTM G57 06 Field Measurement of Soil Resistivity Using the Wenner
Four-Electrode Method.
https://standards.aramco.com.sa:10009/mycommittee.asp?fol=Inspection_Requirements&committee_id=8&sm=175-091300
Document Responsibility: Paints and Coatings Standards Committee SAEP-H-092
Issue Date: 01 JUN 2017 Shop Application of FBE to the External Surfaces of Line Pipes
Saudi Aramco: Company General Use
Previous Issue: 01 JUN 2017 Next Planned Update: 01 JUN 2020 Page 5 of 26
Primary contact: Mana Mansour
ASTM G162 Conducting and Evaluating Laboratory Corrosion Tests in
Soils.
ASTM G187-12A Measurement of Soil Resistivity Using the Two-Electrode
Soil Box Method.
ASTM G200-09 Measurement of Oxidation-Reduction Potential (ORP) of
Soil
ASTM G6677-01 Adhesion Testing
International Organization for Standardization
ISO 8502-3 Assessment of Dust on Steel Surfaces (pressure sensitive
tape method)
ISO 8502-9 Preparation of steel substrates before application of paints
and related products Tests for the assessment of surface
cleanliness Part 9: Field method for the conductometric
determination of water-soluble salts
The Society for Protective Coatings (SSPC)
SSPC PA 2 Measurement of Dry Coating Thickness with Magnetic
Gages.
Canadian Standards Association
CAN/CSA-Z245.20 External Fusion Bond Epoxy Coating for Steel Pipe.
NACE
NACE RP0394 Application, Performance, and Quality Control of Plant-
Applied Fusion Bonded Epoxy External Pipe Coating.
NACE SP0169 Control of External Corrosion on Underground or
Submerged Metallic Piping Systems
Miscellaeneous
DIN 50929-3 Metal corrosion; corrosion probability of metallic
materials with external exposure to corrosion; ducts and
structural elements i
