Definition of hazard
• A characteristic or group Of characteristics
that provides the potential for a loss.
• Examples: Internal and external corrosion,
stress corrosion crack, material defects, third-party damage and environment
including toxicity, flammability, exposed pipes, lack of signage, etc. Pipeline
Corrosion Control
• Coating is the main corrosion control
technique.
• But dependence on one source for protection
is not a very wise approach - No coating is perfect.
• To protect
coating flaws, cathodic protection (CP) is applied.
• Coatings and CP are successful combination
for corrosion control. External corrosion on a pipeline could be
microbiologically induced corrosion (MIC), or from galvanic action or elec-
trochemical reaction, where the steel pipe becomes an anode in an
electrochemical cell. This is a tinl&dependent hazard,and occurs after some
time iri service.
To address these threats, collection of data is carried out,
and based on the analysis of those data, a risk assessment plan is prepared.
This is an important step. The data collection process is a painstaking and
detailed activity. In the beginning, the collected data may be verwhelming and intimidating, but a good risk
assessment program is data dependent. In fact, most of these data are already
in the computers of the pipeline op erators but they keep sitting as dead data.
In the world ofcomputers, it is easy to share, download, and transfer most of
these valuable data and put them to better use. "Better use" IS the
availability of the data for analysis that helps manage the risk. Periodically
this collection ofdata can be refreshed and updated. There is no limit to the
available data and its possible use. However, the basic data that needs to be
collected in this context is listed below:
a. Pipeline year of installation
b. Pipe grade (ASTM A 106 Grade B, API 5L Grade
B, X42, X65, X70, etc.)
c. Pipe diameter and wall thickness
d. Maximum operating pressure (MAOP) (or design
pressure) and temperature e.
seamless, double submerged arc welding (DSAW)
f. Pipe seam type, e.g., electric resistance
welding (ERW), Coating type, e.g., coaltar enamel, fusion bonded epoxy (FBE),
three-layer polyethylene (3LPE)
g. Coating condition at the time of lxst
inspection (updated periodically)