chapter 2 pipeline mechanical integrity assesment methodoligies Flashcards
Gas pipeline incident data classified into ___ ______ causes
22 root
one of the 22 root causes is _______
unknown
three time dependent corrosion threats are
external
internal
stress
stable threats due to manufacturing-related threats
defective pipe seams
defective pipes
stable threats due to welding or fabrication related
defective pipe girth weld
defective fabrication weld
wrinkle bend or buckle
stripped threads/broken pipe/ coupling failure
manufacturing-related threats, and welding/fabrication related are _______ threats
stable
Third party/mechanical damage
incorrect operational procedures
weather related and outside force
are all _____ ______ threats
Time-independent
damage inflicted by first, second or third parties
previously damaged pipe
vandalism
are all ______ _______ / ________ threats
third party/mechanical
listed under time independent
incorrect operational procedures
listed under time-independent
cold weather
lightning
heavy rains or floods
earth movements
weather related and outside force
listed under time-independent
identify threat gather integrate data risk assessment integrity assessment mitigation/inspection intervals updated, integrate, and review data reassess risk
seven step conducted to complete the integrity management process.
three generally accepted methods for assessing the integrity of pipelines
In-Line inspections
Hydrostatic pressure tests
Direct assessment
for validating the mechanical integrity of pipelines, used as a strength test and as a leak test
pressure test or
hydrostatic test
a limitation of pressure testing that occurs when a defect survives a higher hydrostatic test pressure but fails at a lower pressure.
pressure reversal
used for liquid lines
MOP
used for gas lines
MAOP
pressure testing can be used on new or
previous installations
the strength test requirements for steel pipeline to operate at a hoop stress of ___% or more of SMYS (specified minimum yield strength)
30
changes that happed slowly over a period of time
creep
line must be reasonably free of air or other entrapped gases.
Line fill
volume and pressure variation ratio (DV/DP)[delta variation/delta pressure]
pre-test calculation
several factors that affect accuracy of test results.
fluid temperature
entrained air
coefficient of thermal expansion
instrument with one psi increments and a calibrated pressure chart recorder
dead weight tester
pressure test advantages
cost effective
eliminates defects
