Page 147 - Pipeline Risk Management Manual Ideas, Techniques, and Resources

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Awarding of points for this item should be based on the adjustments to route or depth, and addition of valves or connec-
existence and use of control documents and procedures that tions. The stability of the buried pipeline during modifications
govern all aspects of pipeline material selection and installa- is often a critical consideration. Construction activities near or
tion. Two points are awarded for the best use of controls, 0 in the pipeline right of way may produce slopes that are not sta-
points if controls are not used. ble and could put the pipeline at risk. These activities include
excavation for road or railway cuts, removal of material from
A5. Checks (0-2 pts) the toe of a slope, or adding significant material to the crest of a
slope, in addition to construction activities on the pipeline
Here, the evaluator determines if design calculations and deci- itself. Slope alterations near, but outside, the right of way by
sions were checked at key points duringthe design process. In the third parties should be monitored and the responsible parties
U.S., a licensed professional enpeer often certifies designs. notified and consulted about their project’s effect on the
This is a possible intervention point in the design process. Design pipeline.
checks by qualified professionals can help to prevent errors and The evaluator can assess the potential for human error in the
omissions by the designers. Even the most routine designs construction phase by examining each of the variables listed
require a degree of professional judgment and are consequently above and discussed in more detail next.
prone to error. Design checks can be performed at any stage in
the life of the system. It is probably impossible to accurately B1. Inspection (0-10 pts)
gauge the quality of the checks-evidence that they were indeed
performed will probably have to suffice. Maximum points can be awarded when a qualified and consci-
Two points are awarded for sections whose design process entious inspector was present to oversee all aspects of the con-
was carefully monitored and checked. struction and the inspection provided was ofthe highest quality.
A check of the inspector’s credentials, notes during construc-
tion, work history, and maybe even the constructor’s opinion of
B. Construction (suggested weighting: the inspector could be used in assessing the performance. The
20%) scoring of the other construction variables may also hinge on
the inspector’s perceived performance.
Ideally, construction processes would be well defined, invariant If inspection is a complete unknown, 0 points can be
from site to site, and benefit from a high pride of workmanship awarded. This variable commands the most points under the
among all constructors. This would, of course, ensure the construction category because current pipeline construction
highest quality and consistency in the finished product and practices rely so heavily on proper inspection.
inspection would not be needed.
Unfortunately, ths is not the present state of pipeline con- B2. Materials (0-2 pts)
struction practice. Conformance specifications are kept wide to
allow for a myriad of conditions that may be encountered in the Ideally, all materials and components were verified as to their
field. Workforces are often transient and awarding of work authenticity and conformance to specifications prior to their
contracts is often done solely on the basis of lowest price. This installation. Awareness of potential counterfeit materials should
makes many projects primarily price driven; shortcuts are be high for recent construction. Requisition of proper materials
sought and speed is often rewarded over attention to detail. is probably not sufficient for this variable. An on-site material
For the construction phase, the evaluator should find evidence handler should be taking reasonable steps to ensure that the right
that reasonable steps were taken to ensure that the pipeline material is indeed being installed in the right location.
section was constructed correctly. This includes checks on the Evidence that this was properly done warrants 2 points.
quality of workmanship and, ideally, another check on the design
phase. B3. Joining (0-2 pts)
While the post-construction pressure test verifies the system
strength, improper construction techniques could cause prob- Pipe joints are sometimes seen as having a higher failure poten-
lems far into the future. Residual stresses, damage to corrosion tial than the pipe itself. This is reasonable since joining nor-
prevention systems, improper pipe support, and dents or mally occurs under uncontrolled field conditions. Highest
gouges causing stress risers are some examples of construction points are awarded when high quality of workmanship is seen
defects that may pass an initial pressure test, but contribute to a in all methods of joining pipe sections, and when welds were
later failure. inspected by appropriate means (X-ray, ultrasound, dye pene-
Variables that can be scored in the assessment are as follows: trant, etc.) and all were brought into compliance with governing
specifications. Where weld acceptance or rejection is deter-
B1. Inspection 10 pts mined by two inspectors, thereby reducing bias and error,
B2. Materials 2 pts assurances are best. Point values should be decreased for less
B3. Joining 2 pts than 100% weld inspection, questionable practices, or other
B4. Backfilling 2 pts uncertainties. Otherjoining methods (flanges, screwed connec-
B5. Handling 2 pts tions, polyethylene fusion welds, etc.) are similarly scored
B6. Coating 2 pts based on the quality of the workmanship and the inspection
techmque.
These same variables can also apply to ongoing construction 100% inspection of all joints by industry-accepted practices
practices on an existing pipeline. This might include repairs, warrants 2 points in this example.