Page 152 - Pipeline Risk Management Manual Ideas, Techniques, and Resources

Operation 6/129
Deformation detection by pigging Maps and Records
Population density surveys
Depth of cover surveys In general, facility records maintained by the utility owners or pipeline
Sonar (subsea) surveys operators are the most widely used sources of information about the
Thermographic surveys underground infrastructure. In the U.S., operators are required to iden-
Leak detection tify facilities in environmentally sensitive areas and in densely populated
Airpatrol areas. In many pipeline environments, however, there is no specific
requirement for system operators to maintain a comprehensive system
Each item is intended to identify areas of possible threat to map oftheir underground facilities. Nevertheless. many do maintain this
the pipeline. A formal program of surveying, including proper information to facilitate their business operations.
documentation, implies a professional operation and a measure System records developed prior to the widespread use of computer
of risk reduction. Routine surveying Further indicates a more technology most likely exist as architectural and engineering diagrams
proactive, rather than reactive, approach to the operation. For For some systems, these diagrams have been electronically imaged so
the pipeline section being evaluated points can be awarded that they are easier to reference. update, and store. Digitized versions of
based on the number of surveys performed versus the number early maps do not always reflect the uncertainty of information that may
of useful surveys that could be performed there. Survey have been inherent on the hand-drafted version. Structural references
information should become a part of maps and records and landmarks that define the relative locations of underground facili-
whereby the survey results are readily available to operations ties also change over time and may not he reflected on maps.
and maintenance personnel. Many system maps lack documentation of abandoned facilities
Maps and records document critical information about the Abandoned facilities result when the use of segments of the under-
pipeline systems and therefore play a role in error reduction. ground system are discontinued, or when replaced lines run in new loca-
That role can be evaluated here. tions, or when entire systems are upgraded. Without accurate records of
As discussed in the third-party damage index discussion abandoned facilities, excavators run the risk ofmistaking the abandoned
(Chapter 3). there is often a need to routinely locate a pipeline line for an active one. thereby increasing the likelihood of hitting the
to protect it from pending excavations. When indirect means of active line.
line locating, such as drawings and other records, are used, In addition to documenting the location of a facility. utility map
there is an increased opportunity for incorrect locating. This is records may also contain information on the age of the facility, type and
due to the human error potential in the creation and use of dimensions of the material. history of leakage and maintenance. status
maps, including: of cathodic protection, soil content, and activity related to pending con-
struction. However, the quality ofthis information varies widely.
Incorrect initial measurements of the line location during Excavators. locators, and utility operators can use GPS information to
installation identify field locations (longitude and latitude coordinates). and they
Errors in recording of these measurements can use this information to navigate to the sites. With the added capabil-
Errors in creation of the record documents ity of differential GPS. objects can be located to an accuracy of better
Failure to update documents than 1 meter (1. I yards). This degree of accuracy makes differential GPS
Incorrect filing and retrieval ofthe documents appropriate for many aspects of mapping underground facilities.
Incorrect interpretation and communication of the data from Subsurface utility engineering (SUE) is a process for identifying, ver-
the document. ifying. and documenting underground facilities. Depending on the
information available and the technologies employed to verify facility
While some pipe movement after construction is possible, locations, a level of the quality of information can he associated with
this is normally not an important factor in line location. underground facilities. These levels, shown in Table I, indicate the
Maps and records are increasingly being stored on and degree of uncertainty associated with the information; level A is the
retrieved from computers. Whether in digital or paper form, most reliable and level D the least reliable. This categorization is a direct
and similar to the evaluation of procedures discussed previ- result of the source of information and the technologies used to venfy
ously, the scoring of surveys/maps/records can be based on the information.
aspects such as:
C6. Training (0-10 pts)
Comprehensiveness-amount of the system covered by
maps and records Training should be seen as the first line of defense against
Detail-level of detail shown (depth, landmarks, pipe speci- human error and for accident reduction. For purposes of this
fications, leak history, current condition, etc.) risk assessment, training that concentrates on failure preven-
Clariwase of reading; chance of misinterpretation of tion is the most vital. This is in contrast to training that empha-
information sizes protective equipment, first aid, injury prevention, and
Timeliness of updates even emergency response. Such training is unquestionably cnt-
0 Document management system--ensuring version control ical, but its impact on the pipeline probability of failure is indi-
and ready access to information. rect at best. This should be kept in mind as the training program
is assessed for its contribution to risk reduction.
Examples of common pipeline survey techniques are shown Obviously, different training is needed for different job
in Appendix H. The following information on maps and records functions and different experience levels. An effective training
is excerpted from a 1997 study, Ref. [64]: program, however, will have several key aspects, including