safety skills
A new ASME standard guides pipeline operators
in making sure that personnel are up to the job.
by Bernie Selig and Gerry Eisenberg
Shortly before 9
o'clock on an August morning two years ago, gas leaking from an underground
pipeline exploded, destroying a home and killing two people. The Department
of Transportation, which has jurisdiction over pipelines, sent investigators
from the National Transportation Safety Board to the accident site, on
Woodland Lane in DuBois, Pa.
Digging disturbed the evidence before they arrived, but the accident investigators
were able to recover the pipe and make observations about a joint that
connected two lengths of it. They concluded, in a report issued this past
May, that the probable cause of the leak and the subsequent explosion
and fire was a faulty butt-fusion joint in the 2-inch-diameter plastic
main line pipe. It was unable to hold under the drag force that the pipe
experienced.
The board's report also cited the pipeline operators' "failure to have
an adequate program to inspect joints and replace those not meeting inspection
criteria."
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| Finding Fault: This fault tree for external corrosion is one of the examples in the text of the B31Q standard. |
Among the board's recommendations to the operator was this: "Revise your
initial qualification and requalification procedures for plastic gas pipe
to ensure fusers produce test joints made from coiled pipe with characteristics
similar to those experienced in the field."
A new standard issued by ASME is a first attempt to establish that personnel
industrywide are qualified to make and inspect joints, and to perform
any task critical to the safety or integrity of a pipeline.
The standard, B31Q, Pipeline Personnel Qualification, sets out
instructions for identifying critical tasks, and how and when to qualify
employees to carry them out. The standard is performance based; that is,
it describes what must be done and gives options on how to perform specific
functions.
After a number of years of rule-making attempts by the Department of Transportation
to standardize personnel qualification, the pipeline industry asked ASME
to sponsor the development of a consensus standard. The ASME Codes and
Standards B31 Committee for Pressure Piping formed the B31Q committee,
which met for the first time in August 2003. The project team included
representatives from federal and state regulatory agencies, contractors,
industry associations, labor, and the three pipeline industry sectors—hazardous
liquid, gas transmission, and local gas distribution companies. The team
met regularly over a period of 20 months.
B31Q was approved as an American National Standard on July 10, 2006, and
ASME published it on Sept. 15. It is available for purchase on the ASME
Web site, www.asme.org.
The standard discusses methods for determining covered tasks, training,
evaluation, and documentation.
It includes several appendices to provide guidance for users of the standard.
The development team recognized that large pipeline companies as well
as very small gas distribution operators, with only a few employees, would
use the standard. While any operator could use them, the appendices enable
small operators to develop their own operator qualification programs.
One appendix lists more than 150 potential tasks that affect the safety
or integrity of pipelines. Tasks range from tapping a pipeline to using
measurement equipment to take a reading of the electrical potential between
a structure and soil.
The list describes the steps needed to carry out each task successfully,
its potential applicability, estimated difficulty, interval of requalification,
method of testing, and span of control. Expressed as a ratio, span of
control reflects the acknowledgment that people not formally qualified,
if they are working under the direct observation of someone who has been
qualified, can perform many of the covered tasks. A span of control of
1:2 is a recommendation that no more than two unqualified personnel perform
a task under the observation of one qualified supervisor. Some tasks,
such as those involving underwater inspection or repair, have a ratio
of 1:0. The recommended maximum span of control is 1:5.
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| Eaten Away: These examples of external corrosion on pipelines show the type of deterioration that can result in a dangerous condition. The fault tree on the facing page identifies events that can lead to failure due to corrosion. |
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The task list is offered by way of suggestion. The operator is advised
to determine which tasks should be covered. There are listed tasks that
may be irrelevant in some cases. For instance, a pipeline may not have
a reciprocating compressor and, therefore, an operator will not need to
qualify someone in the proper way to inspect one.
The standard offers methods for determining covered tasks—consultation
with subject matter experts, the use of the fault tree method, the use
of the task list appendix, or any other technically appropriate method.
Subject matter experts are defined as individuals who possess knowledge
of the discipline or process and have work experience in the area.
The fault tree method, first developed in the aerospace industry in the
1960s and '70s, works back from an unwanted outcome—say, the failure
of a pipeline from corrosion—to identify all the actions done and
undone that contributed to the result so that faults can be foreseen and
forestalled.
The standard used nine threats to pipelines that form the basis of another
pipeline standard, ASME B31.8S-2001, Managing System Integrity of Gas
Pipelines, to develop nine fault trees. With the aid of subject matter
experts, the fault trees led to the list of "covered tasks" in the appendix
of the standard.
Similarly, a technical process, the DIF (difficulty, importance, and frequency)
decision tree process, was used to develop reevaluation intervals, the
time from the first qualification for a covered task to the reevaluation
to continue the person's qualification.
The standard applies to individuals performing any covered task, whether
they are company employees, contractors, union crafts people, or mutual
aid employees from another pipeline company.
The federal pipeline regulator, The Pipeline and Hazardous Materials Safety
Administration, was a full participant in the development of the standard
and has proclaimed that pipeline companies meeting the standard will meet
the OQ regulations.
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A Task at a Time ASME's B31Q standard includes
an appendix listing more than 150 tasks that affect the safety and
integrity of pipelines. The list is intended to offer examples of
the kinds of tasks that must be identified and for which personnel
need to be qualified. Task 0171: Measure External Corrosion (2) Prepare surface (3) Perform test equipment check (4) Take measurement (length, depth,
width, (5) Identify characterisitics of corrosion (6) Recognize and react to AOCs (7) If required, complete documentation AOCs are abnormal operating conditions.
Under |
Bernie Selig is a consultant and, before he retired,
was vice president for technology with Hartford Steam Boiler Inspection
and Insurance Co. in Hartford, Conn. Gerry Eisenberg is director of pressure
technology Codes & Standards at ASME.
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© 2006 by The American Society of Mechanical Engineers