Ask the Experts
Every month our technical experts answer your questions about pipeline condition assessment and leak detection. Do you have a question that you would like answered by our technical program managers?
Disclaimer: The answers provided in the PPIC "Ask the Experts" column should be considered general opinions and should not be taken as formal engineering advice. Site visits are recommended to provide answers to specific challenges that a client may be facing. PPIC does not assume any responsibility for action taken by readers based on the opinions provided in this column.
Q: I’ve heard that RFTC doesn’t work on embedded cylinder pipe that was made without shorting straps or lined cylinder pipe. Is this true?
No, the RFTC system works on both of those pipe types.
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Q: What are the different methods of getting PipeDiver™ into and out of a live pressurized pipeline?
The standard way to launch and retrieve PipeDiver, is to use specially designed launch and retrieval tubes.
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Q: I understand that an RFTC inspection will provide me with the number of wire breaks in my PCCP, but how do I use that information to make rehabilitation decisions? Are there a number of wire breaks that I can use to determine which pipe needs repair?
Unfortunately there is no universal number of wire breaks that indicates it’s time to rehabilitate a pipe. The number of wire breaks alone is not sufficient to determine which pipe takes priority.
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Q: We're a medium sized city with a single water main that we can't take out of service but we're losing water! What can we do?
Many medium sized cities are supplied by a single large main which cannot be taken out of service. It is not unusual for these mains to be quite old, and older metallic mains are prone to leaking.
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Q: Why did my pipeline fail? How can I minimize the chance of ruptures?
Pipe failures are stressful events. Almost always unexpected, a pipeline failure usually means unhappy customers, unhappy employees and unhappy pipeline owners. If a failure occurs, a utility’s immediate concerns are public safety and getting the line back in service as quickly as possible.
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Q: I'm trying to commission a new pipeline, but I can’t pass the hydrostatic pressure test. How can PPIC help?
PPIC has established a tremendous track record in helping contractors to get a troublesome pipeline to pass a hydrostatic pressure test.
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Q: I’ve noticed that there are several different RFTC tools, in what situations are these various tools used?
The selection of RFTC tool used for an inspection will depend on the operating condition and the diameter of the pipeline.
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Q: I was at the ASCE Pipelines conference and I heard a lot of talk about "false positives" with respect to electromagnetic inspections. What are these and why do they happen?
A false positive is used when comparing estimated results to actual results. In the case of electromagnetic inspection, a false positive refers to when a pipe has been identified to have wire breaks but actually has none.
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