For most of the ultrasonic investigations we become involved, only unsupported speculation originally exists to the severity, extent, and cause of the corrosion problem. Six different involved individuals involved with a corrosion problem often means that there are 6 different and often mistaken opinions based upon speculation and no hard facts whatsoever. Unfortunately, substantial cost and valuable time is wasted pursuing the wrong direction before the facts of the corrosion problem are finally established.
CorrView International, LLC approaches every corrosion question as a forensic investigation - pursuing hard evidence, documenting and defining pipe condition through the use of well established ultrasound technology. We also provide additional services directly related to ultrasonic testing and the field of corrosion control and mitigation; with a large resource of other successful professionals to call upon when required.
We believe in bringing overwhelming evidence and proof of a corrosion problem to the table in any litigation. To establish and firmly document a corrosion problem and degree of damage to a piping system so thoroughly and irrefutably that no possible defense exists.
The same primary intent and attitude exists for disproving a corrosion problem as well. Given the poor quality and inaccuracy of many ultrasonic reports, some bordering on inept, a thorough and comprehensive pipe testing report covering every aspect of the issue can devistate an opponent's complaint and argument.
While other forensic methods of proof to a corrosion problem are often also appropriate, such as metallurgical testing and internal robotic video inspection, it is a thorough ultrasonic evaluation which is almost always the first critical step necessary in order to steer additional investigation to the most appropriate and informative piping areas.
We approach each ultrasonic piping evaluation as an investigation rather than a procedure. That is, to adapt and modify the focus of the investigation as it progresses, rather than strictly test pipe every 20 ft., 100 ft., 500 ft., etc. To thoroughly identify and prove (or disprove) the conditions taking place, multiple disciplines may be required. (Please see our article on this subject in the British journal World Pipelines)
In many investigations metallurgical testing will be necessary to determine the underlying cause of the corrosion problem or failure, with ultrasonic testing able to direct the most appropriate example of pipe to remove rather than cut it out randomly with the hope of blindly selecting the most appropriate location.
Elsewhere, microbiological testing, and even DNA analysis may be required to confirm a micro biologically influenced corrosion (MIC) condition. For further confirmation to the prediction of high rust deposits, clogged pipe, or to inspect areas of pipe behind walls and inaccessible, remote video inspection (RVI) provides the best inspection tool.
An FM or UL label and official stamp on pipe is assumed to define it suitable for installation and at ASTM factory specifications. But in fact, steel pipe can be + / - 12.5% of those specifications and still be approved for service.
Today, most steel pipe and some copper is produced substantially undersized due to what we believe are closer manufacturing tolerances enabling manufacturers to produce a lighter but still approved product within the limits of the ASTM code. Extensive testing of new steel pipe has consistently found undersized material statistically beyond the possibility of being a random event.
The combination of lower than expected pipe wall, more corrosion susceptible steel, less effective chemical inhibitors, and higher corrosion levels, frequently results in severe corrosion problems at new systems that were unheard of decades ago.
We now offer a new service to certify new pipe prior to installation. Submitted samples are submitted to metallurgical lab analysis and its chemical composition, tensile strength, grain structure, and wall thickness documented and compared to ASTM specifications for compliance to such standards.
Samples are also measured ultrasonically for baseline comparison and then submitted to a salt spray environment in order to estimate its susceptibility to corrosion.
Results are presented in a full comprehensive report useful not only in ensuring that the design specifications for the project are met, but in reducing future corrosion problems by highlighting any vulnerability to corrosion inherent in the product itself.
Stated previously, the initial wall thickness of new steel piping products, and even copper pipe, can vary dramatically. Often, it is undersized to near its maximum allowed lower limit.
By installing a fixed testing template at various locations throughout a new piping installation, and prior to the introduction of water, a baseline of pipe wall thickness can be established and compared to true ASTM specifications.
Such proactive planning allows precise follow-up ultrasonic testing during the early stages of system commissioning such as chemical cleaning, pressure testing, and flushing - where the highest wall loss typically occurs to any new piping system.
Future thickness testing then has a known baseline to more accurately define corrosion rate activity, and potentially suggest the need for corrective actions years before a corrosion problem might otherwise reveal itself.
A substantial volume of ultrasonic testing by supposedly qualified individuals is performed poorly in terms of accuracy and procedure. It is not uncommon to see reported wall thickness measurements which are totally beyond the realm of possibility. For example, a report of 12 in. schedule 40 pipe having both a 0.0350 in. and 0.745 in. wall thickness within the same limited section - simply impossible.
An even greater volume of the resulting written reports from such work are incompetently prepared, inaccurate in terms of measurements taken, and therefore entirely worthless. A typical ultrasonic report is often an Excel spreadsheet of a few wall thickness values and nothing else. Some we have seen and carry in our archives are hand written. Either way, questionable information is provided upon which critically important and often costly decisions will be made.
Where questions have been raised to the wall thickness results and conclusions based thereof, a second critical and independent review and assessment of the raw data is always recommended. Such review will immediately highlight inaccurate or unlikely thickness measurements.
It will also define whether seemingly accurate wall thickness measurements have been properly interpreted in terms of estimating corrosion rate activity and remaining service life.
Considering the older age of most building properties under renovation, defining the condition of its piping system at the earliest stages of planning and design is a highly worthwhile precaution against future conflicts. Different piping systems corrode at widely varying rates, and offer varying service life to others.
In addition to age, maintenance and chemical protection varies greatly to prevent any reliable speculation to its condition and future fitness for service.
For some 100 year old properties we have investigated, testing has identified little to no wall loss from schedule 80 specifications and another 250 years of service at least. For others, testing at 10 year old systems have shown high corrosion activity and the pipe approaching the end of its useful service life.
Too often, however, investigation is only initiated after prior leaks, repairs, or some piping problem has been exposed during renovation. As we have documented too many times, it is far too late identifying that 20 sets of perimeter risers are failing and in need of replacement on all 30 floors with the renovation project half way completed.
A thorough and accurate ultrasonic examination of relevant piping systems is always the best first step to any renovation project at older as well as newer building properties. Typically much more involved, costly, and time consuming than an investigation of just one piping service, such precaution is often well justified.
Ideally, the best insurance toward reliable service is to minimize exposure to corrosion problems and prevent pipe failures from ever occurring. Yet for some, insurance is the fallback after the most basic and appropriate maintenance precautions have been ignored.
Although many large insurance underwriters conduct regular building property inspections, they generally fail to recognize those hidden threats common to specific piping systems. Looking at a pipe from the outside, except where multiple pipe clamps are in view, tells absolutely nothing of its internal condition and remaining service life.
Only ultrasonic testing can fully define whether a corrosion problem exists, and to its extent and severity within a building property.
With potentially hundreds of millions of dollars of investment involved, defining the condition of the piping infrastructure prior to purchase is an extremely wise decision. Older properties, which may be approaching retirement for many piping systems, are not the only concern - with even 5 year old properties today showing advanced failures unheard of decades ago.
A thorough fitness for service ultrasonic investigation ensures against surprise failures and expenditures which often remain hidden during more general engineering due diligence surveys.
Preparation to any welding to a live piping system or tank, such as for a wet tap or future service, often requires validation to the remaining wall thickness of the piping or metal surface. This is of special concern where internal corrosion is known to exist and for older properties where no record of materials used is available or current condition known.
Ultrasonic testing is ideal for this function and will provide immediate information about existing wall thickness along the proposed welding zone.
We offer free advice and consultation over the phone when available. Although it is often difficult to pinpoint the cause or define the extent of a corrosion problem by description alone, useful insight and recommendations can often be provided.
Submitting high resolution photographs of any removed piping sections, repairs, corrosion product, prior test reports, or other relevant examples of the piping system will often provide excellent information useful in our speculation to the cause.
For minimal cost, we can also ultrasonically test and evaluate pipe sections which have been cut out and shipped to our office. While not the same as a full ultrasonic investigation relating to 60 or more piping examples, any hard data will always provide useful insight.
With over 30 years of experience in the field of corrosion control, testing, and monitoring, we have worked with many highly qualified experts and sources of valuable information in associated fields such as water filtration, corrosion control, pipe lining, pipe rehabilitation, high pressure water jet cleaning, metallurgical testing, etc.
We have also met our share of near idiots who have caused more harm than good, and have a file folder filled with grossly inaccurate ultrasonic testing reports; incompetent on even a 5th grade level. Sad to say.
CorrView International does not represent others nor sub-contract their work. At request, we will instead suggest contacting those companies which have provided effective and proven solutions in their field should their services seem appropriate.
Full understanding of a corrosion concern is often best started by a review of any existing information - such as prior ultrasonic testing reports, metallurgical or lab analysis, and ideally, photographs of the piping concern, rust deposits, pipe interior, etc.
Please feel free to e-mail your questions. Please include and any relevant information and photographs illustrating the problem.
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P.O. Box 8513Landing, NJ 07850 www.corrview.com Ph: 973-770-7764 Fax: 973-770-6576
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