Overview - Pipe Testing

     Due to the combination of a wide variety of physical factors, building operations and management personnel are finding themselves faced with new and more complex corrosion related piping problems. Many are clearly related to the quality of the water treatment program or a past lack of corrosion protection, some are due to past problems which may have existed during construction and start-up.

     In isolated cases, an engineering design deficiency may be at fault. Many, in fact, are directly related to the quality and origin of the steel pipe itself, and whether or not it is of foreign manufacture. Faulty construction and / or the substitution of sub-standard or thinner piping schedule may show up as an operating problem decades after installation. Review a summary of pipe quality, engineering design changes, and operating demands which have occurred over the past few decades.




The Advantages of Ultrasound

     Identifying the current status of a piping system and the corrosion rate acting upon its metal surface is often difficult or impossible through other destructive and nondestructive means such as x-ray, corrosion coupons, spool pieces, selective pipe removal, or metallurgical testing, etc.

     Ultrasound technology, however, allows the precise measurement of the pipe thickness from the outside surface; thereby providing the means to produce a thorough corrosion evaluation at reasonable cost. Ultrasonic testing differs from corrosion coupons, the most common form of corrosion monitoring, in that it summarizes the cumulative effects of all forms of corrosion over the lifetime of the pipe; providing a measurement of remaining wall thickness over a wide sampling of individual points.

     The advantages of ultrasound testing are many, and include:


Common Applications

     HVAC piping systems for which ultrasonic testing is most frequently employed are:

     Less frequently tested HVAC piping applications are:

     Ultrasonic testing is suitable for determining the thickness of all materials, and is most commonly applied to:


Recommended Levels of Testing

     Identifying the current status of any piping system requires a large number of sampling points upon which to base a final determination. This means evaluating multiple locations at the top, bottom and middle of the property, at horizontal and vertical sections, at large and small diameter sections, and at welded, threaded and grooved joint areas. As a general rule - the greater the number of wall thickness tests taken over the greater number of individual pipe locations equals the most reliable results.

     This high number of required test points generally eliminates cutting out samples regularly spaced throughout a piping system for metallurgical analysis, and often leads to the dangerous practice of basing the evaluation of an entire system upon the results of just one or two piping sections.

     It also eliminates taking a few random ultrasonic wall thickness measurements, printing them out on a standard spreadsheet, and calling it an evaluation. This is why each report produced by ECI is based upon a detailed investigation of 30, 50, 75 or more individual physical locations within one or more piping systems.

     A total of 12 individual measurements are taken along the pipe circumference at each individual test location to provide a basis of several hundred wall thickness measurements for analysis. Data is offered in summary form as well as in fine detail, and provides valuable and reliable information on corrosion rate, actual pipe loss, percentage of allowable loss, remaining pipe life, and estimated retirement date.


Testing Accuracy

      The basis of each evaluation is, of course, the measurement of the remaining pipe wall at the locations tested. Accuracy alone of the equipment we employ is approximately 1 mil or 0.001 in. for most applications.

     Our use of on-site verification of each ultrasound measurement ensures the accuracy of each thickness reading, and eliminates the questionable practice often used by other testing services of discounting the highest and lowest readings within any set of measurements - in some cases discarding as many as 50% of the wall thickness readings taken. Existing thickness readings can then be compared to original pipe specifications and minimum acceptable wall thickness values to produce average and minimum based estimates of corrosion rate and remaining service life.


Reporting Criteria

     Rather than produce retirement date calculations based upon some arbitrary percentage of the original pipe wall, a commonly employed practice having no basis in fact or theory, we refer to established engineering formulas for minimum acceptable wall thickness which take into account pipe size, service or application, construction, pressure, material strength efficiency, and other operating factors.

     The result - a report conclusion that does not recommend premature or unnecessary pipe replacement, nor one that fails to recognize those operational factors which may lead to unexpected failure. Our remaining service estimates have been shown accurate at predicting pipe failures in many cases, and have saved the unnecessary replacement of pipe with decades of remaining life.


Field Testing

     Testing can usually be accomplished during normal working hours. Steam and steam condensate piping, while it can be tested "live", is best performed during any available or scheduled downtime. Typically, it requires one day of on-site testing per 25 to 35 pipe locations, and approximately 4-7 days to analyze the data and prepare the final report.

     Insulated piping requires the removal of small individual sections for access to the pipe surface. Severely corroded outer surfaces may require mild grinding to produce an acceptable base measurement platform. Paint can generally be accounted for by a special feature of our test instrumentation which negates the paint or coating from the overall wall thickness - thereby eliminating the need to wire brush and repaint any test areas. This is always a savings to building maintenance.


Pricing Guidelines

     Fees are based upon the total number of days of field work required, and include two copies of our full color report. Additional report copies are available, and all reports are archived by ECI for a period of 10 years.

     In general, fees equal $100 per individual test location, with the assumption that we can access the necessary areas within a property to test 25 - 35 locations per each day of field work. This translates to $2,500 to $3,000 per day of field testing - although the off-site data analysis and report preparation constitutes the bulk of time and effort spent for any piping evaluation. Overall, approximately 5 days of combined effort is necessary for each 25 - 35 location test report.

     Pipe testing that is located outside the immediate New York City area is priced at a slightly higher rate to compensate for travel times, and with the addition of actual expenses for travel and hotel accommodations.


Pipe Testing Report Samples

     A selection of reprinted pages from a typical client report can be accessed from the navigation bar at the left, and is provided in order to illustrate the level of detail provided for each pipe location tested. Although such high detail is requested by many of our clients, summary information in the form of written text and graphics is also provided in each report.

     Graphed summaries are particularly useful for identifying various trends which may exist, and for comparing and evaluating the cumulative data derived from all test locations. A separate priority worksheet is provided, and lists all test locations in descending order of life expectancy. Specialized piping problems and visually observed defects are documented with a photograph and commented upon.

     Each report offers both an executive summary as well as a detailed discussion of our findings. Written recommendations and corrective measures are also made addressing any piping deficiencies identified in the report. A photograph of each pipe location showing the actual test area is incorporated into each detail page of the report in order to better identify the test site to the reader, and to aid follow-up testing or future investigators.

     Since a high level of detail is provided in each ECI ultrasound report, and because we do not always have the opportunity to present our findings personally, we provide the written explanation and background information necessary to understand its content as best possible. A typical 50 point report will cover between 100 and 125 pages, and is written and arranged in an easy to read and understand format. Our pipe testing report has been termed by many within the building management industry as, "An invaluable piping and corrosion reference book." A full appendix of relevant wall thickness data and other valuable information is also provided.

     Each report is preceded with a thorough explanation of the testing procedure, equipment used, basic theory of ultrasonic measurement, and necessary assumptions related to our testing and reporting procedure. Due to the fact that our pipe testing reports are often submitted past a wide range of individuals including building owners, operating engineers, consulting engineers, and lawyers, among others, we have always strived to provide information ranging from the most basic conclusions to the most detailed technical information. An abbreviated sample report will soon be available in Adobe Acrobat.

     For further, more detailed information regarding the actual testing procedures used, please view our Pipe Testing Specifications and Procedures at the navigation bar at the left. A wide variety of Technical Bulletins related to piping specialties are also offered.


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