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Nondestructive Testing

A majority of commercial real estate properties are now approaching 50-60 years of service; many have already exceed that age.  While most properties have upgraded or replaced their HVAC, communications, elevator, pneumatic, and electrical services to meet modern demands, few have given any consideration to the condition of the various types of pipe so critical to their daily operation.  Such concerns are often first raised only after a leak or some other water related problem occurs.

Chemical water treatment, relied upon exclusively to slow the rate of corrosion and keep the piping clean, often fails to provide the necessary protection to ensure extended pipe life.  The various forms of corrosion monitoring available, and especially corrosion coupons, rarely indicate true pipe conditions, and cannot offer any estimate on remaining service life.

A corrosion problem at a fire sprinkler system, more than just a leak problem or the need to replace pipe, can actually threaten the lives of many due to that same rust product clogging the pipe and rendering useless the entire fire protection system.  For sprinkler piping, where corrosion is not generally recognized nor tested for, a water leak can actually be a benefit in signaling a corrosion problem prior to a true fire emergency.

• Different Test Methods

Test methods such as corrosion coupon monitoring, x-ray, spool pieces, and selective metallurgical analysis, will provide some information related to the corrosion rate over a fixed period of time, and for a specific location.  However, they fail to provide sufficient information upon which a sound and reliable overall piping evaluation can be based.

For many facilities, corrosion monitoring is generally inadequate or ignored, often in error, or simply nonexistent.  Given the many different forms of corrosion which can coexist within the same piping system, a thorough and accurate evaluation means is required.

Corrosion coupons, the most commonly used testing method in use, often fail to present an adequate view of piping status.  They provide instead a general indication of the corrosivity of the water, an estimate of corrosion activity at very specific test loop locations, and short term results only over a very narrow test period.  They do not, however, indicate the most important information desired – which is the wall loss occurring at the piping interior itself.  Multiple examples are provided on this Internet site to overwhelmingly document this issue.

• Ultrasound The Best Method

Considering all available methods, only ultrasonic testing offers the ability to achieve a cost-effective, wide ranging, and informative piping evaluation.  By utilizing ultrasonic diagnostic equipment and detailed computer analysis, it is possible to take extensive wall thickness measurements throughout an entire facility.

With a properly performed piping evaluation being comprised of 750 or more individual ultrasonic tests per individual piping system, a clear and reliable determination of the interior piping condition can be produced.

In almost all cases, a thorough ultrasonic investigation will provide building owners and plant operators with the information they need to make both short and long term maintenance and capital planning decisions.

• Valuable Information Derived

Unlike most other forms of pipe analysis, ultrasonic testing is nondestructive, and does not require a system shutdown or any special preparations.  From an initial set of wall thickness measurements and review of the building or plant history, it is possible to derive valuable information regarding the present state of each location tested.  Information such as:

• • • Pipe metal loss
    • Corrosion rate
    • Percentage of allowable loss to minimum standards
    • Remaining pipe service life
    • Estimated retirement date
    • Pass or fail recommendation for acceptable condition
    • Overall piping condition

In addition, the information from all test locations can be combined into extremely informative summary graphs – each of which will provide a powerful tool in understanding the corrosion activity and trends within any piping system.  Given sufficient wall thickness testing, it is possible to create graphs allowing the comparison of:

• • • Original pipe thickness vs. measured values
    • Corrosion rates
    • Estimated remaining pipe life
    • Percentage of allowable pipe loss
    • Actual pipe loss
    • Overall pipe status
    • Corrosion rate vs. pipe size
    • Corrosion rate vs. physical location
    • Differences in supply or return service
    • Corrosion rate vs. pipe orientation
    • Differences in new and older piping

• Clear Presentation Of Results

Key to any form of investigation is the need to be thorough, accurate, conclusive if possible, and clear and organized in the final presentation of results.  Due to the number of individuals likely involved in the information chain, and having interest in any piping problem, the report should be understandable to the professional engineer, management company, building owner, plant operator, and layman alike.  In other words, a spreadsheet full of raw test data for the client to interpret should never be considered acceptable.

The below photo, taken directly from a typical ultrasonic testing report performed by CorrView International, LLC, illustrates the level of detail provided for each and every piping area investigated.  A full Interactive Sample Report is also provided here.

Report Sample Data Pages

• Trend Analysis

A graphical summary of an ultrasonic piping evaluation provides a tremendous volume of useful information – often tying the entire investigation together in one clear picture.  The below graph shows the relationship between the average and minimum measured wall thicknesses as compared to original pipe wall thickness over 25 different locations tested.  Trending of test results is possible only given sufficient data points to plot.

In this condenser water evaluation of a New York City office property (based upon a separate data set from the above example), various diameter pipe sizes between 10″ and 3″ were tested – thus the rear descending grey base line of original wall thickness as pipe size reduces.

In this investigation, ultrasonic testing showed a relatively even corrosion rate throughout all pipe sizes at the locations tested; with mild pitting present as evidenced by the lower profile of the red minimum pipe thickness value.  Actual wall loss is shown as very consistent throughout the condenser system, and suggests that other points, not tested, will likely exist having similar losses.

Wall Thickness Summary

• Cost Effective Reliable Information

Overall, ultrasonic testing offers the greatest amount of accurate and reliable corrosion rate and remaining service life information available.  It is unquestionably the major starting point to identifying the severity and extent of any pipe corrosion problem, and will provide benefit to any follow-up investigative work.  Any further testing is always far more relative and informative if based upon prior ultrasonic data.

While we believe that the primary benefit of ultrasonic testing is its ability to produce the most thorough piping evaluation, its low comparative cost is also a significant factor.  A typical ultrasonic evaluation cost of $100 per section of pipe offers significant savings when compared to the costs involved with shutdowns, removing and replacing pipe, and a metallurgical analysis – often near $4,000 per individual sample.

For the price of evaluating one section of pipe through metallurgical lab analysis, ultrasound can often provide precise and detailed information about 50 different locations, or more – a tremendous benefit to any building owner or plant operator in need of firm and reliable information.

• Nationwide Testing Service

CorrView International, LLC provides ultrasonic testing in our local New York area, as well as throughout the United States.  We have a team of qualified and certified Level II NDT inspectors available to address any pipe corrosion problem nationwide.  With sufficient preparation , we can address corrosion issues outside the United States as well.

Fees are in the range of $100-$125 per each general piping location tested, with any necessary travel expenses additional.  Most ultrasonic testing evaluations involve between 50 and 75 test locations, and provide the highest degree of information not found elsewhere.

Typical UT testing costs will range between $2,500 and $6,500 – the equivalent of cutting out and metallurgically testing 1-2 pipe samples.  We recommend dedicating at least 20 test areas at any one piping system, at exclusively the condenser water system, for example, in order to provide a representative and reliable final report.  Typically, 30-40 individual locations can be tested during a normal work day – with our progress generally determined by building and piping layout, insulation, pipe quality, and on-site assistance.

Recently, we adapted our customer database to automatically produce a single page “live” statistical resume of our work and experience in the ultrasonic testing field.  With each additional project completed, new data is automatically added and the resume updated.

We offer this statistical resume below, and also provide further background information, client listings, and business references upon request.

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First hand references from some of our past clients are available upon request.

© Copyright 2023 – William P. Duncan, CorrView International, LLC