•  Carrier


Seeing What Lies Inside 
A New Approach to Corrosion Mapping and Internal Pipe Condition Assessment

The age-old challenge of knowing when pipes may break may have found its solution in a non-invasive new technology. 

By Tim Frederick, M.SAME  


Pipe, as simple and benign as it appears to be, can be operationally crippling and potentially life threatening, yet it is almost always pushed to the back of the action item list. 

Consider these three questions: What would be the impact if a pipe leaks water on your property? What if you lost cooling? What if your fire sprinkler pipe was too corroded to control a fire? Any of these scenarios can be catastrophic, all are very real, and each is fully preventable.

We have all seen pipe failure on some level. But it is critical to remember that unattended issues do not get better over time. Problems typically fly under the radar until a failure results in a loss, creating an endless quagmire forcing you to play catchup while justifying mitigation expenses, and creating unnecessary risk to operations.

Oxygen corrosion, microbiologically influenced corrosion, scale, velocity erosion, and pitting from trapped air and water are the primary catalysts surrounding pipe failure. The trick is in knowing how to address these issues with minimal disruption to operations and at the lowest cost. Unfortunately, the most common methods have largely remained unchanged over the years and provide little valuable information. Historically, we have relied on clues like a visual leak, a running sprinkler compressor, reduced desiccant filter life, or debris found during an obstruction test to spur any action.  



Inconveniences and Risks: 

  • Most require system shut down and draining
  • Asset risk from technician error (dropping tools, spilling water)
  • Potential for system failure when bringing  the system back online
  • Logistical outlays incurred by you when shutting down these systems, including likely need for a fire marshal
  • Testing has typically been employed “after the fact” due to logistics and effectiveness, so the benefits of preventative maintenance are lost.

Data Value: All commonly used methods provide a very small representative sample of the system condition and all leave out important bits of information, often requiring multiple methods to gain any useable insight. 

Knowledge: How do you justify replacement or repair of a system without knowing exactly where or why the issues exist or the best way to address them? Do all the pipes need to be replaced or just a few bad sections, will the use of a corrosion inhibitor or nitrogen actually help, or do you need to install vents or drains? Since there is no cure-all for corrosion mitigation, it is likely that the solution will require a combination of several available tools. Without comprehensive knowledge of the system condition, mitigation is a guessing game.

Cost: Preventative maintenance is key to keep costs low. Full replacement or performing repeated “patch” repairs on a degraded system are very expensive options, particularly when they are emergency repairs.


Scanning using ULGW technologyTHERE IS A BETTER WAY

Ultrasonic Localized Guided Wave (ULGW) technology may hold the answer to this long-existing problem. The technology uses a handheld scanner that guides a harmless ultrasonic sound wave around the pipe circumference from the outside wall. Conditions inside the pipe impact the shape of the sound wave, revealing internal pipe condition before leaks or other catastrophes occur. A ULGW report will map the location and severity of internal pipe issues such as the effect of pitting, buildup, unwanted air or water, and velocity erosion.

Technological advancements have made great strides, vastly improving ULGW’s capabilities over existing nondestructive evaluation methods. ULGW is a proven technology to help make educated decisions regarding corrosion mitigation by knowing the cause, location, and extent of all common corrosion issues, with minimal to no risk to operations, facility assets, or service levels.



Conveniences and Benefits: 

  • Inspections are performed by a team of two technicians using an easily transportable handheld device, and are typically performed without any impact on daily operations.
  • Most inspections are performed with the system 100 percent operational: no shutdown and therefore no need to bring the system back online later; no system drainage, no worry of spilling water or dropping pipes or tools on sensitive equipment; and no introduction of new oxygenated bacteria rich water.
  • ULGW is safe to use around people, electronics, and sensitive inventory.
  • There will be little to no logistical outlay.
  • Convenience can allow for a preventive approach, so issues can be found and repaired before failure—no more need for 3:00 a.m. service calls on New Year’s Day and most importantly, no down time.

Data Value: 
Typical ULGW inspections will map the severity of internal pipe wall condition through direct measurement techniques. You will know the system condition without inferring based off snippets of circumstantial data. As referenced in Chapter 14 of NFPA 25 (2014 ed), ULGW satisfies the five-year “Internal Piping Condition and Obstruction Investigation” requirement without flooding the system and potentially damaging your valuable assets.

Knowledge: Don’t play the magical crystal ball guessing game by relying on damaged pipe around your critical assets. With a corrosion map of the piping system, you are now armed with the knowledge to make cost-effective mitigation decisions. Replace what is bad, repair what is salvageable, and save the rest. ULGW will reveal which sections of pipe have the most severe issues, narrowing down mitigation to the bare minimum needed to maintain system integrity.

CostAt a glance, traditional inspection methods appear to be less expensive; however the scale tips to benefit ULGW when examining the total cost model. 

  • Perform mitigation within your budget and operational schedule.
  • Knowledge allows for efficient mitigation choices.
  • Collateral damage to equipment and interruption of services is all but eliminated.


The technology uses a handheld scanner that guides a harmless ultrasonic sound wave around the pipe circumference from the outside wall. Conditions inside the pipe impact the shape of the sound wave, revealing internal pipe condition before leaks or other catastrophes occur.




ULGW technology is a more effective way to assess pipe condition. It can potentially prevent failure, leaks, property damage and emergencies while transforming pipe maintenance from a reactionary function into a well-planned, proactive system. There are several projects that successfully use ULGW. Most list cost savings and improvements that were made possible through this new method.

Marine Corps Base Quantico, Va.Evaluation of internal sprinkler pipe condition in several key facilities throughout the base. The reporting revealed sufficient information to deem base-wide chemical treatment of the system to be unnecessary, saving approximately $100,000 annually.

Veterans Affairs Hines Data Center, Ill.Preventative evaluation of mission critical cooling loop piping system, while the system and the facility operations remained fully operational. A small number of deficiencies were revealed, preventing a catastrophe that could’ve taken down data center operations.

Strategic Weapons Facility Atlantic Kings Bay, Ga.Preventive fire sprinkler pipe assessment in highly classified regions of the base. Assessment revealed internal pipe condition and areas in need of remediation, all without impact to system operation. 

While each methodology can provide value at various stages of the corrosion assessment process, when comparing the risk, convenience, comprehensiveness, quality of data, and overall value, it is clear that ULGW is the superior choice over traditional inspection methods for the initial pipe integrity evaluation. 



Tim Frederick, M.SAME, is Founder & President, SoniTech NDT; 303-552-1099, or This email address is being protected from spambots. You need JavaScript enabled to view it..