Corrosion Galleries

A result of our 30+ years of involvement in the field of corrosion control, corrosion monitoring, and ultrasonic testing has been a very large archive of corrosion realted photographs taken from actual case histories.

These photos have been broken down into three general galleries related to common corrosion problems, piping system specific corrosion issues, and those associated with water storage tanks and vessels. Within each category are further divisions based upon specific problem examples, such as galvanic corrosion, dry fire piping, or domestic cold water tanks.

We offer these galleris for the two-fold purpose of providing a comparison upon which to categorize and assess a potential corrosion problem, as well as to illustrate the all to frequent end result of a corrosion problem hidden from view or left unaddressed.

Corrosion Gallery Categories

Forms Of Corrosion		Provided are 25 individual photo galleries related to specific forms of corrosion or their related end result. Common problems such as galvanic corrosion, under deposit corrosion, MIC, corrosion under insulation, weathering, and dezincification are detailed. Also detailed are the end result of different corrosion conditions resulting in interior rust deposits, thread failures, wet insulation, and separated cut grooved pipe.

Fire Pipe Corrosion		Various examples of corrosion at wet and dry fire piping systems are provided to illustrate the wide difference in corrosion events which exist. Variables in pipe schedule, materials, design, operation, and testing dramatically vary the lvel of corrosion occurring. Dry and preaction systems typically show the greatest deterioration, while presenting the highest potential for system failure due to the volume of iron oxide rust products which can be generated. Examples of internal corrosion products significantly constricting the pipe are shown for both wet and dry fire systems.

Tanks And Vessels		Tanks and pressure vessels are often overlooked as a source of a corrosion problem. For some serving domestic cold water service, required annual inspections will often reveal a problem in time to address it, although our gallery is proof that such is not always the case. Stand alone fire protection water storage tanks are significantly different, and generally do not receive regular maintenance. Corrosion activity is typically slower, but can produce failures after a few decades.

		Installed in an isolated loop, corrosion coupons never suffer the same environmental effects as the pipe itself, and rarely provide accurate test results. Hardened deposits, electrical activity, under deposit corrosion, micro biological buildup, flow effects, and other common environmental factors typically do not exist for corrosion coupons. A flow requirement, by definition, prevents their installation in precisely those locations traditionally showing the highest corrosion threat. In addition, installing corrosion coupon racks at multiple points throughout a circulating system is not practical and is almost never performed - thereby forcing the unlikely assumption that the test results shown for one specific location are representative over the entire piping system.
		Periodically cutting out samples of pipe for metallurgical analysis is extremely expensive, usually requires a system shutdown, is rarely carried out for large diameter piping, and for any critical or 24/7 operation - is virtually impossible to perform. Combined maintenance and metallurgical costs can easily exceed $4,000 per sample. Metallurgical analysis does offer valuable information unavailable through any other means, and is especially useful in order to identify the cause of a corrosion condition, but is generally limited in use due to its cost and inconvenience. Metallurgical analysis usually plays an inportant role in defining a corrosion problem, rather than discovering one.
		Spool pieces, which are nothing more than removable sections of actual pipe within the system, provide valuable information regarding the actual net effect of corrosion activity against the pipe surface. Unfortunately they are only applicable for smaller diameter piping separate from the main lines. Properly installed, spool pieces offer a true inside look at deposits, surface pitting, inhibitor and cleanout effectiveness, as well as provide samples for micro biological cultures. Like corrosion coupon racks, however, they are rarely installed throughout a piping system and enjoy limited use.
		Ultrasonic wall thickness testing provides the greatest volume of reliable data, and will typically produce a thorough corrosion evaluation as long as a sufficient number of test points are taken. Ultrasound is often used as a prerequisite to other testing methods due to its low cost and wide coverage, or as a confirmation that wall thickness conditions known to exist in one area do or do not exist elsewhere within the piping system. It is most often used as a tool to identify the extent of an already recognized leak or rusting problem, and long term corrosion monitoring using ultrasound requires establishing specialized testing procedures. Read more about ultrasonic pipe testing.
		A wide variety of electronic techniques eixst to produce an estimate of corrosion rate generally based upon the principal of Linear Polarization Resistance, or LPR. LPR provides the benefit of an immediate corrosion measurement that can be routed to monitoring electronices, or data logged for download, and offers an extremely useful corrosion measurement tool. LPR is generally expensive to install and maintain. Regular celaning and calibration is often required, and even then, results may not approximate true corrosion activity - expecially if underdeposit corrosion or MIC is active.
		The insertion of a remotely controlled camera into the pipe offers a valuable thought very limited inspection option. Its use requires the system to be out of service and drained, and is greatly limited by access into the piping system. Pipe size, physical configuration, internal conditions, and length of travel offer further restrictions in its use. Remote Video Inspection (RVI) cannot provide any wall thickness data, but can quickly locate those internal indications that wall loss has occurred - such as tubercular deposits, deep pitting, or suspected MIC growths. Combined with ultrasound or metallurgical testing, RVI can quickly and cost effectively document whether similar problem conditions exist in other areas of a piping system.
		X-ray offers limited application for a piping evaluation primarily due to its high cost and safety concerns. While x-ray can provide the wall thickness values necessary for a true pipe condition analysis, it is most often used for the inspection of weld integrity or for identifying cracks, voids, or a major localized deterioration in a pipe material. Cost, health, and environmental issues severely restrict its use in all but the most critical of applications.
		Similar technology also exists for an excellent but rarely used tool in measuring a wide variety of piping related problems. Its use of safe, low powered gamma radiation rapidly identifies areas of higher wall loss - quickly locating those areas in need of further investigation. By detecting variations in metal density, this hand held device can also detect pipe blockages, identify wet insulation, show liquid level, or confirm pipe schedules, etc.