We have been involved with chemical treatment and corrosion control since 1981, ultrasonic testing and corrosion monitoring since 1994, and the manufacture and distribution of our exclusive CorrView corrosion monitor since 2005.
Such first-hand involvement in the various fields related to corrosion at HVAC piping and fire protection systems over the past 30 years has provided to us valuable information related to what works and what does not. Reasonable and proven solutions to a problem, vs. unrealistic expectations from unproven technology. And of course - a clear understanding to the underlying cause of much of today's corrosion problems. A large volume of that information is provided on this site as an aid to others.
We do not offer, broker, or sub-contract the below services, but have had first hand experience with the technology, with those providing such technology, and can attest to their effectiveness. Please contact CorrView International should you have an interest in any specialty and we will provide further direct contact information.
Our new Business Directory offers various products and services related to the HVAC and corrosion related fields.
In most cases where the pipe is accessible, there is arguably no excuse for an outer pipe corrosion problem other than a lack of maintenance. While repairs are often extensive and costly, they are at least possible to directly address - unlike internal pipe corrosion.
Common commercial paints are generally inadequate; thereby requiring both specialty coating products. Possibly more important to the selection of the coating is surface preparation to white metal standards through sand blasting.
Available are contract services to rehabilitate the exterior of most piping systems and metal structures through effective rust removal and the application of specialty coatings.
High quality specialty coating products are also widely availale for in-house application. Suitable for outdoor weathering problems, corrosion under insulation (CUI), and any form of metal corrosion protection.
With the generally higher level of corrosion activity at most HVAC piping systems, effective water filtration is no longer an option, and more of a necessity to good corrosion control and long system life.
Available are a wide variety of filtration products from simple single cell basket units to multicell units, centrifugal units, and sand filters to full flow automatic backwashing filtration.
With the larger and automatic units commanding a high cost, and smaller units often inadequate in terms of water flow or capture capacity, defining the extent of a corrosion concern is a best first step.
For all forms of water filtration, improper installation is extremely common - thereby reducing its effectiveness in solving the corrosion problem which it was originally intended.
Over 95% of all water filtration units we see are limited in their effectiveness by where they have been installed in the system. For many, the take-off to the filter is in the worst of all possible locations - thereby nearly eliminating its planned benefit.
This is an excellent cost-effective alternative to chiller tube replacement. The tubes are lightly sand blasted to a white metal finish and then coated with various epoxy materials dependent upon application. Suitable for some shell and tube type heat exchangers as well.
This process does not add any heat transfer loss, and will typically offer near 20 years of additional service life by stopping further corrosion activity. Ideal for enhanced rifled tubes which have such higher vulnerability to corrosion and deposits.
This is a near necessity where the corrosion mechanism is unknown, and often influences what response to a corrosion problem is provided. Ideally suited where the failed example of pipe, having all the answers to why it failed, has been saved.
Rule # 1 for any pipe failure - Do not throw away the damaged pipe.
Properly performed to sufficient depth, metallurgical testing will identify the underlying cause of the pipe corrosion or failure problem. Excellent for confirming ASTM grade, weld integrity, galvanized finish thickness and bond, MIC conditions, cell corrosion attack, erosion, galvanic attack, dezincification of brass, and many other destructive corrosion events.
The downside is the need to isolate and drain the system to allow pipe sections to be cut out and replacement sections installed - work typically costing far more than the metallurgical lab fees themselves.
Performing an ultrasonic analysis of a piping system is a recommended first step to any metallurfical investigation in order to direct attention to the most appropriate area - rather than relying on random selection and chance.
Plate and frame heat exchangers are finding much wider use, both for free cooling and to isolate critical condenser water systems from the more corrosive atmospheric influences of open systems. Most are efficient enough to provide only a few degrees of temperature differential.
After years of operation under even the best low corrosion conditions, most require disassembly and cleaning in order to restore their heat trasnfer efficiency to factory low specifications. Under higher corrosion conditions, frequent cleaning will be required. Unnecessary energy loss is the result where maintenance is lacking.
A corrosion problem can be discovered at various stages of severity. At its midpoint between having destroyed the entire piping system and where still acceptable wall thickness remains, rehabilitating the pipe offers a very cost-effective solution.
Various forms of relining are available, with all requiring thorough and effective pipe surface preparation by either high pressure water jet or sand blasting. As such, its applicability and success is greatly dependent upon the piping layout itself and all associated factors such as size, pipe diameter, construction, material, etc. Major preparations and entry points into the system are required.
Removing internal pipe deposits are an absolute first step to stopping or controlling a high corrosion condition. We consider it virtually impossible to address any high corrosion problem through chemical treatment changes, filtration, or any other step unless the internal rust deposits are first removed.
While acids and chelating agents work well for less heavily contaminated systems, and are today well inhibited against attacking the pipe itself, they are often inadequate for heavily fouled systems having potentially thousands of pounds of corrosion product strongly attached.
High pressure water jet at about 15,000 PSI will strip virtually all iron oxide rust deposits and tuberculation from the pipe quickly and safely, and again expose the bare pipe surface to the chemical corrosion inhibitors required to slow the corrosion process.
Once again, its use is highly dependent upon piping layout and size, the complexity of the piping design, availability to shut down, access points, and many other factors requiring advance and very detailed planning.
We have worked closely with some outstanding mechanical engineering firms, mostly in the New York City area, but also throughout the United States. Please contact us for referrals in the area of interest.
Presumably, steel HVAC pipe placed underground would have been protected from water and the environment by a strong outer protective coating, Ric-Wil casing, hard jacket, or some form of barrier system. In reality, we often find poor protection applied to this critical and most vulnerable area and therefore a second corrosion front.
Where a pipe leak occurs underground, and is not of sufficient volume to make its location known through to the ground surface, a specialized form of ultrasonic testing allows nearly pinpoint location of the leak.
Pressure is required within the piping system and access available to both ends of the pipe. Ultrasound transmitters establish a sound echo pattern which is interrupted at the source of the leak. An extremely useful diagnostic tool with with inherent limitations.
Microbiological agents are commonly involved in many corrosion problems, whether recognized or not. Most frequently suspected at condenser water and fire protection systems, an accurate identification of the infectious agent(s) can be elusive.
Dip slide kits to produce rough cell colony counts will provide a representative number suggesting the level of bacterial infection, but not its identification. Often, more detailed analysis will produce a false identification entirely - thereby shifting a corrosion control response into the wrong direction. Some lab reports we have seen are worthless.
Where fresh and viable deposit samples are not available, itself a common event, standard plate culturing may not be possible. For anerobic bacteria commonly
Precise identification of genus and species, however, can be performed at live or dead sample material using DNA. DNA testing is relatively inexpensive considering the level of identification provided.
Pleasefeel free to contact CorrView International at any time regarding the above outside services or to discuss any corrosion related 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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