Corrosion: What Is It and How to Control It
What is corrosion? Corrosion is the degradation or deterioration of a material caused by a reaction to its environment. In building plumbing systems, corrosion can occur in our piping systems and water-bearing equipment due to reactions, chemicals, and impurities in the water. These processes result in uniform corrosion, pitting, cracking, or erosion, ultimately causing the breakdown and failure of the piping system and components. How does it impact plumbing? Corrosion significantly impacts the plumbing system, operations, maintenance, costs, and equipment. It can lead to pinhole leaks in the piping and pipe blowouts, which can ultimately cause water damage to the surrounding area. Corrosion can also cause loss of efficiency, reduction in performance, blockages, and total equipment failure of valves, pipes, pumps, and heaters. All corrosion impacts have significant financial consequences, including pipe and equipment replacement, labor for repairs, maintenance and system interruptions, and downtime. What causes it? The corrosivity and corrosion rate of our building’s water systems depends on several water characteristics, including sediment levels, flow, temperature, chemical treatment programs, and microbial communities. How can it be controlled? Avoiding corrosive water treatment methods, such as chlorine, chlorine dioxide, and monochloramine, will significantly impact the life of plumbing systems. An alternative technology, copper-silver ionization, has greater efficacy against waterborne pathogens and does not increase the corrosivity of the water system. Installing a sediment filtration system on the incoming water supply will significantly reduce the amount of sediment entering the building water system. This protects the water system from sediment accumulation, which can lead to corrosion of equipment and pipes. The filtration system will also protect against external disruptions or surges in sediment, which can build up in a system, erode equipment, and impact equipment life. Case study: Colorado hospital sediment filtration success story Sediment in the incoming water supply caused pinhole leaks, forcing the replacement of two-year-old piping for $80K. Installing a LiquiTech™ Sediment Filtration System reduced sediment entering the building’s water system. Read the full case study here. Sediment levels (96.7% reduction) Download: corrosion fact sheet Fill out the form below to download our corrosion fact sheet to keep on hand or to share with your team.
The Biocide Chlorine Dioxide Stimulates Biofilm Formation in Bacillus subtilis by Activation of the Histidine Kinase KinC
MOSHE SHEMESH, ROBERTO KOLTER, RICHARD LOSICKAMERICAN SOCIETY FOR MICROBIOLOGY, JOURNAL OF BACTERIOLOGY, DECEMBER 2010 IntroductionThe goal of this study was to examine how biofilm formation is stimulated by chlorine dioxide, a chemical that is typically very effective and fast-acting against bacteria. The study examined how chlorine dioxide works and how the biofilm acts as a protector of cells. ResultsThe findings showed that chlorine dioxide accelerated biofilm formation and stimulated matrix gene transcription. The more matrix genes that are transcribed, the easier it is for the biofilm to grow and spread. The study suggested that disruptions in the membrane caused by chlorine dioxide are recognized as a stress signal by KinC, an essential membrane-bound enzyme, prompting biofilm formation. ConclusionSublethal doses of chlorine dioxide can increase the rate of biofilm formation for Bacillus subtilis and other bacteria. Chlorine dioxide acted with KinC, an essential membrane-bound enzyme, and activated the expression of the genes needed for matrix production. The study concluded that biofilm formation is a response to the stress invoked by chlorine dioxide. Full study
Controlling Legionella in Hospital Drinking Water: An Evidence-Based Review of Disinfection Methods
YUSEN LIN, JANET E. STOUT, VICTOR YUCAMBRIDGE UNIVERSITY PRESS, INFECTION CONTROL AND HOSPITAL EPIDEMIOLOGY, FEBRUARY 2011 IntroductionThis study reviewed the efficacy of different disinfection methods for controlling Legionella in hospitals, including copper-silver ionization, chlorine dioxide, hyperchlorination, monochloramine, UV, point-of-use filtration, and superheat-and-flush. The four criteria each disinfection method must meet to validate efficacy include: ResultsA summary of findings for each disinfection method is included below. Copper-silver ionization– Only method validated by the four criteria– Easy installation and maintenance– Not impacted by higher temperatures– Residual levels are maintained for a prolonged period– Efficacy declines in pH greater than 8.5 Chlorine dioxide– Penetrates biofilm– Effective over a wide range of pH levels– Creates harmful byproducts– Difficult to maintain residual levels Monochloramine– Penetrates biofilm– Effective over a wide range of pH levels– Can cause anemia in dialysis patients– On-site generation can be complicated Hyperchlorination– Most expensive and unreliable of all methods– Causes corrosion– Does not penetrate biofilm– Introduces carcinogens into the water Point-of-use filtration– Effective against Legionella and Mycobacterium– Provides immediate protection making them a good option for outbreaks– Not cost-effective for long-term use UV– Non-chemical– Works best when installed on the incoming water supply– Does not provide systemic disinfection Superheat-and-flush– Effective in emergencies– Not effective for prolonged use– Limited to hot water lines ConclusionThere are several viable methods for controlling Legionella, but copper-silver ionization was the only method validated by the four criteria at the time of this study. The researchers concluded that “copper-silver ionization appears to be the best available technology today for controlling Legionella colonization in hospital water systems.” They suggested that rigorous maintenance plans, regular monitoring of ion concentrations, and frequent Legionella testing are necessary to ensure long-term success. Full report
Control of Legionella Contamination and Risk of Corrosion in Hospital Water Networks Following Various Disinfection Procedures
ISABELLA MARCHESI, GRETA FERRANTI, ANTONELLA MANSI, ANNA M. MARCELLONI, ANNA R. PROIETTO, NAVNEET SAINI, PAOLA BORELLA, ANNALISA BARGELLINIAMERICAN SOCIETY FOR MICROBIOLOGY, APPLIED AND ENVIRONMENTAL BIOLOGY, MAY 2016 IntroductionThis study evaluated four disinfection methods for their efficacy in controlling Legionella and their corrosive effects on water pipes. The four methods included: ResultsLegionella controlOf the four disinfection methods analyzed, monochloramine had the lowest Legionella positivity rate (percentage of test sites positive for Legionella), followed by chlorine dioxide, hydrogen peroxide, and heat. None of the methods eliminated Legionella. The results from the lowest Legionella positivity rate (most effective) to the highest (least effective): CorrosionHydrogen peroxide and chlorine dioxide caused pitting on the pipe’s interior surface. Pitting is a type of corrosion that can lead to holes. Monochloramine and heat appeared to be less aggressive, with monochloramine exhibiting uniform corrosion with the rare formation of pitting. Heat showed corrosion similar to that observed on the untreated samples. ConclusionContinuous chemical disinfection is effective to an extent and is significantly more effective than using only heat, and each modality displayed different morphologies of corrosion. Full report
Use of Copper-Silver Ionization for the Control of Legionella in Alkaline Environments at Healthcare Facilities
DAVID M. DZIEWULSKI, ERIN INGLES, NECULAI CODRU, JOHN STREPELIS, DIANNA SCHOONMAKER-BOPPELSEVIER, AMERICAN JOURNAL OF INFECTION CONTROL, JULY 2015 IntroductionThis study examined two healthcare facilities using copper-silver ionization to control Legionella in alkaline water conditions. One facility was an acute care facility with a pH range of 8.7-9.9. The other was a long-term care facility with a pH range of 8.9-9.7. Both had previously used disinfection methods without success, including superheat-and-flush, hyperchlorination, and chlorine dioxide. ResultsAcute care facilityThe acute care facility reported six cases of Legionnaires’ disease before installing the copper-silver ionization system. After installation, the Legionella positivity rate (percentage of test sites within the building positive for Legionella) was reduced to 0%. Long-term care facilityThe long-term care facility reported two Legionnaires’ cases before installing the copper-silver ionization system. During the early stages of treatment, instabilities in both copper and silver concentrations occurred and were attributed to electrode scaling. This was followed by an increase in Legionella. Once ion concentrations were stabilized, the Legionella positivity rate was reduced to 0%. ConclusionCopper-silver ionization successfully controlled Legionella under alkaline water conditions but required frequent monitoring and system adjustments to maintain efficacy. The study found that alkaline water conditions reduce copper ion concentrations, however, the facilities were able to achieve non-detect as silver ions were less impacted and appeared to be the main ion controlling Legionella. Full study
