Copper-silver ionization
Encyclopedia
Legionella
Legionella is a pathogenic Gram negative bacterium, including species that cause legionellosis or Legionnaires' disease, most notably L. pneumophila. It may be readily visualized with a silver stain....
, the bacteria responsible for legionellosis
Legionellosis
Legionellosis is a potentially fatal infectious disease caused by gram negative, aerobic bacteria belonging to the genus Legionella. Over 90% of legionellosis cases are caused by Legionella pneumophila, a ubiquitous aquatic organism that thrives in temperatures between , with an optimum temperature...
(Legionnaires' disease).
Process
Copper-silver ionization is a dispersive process that introduces long-lived, stable, positively charged copperCopper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
and silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
ion
Ion
An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...
s into the water system. The ions bond electrostatically with negative sites on bacterial cell walls and denature proteins. Over the long term, ionization thus disperses and destroys biofilms and slimes that can harbor Legionella
Legionella
Legionella is a pathogenic Gram negative bacterium, including species that cause legionellosis or Legionnaires' disease, most notably L. pneumophila. It may be readily visualized with a silver stain....
, the bacteria responsible for legionellosis
Legionellosis
Legionellosis is a potentially fatal infectious disease caused by gram negative, aerobic bacteria belonging to the genus Legionella. Over 90% of legionellosis cases are caused by Legionella pneumophila, a ubiquitous aquatic organism that thrives in temperatures between , with an optimum temperature...
(Legionnaires' disease). Complete control of a water system can take 30 to 45 days. Flow cells should be cleaned periodically to maintain the system; in a hospital, this task can be delegated to the facility's utility engineers.
Forensic scientist Randy Fornshell of the Sedgwick County Regional Forensic Science Center explains that copper-silver ionization is a modern implementation of the ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
practice of reducing bacteria in wine vessels by lining them with silver, and controlling algae and fungi with copper. Fornshell notes that copper-silver ionization has been effective in swimming pools (it is an alternative to chlorine) and is becoming adopted by larger municipalities.
Replacing chlorination with copper-silver ionization to keep water safe was one response of Frederick Memorial Hospital, Frederick, Maryland
Frederick, Maryland
Frederick is a city in north-central Maryland. It is the county seat of Frederick County, the largest county by area in the state of Maryland. Frederick is an outlying community of the Washington-Arlington-Alexandria, DC-VA-MD-WV Metropolitan Statistical Area, which is part of a greater...
, to new requirements in the 2001 Guidelines for Design and Construction of Hospital and Healthcare Facilities, issued by the American Institute of Architects
American Institute of Architects
The American Institute of Architects is a professional organization for architects in the United States. Headquartered in Washington, D.C., the AIA offers education, government advocacy, community redevelopment, and public outreach to support the architecture profession and improve its public image...
. Ionization is in many cases installed because more convenient and cost-effective than other approaches.
Effectiveness
Ionization is an effective industrial control and prevention process to eradicate Legionella in potable water distribution systems and cooling towers found in health facilities, hotels, nursing homes and most large buildings. In 2003, ionization became the first such hospital disinfection process to have fulfilled a proposed four-step modality evaluation; by then it had been adopted by over 100 hospitals. Additional studies indicate ionization is superior to thermal eradication.A 2011 study by Lin, Stout and Yu http://www.legionella.org/LinStoutYu2011ICHE.pdf found Copper-Silver ionization to be the only Legionella control technology which has been validated through a 4 step scientific approach.
Regulation & Guidelines
Ionization is recognized by the U.S. Environmental Protection Agency (EPA) to control infections of LegionellaLegionella
Legionella is a pathogenic Gram negative bacterium, including species that cause legionellosis or Legionnaires' disease, most notably L. pneumophila. It may be readily visualized with a silver stain....
. The level of ions generated has been reported to be usually below EPA Safe Water Drinking Act Lead and Copper Rule limits. EPA-approved levels of copper or silver in potable water are 1.3 ppm (Cu) and 0.1ppm (Ag). Suboptimal timing of specimen shipment for testing at reference laboratories may contribute to silver concentration above recommendations. Industry leaders who manufacture coper silver ionization technology recommends copper concentration of 0.4 to 0.8 parts per million (ppm) and silver at 40 to 60 parts per billion (ppb), as compliant with EPA drinking water standards.
The British Health and Safety Commission
Health and Safety Commission
The Health and Safety Commission , was a United Kingdom non-departmental public body. The HSC was created by the Health and Safety at Work etc. Act 1974 . The Commission consisted of a chairman and between six and nine other people, appointed by the appropriate Secretary of State, latterly the...
regulates U.K. ionization, advising regular system monitoring to ensure ions reach all water circuits. Also, copper in drinking water is limited to 2 ppm (mg/L) by the European Community whereas Legionella control only requires 0.4 to 0.8 ppm in concentration...well bellow the permissible limits. Headquarters (ECH) in Brussels, Belgium, and silver is not prescribed by the ECH.
Netherlands companies that install and maintain ionization systems have to register with the CTGB http://www.ctb.agro.nl/ (Board for the authorization of pesticides and biocides) and have to comply to Kiwa guidelines. Copper in drinking water is limited to 2 ppm (mg/L) and additionally silver concentrations are limited to 50 ppb (µg/L).
USA maximum copper limits for potable water is set at 1.3ppm whereas EU limitations is 1.0 ppm. Silver limits in the USA is set at 0.1 ppm (100 ppb) yet the EU does not have any guidelines for ionic silver concentrations.
Most industrial or residential ion generators sold around the world do not meet modern commercial fire building codes as a result of the plastic materials that enclose the electrodes. Pressure and temperature limitations are also associated to plastic chamber cells. Plastic ion chamber cells made with materials such as PVC, CPVC, ABS etc... have clear engineering limitations. Industrial type ion chamber cells with the intentions of Legionella control and prevention should be constructed of either powder coated steel or stainless steel engineered for commercial / industrial applications.