| | 100+ Year Sewers
See List of Cities with VCP in Use Over 100 years Manufacture
Vitrified clay pipe is truly unique in its corrosion and abrasion resistance qualities. Clays and shales are chemically inert materials which are mined and then are transformed into dense and hard clay body through firing in kilns to 2000 degree temperatures (1100 deg C). At this high temperature, vitrification occurs as the clay mineral particles become fused into an inert and stable material.
Early Uses
Original planners and engineers of sanitary sewer systems did not include any sewage treatment of wastewater as we know it today. The need for water tight joints was not apparent since I/I (infiltration and inflow) had no negative impact, since there were no treatment plants. In fact the flow helped reduce odors and aided in the ultimate dilution with the higher volume of I/I. |  Ephesus, Greece (now Turkey) 2600 Year Old Pipe |
A History of Sewerage Treatment shows that terra cotta pipes the predecessor to today's Vitrified Clay Pipes (VCP) were used in the Mediterranean cultures as early as 1700-1500 B.C.E. Note the above photo from Ephesus that shows crudely made, but intact terra cotta pipes that are 2600 years old. The new clay pipes of today have joint pressure ratings that range above 29 psi and are made with high densification extruding equipment and are fired consistently at high temperatures. The results are an essentially inert corrosion free material that will not deteriorate with time and greatly out performs limited life plastics and metals. A 1935 Metcalf & Eddy study, American Sewerage Practice reported in ENR magazine, showed that only 7% of all sewage disposal systems used an activated sludge processes and 99% used dilution for all or part of the treatment solution. Indeed, the phrase, "Dilution is the solution to pollution" was accurate for the times. As a result, the pipe systems of those times did not require nor have air tight joints as we know them today.
Technological Improvements
Through decades of technological improvements vitrified clay pipe (VCP) has evolved into a high performance system with high strengths and flexible water tight joints. The elostomer compression joint systems used in VCP are water and air tight. The vitrified clay pipe has high strength and unequalled corrosion resistance. Can Clay Corporation is the first North American manufacturer of VCP to be certified to the internationally recognized ISO 9002 Quality System Standards.
Today's Pipe
Today new joint designs have been developed for ease of installation and for pipe jacking, pipe bursting and microtunneling installations. NoBel™ is a low profile jointed trouble free and easy to install. Can Clay's Denlok™ pipe has a stainless steel sleeve and typical compressive strengths of 16,000 psi. Denlok™ has the highest jacking strength of any North American made pipe and has been successfully installed on five continents. Vitrified clay is the only pipe that has a 100 year plus service life rating by the U.S. Army Corps of Engineers.
The following is only a list of a few of the many municipalities where vitrified clay sewers continue to serve for one hundred years or more. City
100 Year Life Systems of VCP | Date First
Clay Pipe Installed |
Washington, District of Columbia
Philadelphia, Pennsylvania
Boston, Massachusetts
Sydney, N. S. Wales
Manchester, England
Liverpool, England
London, England
Clinton, Iowa
Edinburgh, Scotland
Rigby, England
Croydon, England
Darlington, England
Chicago, Illinois
Cleveland, Ohio
New York, NY
Erie, Pennsylvania
Grand Rapids, Michigan
St. Louis, Missouri
Hartford, Connecticut
Indianapolis, Indiana
Los Angeles, California
New Haven, Connecticut
St. Paul, Minnesota
Portland, Oregon
Raleigh, North Carolina
Bloomington, Il
Lawrence, Kansas
Baltimore, Maryland
Portland, Maine
San Francisco, California
Jacksonville, Florida
Albany, Georgia
St. Joseph, Missouri
Davenport, Iowa
Kansas City, Missouri
New Bedford, Massachusetts
Bucyrus, Ohio
Omaha, Nebraska
Camden, New Jersey
Memphis, Tennessee
Parkersburg, West Virginia
Providence, Rhode Island
Nashville, Tennessee
Rome, Georgia
Rockford, Illinois
Terre Haute, Indiana
Sioux City, Iowa
Red Wing, Minnesota
Reno, Nevada
Fargo, North Dakota
Dallas, Texas
Denver, Colorado
Napa, California
Kalamazoo, Michigan
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Source: National Clay Pipe Institute, Clay Pipe Engineering Manual |
