Clay Pipe Engineering
ManualClay Pipe Engineering
Manual
Vitrified clay pipe is truly unique in its corrosion and abrasion resistant qualities. It is manufactured from clays and shales, the earthy mineral aggregates which are the end products produced by the weathering forces of nature. Through centuries of time the soluble and reactive minerals have been leached from rock and soil, leaving an inert material. This chemically inert material is transformed into a dense, hard, almost homogeneous, clay body through firing in kilns at temperatures about 2000o F (1100o C). At this point "vitrification" occurs, as the clay mineral particles become fused into an inert, chemically stable compound, integrally bonded by its very nature, independent of any outside or artificial agent.
Only specialized raw clay materials, found in hydrous alumina silicates, are suitable for the manufacture of vitrified clay pipe. The requisite characteristics they must possess are:
Clay pipe manufacturers blend the fire clays and shales to develop the inherent strength and load bearing capacities of the pipe. As noted in the manufacturing chart on pages 6 and 7, the principal steps in the manufacture of clay are mining, blending, grinding, pugging, forming, finishing, drying, firing and testing the pipe and joint.
The high quality of vitrified clay pipe manufacture and performance is maintained in accordance with Standards issued by the American Society for Testing and Materials (ASTM). These specifications are prepared by a committee consisting of engineers from the consulting, governmental, laboratory testing and educational fields. The engineering team continually reviews and upgrades clay pipe standards for quality and performance as the latest manufacturing methods and automated processes are introduced.
When clay pipe manufacturers apply modern day automated procedures to nature's perfect material conforming to standards established by recognized technical societies, the finest engineering material available today for gravity sewers is produced. It should be noted that Vitrified Clay is the only piping material exclusively designed to convey the full range of materials that a community or an industry may discharge into it. It will not rust, shrink, elongate, bend, deflect, erode, oxidize or deteriorate. It is structurally sound, with a permanently fused body independent of chemically reactive bonding agents. This is why vitrified clay pipe can satisfy all of the following factors which must be considered in the selection of materials for sewer construction.
Life expectancy: over 100 years of proven performance.
Industrial users regularly specify clay pipe to carry aggressive effluent.
is one of man's most enduring materials. The manufacture of Clay Pipe involves many important steps.
This manufacturing process produces a homogeneous, heat-bonded, chemically inert material which provides a permanent and durable product for all sewer systems. Vitrified Clay Pipe installed over one-hundred-fifty years ago are still performing as efficiently as the day they were first installed.
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1. MINING THE CLAY Vitrified Clay Pipe is made of selected clays and shales. Laboratory tests determine the correct properties of all raw materials for maximum strength and other physical characteristics. |
| 2. BLENDING THE CLAYS Many clays are aged to various degrees and then blended in the proper combinations. |
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3. GRINDING THE CLAYS Clay are ground in heavy, perforated metal pans by large crushing wheels. The clay is ground fine enough to fall through the perforations in the metal pan. |
| 4. PUGGING THE CLAYS Ground raw materials are mixed with water in a pug mill. This material is forced through a vacuum, de-airing chamber to produce a smooth, dense mixture. |
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5. FORMING THE PIPE The moistened clay is extruded under extreme pressure to form the barrel and socket as an integral unit. |
| 6. FINISHING THE EXTRUDED PIPE Automatic machines trim and finish the moist pipe. |
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7. DRYING THE PIPE The pipe is transferred to large, heated drying rooms to remove moisture. |
| 8. SETTING THE KILN The pipe is then set on tunnel kiln cars, as illustrated, or in the familiar beehive kiln. |
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9. FIRING THE PIPE The temperature in the kiln is gradually increased to the intense heat required for vitrification of the pipe, which is approximately 2000O F (1100OC). |
| 10. TESTING THE PIPE AND JOINT Representative samples are tested for performance. |
| These are only a few of the many municipalities where vitrified clay pipe sewers have served for one hundred years or more. | |||
| City | Date First Clay Pipe Was Installed |
City | Date First Clay Pipe Was Installed |
| 1. Washington, D.C. 2. Philadelphia, PA 3. Boston, MA 4. Sydney, N.S. Wales 5. Manchester, England 6. Liverpool, England 7. London, England 8. Clinton, IA 9. Edinburgh, Scotland 10. Rigby, England 11. Croydon, England 12. Darlington, England 13. Chicago, IL 14. Cleveland, OH 15. New York, NY 16. Erie, PA 17. Grand Rapids, MI 18. St. Louis, MO 19. Hartford, CT 20. Indianapolis, IN 21. Los Angeles, CA 22. New Haven, CT 23. St. Paul, MN 24. Portland, OR 25. Raleigh, NC 26. Lawrence, KS 27. Baltimore, MD 28. Portland, ME 29. San Francisco, CA |
1815 1829 1829 1832 1845 1846 1848 1850 1850 1851 1851 1852 1856 1861 1866 1868 1869 1869 1870 1872 1873 1873 1873 1873 1873 1874 1875 1875 1876 |
30. Jacksonville, FL 31. Albany, GA 32. St. Joseph, MO 33. Davenport, IA 34. Kansas City, MO 35. New Bedford, MA 36. Bucyrus, OH 37. Omaha, NE 38. Camden, NJ 39. Memphis, TN 40. Parkersburg, WV 41. Providence, RI 42. Nashville, TN 43. Rome, GA 44. Rockford, IL 45. Terre Haute, IN 46. Sioux City, IA 47. Red Wing, MN 48. Reno, NV 49. Fargo, ND 50. Dallas, TX 51. Denver, CO 52. Napa, CA 53. Kalamazoo, MI 54. Le Mars, IA 55. Salt Lake City, UT 56. San Jose, CA 57. Massilon, OH |
1876 1876 1876 1877 1877 1877 1877 1878 1879 1879 1879 1879 1879 1880 1880 1880 1880 1880 1880 1880 1880 1880 1880 1881 1884 1888 1890 1892 |
The National Clay Pipe Institute is an organization established for the purpose of providing technical information concerning vitrified clay pipe to the consulting engineering profession and to the various federal, state and local agencies involved in the design and construction of sanitary sewer systems.
NCPI maintains offices in South Gate, California and in Lake Geneva, Wisconsin. These offices provide engineering information pertaining to the design and construction of sewerage systems.
Sponsored research is in progress at major Universities and by NCPI member manufacturers to further improve the product and to develop advanced techniques related to the design and installation of sewer lines. Typical projects include a continuing study of:
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Installation and subsequent behavior of rigid pipe in varying embedment conditions. |
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Finite element analysis of trench loads and bedding factors |
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Corrosive and abrasive conditions encountered by sewer systems and the resistance of various types of sewer piping materials to these conditions. |
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Computer analysis of factors relating to the selection, performance and economic justification of sewer pipe materials. |
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Innovative and alternative design and installation technologies i.e. deep burial, flat slopes, microtunneling. |
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The design of compression type joints, including the chemical and bacterial resistance of jointing materials. |
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The physical properties of vitrified clay pipe as related to the mineralogical characteristics of types of clays required in clay pipe manufacture. |
| Chapter 1 | Chapter 2 | Chapter 3 | Chapter 4 | Chapter 5 | Chapter 6 | Chapter 7 | Chapter 8 | Chapter 9 | Chapter 10 | Chapter 11 |
Request a copy of the Clay Pipe Installation Manual or other publications from NCPI
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Copyright © 1998 National
Clay Pipe
Institute
Last
modified: April
1, 1998