Cured-in-place pipe
Encyclopedia
A cured-in-place pipe is one of several trenchless rehabilitation methods used to repair existing pipelines. CIPP is a jointless, seamless, pipe-within-a-pipe with the capability to rehabilitate pipes ranging in diameter from 0.1–2.8 meter (4"–110"). As one of the most widely used rehabilitation methods CIPP has application in water, sewer, gas, and chemical pipelines.
-saturated felt
tube made of polyester
is inverted or pulled into a damaged pipe. It is usually done from the upstream access point (manhole or excavation). It is possible to invert the liner upstream (e.g. from the downstream access point) but this carried greater risk. It is possible to install a liner from the downstream access point, upstream to a blind end however this carried the highest risk of all the CIPP installation methodologies. Little to no digging is involved in this trenchless process, making for a more environmentally friendly
method than traditional "dig and replace" pipe repair methods. The liner can be inverted using water or air pressure. The pressure required for inversion can be generated using pressure vessels, scaffolds or a "Chip unit". Hot water, UV light, ambient cured or steam
is used to cure the resin and form a tight-fitting, jointless and corrosion
-resistant replacement pipe. Service laterals are restored internally with robotically controlled cutting devices. These can be sealed with additional seals into the lateral connection (Lateral Junction Repair). The rehabilitated pipe is then inspected by closed-circuit television
(CCTV). CIPP is considered a trenchless technology.
, England
. He called the CIPP process insit u form, derived from the Latin
meaning "form in place." Wood applied for U.S. patent
no. 4009063 on January 29, 1975. The patent
was granted February 22, 1977 and was commercialized by Insituform
Technologies until it entered the public domain on February 22, 1994.
, thermoformed pipe, close-fit pipe, spiral wound pipe and sliplining
as these other methods can provide a similar design solution for similar or less cost in certain situations. CIPP must also be carefully monitored for release of chemical agents utilized in the reaction process for contamination downstream of rehabilitated pipes. The liner material used for common sizes is normally a felted fabric (weave) and does not go around bends well without wrinkling and going out of round on corners. Liners used for pipes with bends (particularly 100 mm pipes) are made from a woven fabric allowing it to go around bends with minimal wrinkling. The more flexible the liner, the more care needs to be taken during inversion to ensure the liner remains on the correct alignment.
The CIPP Process
A resinResin
Resin in the most specific use of the term is a hydrocarbon secretion of many plants, particularly coniferous trees. Resins are valued for their chemical properties and associated uses, such as the production of varnishes, adhesives, and food glazing agents; as an important source of raw materials...
-saturated felt
Felt
Felt is a non-woven cloth that is produced by matting, condensing and pressing woollen fibres. While some types of felt are very soft, some are tough enough to form construction materials. Felt can be of any colour, and made into any shape or size....
tube made of polyester
Polyester
Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate...
is inverted or pulled into a damaged pipe. It is usually done from the upstream access point (manhole or excavation). It is possible to invert the liner upstream (e.g. from the downstream access point) but this carried greater risk. It is possible to install a liner from the downstream access point, upstream to a blind end however this carried the highest risk of all the CIPP installation methodologies. Little to no digging is involved in this trenchless process, making for a more environmentally friendly
Environmentally friendly
Environmentally friendly are terms used to refer to goods and services, laws, guidelines and policies claimed to inflict minimal or no harm on the environment....
method than traditional "dig and replace" pipe repair methods. The liner can be inverted using water or air pressure. The pressure required for inversion can be generated using pressure vessels, scaffolds or a "Chip unit". Hot water, UV light, ambient cured or steam
Steam
Steam is the technical term for water vapor, the gaseous phase of water, which is formed when water boils. In common language it is often used to refer to the visible mist of water droplets formed as this water vapor condenses in the presence of cooler air...
is used to cure the resin and form a tight-fitting, jointless and corrosion
Corrosion
Corrosion is the disintegration of an engineered material into its constituent atoms due to chemical reactions with its surroundings. In the most common use of the word, this means electrochemical oxidation of metals in reaction with an oxidant such as oxygen...
-resistant replacement pipe. Service laterals are restored internally with robotically controlled cutting devices. These can be sealed with additional seals into the lateral connection (Lateral Junction Repair). The rehabilitated pipe is then inspected by closed-circuit television
Closed-circuit television
Closed-circuit television is the use of video cameras to transmit a signal to a specific place, on a limited set of monitors....
(CCTV). CIPP is considered a trenchless technology.
History
In 1971, Eric Wood implemented the first cured-in-place pipe technology in LondonLondon
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
. He called the CIPP process insit u form, derived from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
meaning "form in place." Wood applied for U.S. patent
United States patent law
United States patent law was established "to promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries;" as provided by the United States Constitution. Congress implemented these...
no. 4009063 on January 29, 1975. The patent
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....
was granted February 22, 1977 and was commercialized by Insituform
Insituform
Insituform Technologies, Inc. is a worldwide provider of trenchless technologies for gravity and pressure pipelines. It is publicly traded on the NASDAQ ....
Technologies until it entered the public domain on February 22, 1994.
Advantages
As a trenchless technology, CIPP does not require excavation to rehabilitate a pipeline that is either leaking or structurally unsound. Depending upon design considerations an excavation may be made, but the liner is often installed through a manhole or other existing access point. Anything larger than 60" must be excavated in order to install. Liner is installed as it is wet out on site in these instances. In the case of sewerlines, lateral connections are also restored without excavation via a remote controlled device that drills a hole in the liner at the point of the lateral connection. If larger than 24" and it is safe to do so someone will reinstate laterals by hand. CIPP has a smooth interior and no joints. While CIPP can repair a pipe with bends, special design considerations must be taken into account to prevent wrinkling and stretching. CIPP can effectively reduce infiltration and leaks in pipeline systems without digging.Disadvantages and Limitations
Except for very common sizes, liners are not usually stocked and must be made specifically for each project. CIPP requires bypass of the flow in the existing pipeline while the liner is being installed. The curing may take from five hours to 30 hours depending on pipe diameter and must be carefully monitored, inspected, and tested. Obstructions in the existing pipeline, such as protruding laterals, must be removed prior to installation. Cost should be compared with similar methods such as ShotcreteShotcrete
Shotcrete is concrete conveyed through a hose and pneumatically projected at high velocity onto a surface, as a construction technique....
, thermoformed pipe, close-fit pipe, spiral wound pipe and sliplining
Sliplining
Sliplining is one of the oldest methods for trenchless rehabilitation of existing pipelines. Sliplining is used to repair leaks or restore structural stability to an existing pipeline. Sliplining is completed by installing a smaller, "carrier pipe" into a larger "host pipe", grouting the annular...
as these other methods can provide a similar design solution for similar or less cost in certain situations. CIPP must also be carefully monitored for release of chemical agents utilized in the reaction process for contamination downstream of rehabilitated pipes. The liner material used for common sizes is normally a felted fabric (weave) and does not go around bends well without wrinkling and going out of round on corners. Liners used for pipes with bends (particularly 100 mm pipes) are made from a woven fabric allowing it to go around bends with minimal wrinkling. The more flexible the liner, the more care needs to be taken during inversion to ensure the liner remains on the correct alignment.
External links
- Information on U.S. Patent no. 4009063: http://patft.uspto.gov/netacgi/nph-Parser?u=%2Fnetahtml%2Fsrchnum.htm&Sect1=PTO1&Sect2=HITOFF&p=1&r=1&l=50&f=G&d=PALL&s1=4009063.PN.&OS=PN/4009063&RS=PN/4009063
- Related information on CIPP patents:http://www.patentstorm.us/patents/5736166-description.html
- Trenchless Technology: http://www.trenchlessonline.com/pdfs/06_magazines/prg_all.pdf
- How CIPP is installed: http://www.insituform.com/content/190/how_insituform_cipp_is_installed.aspx