Product Code Database
A cured-in-place pipe ( CIPP) is a trenchless rehabilitation method used to repair existing pipelines. It is a jointless, seamless pipe lining within an existing pipe. As one of the most widely used rehabilitation methods, CIPP has applications in sewer, water, gas, chemical and district heating pipelines ranging in diameter from 0.1 to 2.8 meters (2–110 inches).
The process of CIPP involves inserting and running a felt lining into a preexisting pipe that is the subject of repair. Resin within the liner is then exposed to a curing element to harden it and make it attach to the inner walls of the pipe. Once fully cured, the lining now acts as a new pipeline.
Samples should be representative of the installation environment since the liner is installed in the ground. Wet sandbags should be used around the restraint where the test sample will be extracted from. As with any specimen preparation for a materials test, it is important to not affect the material properties during the specimen preparation process. Research has shown that test specimen selection can have a significant effect on the CIPP flexural testing results. A technical presentation at the CERIU INFRA 2012 Infrastructures Municipales Conference in Montreal outlined the results of a research project which examined the effects of test specimen preparation on measured flexural properties. Test specimens for ASTM D790 flexural testing must meet the dimensional tolerances of ASTM D790.
The North American CIPP industry has standardized around the standard ASTM F1216 which uses test specimens oriented parallel with the pipe axis, while Europe uses the standard EN ISO 11296–4 with test specimens oriented in the hoop direction. Research has shown that flexural testing results from the same liner material are usually lower when determined using EN ISO 11296-4 as compared to ASTM F1216.
In 2017, CALTRANS backed university researchers examined water impacts caused by CIPPs used for stormwater culvert repairs.Currier B. (2017). "Water Quality of Flow Through Cured-in-Place-Pipe (CIPP) FINAL REPORT", Prepared for CALTRANS, Sacramento, CA.
In April 2018, a study funded by six state transportation agencies (1) compiled and reviewed CIPP-related surface water contamination incidents from publicly reported data; (2) analyzed CIPP water quality impacts; (3) evaluated current construction practices for CIPP installations as reported by US state transportation agencies; and (4) reviewed current standards, textbooks, and guideline documents. In 2019, another study funded by these agencies identified actions to reduce chemical release from ultraviolet light (UV) CIPP manufacturing sites.
With proper engineering design specifications, contractor installation procedures, and construction oversight many of these problems can likely be prevented.
On August 25, 2017, the National Association of Sewer Service Companies, Incorporated (NASSCO), which is a (501c6) nonprofit dedicated to "improving the success rate of everyone involved in the pipeline rehabilitation industry through education, technical resources, and industry advocacy", posted a document on its website bringing up several important concerns and unanswered questions regarding the study, and its messaging. NASSCO then sent a letter to the researchers who then responded.
On September 22, 2017, NASSCO announced it would fund and coordinate an assessment of previous data and studies, and an additional study and analysis of possible risks related to the CIPP installation and curing process. Later in September, the NASSCO posted a request for proposals to "review of recent publication(s) that propose the presence of organic chemicals and other available literature relating to emissions associated with the CIPP installation process, and a scope of services for additional sampling and analysis of emissions during the field installation of CIPP using the steam cure process." The request specifically identified the project would review studies conducted by the Virginia Department of Transportation, California Department of Transportation, and Purdue University.
At the federal and state levels in September 2017, on September 26, the US Centers for Disease Control and Prevention (CDC) National Institute for Occupational Safety and Health (NIOSH) published a Science Blog contribution regarding Inhalation and Dermal Exposure Risks Associated with Sanitary Sewer, Storm Sewer, and Drinking Water Pipe Repairs. In September 2017, the California Department of Public Health issued a notice to municipalities and health officials about CIPP installations. One of several statements in this document was that "municipalities, engineers, and contractors should not tell residents the exposures are safe."
On October 5, 2017, the National Environmental Health Association sponsored a webinar about the hazards involved for workers and residents associated with cured-in-place pipe repair. The video can be found here. Several questions about the webinar, and the study have been raised, and feedback noted by industry members.
On October 25, 2017, a 22-year old CIPP worker died at a sanitary sewer worksite in Streamwood, Illinois. The U.S. Occupational Safety and Health Administration (OSHA) completed their investigation April 2018 and issued the company a penalty. Chemical exposure was a contributing factor in the worker fatality.
In 2018, NASSCO funded a study on chemical emissions from six CIPP installations. In 2020, the study was completed. A few locations and worker tasks were identified of potential chemical exposure concern and worksite recommendations were provided.
In 2019 and 2021, the U.S. National Institute for Occupational Safety and Health published a safety evaluations ofUV, steam and hot water CIPP worksites. A UV CIPP company was the first to engage NIOSH. Study results indicated several worker chemical exposure conditions that exceeded recommended limits, and this US federal agency recommended several actions to reduce worker exposures. Two years later, the NIOSH published results of a steam and hot water CIPP worksite study. Results indicated several worker chemical exposure conditions that exceeded recommended limits. The US federal agency recommended several actions to reduce worker exposures.
In 2020, the Florida Department of Health issued their own factsheet about CIPP to municipalities and health departments. The document explained the CIPP process, health concerns, chemicals used and created, how persons living nearby can protect themselves from exposure, and biomonitoring and blood testing considerations after exposure.
In 2022, researchers made several additional discoveries. In the Journal of Hazardous Materials, a study funded by the National Institute of Environmental Health Sciences and National Science Foundation revealed CIPP pressure makes blowback from sinks and toilets in nearby buildings possible and provided recommendations for emergency responders and health officials. Later that year, a study in the Journal of Cleaner Production revealed that by modifying the initiator loading, an ingredient in thermal based CIPP resins, pollution potential of the process could be reduced by 33-42%. Though, also found was that non-styrene CIPP resin contained styrene due to handling at the resin processing facility. In October, researchers discovered that steam based CIPP creates and emits Microplastics into the air during plastic manufacture. Results of these investigations help better understand the occupational safety, bystander safety, and environmental pollution risks associated with current practices, and also improve technology and practice to reduce undesirable consequences.
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