Skip navigation

Reports and Other Documents

Available at https://doi.org/10.1039/D0EM00190B or contact us for a copy

Summary

The in situ manufacture of cured-in-place-pipe (CIPP) plastic liners in damaged sewer pipes is an emerging mobile source of anthropogenic air pollution. Evidence indicates volatile organic compounds (VOCs) can be released before, during, and after manufacture. The chemical composition of a popular uncured styrene-based CIPP resin was examined, along with the VOCs that remained in the new cured composite. The roles of curing temperature and heating time in waste discharged into the air were examined. Uncured resin contained approximately 39 wt% VOCs. Multiple hazardous air pollutants were present, however, 61 wt% of the uncured resin was not chemically identified. A substantial mass of VOCs (8.87 wt%) was emitted into the air during manufacture, and all cured composites contained about 3 wt% VOCs. Some VOCs were created during manufacture. Curing temperature (65.5-93.3 °C) and heating time (25-100 min) did not cause different composite VOC loadings. High styrene air concentrations inhibited the detection of other VOCs in air. It is estimated that tens of tons of VOCs may be emitted at a single CIPP manufacturing site. Regulators should consider monitoring, and potentially regulating, these growing mobile air pollution and volatile chemical product sources as they are operating in urban and rural areas often in close proximity to residential and commercial buildings.

Available at https://doi.org/10.1177%2F0021998320913988 or contact us for a copy

Summary

Ultraviolet light cured-in-place pipe is a popular trenchless rehabilitation technology used to repair existing buried pipelines without soil excavation. A polymer composite liner is manufactured directly in the field. After curing is complete, the new liner is placed in service to convey flowing water. Long-term water exposure has the potential to degrade the fiber reinforced cured-in-place pipe liners. Like other composites, liner hygrothermal stability could be a major challenge, especially for undercured materials. The objective of this study was to investigate the effect of aggressive environmental conditions such as water, salt solution, and simulated concrete pore solution at 50℃ on cured-in-place pipe liner mechanical and thermo-mechanical performance. Liners were exposed to aqueous solutions ranging from a typical exposure environment to a very aggressive alkaline environment. Cured-in-place pipe liner samples were collected from New York storm sewer installation sites. Specimens were assessed for the degree of curing as determined by differential scanning calorimetry and TGA. Samples were then immersed in aforementioned solutions for investigating the stability of the liners as a function of degree of cure. Both interlaminar shear strength and thermo-mechanical properties significantly differed based on the degree of cure. Cured-in-place pipe liner mechanical and thermo-mechanical properties were significantly impacted by water, salt, and pore solutions exposure. Long-term exposure to salt and alkaline environments may have a detrimental effect on the performance of cured-in-place pipe liners and desires additional scrutiny.

Available at https://doi.org/10.1080/08958378.2019.1621966 or contact us for a copy

Summary

US water infrastructure is in need of widespread repair due to age-related deterioration. Currently, the cured-in-place (CIPP) procedure is the most common method for water pipe repair. This method involves the on-site manufacture of a new polymer composite plastic liner within the damaged pipe. The CIPP process can release materials resulting in occupational and public health concerns. To understand hazards associated with CIPP-related emission exposures, an in vitro toxicity assessment was performed.

Available at https://doi.org/10.1177/0021998319839132 or contact us for a copy

Summary

Cured-in-place pipe (CIPP), a popular trenchless technology, has gained wide attention for drinking water, sewerage and storm water pipe rehabilitation because of its ease of installation. Here, the physical and thermal properties of steam-cured PET felt/polyester resin CIPPs were studied. 1H NMR and GC-MS analysis was performed to identify the unreacted volatile organic compounds in cured CIPPs and results were compared to uncured resin and laboratory cured liner characterizations. Results indicated that organic chemicals in cured CIPP altered the mechanical properties and may be leached out with water. Significantly, lower porosity, density and amount of unreacted volatile organic compounds were much less in the CIPP's inner layer as compared to its outer layer. Water conditioning was conducted to investigate the influence of water on CIPP physical and mechanical properties. No changes were observed for density and porosity for either the CIPP's inner and outer layer; however, the flexural modulus increased slightly due to unreacted organic chemical leaching from the CIPPs.

Available at https://doi.org/10.1016/j.jhazmat.2019.02.097 or contact us for a copy

Summary

Cured-in-place-pipes (CIPP) are plastic liners chemically manufactured inside existing damaged sewer pipes. They are gaining popularity in North America, Africa, Asia, Europe, and Oceania. Volatile and semi-volatile organic compound (VOC/SVOC) emissions from storm sewer CIPP installations were investigated at a dedicated outdoor research site. Tedlar bag, sorbent tube, and photoionization detector (PID) air sampling was conducted for five steam-CIPP installations and was coupled with composite characterizations. New CIPPs contained up to 2.21 wt% volatile material and only 6–31% chemical mass extracted per CIPP was identified. Each 6.1 m [20 ft] liner contained an estimated 5–10 kg [11–22 lbs] of residual chemical. Extracted chemicals included hazardous air pollutants and suspected and known carcinogens that were not reported by others. These included monomers, monomer oxidation products, antioxidants, initiator degradation products, and a plasticizer. PID signals did not accurately represent styrene air concentration differing sometimes by 10s- to 1000s-fold. Multiple VOCs found in air samples likely affected PID responses. Styrene (>86.4 ppmv) and methylene chloride (>1.56 ppmv) air concentrations were likely greater onsite and phenol was also detected. Additional studies are needed to examine pollutant emissions so process monitoring can be improved, and environment impacts and associated human exposures can be minimized.

Available at https://docs.lib.purdue.edu/jtrpaffdocs/30/ or contact us for a copy

Summary

Millions of miles of existing U.S. storm water culverts are critical for roadway safety but much of this infrastructure requires repair. State departments of transportation (DOT) are increasingly choosing to rehabilitate culverts with spray-on and cured-in-place pipe (CIPP) lining processes. These culvert lining practices involve the manufacture of a new plastic liner inside a damaged culvert. DOTs are selecting these outdoor plastic manufacturing methods partly to avoid open-trench excavation, which can cause traffic disruption and work zone traffic safety issues. This study was conducted to better understand current knowledge about culvert lining caused environmental contamination, final product quality, and recommend improved construction specifications, project oversight, and testing requirements to limit undesirable consequences. Literature reviews, a survey of construction specifications and special provisions for 32 transportation agencies, as well as field- and bench-scale testing for CIPP projects in California, New York, and Virginia, were completed. During this project, the safety of workers, transportation agency employees, and the general public at lining installation sites, was raised as a concern by state and federal agencies. Due to previously unreported hazards which were encountered at multiple CIPP field sites, the provision of worksite safety recommendations for DOTs was added to this study. Recommendations are provided for spray-on lining and CIPP lining culvert repair projects that can (1) limit environmental contamination, (2) improve worksite safety, and (3) aid DOTs in better understanding the quality of their new liners.

Available at https://www.sciencedirect.com/science/article/pii/S0269749118329804 or contact us for a copy

Summary

Storm water culverts are integral for U.S. public safety and welfare, and their mechanical failure can cause roadways to collapse. To repair these buried assets, ultraviolet (UV) light cured-in-place-pipes (CIPP) are being installed. Chemical emission and residual material left behind from the installation process was investigated in New York and Virginia. Samples of an uncured resin tube and field-cured styrene-based resin CIPPs were collected and analyzed. Also collected were air and water samples before, during, and after installations. Chemicals were emitted into air because of the installation and curing processes. Particulates emitted into the air, water, and soil contained fiberglass, polymer, and contaminants, some of which are regulated by state-level water quality standards. The uncured resin tube contained more than 70 chemical compounds, and 19 were confirmed with analytical standards. Compounds included known and suspected carcinogens, endocrine disrupting compounds, hazardous air pollutants, and other compounds with little aquatic toxicity data available. Compounds (14 of 19 confirmed) were extracted from the newly installed CIPPs, and 11 were found in water samples. Aqueous styrene (2.31 mg/L), dibutyl phthalate (12.5 μg/L), and phenol (16.7 μg/L) levels exceeded the most stringent state water quality standards chosen in this study. Styrene was the only compound that was found to have exceed a 48 h aquatic toxicity threshold. Newly installed CIPPs contained a significant amount volatile material (1.0–6.8 wt%). Recommendations provided can reduce chemical emission, as well as improve worksite and environmental protection practices. Recommended future research is also described.

Available at https://onlinelibrary.wiley.com/doi/full/10.1002/awwa.1042 or contact us for a copy

Summary

Cured-in-place-pipe (CIPP) technology has been used to rehabilitate sanitary sewer, storm sewer, and drinking water pipes. However, utilities, regulators, and health officials have raised environmental, occupational, and public health concerns regarding chemical emissions into air and water. To better understand emissions into water, available literature was reviewed. Water contamination has been documented in 10 states and Canada due to the release of uncured resin, solvents, manufacturing byproducts, and wastes during and after construction. Odor, fish kill, and drinking water contamination incidents have been reported. The few field- and bench-scale studies available show that a variety of VOCs and SVOCs have been released into water and contamination was detected for several months. CIPP waste was acutely toxic to aquatic organisms. Chemical release is likely influenced by formulation, installation, and environmental conditions. CIPP installation and inspection recommendations were suggested. Studies are needed to develop evidence-based construction and monitoring practices to minimize risks.

Available at  http://pubs.acs.org/doi/10.1021/acs.estlett.7b00237 or contact us for a copy.

Summary

Chemical emissions were characterized for steam-cured cured-in-place-pipe (CIPP) installations in Indiana (sanitary sewer) and California (stormwater). One pipe in California involved a low-volatile organic compound (VOC) non-styrene resin, while all other CIPP sites used styrene resins. In Indiana, the uncured resin contained styrene, benzaldehyde, butylated hydroxytoluene (BHT), and unidentified compounds. Materials emitted from the CIPP worksites were condensed and characterized. An emitted chemical plume in Indiana was a complex multiphase mixture of organic vapor, water vapor, particulate (condensable vapor and partially cured resin), and liquid droplets (water and organics). The condensed material contained styrene, acetone, and unidentified compounds. In California, both styrene and low-VOC resin condensates contained styrene, benzaldehyde, benzoic acid, BHT, dibutyl phthalate, and 1-tetradecanol. Phenol was detected only in the styrene resin condensate. Acetophenone, 4-tert-butylcyclohexanol, 4-tert-butylcyclohexanone, and tripropylene glycol diacrylate were detected only in the low-VOC condensate. Styrene in the low-VOC condensate was likely due to contamination of contractor equipment. Some, but not all, condensate compounds were detected in uncured resins. Two of four California styrene resin condensates were cytotoxic to mouse alveolar type II epithelial cells and macrophages. Real-time photoionization detector monitoring showed emissions varied significantly and were a function of location, wind direction, and worksite activity.

Key Recommendations

Until more CIPP air monitoring and chemical toxicity data are available, the recommendation is that persons at or near CIPP sites
(1) minimize dermal and inhalation exposures,
(2) monitor emissions,
(3) use appropriate personal protective equipment (section S2), and
(4) capture emissions and confirm this by monitoring.

Response available at https://engineering.purdue.edu/CIPPSafety/Incorrect-Assertions-About-CIPP-Study.pdf.

Important Points

1) Statements issued and distributed by NASSCO, Incorporated and distributed by other parties have incorrectly described the Purdue University study. The researchers addressed some of the incorrect information in this document.
2) Again, the Purdue University researchers offered to work with those interested in better understanding and improving worker and public safety at and near CIPP water pipe repair sites.
3) Researchers again recommended that additional investigations should be conducted to understand emissions from CIPP installations, and to determine the occupational, public health, and environmental risks.
4) Due to human health concerns, the researchers directed persons who install CIPP to contact the National Institute for Standards and Health (NIOSH) to request Health Hazard Evaluations.
5) Due to human health concerns, the researchers directed persons who visit CIPP worksites such as municipal employees and consulting engineer employees, to contact NIOSH for assistance.
6) The Purdue University researchers stated that CIPP technology could likely be used without endangering human health or the environment if appropriate safeguards were instituted.

Available free online at https://www.nspe.org/resources/pe-magazine/september-2017/cured-place-pipe-the-role-engineers-worker-and-public-safety.

Important Points

1) Professional Engineers who select, use, and oversee CIPP installations, have a professional and ethical duty to “hold paramount the safety, health and welfare of the public” and make only “truthful and objective statements.”
2) Engineers trained in the use of CIPP often are not warned about potentially immediately dangerous to life and health (IDLH) conditions at CIPP worksites or past air testing studies.
3) Stringent and enforced specification requirements should include proper personal protective equipment (PPE), setback distances, worksite air monitoring, capture and proper disposal of all emissions and waste, as well as the immediate reporting of complaints to health department and fire departments.