The widely used cured-in-place pipe (CIPP) repair technique entails inserting a resin-impregnated fabric tube into a damaged sewer-, storm-water or drinking-water pipe. The tube is cured with hot water or pressurized steam, sometimes with ultraviolet light, resulting in a new plastic pipe manufactured inside the damaged one. And attendant vapor plumes, previously thought to be innocuous steam, are composed of a mixture of organic vapor, water vapor, particulates of condensable vapor and partially cured resin, and liquid droplets of water and organic chemicals.

Such emissions pose a hazard to workers and the public, say researchers from Purdue University (West Purdue researchers perform tests during a CIPP installation. Image credit: Purdue UniversityLafayette, IN). During tests conducted at seven steam-cured CIPP installations in Indiana and California, researchers captured emitted materials and measured concentrations of styrene, acetone, phenol, phthalates and other volatile and semi-volatile organic compounds.

Plume samples from two of four sites tested displayed toxicity effects and two did not during pulmonary toxicology assays involving mouse lung cells.

Due to the air testing results obtained at CIPP installations on the Purdue campus — two of the seven test sites studied — the university required faculty and students to better protect themselves from inhaling the chemicals emitted. The researchers were required to wear full-face-mask carbon filter respirators during their testing in California.

The researchers are working to develop safeguards, including a new type of handheld analytical device that would quickly indicate whether the air at a worksite is safe. A patent application has been filed through the Purdue Research Foundation’s Office of Technology Commercialization.