Health Risks Assessment from Cured-in-Place Pipe Lining Fugitive Styrene Emissions in Laterals

AbstractThe aim of this study was to improve the understanding of styrene emissions in sewer laterals, resulting from the installation and steam curing of a resin impregnated cured-in-place-pipe (CIPP) liner, within a sanitary sewer. The study included development and performance assessment of a controlled field test program that measures and records styrene emissions before, during, and after steam-curing a CIPP liner. Measured styrene emissions are then compared with those of published studies and regulatory exposure guidelines to assess the potential risk exposure. The field study measurements confirmed that high styrene concentrations can exist in sewer laterals during the steam-curing of the CIPP liner. They also confirm that water, in proper functioning P-traps, will prevent high styrene emissions from exiting the lateral and into buildings. Fugitive emission modeling shows that the risk of exceeding the acute exposure guideline limits is very low, even when high styrene concentrations exist in a lateral with a dry P-trap, and the styrene odor threshold is exceeded within the building, that is, when the building occupants smell styrene.