Cured-in-placepipe (CIPP) technology is one of the most commonly used trenchless piperehabilitation methods. In this method, a lining tube containing styrene resinis installed into the pipe, where the tube has a membrane coating forprotection and it also contains the resin.
The resin migrates into the jointsand cracks prior to curing. Subsequent curing with a heat source results in apipe within a pipe. Although this method has many advantages, but Styrene isclassified by the U.S. Environmental Protection Agency (EPA) as a mutagen andis thus potentially carcinogenic (Donaldson 2009). Themain way that humans are exposed to styrene is inhalation. Factors thatdetermine the effects of styrene on health include the dose, the duration, andthe route of exposure.
Chronic exposure to styrene in humans mostly affects thecentral nervous system with symptoms such as headache, depression, weakness,peripheral neuropathy, intellectual dysfunction, minor effects on some kidneyenzyme functions, and short-term memory impairment (DHHS 1993; EPA 2000; ATSDR2012). According to the National Association of Sewer Service Companies(NASSCO), air emission of 0.5 ppm styrene is typical during CIPP activity. Styreneexposure limits for adults are 20-25 ppm according to the InternationalToxicity Estimates for Risk. During a CIPP application in Birmingham, UK, resultsfrom an indoor air test in one house showed styrene levels of 200 ppm, and CIPPcontractors advised some residents to evacuate their homes (Bourbour Ajdari2016).
To prevent the unintentionalrelease of styrene-based resin during installation and the leaching of styrenefrom the finished product, VDOT recommended new CIPP specifications (Donaldson2009). The attainment of discharge-related permits, including air, water, andwastewater treatment; dry installations (i.e., no water is contained orconveyed in the pipe during installation); supplementary lining materials andmeasures to safeguard the containment of resin and styrene; comprehensiverinsing of the finished product; appropriate disposal of cure water, curecondensate, and rinsate; and requirements for water and soil testing before andafter installation are some of the examples from new CIPP specifications byVDOT (Donaldson 2009).Styrenehas some harmful impacts on environment but if correct measures are taken then theycan be reduced to a minimal level. Styrene resins are economical as the non-styreneresins still stay an expensive option because the cost of a non-styrene resincan range from 50 percent higher to easily three or four times the cost of a styrene-basedresin.