There are multiple applications where chlorinated poly(vinyl chloride) (CPVC) may come in contact with glycerin. One common application is in fire suppression systems that could be subjected to subfreezing temperatures. Chlorinated poly(vinyl chloride) is increasingly being used for these systems in place of metal because of its many advantages, including the ease of installation, weight reduction, cost benefits and chemical resistance. When CPVC piping is used in an area that has the potential to freeze, an antifreeze solution must be used in the fire suppression systems to suppress the freezing temperature of the water and reduce possibility of failure of the piping system. Glycerin is a commonly used antifreeze for this application. The following article discusses the effects of using glycerin with CPVC piping and presents a case study of the use of bio-derived glycerin as an antifreeze agent. In general, it was found that glycerin from the bio-diesel industry had adverse effects on the CPVC.