By Bud Coburn
- insulation for electrical wires;
- frames for windows and doors, after impact-modifiers and stabilizers have been added;
- plumbing piping, especially sewage pipes and other applications where corrosion limits the use of metal. Roughly half of the world’s PVC is used in municipal and industrial pipes. In the U.S., 66% of the water distribution pipes and 75% of sewage pipes are constructed from PVC. In addition, PVC pipes can be easily fused together to create permanent and virtually leak-free joints;
- roofing and ceiling systems and membranes; and
- a multitude of other building components, such as flooring, carpet backing, wall coverings, junction boxes, shades and blinds, shower curtains, flues, gutters, downspouts, flashing and moldings.
Inspectors can be aided in the identification of PVC by its color, which often indicates its use: white PVC is used for drain and waste vent pipe and some low-pressure piping; dark gray is used for industrial pressure systems; purple is used for reclaimed wastewater; white, blue and dark gray are all used for cold-water pipe; and green is used for sewer lines.
While PVC is an extremely popular building material, its critics deride it for certain health and environmental dangers, especially when its entire life cycle is considered. Touted for its flame resistance, PVC can smolder unnoticed and release extremely dangerous gasses that present both acute and chronic health hazards to building occupants, fire fighters, and surrounding communities. The following two products of PVC combustion are of particular concern:
- hydrogen chloride, which is a corrosive, highly toxic gas that can burn skin and cause severe, permanent respiratory damage; and
- dioxin, the most dangerous known man-made carcinogen, which will persist in the environment for a long period of time. PVC is the largest contributor to the world’s dioxin burden.
PVC has also been blamed for emitting chemical softeners called phthalates (in vinyl flooring), lead additives (in blinds), and toxic glues. For instance, one study of PVC shower curtains found that they released phthalates capable of causing nausea and damage to the liver and reproductive system. Vinyl chloride, an essential component of PVC, is a carcinogenic and potentially explosive gas with a mild, sweet odor. It can enter drinking water released from contact with PVC pipes, according to the U.S. Environmental Protection Agency.