PVC
Polyvinyl chloride is the third most widely produced plastic, after polyethylene and polypropylene. Over 50% of PVC manufactured is used in construction, because it is cheap, durable, and easy to assemble. PVC production is expected to exceed 40 million tons by 2016.
PVC can be made softer and more flexible by the addition of plasticizers, the most widely used being phthalates. In this form, it is used in clothing and upholstery, and to make flexible hoses and tubing, flooring, to roofing membranes, and electrical cable insulation. It is also commonly used in figurines and in inflatable products such as waterbeds, pool toys, and inflatable structures.
Applications
PVC's intrinsic properties make it suitable for a wide variety of applications. It is biologically and chemically resistant, making it the plastic of choice for most household sewerage pipes and other pipe applications where corrosion would limit the use of metal. With the addition of impact modifiers and stabilizers, it becomes a popular material for window and door frames. By adding plasticizers, it can become flexible enough to be used in cabling applications as a wire insulator.
Electric wires
PVC is commonly used as the insulation on electric wires and sheaths for cables; the plastic used for this purpose needs to be plasticized. In a fire, PVC-coated wires can form HCl fumes; the chlorine serves to scavenge free radicals and is the source of the material's fire retardance. While HCl fumes can also pose a health hazard in their own right, HCl dissolves in moisture and breaks down onto surfaces, particularly in areas where the air is cool enough to breathe, and is not available for inhalation.
Frequently in applications where smoke is a major hazard (notably in tunnels and communal areas) PVC-free cable insulation is preferred, such as low smoke zero halogen (LSZH) insulation.
For high performance cables polyethylene is more commonly used for insulation and also for the outer sheath on many communication cables due to it's improved water resistance but it is a fire hazard for indoor cables where pvc or LSOH sheaths are used