ABSTRACT
After the skeleton, environment enclosure, and exterior adornments, a building begins to function, take on a life of its own in the form of electrical, plumbing, and mechanical systems without which a building would be a mere shell. Plumbing has transitioned from lead to plastic. Electricity transmission has transitioned from knob-and-tube wiring to plastic wiring. Galvanized steel pipe was commonly used in plumbing from the 1800s to the mid- to late 1900s. With advances made in the 1960s, plastic pipes began to replace metal pipes and became commonplace within the plumbing industry in the mid-1980s. With the introduction of plastics, most modern electric wire/cable insulation has found its home in "thermoplastics"–some with paper wrap around the individual conductors. Polyvinyl chloride (PVC) insulation is used in the lion's share of commercial and residential buildings whereas rubber-like synthetic polymer insulation is used on industrial cables and on underground cables.
