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Feature Articles - Housing


Environmental Systems

Ronn Phillips, Arch.D., and Bobbi Hauptmann, Architectural Studies, College of Human Environmental Sciences, University of Missouri-Columbia


Environmental systems are the mechanical systems in a house that are required to support human activities. Knowledge about what these systems are and how they operate is important to every homeowner.

Plumbing Systems: Residential plumbing systems can be divided into two types: (a) water supply, and (b) waste drainage. Supply lines may be of copper, galvanized steel, or plastic, with copper being the most prevalent. The sanitary drainage system relies on gravity for its discharge; its pipes are much larger than the water supply lines, which are under pressure. Drainage lines may be of cast iron or plastic.

Heating, Ventilating, and Air-Conditioning (HVAC): system selection should consider the following issues:

  • Performance, efficiency, and the initial and life costs of the system
  • Fuel, power, air, and water required
  • System flexibility to service different zones of the house
  • Space requirements for the mechanical equipment and distribution system
  • Access required for service and maintenance
  • Degree of visibility, whether concealed within the construction or exposed to view

Thermal Insulation: The following types of insulation are common:

  • Rock Wool - blanket form and most common before 1950.
  • Fiberglas - most common since 1950; more resilient than rock wool.
  • Cellulose - made from scrap paper products.
  • Perlite - A loose material usually used to fill voids; inorganic, noncombustible and moisture and insect resistant.
  • Vermiculite - Naturally occurring mica-ike material that expands by heating; used as loose fill; organic, noncombustible and resists decay and insects.
  • Polystyrene Form - Usually in pellet form or as bead-board; inorganic polymer that is combustible but decay, moisture, and insect resistant.
  • Polyurethane & Polylsocyanaurate Foam - Usually in rigid board form; formable and subject to dimensional changes due to curing and aging.
  • Formaldehyde Foam - Inorganic foam pumped into wall cavities most common as a retrofit on older homes.

Electrical Systems: One hundred percent copper wiring is ideal wiring material for home construction. Special electrical receptacles -- ground fault interrupters (GFI) -- are placed in all bathrooms and on the home's exterior. The GFI trips the breaker in 1/200 of a second to ensure instant and total safety in case of an accident (i.e., a dropped hairdryer or electric shaver in a sink of water).

Providing Electric Service: the service connection to your home may be overhead or underground. Overhead service is less expensive, easily accessible for maintenance, and can carry high voltages over long runs. Underground service is more expensive but is frequently used in high-density urban areas. The service cables are run in pipe conduit or raceways for protection and to allow for future replacement. Direct burial cable may be used for residential connections.




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Last update: Wednesday, May 06, 2009