Chapter 2: The Building as a System

Vocabulary terms and definitions covering building systems, energy flow, HVAC, water systems, controls, and fire protection based on Chapter 2.

System (Interdependent elements)

A group of interacting, interrelated, or interdependent elements forming a complex whole.

System (Functional group)

A functionally related group of elements, especially a group of interacting mechanical or electrical components.

System (Classification)

A set of objects or phenomena grouped together for classification or analysis.

System Boundary

An imaginary line encircling a portion of a building, such as the whole facility or a specific component like a boiler room, used for energy analysis.

Energy Inflows

Purchased energy that crosses the energy system boundary.

Energy Outflows

Energy discharged to the external environment in its final form, typically as radiated heat, heated water, heated air, or other warm fluids.

Building Envelope

Everything that separates the interior of a building from the outdoor environment, including windows, walls, foundation, basement slab, ceiling, roof, and insulation.

HVAC System

Heating, Ventilation and Air Conditioning; a network of motors, pumps, ducts, fans, controls, and heat exchange units that maintain environmental conditions, moisture levels, and air quality.

Building Control Systems

Systems used to achieve and maintain required levels of building services such as heating, cooling, lighting, and humidity.

Direct Digital Control (DDC)

A control system involving the use of one or more programmable devices.

Building Automation Systems (BAS)

Fully automated, integrated systems that use microprocessors to optimize building conditions and system efficiency; often referred to as "intelligent" systems.

Domestic cold water

Cold water used in personal applications such as drinking water.

Domestic hot water

Hot water used in personal applications such as bathing.

Process water

Water used for boilers, chillers and refrigeration, humidification, industrial processes, laboratories, and other specialized uses; requires treatment before use.

Outdoor water

Water used for irrigation of grounds, outdoor fountains, outdoor cleaning, and similar external applications.

Plumbing

The apparatus, such as pipes and fixtures, concerned in the distribution and use of water in a building.

Open recirculating systems

Water systems in which the water is open to the atmosphere.

Closed systems

Water systems that are not open to the atmosphere.

Fire prevention

The process of minimizing ignition sources and educating building occupants on fire safety.

Passive fire protection

Building design elements that minimize damage due to fire and allow time for building occupants to evacuate.

Active fire protection

Control systems that detect, control, and extinguish fires within buildings.