OBC Building Services key terms

The mechanical, electrical, plumbing, and life-safety systems installed in a building to make it usable, comfortable, and safe for occupants, including heating, cooling, water, power, lighting, and fire protection.

The combined equipment and ductwork that heats, cools, ventilates, and controls humidity in a building to maintain acceptable indoor conditions for occupants and processes throughout the year.

A factory-assembled or field-built box containing a fan, coils, filters, and dampers that conditions air and distributes it through ductwork to served spaces, often located in a mechanical room.

A network of rigid or flexible conduits, usually galvanized steel or aluminum, that carries conditioned or return air between air handling equipment and the rooms it serves, including fittings and terminals.

An HVAC arrangement that varies the quantity of cooled air delivered to each zone while holding supply temperature roughly constant, using terminal boxes with modulating dampers to match changing loads.

A refrigeration machine that removes heat from water or another fluid, producing chilled water for cooling coils in air handling units or terminal units, and rejecting that heat to a condenser loop.

An outdoor heat-rejection device that evaporates water to discharge condenser heat from chillers or refrigeration equipment to the atmosphere, typically serving as the condenser-water source for a plant.

A closed vessel that burns fuel or uses electric resistance to heat water or generate steam for space heating, domestic hot water, or process loads, distributing heat through pipes or steam lines.

A heating method that circulates hot water or steam through pipes to radiators, convectors, or coils, transferring heat to occupied spaces without moving large volumes of air.

A heat-emitting device, usually cast iron or steel, that releases heat from hot water or steam into a room mainly by radiation and convection, often mounted along an exterior wall.

A movable plate or blade inside ductwork or an air opening that regulates airflow volume or shuts off air, operated manually or by motorized actuators in response to controls.

An air terminal device with vanes or slots that spreads supply air into a room in a controlled pattern, promoting mixing with room air and avoiding drafts on occupants.

A control device that senses space temperature and switches or modulates heating and cooling equipment to hold the space near a chosen setpoint, often programmable or networked.

A networked control system that monitors and commands HVAC, lighting, and other building equipment, using sensors, controllers, and a central operator interface to schedule and optimize performance.

Software and controls that track and optimize energy use across building systems, scheduling equipment, monitoring consumption, and identifying waste to reduce operating cost and demand.

The network of pipes, fixtures, valves, and fittings that supplies potable water and removes wastewater and stormwater from a building, including vents and traps that protect health.

The piping and equipment that delivers potable water at adequate pressure and temperature to fixtures and appliances, including service lines, meters, pumps, heaters, and distribution piping.

The sloped piping and fittings that carry wastewater and sewage by gravity from fixtures to the building sewer, including soil stacks, waste lines, and vent connections.

A U-shaped fitting that holds a water seal to block sewer gas from entering a building through a fixture drain, while still allowing wastewater to pass.

A vertical pipe that admits air into a drainage system and releases gases above the roof, protecting trap seals from siphonage and allowing wastewater to flow freely.

A device that stops contaminated water from reversing flow into a potable water supply, using check valves, air gaps, or reduced-pressure assemblies to protect public health.

Equipment that raises domestic water temperature by gas, electric, or solar energy, storing hot water in a tank or heating it on demand for fixtures, cleaning, and process needs.

The combined detection, alarm, and suppression features of a building, including sprinklers, standpipes, extinguishers, and alarms, designed to detect fire and control it until help arrives.

A network of pressurized pipes and heat-activated heads that discharges water onto a fire to control or extinguish it, often arranged by hazard class and coverage area.

A fixed piping system with hose connections at various levels that lets firefighters attach hoses and deliver water to upper floors without dragging hose up stairs.

A pump that boosts water pressure and flow to fire protection piping when the public supply is inadequate, ensuring sprinklers and standpipes receive design demand during a fire.

A network of detectors, manual pull stations, notification appliances, and a control panel that detects fire conditions and alerts occupants and responders, often triggering other systems.

A device that senses smoke particles by ionization or photoelectric means and sends a signal to the fire alarm panel, providing early warning so occupants can evacuate.

A rated closure installed inside ductwork at a fire-rated wall or floor penetration that closes automatically on heat or smoke detection to stop fire and smoke from spreading through ducts.

The service entrance, switchgear, panels, transformers, and feeders that bring utility power into a building and divide it into circuits serving lighting, equipment, and receptacles.

A metal enclosure holding circuit breakers that divide incoming power into branch circuits, providing overcurrent protection and a means to switch circuits off for maintenance or emergencies.

An automatically operated switch that interrupts current when it exceeds a safe level, protecting wiring from overload or short circuit and allowing the circuit to be reset after a trip.

A device that changes alternating-current voltage between levels by magnetic induction, stepping utility voltage down for building use or adjusting levels between distribution sections.

A deliberate conductive connection between electrical equipment and earth that provides a safe path for fault current and limits voltage, reducing shock and fire hazards.

The lamps, luminaires, ballasts or drivers, and controls that provide illumination in a building, designed for task needs, energy efficiency, and visual comfort.

A complete lighting fixture including the lamp, housing, reflector, lens, and mounting hardware that distributes light and connects to the electrical circuit.

A device that detects whether people are present in a space, using infrared, ultrasonic, or microwave sensing, and switches lighting or equipment off when the area is vacant.

The design practice of admitting natural light through windows, skylights, or light shelves to illuminate interior spaces, often paired with dimming controls to cut electric lighting use.

Achieving the required building services output with less energy input, through better equipment, controls, insulation, and operating practices that lower cost and environmental impact.

A quality-focused process that verifies building systems are designed, installed, tested, and balanced to perform according to the owner's requirements before occupancy and during early operation.

Scheduled inspection, cleaning, lubrication, and replacement of building services equipment to prevent failures, extend equipment life, and keep systems operating at design efficiency.