Buildings and Architecture Glossary: S, T, U

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- S -

Sash: The portion of a window frame, often movable, that holds the glass.

Scaffolding: Temporary platforms for the convenience of construction workers.

Scupper: An opening through a parapet or curb for draining water from a roof.

Sealant: An elastic substance used to close a seam or opening in the enclosure of a building. Most sealants are injectable mastics, but some are tapes, gaskets, or expanding foams.

Self-opening roof vent: A roof hatch that opens automatically during a building fire so as to allow smoke and heat to escape.

Sensible heat: Heat that raises or lowers the temperature of a substance without changing its phase.

Septic tank: A watertight underground vessel designed to foster the anaerobic decomposition of sewage and to separate the decomposed sewage into a precipitate (sludge) and a super natant (effluent).

Service panel: A metal box that contains the circuit breakers for a number of electrical circuits and from which the wiring for these circuits radiates.

Sewage: Wastewater from a building.

Sewerage: A network of underground pipes that collect sewage and conduct it to a treatment plant.

Shaft: A vertical opening through multiple floors of a building to house elevators, pipes, ducts, or wires.

Shear: A relative motion, force, or stress of two masses of material that are pushed or pulled in opposite directions along a common plane.

Shear panel: A planar element of structure that resists lateral loads by means of forces within its plane.

Shelter: Any natural or constructed object that offers protection from wind, precipitation, sun, and /or extremes of temperature.

Shelter belt: A swath of trees planted to obstruct the wind.

Shingle: A small, flat piece of material overlapped with similar pieces on a wall or steep roof in such a way that water will drain off by gravity before it can penetrate.

Shoring: A temporary compression member erected to support a wall of an excavation or a newly poured concrete structure against collapse.

Short circuit: An accidental or inadvertent interconnection of a hot wire with a neutral wire.

SI units: Système internationale d’unites, a rationalized system of measurement based on the meter. In order to avoid con fusion in linear measurements, the centimeter is not used in SI.

Siamese connection: A Y-shaped pipe connection at the base of a building that allows one or two pumper trucks to connect to a building’s standpipe or sprinkler system.

Sick building syndrome: A condition of being uninhabitable because of poor interior air quality due to molds, mildew, spores, organic chemicals, sewer gases, combustion products, or other causes.

Sill: The horizontal lower edge of a window or door. The portion of a building frame that rests on the top of the foundation.

Simply supported beam: A beam that is supported by hinges and /or rollers at its ends.

Single-phase electricity: Alternating current that varies in volt age as a single sine wave.

Skylight: A window in a roof.

Slab: A horizontal, planar element of concrete, usually rein forced or post-tensioned, used most commonly as a floor, roof, walkway, or roadway.

Slab-on-grade: A concrete slab that rests directly on the ground.

Slow-burning construction: A heavy timber frame that meets certain code requirements for minimum sizes of members.

Sludge: The precipitate of decomposed sewage.

Smoke-proof enclosure: An exit stairway that is protected from smoke by being accessible only by means of a balcony ventilated to the outdoors or by mechanically forced introduction of fresh air.

Snow fencing: A slatted fencing used to induce drifting of snow at a distance from a roadway so as to keep it from drifting onto the roadway.

Solar flux: The flow of radiant energy from the sun.

Solar heating: Using sunlight as a heat source for a building comfort system.

Solstice, summer or winter: A date when one pole of the earth is closest to the sun.

Space frame: A three-dimensional truss that spans with two- way action.

Spalling: The flaking off of chips of material from a surface.

Spandrel: The zone of a wall between the heads of windows on one floor and the sills of windows on the floor above. Also, the area of wall between a masonry arch and an imaginary rectangle that would contain the arch.

Specific heat: The ratio of the unit heat storage capacity of a material to that of water.

Specifications: Written documents that specify standards of quality and workmanship for a construction project.

Splay: A divergence in the interior surfaces of the jambs of a window.

Spline: A strip of material used to keep two adjacent building components in alignment.

Spread footing: A block of concrete that distributes the force from a column or load-bearing wall over an area of soil in a foundation.

Spring: A naturally occurring flow of water from the earth.

Sprinkler system, automatic: A system of water pipes and sprinkler heads in which a fusible link opens a head to extinguish an incipient fire if the temperature at the head rises substantially above normal levels.

Standing waves: Single-frequency sound that is reinforced by repeated reflections back and forth between parallel walls whose distance from one another is a multiple of the wave length of the sound.

Standpipe, fire: A vertical pipe that serves fire hose outlets at each level of a building.

Step ramp: A stair with very broad, sloping treads.

Stiffener: A ridge of material added to a structural element to increase its resistance to buckling.

Stirrups: Loops of reinforcing steel used to resist diagonal tension near the ends of concrete beams.

Stock plan: A generic design for a building that is sold in the form of construction drawings, ready to build.

Stove, heating: A self-contained heating device, located within the occupied space of a building, that burns fuel within a metal enclosure that transfers heat to the surrounding air.

Strain: Change of dimension in a structural material caused by structural stress.

Stress: Force divided by the cross-sectional area of material over which it's distributed.

Stress, allowable: A stress at which a structural material may safely function. Allowable stress is the product of yield stress and factor of safety.

Stress, yield: The stress at which a material begins to deform irreversibly.

String course: A projecting horizontal molding on the face of a building.

Strip footing: A linear spread footing that supports a wall.

Structureborne sound: Sound transmitted through the solid material of a building rather than through the air.

Structure-enclosure joint: A joint that allows differential movement between the frame of a building and the enclosure of the building.

Strut: A linear compression element in a structure.

Subcontractor: A specialty contractor who works under an agreement with the general contractor on a building project; for example, a plumbing contractor.

Sump: A pit in a basement floor used to accumulate any water that may leak into the basement.

Superinsulated, sun-tempered: An approach to energy efficiency in a building that emphasizes high levels of thermal insulation and airtight construction, coupled with a limited amount of south-facing glass for direct solar gain.

Surface film: A thin layer of air held by friction on the surface of a building.

Sustainable building: Building in such a way as to satisfy the needs of the current generation without compromising the ability of future generations to satisfy their needs.

Synclastic: The property of a surface of having the same sense of curvature, either concave or convex, along both its principal axes.

Système internationale d’uriités: See SI units.

- T -

Tensile: Having to do with stretching of material.

Tensile stress: The intensity of tension in a material, measured in units of force per unit of cross-sectional area.

Tension: A stretching or pulling apart.

Terminal reheat system: An air conditioning system in which chilled air is circulated through ducts to points of use, where it's heated with a thermostatically controlled hot water coil to adjust its temperature.

Termite shield: A sheet metal flange that projects from the junction between a foundation wall and the sill of a building, over which termites must build their tubes if they are to infest a building. The flange makes it easy to detect the presence of termite tubes.

Terrazzo: A decorative concrete flooring produced by grinding and polishing a slab made of colored marble chips and selected colors of fine aggregate and cement.

Terrestrial: Having to do with the earth.

Terrestrial radiation: Thermal radiation from the earth or among objects on earth.

Thatch: See Roof, thatched.

Thermal break: A layer of low-conductivity material placed between parts of a metal frame to reduce its conduction of heat.

Thermal bridge: A highly conductive path that transmits comparatively large amounts of heat through an otherwise well-insulated building assembly, such as a metal framing member in an insulated wall.

Thermal capacity: The ability of a material to store heat.

Thermal “feel”: Whether a material seems warm or cold when contacted by the human body.

Thermal resistance: The ability of a material to retard the flow of heat.

Thermostat: A device that turns another device off and on depending on whether the ambient temperature is above or below a preset temperature.

Tholos: A corbeled dome.

Three-phase electricity: Electric current that is made up of three overlapping sine waves of alternating current so as to furnish more constant energy for large electric motors.

Tie: A tensile structural member. A tensile connecting device. Total energy system: A system in which an on-site generator driven by an internal combustion engine creates electricity for a building or complex of buildings, and the cooling water from the engine is used to heat water or air.

Transformer: A device for reducing or increasing the voltage of electric current by means of two coils of a differing number of turns of wire wrapped around a single magnetic core.

Trap, plumbing: A U-shaped piece of waste pipe that holds a small quantity of waste water that acts as a seal to prevent sewer gases from entering the building.

Trap siphoning: The evacuation of the water seal from an unvented plumbing trap.

Tread: A horizontal plane in a stair.

Trombe wall: An east-west wall of concrete, masonry, or containers of water, placed near a south-facing wall of glass to absorb and later re-radiate solar heat.

Truss: A structural spanning device in which loads are translated into axial forces in a triangulated system of slender members.

Two-way structural action: Resisting bending in two mutually perpendicular directions, as occurs in a concrete two-way flat plate or two-way flat slab.

- U -

Ultraviolet light (UV): Electromagnetic radiation of shorter wavelengths than violet light.

Underpinning: Strengthening the foundations of an existing building by temporarily supporting the building on jacks while adding or enlarging foundation components.

Unit air conditioner: A small, self-contained electric-powered device that utilizes a compression cycle to cool and de humidify room air, usually mounted in a window opening or in an opening in an exterior wall.

Unit ventilator: A device in an exterior wall that recirculates room air, exhausting a fraction of it to the outdoors and taking in a similar fraction of outdoor air, while passing the air over coils that heat or cool it as needed.

Universal design: An approach to building design that gives equal access and convenience to all people regardless of physical handicaps, avoiding separate, special provisions for the handicapped.

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