Building Utilities (Mechanical) Flashcards
A measure of the warmth or coldness of a substance, object, or environment with reference to some standard value.
Temperature
An instrument for measuring temperature, consisting typically of a glass tube with a numbered scale and bulb containing a liquid, such as mercury, that rises and falls with changes in temperature.
Thermometer
The quantity of heat required to raise the temperature of one pound (0.4kg) or water 1 degree F.
British thermal unit
A unit of heat equal to 100,000 British thermal unit.
Therm
A unit of heat equal to the quantity of heat required to raise the temperature of one gram of water 1 degree C at a pressure of one atmosphere, equivalent to 4.186 joules.
Calorie
A unit of heat equal to the quantity of heat required to raise the temperature of one kilogram of water 1 degree C at a pressure of one atmosphere, equivalent to 1000 small calories.
Kilocalorie
A temperature scale in which 32°F represents the freezing point and 212°F the boiling point of water under standard atmospheric pressure.
Fahrenheit scale
A temperature scale divided into 100 degrees, in which 0°C represents the freezing point and 100°C the boiling of water under standard atmospheric pressure.
Celsius scale
An absolute scale of temperature having a zero point of - 273.16°C.
Kelvin scale
A temperature scale based on absolute zero with scale units equal in magnitude to centigrade degrees.
Absolute scale
The hypothetical lowest limit of physical temperature characterized by complete absence of heat, equal to -273.16° C or -459.67°F.
Absolute zero
Temperature as measured on an absolute scale.
Absolute temperature
The base SI unit of temperature equal to 1/273.16 of the triple point of water.
Kelvin
The particular temperature and pressure at which the liquid, gaseous, and solid phases of a substance can exist in equilibrium.
Triple point
The transfer of heat by the circulatory motion of the heated parts of a liquid or gas owing to a variation in density and the action of gravity.
Convection
The transfer of heat from the warmer to the cooler particles of a medium or of two bodies in direct contact, occurring without perceptible displacement of the particles themselves.
Conduction
The process in which energy in the form of waves or particles is emitted by one body, passed through an intervening medium or space, and absorbed by another body.
Radiation
The time rate of heat flow through a unit area of a given material of unit thickness when the temperature difference across the thickness is one unit of temperature.
Thermal conductivity
The time rate of heat flow through a unit area of a given material when the temperature difference across a specified thickness of the material is one unit of temperature.
Thermal conductance
An element of low thermal conductivity placed in an assembly to reduce the flow of heat between highly conductive materials.
Thermal break
The reciprocal of thermal conductance expressed as the temperature difference required to cause heat to flow through a unit area of a material of given thickness at the rate of one heat unit per unit time.
Thermal resistance
A measure of thermal resistance of a given material, used esp. to specify the performance of thermal insulation.
R-value
The time rate of heat flow through a unit area of a building component or assembly when the difference between the air temperature on the two sides of the component or assembly is one unit of temperature.
Thermal transmittance
A measure of the thermal transmittance of a building component or assembly, equal to the reciprocal of the total R-value of the component or assembly.
U-value
The flow of outside air into an interior space through cracks around windows and doors or other openings in the envelope of a building.
Infiltration
A strip of metal, felt, vinyl, or foam rubber, placed between a door or window sash and its frame to provide a seal against windblown rain and air infiltration.
Weather strip
Any of various lightweight, inorganic, fibrous materials used esp. for thermal and sound insulation, such as glass wool and rock wool.
Mineral wool
Spun glass fibers resembling wool and used for thermal insulation and air filters.
glass wool
A material consisting of extremely fine filaments of glass, woven into fabric, massed for use as a thermal and acoustical insulator, or embedded to reinforce various materials.
Fiberglass
Trademark for a brand of fiberglas
Fiberglas
Mineral wool made by blowing steam or air through molten slag or rock.
Rock wool
Plastic, such as polyurethane or polystyrene, made light and cellular by the introduction of pockets of gas or air and used as thermal insulation.
Foamed plastic
A rigid expanded polyurethane having a closed-cell structure and used as thermal insulation.
Polyurethane foam
A rigid polystyrene foam having an open-cell structure and used as thermal insulation.
Molded polystyrene
A rigid polystyrene foam having a closed-cell structure and used as thermal insulation.
extruded polystyrene
Trademark for a brand of formed plastic made from polystyrene.
Styrofoam
Cellular glass made by forming softened glass and molding it into boards or blocks for use as thermal insulation.
Foam glass
Fine wood shavings, usually of pine or chemically treated wood fibers, used as an insulating material, as a binder in plaster, and for packing.
Wood wool
The passageway required for the circulation of air between batt insulation and roof sheathing.
Airway
Flexible, fibrous thermal insulation of glass or mineral wool, made in various thicknesses and lengths and 16-in (400mm) or 24 in. (610mm) widths to fits between studs, joist, sometimes faced with a vapor retarder of kraft paper, metal foil, or plastic sheet.
Batt insulation
A strong, usually brown paper, processed from wood pulp and sized with resin.
Kraft paper
A preformed, nonstructural insulating board of foamed plastic or cellular glass. Cellular glass insulation is fire-resistant, impervious to moisture, and dimensionally stable, but has a lower thermal-resistance value than foamed plastic insulations, which are flammable and must be protected by a thermal barrier when used on the interior surfaces of a building.
Rigid board insulation
Thermal insulation in the form of a foamed plastic, such as polyurethane, that is sprayed or injected into a cavity where it adheres to the surrounding surfaces.
Foamed-in-place insulation
Thermal insulation in the form of mineral wool fibers, granular vermiculite or perlite, or treated cellulosic fibers, poured by hand or blown through a nozzle into a cavity or over a supporting membrane.
Loose-fill insulation
Thermal insulation in the form of a material of high reflectivity and low emissivity, such as paper-backed aluminum foil-backed gypsum board, used in conjunction with a dead-air space to reduce the transfer of heat by radiation.
Reflective insulation
An unventilated air space in which the air does not circulate.
Dead-air space
A material providing high resistance to heat flow, such as mineral wool, vermiculite, or foamed plastic, fabricated in the form of batts, blankets, boards or loose fill.
Thermal insulation
To make a house or building secure against cold or stormy weather, as by adding thermal insulation or storm windows, or by sealing joints.
Weatherize
An insulating board made of wood or cane fibers compressed and cemented into rigid sheets, used as an inexpensive wall finish or as ceiling tiles.
Fiberboard
Insulating fiberboard treated or impregnated with asphalt for water resistance and used primarily for sheathing light wood frame walls.
Fiberboard sheathing
The ability of a surface to emit heat by radiation, equal to the ratio of the radiant energy emitted to that emitted by a black body at the same temperature.
Emissivity
Human comfort as determined by the ability of the body to dissipate the heat and moisture it produces by metabolic action.
Thermal comfort
A temperature representing the combined effect of ambient temperature, relative humidity, and air movement on the sensation of warmth or cold felt by the human body, equivalent to the dry-bulb temperature of still air 50% relative humidity, which induces an identical sensation.
Effective temperature
The temperature recorded by the wet-bulb thermometer in a psychrometer.
Wet-bulb temperature
The temperature at which air becomes saturated with water vapor.
Dew point
The range of dry-bulb temperature, relative humidity, mean radiant temperature, and air movement judged to be comfortable by a majority of Americans and Canadians tested.
Comfort zone
A chart relating the wet-bulb and dry-bulb readings from a psychrometer to relative humidity, absolute humidity, and dew point.
Psychrometric chart
The sum of the temperatures of the surrounding walls, floor, and ceiling of a room, weighted according to the solid angle subtended by each at the point of measurement.
Mean radiant temperature
The temperature recorded by the dry-bulb thermometer in a psychrometer.
Dry-bulb temperature
An instrument for measuring atmospheric humidity, consisting of two thermometers, the bulb of one being dry and the bulb of the other being kept moist and ventilated so that the cooling that results from evaporation makes it register a lower temperature than the dry one, with the difference between the reading being a measure of atmospheric humidity.
Psychrometer
Heat energy transmitted by the radiation of electromagnetic waves in contrast to heat transmitted by conduction or convection.
Radiant heat
The ratio of the mass of water vapor to the mass of dry air in a mixture of air and water vapor.
Humidity ratio
A measure of the total heat contained in a substance, equal to the internal energy of the substance plus the product of its volume and pressure.
Enthalpy
A rise in temperature occurring without the addition or removal of heat, as when excess water vapor in the air condenses and the latent heat of vaporization of the water vapor is converted to sensible heat in the air.
Adiabatic heating
A drop in temperature occurring without the addition or removal of heat, as when water evaporates and the sensible heat of the liquid is converted to latent heat in the vapor.
Evaporative cooling
A protective sleeve of sheet metal passing through the wall of a chimney, for holding the end of a stovepipe.
Thimble
A pipe, usually of sheet metal, serving as a stove chimney or connecting a stove with a chimney flue.
Stovepipe
A cast-iron stove resembling an open fireplace but having enclosed sides, back, top, and bottom and a front completely open or able to be closed with doors.
Franklin stove
A pipe by which products of combustion are carried from a furnace or other appliance to the outside.
Vent
The air required for the combustion of fuel in a furnace.
Combustion air
A furnace designed for installation in a low attic or crawl space.
Horizontal furnace
A furnace recessed in or mounted on a wall and supplying heated air directly to a space without the use of ducts.
Wall furnace
An apparatus in which heat is produced, as for heating a house or producing steam.
Furnace
A furnace in which the heat required is produced through electricity.
Electric furnace
A furnace using a gas as a fuel.
Gas furnace
A furnace or boiler that burns fuel oil.
Oil burner
A burner designed for installation in a furnace that originally used another fuel.
Conversion burner
The hourly rate of net heat loss in an enclosed space, expressed in BTU per hour and used as the basis for selecting a heating unit or system.
Heating load
A degree-day below the standard temperature of 65ºF (19ºC), used in estimating fuel or power consumption by a heating system.
Heating degree-day
A unit that represents one degree of departure in the mean daily outdoor temperature from a given standard temperature.
Degree-day
Any of the systems that provide essential services to a building, such as water supply, sewage disposal, electric power, heating, ventilation, air-conditioning, vertical transportation, or fire fighting.
Mechanical system
The heating of a limited area, as a room, esp. by means of a heat source located within the space.
Space heating
A mechanical system that supplies heat to an entire building from a single source through a network of ducts or pipes.
Central heating
A fluid substance, such as warm air, hot water, or steam, capable of conveying heat from a source to the space being heated.
Heating medium
A device that automatically responds to changes in temperature and activates switches controlling such equipment as furnaces, refrigerators, and air conditioners.
Thermostat
A device for measuring temperature in which a pair of dissimilar metals, such as copper and iron, are joined so that a potential difference generated between the points of contact is a measure of the temperature difference between the points.
Thermocouple
A material made by bonding two metallic strips having different coefficients of expansion, used in temperature-indicating and temperature-controlling devices.
Bimetallic element
A system for heating a building be means of air heated in a furnace and distributed by a fan through ductwork to register or diffusers.
Forced warm-air heating
A perimeter heating system in which the main duct conveys warms air to a number of branch ducts, each serving a single floor register.
Extended plenum system
A chamber at the top of a hot-air furnace from which the leaders emerge.
Bonnet
A duct for conveying warm air from a furnace to a stack or branch duct.
Leader
A pipe or duct fitting having several outlets for making multiple connections.
Manifold
A heating system that distributes warm air to registers placed in or near the floor along exterior walls.
Perimeter heating
A device having slats at different angles for deflecting warm or conditioned air from an outlet in various directions.
Diffuser
A grille through which return air is withdrawn from an air-conditioned space.
Return grille
A duct for conveying cool air back to a furnace for reheating.
Cold-air return
A tapered section of a duct or flue forming a transition between two sections, one of which has a greater area than the other.
Gathering
A duct fitting forming a transition between two sections that vary in cross-sectional shape.
Boot
A perimeter heating system in which a loo[ of ductwork, usually embedded in a concrete ground slab, distributes warm air to each floor register.
A perimeter loop system
The distance a projected airstream travels from an outlet to a point where its velocity is reduced to a specified value.
Throw
A perimeter heating system in which a leader from a centrally located furnace carries warm air directly to each floor register.
Perimeter radial system
A pipe or conduit of sheet metal or fiberglass for conducting heated or conditioned air.
Duct
A system of ducts, connectors, and dampers for conveying air in a heating, ventilating, or air-conditioning system.
Ductwork
A vertical duct for conveying warm air from a leader to a register on an upper floor.
Stack
A continuous space or recess built into a wall or through a floor for pipes or ducts.
Chase
A grating or perforated screen for covering, concealing, or protecting a wall, floor, or ceiling opening.
Grille
A device for controlling the flow of warm or conditioned air from an outlet, composed of a grill with a number of parallel blades that may be adjusted so as to overlap and close the opening.
Register
A pliable, airtight fitting installed between two ducts, or between a fan and a duct, to prevent the transmission of noise and vibrations along the ductwork.
Flexible duct
A fiberglass blanket for lining the inside of a duct to reduce noise and serve as thermal insulation.
Duct liner
The distance a projected airstream travels from an outlet to a point where its velocity is reduced to a specified value.
Throw
The average velocity of a projected airstream at the end of the throw.
Terminal velocity
The vertical distance a horizontally projected airstream falls the elevation of its outlet, measured at the end of the throw.
Drop
The extent to which a projected airstream diffuses at the end of the throw.
Spread
A heating device consisting of a series or coil of pipes through which hot water or steam passes.
Radiator
A valve for eliminating air and condensed moisture from a radiator without allowing steam to escape.
Bucket trap
A valve for draining a pipe, radiator, or tank.
Bleeder
A two-pipe hot-water system in which the lengths of the supply and return pipes for each radiator or convector are nearly equal.
Reverse return
A two-pipe hot-water system in which the return pipe from each radiator or connector takes the shortest route back to the boiler.
Direct return
A return pipe in a steam-heating system that carries both air and water of condensation.
Dry return
A heating unit in which air heated by contact with a radiator or fin tube circulates by convection.
Convector
A type of radiator having horizontal tubes with closely spaced vertical fins to maximize heat transfer to the surrounding air.
Fin tube
A long, narrow hydronic or electric convector designed for installation along the base of a wall.
Baseboard heater
A self-contained electric or gas-fired space heater, consisting of a heating element, fan, and a directional outlet.
Unit Heater
A device for heating the space in which it is located, esp. a unit that has no external heating ducts or connecting to a chimney.
Space heater
An electric space heating elements sealed in quartz-glass tubes that produce infrared radiation in front of a reflective backing.
Quartz heater
A special fitting used in a one-pipe system to induce the flow of water from a return branch into the supply main.
Venturi tee
A relief valve that opens when actuated by a gas or vapor pressure above a predetermined level, allowing the gas or vapor to escape until its pressure is reduced to a safe or acceptable level.
Safety valve
A valve that opens when actuated by static pressure above a predetermined level in order to reduce the pressure to it.
Relief valve
A small faucet or valve for draining or releasing comparison in pipes, radiators, and boilers.
Petcock
A system for heating a building by means of water heated in a boiler and circulated by a pump through pipes to radiators or convectors.
Hot-water heating
