Glossary Flashcards
(133 cards)
1
Q
The percentage of incoming energy that is absorbed. In measuring radiant energy (light or heat) it is a unitless ratio that may vary depending on the wavelength. In acoustics, it is called a sabin and may vary depending on frequency.
A
Absorption Coefficient
2
Q
A cooling process resulting from the absorption of vapor by brine solution that is then heated to remove the moisture. The heat may be supplied by solar or other heating sources.
A
Absorption Refrigeration
3
Q
The abbreviation for either air conditioning or alternating current, depending on the context.
A
AC
4
Q
An unobstructed vertical path, open to the atmosphere, separating the outlet of a faucet from the overflow rim of the fixture it serves. The purpose is to prevent a momentary vacuum in the supply pipe from siphoning water from the fixture back into he supply pipe.
A
Air Gap
5
Q
An electric current that reverses its direction at regular intervals, generally 60 times per second in the US. A plot of voltage over time is a sine wave.
A
Alternating Current
6
Q
Relating to a general of all surrounding condition. In thermal processes, it refers to the air temperature, as distinct from that of surfaces or objects. In lighting, it refers to the background light level, and in acoustics it refers to the background noise level.
A
Ambient
7
Q
The abbreviation for the American Society of Heating, Refrigerating, and the Air Conditioning Engineers, the source of most of the standardized information on the subject.
A
ASHRAE
8
Q
The ratio of the longer to shorter dimension of an air conditioning duct, that affects duct friction, or of a room, that relates to light reflection.
A
Aspect Ratio
9
Q
The automatic drain valve at the base of a dry standpipe.
A
Ball Drop
10
Q
The drain that removes dirt that builds up in the floor pool of an evaporative cooling tower
A
Blow Down
11
Q
The abbreviation for British Thermal Unit, a unit of heat energy, which is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit.
A
BTU
12
Q
The abbreviation for Btu’s per hour, an energy flow rate.
A
BTUH
13
Q
The control by automatic equipment of many functions in a large building, usually including HVAC system, the fire detection and alarm system, and building security.
A
Building Automation
14
Q
The abbreviation for cubic feet per minute, which is the flow rate of air in a mechanical system or duct.
A
CFM
15
Q
A piece of equipment that cools water for use in an air conditioning system.
A
Chiller
16
Q
A fictitious temperature assigned to a combination of actual temperature and wind velocity that has the same physiological effect as still air at the chill factor temperature
A
Chill Factor
17
Q
The addition of small amounts of chlorine to a water source to kill bacteria.
A
Chlorination
18
Q
In sanitary drainage, any vent that serves two or more traps.
A
Circuit Vent
19
Q
A window above eye level that admits daylight, such as the high windows in a cathedral.
A
Clerestory
20
Q
An organized body of rules and regulations adopted and enforced by a governmental unit, such as building code.
A
Code
21
Q
The ratio of the amount of heat energy delivered by a heat pump to the amount of energy removed by a refrigeration machine to the amount of energy expanded in its removal. It is similar to efficiency, but often exceeds 100 percent, and is therefore expressed as a number, i.e. 2.7 which is typical for a heat pump.
A
Coefficient of Performance
22
Q
The ratio of useful light arriving at a work plane to the amount of light emitted by the source. The CU depends on the reflectivity of different surfaces and the aspect ratio of the ceiling, wall and floor cavities.
A
Coefficient of Utilization
23
Q
The combination of thermal and environmental conditions within which a human is comfortable, often shown on a psychometric chart.
A
Comfort Zone
24
Q
The rate at which a specific thickness of a given material conducts heat.
A
Conductance (C)
25
The heat transfer process that occurs when a warm fluid rises, displacing cold fluid which then falls.
Convection
26
One complete set of repeating events, typically used with alternating current or sound.
Cycle
27
A measure of frequency in electric current or acoustics, i.e., the number of cycles per second of a wave or oscillation. In acoustics, the term has been largely replaced by Hertz, where 1 cps=1Hz
Cycles per Second (CPS)
28
The use of natural light from outside to replace or augment electrical light outdoors, which produces energy savings.
Daylighting
29
A decibel measured in the A scale, that is weighted to account for the special sensitivities of the human ear.
dBA
30
A logarithmic measure of sound intensity level.
Decible (dB)
31
The amount by which the average outdoor temperature at a particular location is below 65 degrees F for one day. Degree days may also be summed and stated for a month or a year.
Degree Day (DD)
32
A method of connecting windings on a three phase transformer, end to end, that results in a triangular shape.
Delta Connection
33
The temperature of air at that the water contained in the air begins to condense and form dew. The dew point for a given sample is always lower than or equal to its current temperature.
Dew Point Temperature
34
A device through which the air from a duct enters a room, or a device through which the light from a fixture enters a room.
Diffuser
35
The temperature of air as read on an ordinary glass thermometer
Dry Bulb (DB)
36
A sprinkler system whose pipes are normally pressurized with only air, thus being invulnerable to freezing temperatures. Upon actuation, the air is vented and supply pressure forces water through the system.
Dry Pipe Sprinkler
37
An energy saving strategy in which part of the HVAC system is shut off while the rest is used, such as shutting off the refrigeration when the outside air temperature is low, while the fan continues to operate
Economizer Cycle
38
A fictitious temperature having the same physiological effect as air of a standardized temperature, humidity and velocity.
Effective Temperature
39
The ratio of the lumens emitted by a lamp to the electrical power consumed by the lamp.
Efficacy
40
A factor that represents the rate at which a given surface material gives off or emits radiant energy. The emissivity varies from 0 to 10, where 1.0 is the theoretical emissivity of a perfect black box at the same temperature.
Emissivity
41
The total of sensible plus latent heat stored in the air. It is also know as Total Heat.
Enthalpy
42
A continuous and unobstructed means of egress to a public way. Its minimum width is generally 44 inches.
Exit
43
A complete fire-resistive assembly consisting of a fire door, fire damper, or fire window and its mounting frame or hardware. The entire assembly, not just its components, must be approved and labeled by a testing agency that inspects the materials and workmanship during fabrication at the factory. Available ratings are 3/4, 1, 1-1/2 and 3 hours.
Fire Assembly
44
A unit of liquid flow used in sizing both supply and drainage pipes.
Fixture Unit
45
A numerical classification indicating the rate at which flame will spread in or on a given material, in which higher numbers flame up more rapidly.
Flame Spread Rating
46
A valve that releases a definite amount of water into a plumbing fixture each time its actuated.
Flushometer Valve
47
The basic unit of illumination arriving at a work plane. One footcandle is equal to one lumen per square foot.
Footcandle
48
A heating or cooling system that uses a fan to circulate heated or cooled air through ducts to the occupied spaces.
Forced Air System
49
The movement of a fluid by a fan or a pump, in order to force heat exchange.
Forced Convection
50
A hot and chilled water system having separate return lines for each supply line, and with no mixing of the two streams.
Four Pipe System
51
The number of cycles that occur per second, either in alternating current or acoustics. In acoustics, the frequency determines the pitch.
Frequency
52
In a given location, the maximum depth in soil that is expected to freeze in cold weather. Water piping must ordinarily be buried below the frost line to protect against freezing.
Frost Line
53
A piece of wax or paraffin that melts at a predetermined temperature, setting off a sprinkler head, an alarm system or otherwise actuating a fire protection device.
Fusible Link
54
A thermometer that measures Mean Radiant Temperature
Globe Thermometer
55
An electrical conductor connected to the earth or to a pipe extending into the ground, used to dissipate hazardous currents into the earth.
Ground
56
A gaseous fire extinguishing medium that smothers fires, often used in automatic systems in computer rooms.
Halon
57
A refrigeration loop used to bring heat into a space instead of removing heat from it. The term is also used for an entire system of such units attached to a recirculating heat sink.
Heat Pump
58
A high efficiency particulate air filter, which removes dust and other tiny particles from a moving air stream.
HEPA Filter
59
The frequency of a sound, or of an alternating current, equal to the number of cycles per second.
Hertz (HZ)
60
A family of lamps consisting of a quartz envelope inside a glass envelope. The inner quartz tube can stand higher temperatures, and allows for the current to arc between the two electrodes exciting a plasma of mercury, metal halide, or high pressure sodium.
High Intensity Discharge (HID)
61
Horsepower or brake horsepower, a unit of power, equal to roughly 746 watts.
HP or BHP
62
The abbreviation for heating, ventilation and air conditioning
HVAC
63
The intensity of light falling on a surface, usually expressed expressed in footcandles.
Illumination
64
A rating of the degree of isolation of a floor against the transmission of impact noises.
Impact Isolation Class (IIC)
65
The leakage of air through cracks around windows and other building elements.
Infiltration
66
The intensity of sound at a given location, measured in watts per square meter, or more commonly in dB where the reference level is 10^-12 watts/ meter^2
Intensity Level
67
A physical principle that states that the intensity of a phenomenon is inversely proportional to the square of the distance from the source to the measuring device. It holds true for point sources of light, and for sound in an open field.
Inverse Square Law
68
The lowest point of the inside of a drain, pipe, channel, or other liquid carrying conduit.
Invert
69
A process of water softening in which calcium and magnesium ions are replaced by sodium ions. This process is also know as a zeolite process.
Ion Exchange
70
A fire detector that detects the products of combination (POC) even before they are visible to the naked eye.
Ionization Detector
71
The thermal conductivity of one square foot of a material per inch of thickness, with a surface temperature difference of one degree F.
K Factor
72
A unit of electric power, equal to 1,000 watts.
Kilowatt (KW)
73
A rating for transforming equal to the product of volts and amperes divided by 1000. The product of the KVA and the power factor gives the power of kilowatts.
KVA
74
The heat added to or removed from a substance when it changes its state.
Latent heat
75
An overhang, either outside or inside or both, that is used with a clerestory to reflect light up onto the ceiling, and reduce direct light adjacent to the window below.
Light Shelf
76
A unit of light, defined as the amount of light passing through one square foot at a distance of one foot from a one candlepower source.
Lumen
77
A complete light fixture, including lamps.
Luminaire
78
The theoretical law that states that for each doubling of mass in a wall, there is a 6 dB drop in the amount of sound transmitted. In actual practice, it is usually closer to 5 dB.
Mass Law
79
The weighted average of all the temperatures of all the surface visible from a given position.
Mean Radiant Temperature (MRT)
80
A single-number system for specifying a maximum SPL level in a given location, using standardized reference contours. The curves weight the frequencies to which the human ear is sensitive.
NC Curves
81
What does NEC mean
National Electrical Code
82
The wire or conductor in an electrical system that is equidistant in voltage from the phase conductors of the system. It is not the same as ground.
Neutral
83
A one number rating system giving the average sound absorption coefficient of a material at frequencies of 250, 500, 1000 and 2000 Hz.
Noise Reduction Coefficient (NRC)
84
The purpose for which a building is intended to be used.
Occupancy
85
A designation for a group of several occupancies that have comparable fire safety considerations, and which are therefore granted together by the code.
Occupancy Group
86
The abbreviation for the Occupational Safety and Health Act, which regulates working conditions.
OSHA
87
The practice of orienting and sizing a building, its windows, and its internal masses in such a way that it responds to the sun and to the climate, without the use of mechanical equipment.
Passive Solar Design
88
The unit of permeability for a given material, expressing the resistance of the material to the penetration of water or water vapor through it. One perm is equal to the flow of one grain of water vapor through one square foot of surface area per hour with a pressure difference of one inch of mercury.
Perm
89
The property of permitting passage of water vapor through a material without causing rupture or displacement
Permeability
90
Water that is suitable for drinking.
Potable Water
91
In an electrical circuit, the ratio of real power in watts to the product of voltage and current.
Power Factor (PF)
92
The logarithmic expression for the acoustical power at the source of a sound. It is also know as Acoustic Power Level
Power Level (PWL)
93
The abbreviation for parts per million
PPM
94
A graph showing the relationships between temperature, humidity, relative humidity and enthalpy.
Psychrometric Chart
95
The adding of sensible heat to a supply air stream that has been previously cooled.
Reheat
96
The ratio of the moisture content of the air to the maximum possible content at the same temperature.
Relative Humidity (RH)
97
The persistence of sound in an enclosed space after the source has stopped.
Reverberation
98
The time it takes a 60 dB sound to completely die away in a closed room after the source has stopped.
Reverberation Time
99
The unit of sound absorption equivalent to the absorption of one square foot of open window.
Sabin
100
Heat that changes the temperature of a substance, and does not represent the addition of any moisture to the substance, or any change of state
Sensible Heat
101
The ratio of the solar heat gained through a window with shading devices to the solar heat gained by a single pane double strength clear glass window. Shading devices, such as Venetian blinds, lower the SC.
Shading Coefficient (SC)
102
A Y-shaped hose attachment at the base of a building, which allows the fire department to connect a fire hydrant through a pumper truck to provide or augment water flow to a standpipe.
Siamese Fitting
103
A numerical rating derived from a standardized fire test procedure. Larger numbers indicate a greater density of smoke.
Smoke Developed Rating
104
A continuous enclosed stairway separated from the building at each floor by an open vestibule that allows smoke to vent away without entering the stair.
Smokeproof Enclosure
105
A sanitary drainage term referring to the waste from urinals, water closets, and fixtures of similar function.
Soil
106
A subjective system of measuring loudness, based on the reference point of one sone equal to a sound pressure level of 40 dB.
Sone
107
A meter that measures the sound pressure level and gives a reading in dB.
Sound Level Meter
108
The logarithmic expression of the pressure exerted by sound waves on the receiver. The reference pressure is 2x10^-5 newtons per square meter.
Sound Pressure Level (SPL)
109
A single number rating for the evaluation of a particular construction cross-section in terms of its transmission of airborne sound. The higher the STC rating, the more effective the construction is at stopping airborne sound.
Sound Transmission Class (STC)
110
A system used to extinguish fires automatically by releasing water or other substances.
Sprinkler System
111
The portion of a soil or waste stack that is above the highest branch drain connected to the stack. Its sole function is to vent to the outside air.
Stack Vent
112
A vertical supply pipe for fire fighting. Dry standpipes are empty, and must be connected to a fire hydrant via a siamese connection and a pumper truck. Wet standpipes are pressurized and filled with water, to serve attached hoses within the building, on each floor. Wet standpipes also have siamese connections to allow the water flow to be augmented from the fire hydrants.
Standpipe
113
A method of connecting the windings on a three phase transformer in which one end of all three windings is connected to a common neutral center point, forming a Y-shape
Star Connection
114
A device that starts the arc in a neon or fluorescent lamp, or a contractor and overload relay used in starting some electric motors.
Starter
115
A valve that permits passage of air or water, but not steam, often used with steam radiators.
Steam Trap
116
The method of soldering copper plumbing, or the condensation of water on cold pipes or building materials.
Sweating
117
The method of using a heated surface and resulting convection to move a fluid out of a space. In solar hot water heaters, the collector is below the storage tank and the water is circulated automatically by convection when it is heated. This may also be used to ventilate a building by sending the warmed air out to the top, and siphoning in cooler air at the bottom.
Thermosiphon
118
A hot and chilled water system having a common return pipe for both supply lines.
Three Pipe System
119
The amount of cooling required to create a ton of ice in a 24-hour period, equal to a steady rate of 12,000 Btuh
Ton
120
The reduction of sound that occurs when a given wall transmits sound from one room to an adjacent room, expressed in decibels.
Transmission Loss (TL)
121
A form of mass wall that transfers heat by causing convection into the room behind it, as well as conduction.
Trombe Wall
122
A hot or chilled water system having only a supply and return line. It can supply only heated or chilled water to a zone, but not both simultaneously.
Two Pipe System
123
The abbreviation for Uniform Building Code, one the most widely adopted model building codes in the US.
UBC
124
The thermal conductivity of a particular wall section, expressed in Btu's per hour per degree Fahrenheit per square foot.
U Factor or U Value
125
An automatic valve that admits air into a supply pipe rather than allowing the pipe or suction or siphon polluted water back into the supply.
Vacuum Breaker
126
An air conditioning system that accommodates thermal load changes by varying the flow of supply air into a conditioned space instead of varying the temperature of the air.
Variable Air Volume (VAV)
127
A vertical pipe that vents several sanitary drainage lines, in order to break the siphoning suction that would occur when water drops through the system.
Vent Stack
128
The basic unit of electrical power, equal to the product of volts and amperes in direct current systems, equal to 3.41 Btuh.
Watt
129
The length of one complete cycle or waveform, for light or sound waves. In light, the dominant wavelength determines the perceived color.
Wavelength
130
The temperature attained by glass thermometer whose bulb is covered with a wet sock and placed in an air stream moving at 1,000 ft per minute.
Wet Bulb Temperature (WB)
131
A sprinkler system that is continually pressurized with water. If a fusible sprinkler opens, water is immediately forced through the sprinkler head.
Wet Pipe Sprinkler
132
A substance used in water softening, in which a filtering tank is recharged by passing a salt solution through it. The tank may then be used as a filter for the free ions associated with hard water.
Zeolite
133
A portion of building controlled by a single thermostat, because its spaces have similar heating or cooling needs.
Zone
