PPD Flashcards
A balanced air valve positioned so as to admit air to the flue or stack of a furnace in order to maintain a constant about of draft. Also called a draft regulator.
barometric damper
Curved baffles inserted in a duct elbow to decrease pressure loss through the elbow
turning vanes
The basic unit of electrical power, equal to volts x amperes in direct current systems. Equal to 3.41 Btuh
watt (W)
A sound wave that has been reflected with sufficient magnitude and delay so that it is heard as a distinct from that transmitted directly
echo
A pipe fitting used to couple the ends of two pipes, neither of which can be rotated
union
The logarithmic expression for the acoustical power at the source of a sound. Also known as acoustic power level.
power level (pwl)
A device used to collect solar radiation
collector
PPM
parts per million
Parts other than valves or pipe used in a pipe line such as couplings, elbows, tees, unions and reducers.
fittings
intensity level
The intensity of sound at a given location, measured in watts/ sq. meter, or more commonly in dB where the reference level is 10-12 watts/ sq. m
A measure of the tendency of an electrical circuit to restrict the flow of current, or the ratio of voltage to current in a conductor or closed circuit. Unit= ohm
resistance
The intensity of light falling on a surface usually expressed in footcandles.
illumination
The velocity of air in an enclosed space measured in feet/min
air movement
A water seal fitting located in the drain line after a fixture to prevent sewer gases and odors form entering the room.
trap
The amount of light emitted by a source
luminous intensity (I)
An outside faucets for connecting to a garden hose.
sill cock
Water containing so much salt that it is non potable.
brackish
A pump used in hot water systems for maintaining forced circulation of water or other liquid.
circulator
Fire assembly
A complete fire-resistive assembly consisting of a fire door, fire damper or fire window and its mounting frame and hardware.
An absorption or drain field in which septic tank effluents seep through loose pipes and coarse aggregates into the surrounding soil.
leaching field
A set of electrical conductors which extend from the source of energy to a distribution center.
feeder
Forced convection
The movement of a fluid by a fan or a pump in order to force heat exchange.
The leakage of air through cracks around windows and other building elements.
infiltration
The ratio of the moisture content of the air to the maximum possible moisture content at the same temperature.
relative humidity (RH)
A heat exchanger in which refrigerant vapor is condensed (liquified) releasing heat to an external medium.
condenser
The length of one complete cycle or waveform for light or sound waves.
wavelength
Doppler effect
The change in the observed pitch of sound which occurs when the observer of the sound moves
The part of a refrigeration system in which the refrigerant evaporates absorbing heat from the medium to be cooled.
evaporation
The end of a pipe that fits into the bell or enlarged end of another pipe
spigot
The method of soldering coppering plumbing or the condensation of water on cold pipes or building materials.
Sweating
The rate at which a specific thickness of a given material conducts heat.
conductance (c)
The machine that converts mechanical energy into electrical energy by the motion of electrical conductors in a magnetic field.
generator
DWV
drain waste vent
Btuh
Btus/hour
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
The unit of electrical potential or electromotive force
volt (V)
An enclosure in which two air streams are mixed. Commonly used for mixing outside air and return air or hot and cold air in a dual duct system.
mixing box
A flow of air or gas through a flue or chimney
draft
The purpose for which a building is intended to be used.
occupancy
chill factor
a fictitious temperature assigned to a combination of actual temperature and wind velocity which has the same physiological effect as still air at the chill factor temperature.
A value at the end of a pipe providing a means of releasing and controlling water from the pipe
faucet
A mechanical device used to compress or move a fluid
pump
A hot and chilled water system having a common return pipe for both supply lines
three-pipe system
The tendency of a gas or air to rise in a vertical shaft because its density is lower than that of the surrounding gas or air.
stack effect
smoke proof enclosure
A required exit which consists of a vestibule and continuous stairway enclosed from the highest point to the lowest point by walls of 2h fire-resistive construction
oakum
calking made from hemp fiber strand or rope soaked in oil or other substance to make it waterproof and rot-resistant.
effective temperature
A fictitious temperature which would produce the same physiological effect as the combined effects of temperature humidity of air movement.
A heating device arranged to deliver heat to the air primarily by convection.
Convector
Phon
A subjective unit of loudness numerically equal to the sound pressure in decibels of a 1000-Hx tone judged by the listener to have the same loudness as the given sound.
A device for measuring simultaneously the wet bulb and dry bulb temperatures of air and therefore the relative humidity
psychrometer
A hot and chilled water system return lines for each supply line with no mixing of the two streams.
Four-pipe system
Energy received from solar radiation.
insolation
Smoke developed rating
Numerical rating of interior finish materials derived form a standardized fire test procedure. Larger numbers indicate a greater density of smoke.
Free-field room
A room whose boundaries absorb all of the sound striking them. Also known as an anechoic room.
A vent which is a continuation of the trap and drain to which it connects. Also called a common vent.
individual vent
Perm
The unit of permeability for a given material, expressing the resistance of the material to the penetration of moisture. One perm = the flow of 1 grain of water vapor through 1 sq. ft. of surface area / hr with a pressure difference of 1” of mercury.
The 23.5º tilt of the earth’s axis relative to a line perpendicular to the plane of the earth’s orbit.
Declination
Zeolite
Substance used in water softening which changes sodium ions for magnesium or calcium ions in hard water. It is regenerated by passing brine through it which reverses the exchange.
A valve which permits passage of air or water but not steam often used with steam radiators.
Steam trap
The fluid used for heat transfer in a refrigeration system.
refrigerant
A vertical water supply pipe that extends through at least one floor of a building and provides water to fixtures or branches.
riser
A gaseous fire-extinguishing medium which smother fire often used in automatic systems in computer rooms.
Halon
An instrument which measures the relative humidity of the air.
Hygrometer
PWL
Acoustical Power Level: logarithmic expression for the acoustical power at the source of a sound.
A method of connecting windings on a three-phase transformer end-to-end which results in a triangular shape
delta connection
A short piece of pipe with threads at each end used to connect fittings and valves in a pipe line
nipples
An energy-saving strategy in which a part of the HVAC system is shut off
economizer cycle
The lowest point of the inside of a drain pipe channel or there liquid-carrying conduit.
invert
Ion exchange
A process of water softening in which calcium and magnesium ions are replaced by sodium ions.
Another name for the Zeolite process
ion exchange
Hartford loop
A plumbing arrangement on steam builders to avoid rapid loss of water in the boiler due to a break in the condensate return line. Also referred to as an underwriter’s loop
A switch usually magnetically operated which is used to open and close an electrical circuit
contactor
A heating or cooling system that collects and moves solar heat with the assistance of mechanical power.
active solar system
A u-shaped tube used to transfer liquid from an upper level to a lower one by suction.
siphon
A device which converts power in one kind system to power in another form such as a loudspeaker which converts electric power to acoustic power.
transducer
Materials used to store and release heat by means of their latent heat capacity that is they alternately melt and solidly in the normal solar operating temperature range of 80-160º
Eutectic Salts
Ratio of reflected to incident light falling on a surface
reflectance
The time required for the sound pressure level to decrease 60dB after the original sound stops
reverberation time
The number of hours needed for 1 Btu to pass through 1 sq.ft of a material when the temp. differential is 1ºF
Resistance
Enthalpy
Total in a substance, including latent heat and sensible heat.
Vapor barriers should always be located on the ____ side of insulation to prevent moisture from condensing when it cools and reaches the dew point.
warm
A family of lamps consisting of a quartz envelope inside a glass envelope. In the quartz envelope the current causes an intense arc bt two electrodes exciting a plasma of mercury metal halide or high-pressure sodium and producing visible light.
HID - high-intensity discharge
A vertical pipe which vents several sanitary drainage lines in order to break the siphoning suction which would occur when water passes down through the system.
vent stack
POC
Abbreviation of products of combustion usually relative to smoke detection.
The treating of air in an occupied space to control its temperature humidity and cleanliness.
AC
The ratio of maximum demand or expected power usage to the connected load.
demand factor
A device used to generate alternating current by rotating a coil in a magnetic field.
alternator
blowdown
The drain which removes dirt which builds up in the floor pool of an evaporative cooling tower or the discharge of sediment from the bottom of a boiler or heat exchange.
The ratio of useful light arriving at the work plane to the amount of light emitted by the source which depends on the reflectivity of different surfaces and the aspect ratios of the ceiling wall and floor cavities.
coefficient of utilization
The combination of thermal and environmental conditions within which a human is comfortable often shown on a psychrometric chart.
comfort zone
A reverse flow of water often used in water softening to remove sediment
backwash
A wall whose mass is composed of concrete masonry or containers filled with water - the purpose of which is to absorb and store solar heat.
thermal mass storage wall
Innocuous background noise used to mast objectionable sounds.
white noise
The time rate of heat flow which combines the effects of conduction, convection and radiation.
heat transmission
The total of sensible plus latent heat stored in the air.
enthalpy
ABS
acrylonitrile-butadiene-styrene: a plastic used for drainage waste and vent piping and sewer systems
A single-number system for specifying a maximum SPL level in a given location using standardized reference contours.
NC curves
The waste from urinals, water closets and fixtures of similar function.
soil
A cooling system that provides refrigerated air using solar radiation as the prime source of energy.
solar AC
Any device used for transferring heat from one fluid to another where fluids are physically separated.
heat exchanger
The pressure measured by a pilot tube consisting of static pressure and velocity pressure.
total pressure
A fire detector which deflects the products of combustion (POC) even before they are visible to the naked eye.
ionization detector
A valve consisting of a circular plug or disc which is raised or lowered against a circular opening or seat used for adjusting or throttling flow.
globe valve
Two or more cells which utilize the reaction of a chemical solution on two dissimilar metal to produce an electromotive force.
battery
