a device or a method that prevents a reverse flow from the normal direction of flow in a piping system
balancing valve
valve used to add artificial resistance where required to achieve design flow rate
blowdown
a connection at the bottom or lowest portion of a gauge glass, low water cutoff, automatic water feeder, cast iron water column, etc., to facilitate cleaning out or testing of the equipment
boiler
equipment used to heat water or generate steam
boiler trim
the controls, equipment and accessories connected to a boiler for its safe and efficient operation
butt fusion
a joining method that requires ends of pipe to be joined by direct heat application on material such as steel or plastic
CAD
computer aided design; used for drawing, altering and recalling views and details on a computer
chilled water cooling system
piping systems for cooling buildings, equipment or processes by circulating chilled water
circuit
the piping path from a heat exchanger to a heat transfer unit and back to the heat exchanger
condensate return system
a piping arrangement designated to return condensate to a steam generator
contour marker
instrument used in the fabrication of pipe that will trace lines for the cutting of tees, wyes and laterals
control valve
a valve which controls the flow of a liquid or gas automatically as directed by an electrical or pneumatic signal or a capillary tube
controller
device with a sensing element which takes measurements and adjusts the setting of a preselected component accordingly
converter
a piece of equipment used to heat or cool water and other liquids by means of steam, high temperature hot water, or chilled water without the two mediums coming in contact with each other (e.g. heat exchanger; indirect heater)
de-aerator
a device used to remove temporary hardness and unwanted gases (such as oxygen and carbon dioxide) from the make-up water
desuperheater
a device which uses water as a cooling medium to lower the temperature of the superheated steam
direct return
a two-pipe heating system (hydronic system) in which the first unit supplied has the shortest return to the boiler
double-block-and-bleed
a valving system wherein a full flow vent valve is located on piping between two shut-off valves in series for the purpose of bleeding to the atmosphere excess pressure between valves
dry return
a condensate return line which is located above the water line of the boiler and carries condensate and air
equalizer beam
usually used on dual hoist lines to make tandem lifts, but can also be used to equalize the load on sling legs. They are connected with a crane hook connected directly to the beam.
expansion joint
a manufactured, mechanical device to take up or to compensate for the expansion and contraction of a pipe line due to temperature change
feed water
water that is fed into a boiler or systems
flashback
flashback always occurs in the line carrying the lower pressure and will always occur beyond the mixer, and may include the hose and regulator as well. It is usually a devastating explosion or series of explosions, leaving the equipment in shambles
heat exchanger
a device for transferring heat from one fluid to another without mixing the two fluids
heat transfer unit
a device used to transfer heat from a fluid to a space for conduction, convection or radiation
high temperature hot-water system
a system which has hot water above 350°F (180°C)
HVAC system
heating, ventilation and air-conditioning system
indicator
an instrument that shows a measurement, but makes no permanent record, e.g. pressure gauge
isolator
a device used to isolate equipment from its piping for testing or flushing purposes; isolators are also used to give separation from its support to prevent the transmission of noise and/or vibration
low water cut off (LWCO)
a device which shuts off the automatic fuel control valve when the water falls below a safe level in the boiler
make-up water
water supplied to a system that replaces system fluid that has been lost through evaporation, leakage, etc.
pin indexing
refers to a fail-safe design by which end connections for specific gases can only be connected to other ends intended for use with the same gas; for example, equipment intended to utilize oxygen cannot physically be connected to a nitrous oxide gas supply
post heating
use of a heat source to heat an area after a process such as welding takes place
preheating
use of a heat source to heat an area before a process such as welding takes place
resin
a bonding agent used in the fibreglass process; used because of its resistance to acids and alkalines
safety relief valve
a safety device that will open before a dangerous pressure or temperature is reached
saturated steam
steam which is at the same temperature as the boiling water from which it was formed (dry saturated; wet saturated)
single-seated control valve
a control valve with a single seat and a single plug or disc
solvent fusion
joining plastic pipe by the use of a solvent which dissolves the surface of the pipe and forms a continuous bond upon evaporation
spool sheets
detail views of a piping system identifying specific piping and pieces to be fabricated
spreader bar/beam
used to support long, hard-to-handle loads. These bars eliminate load tipping, sliding or bending. They connect by using slings from the beam to the crane hook.
spreaders
a set of chokers or slings of equal length used to lift a load
steam separator
a device used to remove entrained moisture present in steam
steam tracing
a pipe or tube which is placed along or around pipe, vessels and pumps and is filled with steam to control the primary pipe’s medium’s temperature
steam trap
an automatic device which allows the passage of air and condensate but prevents the passage of steam
straightening vanes
device used to take the turbulence out of liquids and gases flowing in pipes so measuring instruments can get an accurate reading
superheated steam
saturated steam with the addition of sensible heat; an increase in temperature of saturated steam without an increase in pressure
superheater
a device used to heat dry or wet-saturated steam and increase the temperature without increasing the pressure of the steam
vacuum pump
a device used to lower atmospheric pressure inside a vessel or piping system
wrap-around
a coil of gasket material used to wrap around pipe, when in the process of marking a pipe
