Air-handling unit
Air changes per hour

How many times the air in a building is changed on an hourly basis
Airflow proving switches
Airflow sensing device to prevent humidification during insufficient airflow
Alternate water seal
Nonstandard P-trap configuration installed before the drain valve on a steam generator
Amps / Current (I)
Measure of the flow of electricity; current is measured in Amps
Controller language
British standard pipe thread
Building volume               
Interior building volume (i.e., ft3 or m3)
Condensate pump
Pump used to push condensate to a more desirable location
Control cabinet with time delay
Control cabinet includes the component that can delay the opening and closing of a valve or relay based on demand
Desired conditions
The desired final relative humidity and dry bulb temperature of a space
Dew point temperature
The saturation temperature corresponding to the humidity ratio and pressure of a given moist-air state
Dew point transmitter
Sensing device based on dew-point used to control demand for a humidifier
Direct steam
Live or pressurized steam as from a boiler
Dispersion product
Steam distributor
Dispersion tube insulation
Insulation applied to dispersion tubes to limit air heat gain and associated condensate losses
(Diameter Nominal) Nominal piping measurement in millimeters
Drip-tee kit
Includes an inline tee connector, two hose cuffs, and four hose clamps
Dry bulb temperature
The temperature of the air indicated by any type of thermometer or thermocouple that has not been affected by evaporation or radiation
A channel or tube for conveying air
End-of-season drain
Opening a drain valve automatically after a period of non-use
F&T trap
Float and Thermostatic trap
Face height
Height of a dispersion assembly area where humidification steam is dispersed
Face width
Width of a dispersion assembly area where humidification steam is dispersed
A bolt-together fitting
Flange, screw-on
Flange that is screwed to a threaded nipple
Generation product

Atmospheric steam generator
Grains of moisture
Mass of water in grains per mass of dry air (i.e., grains/lb dry air or grains/kg dry air)
Hand direction
Right handed or left handed orientation of steam dispersion tube.  Facing into the airstream, where separator is located is the hand direction (left or right).
Hard pipe kit
Includes two hose cuffs and four hose clamps
Header, dispersion assembly
Central steam distribution pipe of a dispersion assembly
Headers inside

Central steam distribution pipe of a dispersion assembly is installed inside a duct or air handling unit
Headers outside
Central distribution pipe of a dispersion assembly is installed outside a duct or air handling unit
Heat gain from assembly
Heat transferred to the air from a dispersion assembly, which can be reduced with insulation
Heat gain from steam
Irreducible heat gain when steam is dispersed into air
High-limit humidistats
Humidity sensing device used to reduce or stop steam generation if airstream is close to saturation
Infiltration volume
Air volume entering a ventilation system through exterior openings (i.e., windows, doors, or leakage)
Input signal
Control signal
Insulation, dispersion tube (nonpressurized steam)
PVDF insulation applied to a dispersion tube
Insulation, dispersion tube jacketed (pressurized steam)
Sheet steel wrapper with insulation between the dispersion tube and wrapper
Insulation, tank
Insulation placed on a humidifier to prevent hot surfaces
Interconnecting piping
The pipe between a steam generator and dispersion assembly
Operability between humidifier and building management system, using a language such as LonTalk, BACnet, or Modbus
IP 66 cabinet
Control cabinet with dust and drip-proof rating
I-P units
Inch/pound measurement
Communication jack
Kilograms per hour
Pounds per hour
Quantity of moisture required to meet relative humidity (RH) requirements (i.e., lbs/hr or kg/h)
Load plus loss
Total moisture required to meet the relative humidity plus offset steam lost as condensate formed in steam piping, measured in lbs/hr or kg/h
Control language used to communicate
Low-water float switch
Low water cutoff
Makeup-air ventilation system
Ventilation system with only outside air

Mixed-air ventilation system
Ventilation system with both return air and outside air
Control language used to communicate
Modulating humidistat
Humidistat that produces a modulating control signal
Multiple-tank control
Single-point control of multiple humidifiers

Natural ventilation system
Ventilation system without the use of a mechanical device
NEMA-1 safety switch
External disconnect for electric humidifier
NEMA-12 cabinet
Control cabinet with dust proof rating
NEMA-4 cabinet
Control cabinet with dust and drip proof rating
Nonpressurized steam dispersion
Dispersion systems designed to accept steam from DriSteem steam generators
National pipe thread
Open space
Area with no ductwork

Outside air intake rate
Rate at which outside air enters a ventilation system
Outside air volume
Air volume entering a ventilation system from outside
Outside conditions
The outside dry bulb temperature and relative humidity
Pilot positioner
Positioning a valve using a pilot air control signal
Potable water

Tap (or drinking) water
Pressurized steam dispersion
Direct or live steam dispersion product
Project, DriCalc
Job name or reference number
Redundant tank              
Backup system or tank
Relative humidity (RH)
The wetness or dryness of air at a given temperature and pressure
Remote temperature sensor
Prevents condensation on structural members
The minimum nonwetting height above the steam outlet
RO/DI water
Reverse-Osmosis filtered, or DeIonized water
Same-side piping
Steam supply and condensate connection are on same side of the steam dispersion assembly
Sealed combustion
Air for combustion is ducted directly to a humidifier
Seismic certified
Humidification equipment that has gone through third party shake testing to validate operation after a seismic event.  May have additional or different support methods or structural enhancements
Steam and condensate separating device
Separator orientation
Separator may be in the upright or horizontal position
SI units
System International metric unit system
Softened water
Water where calcium and magnesium ions have been replaced with sodium ions
Solenoid valve
Electromagnetic valve
The minimum nonwetting width from the steam outlet
SSR sequencing modulation
One heater stage is controlled by a Solid-State Relay while others are controlled contactors
SSR, 100%, modulation
All heater stages are controlled by a Solid-State Relay
Steam dispersion enclosure
Box that contains the header
Steam dispersion panel
Dispersion system with a frame or case
Steam hose
Hose that connects a steam generator to a dispersion assembly and designed to withstand high temperatures
Steam trap
Device that prevents steam flow but allows condensate to flow through
Steam valve Cv/Kv
Flow coefficient of a valve
Steam valve size
Inlet and outlet size of the steam valve body
Generating nonpressurized steam via direct steam and a heat exchanger
Steam filter upstream of the steam valve to remove debris
System (DriCalc)
Humidification system for a space
Tag name
Individual humidifier identification
Temperature switch
Temperature activated switch prevents the operation of a control valve
The minimum nonwetting horizontal distance from the steam outlet
Total air volume
Total volume of air in a ventilation system
TP modulation
Time-proportioned modulation
Hanging support system for a humidifier
Tube spacing on-center
Spacing between dispersion tubes, measured from the tube center line
Thin walled pipe designed to withstand high temperatures
Tubing, insulated
Thin walled pipe with insulating cover
Volts alternating current
Valve control, electric
Electric control signal for steam valve(s)
Valve control, pneumatic
Pneumatic control signal for steam valve(s)
Venting, horizontal
Side wall venting
Weather cover
Enclosure that prevents rain from wetting humidifier components
Wet bulb temperature

An expression of the temperature of the air when a wick or sock, wetted with water, encases the sensing element of a dry bulb thermometer and air is passed over it at a velocity of 700 feet per minute or more
Y connector kit
Includes a Y connector, three hose cuffs, and six hose clamps

Over 50 Years of Innovation

Since 1965, DriSteem has produced custom systems for critical applications such as health care facilities and other buildings requiring precise environmental control.

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Get in touch with your local sales representative for more information about DriSteem products and how to proceed with project planning.

Please call us at (800) 328-4447 for assistance.

In Europe, please call +32 11 82 35 95.

Not in Fairfield, Connecticut ? Click here to find the rep nearest you.