(U M I D IFI C ATI ON 7HITE 0A PER
4ECHNICAL DESIGN INFORMATION FROM )34%%-
!VOIDING THE WET DUCT CALLBACK
%NSURING HUMIDIFICATION ABSORPTION IN
COMMERCIAL AND INDUSTRIAL APPLICATIONS
#/.4%.43
2ELATIVE HUMIDITY AND
TEMPERATURE
$ISPERSING COLD WATER OR
HOT STEAM
-ANAGING WETNESS
&ACTORS THAT AFFECT
ABSORPTION
3IZING DISPERSION
ASSEMBLIES
"Y ,YNNE 7ASNER
)34%%- #ORPORATION
! PROPERLY HUMIDIFIED BUILDING ENHANCES HEALTH AND COMFORT
IMPROVES MANUFACTURING PROCESSES AND PRESERVES MATERIALS
(OWEVER IF NOT SPECIFIED CORRECTLY HUMIDIFICATION SYSTEMS CAN CAUSE
UNEXPECTED WETNESS WHICH CAN LEAD TO MICROBIAL GROWTH IN MOIST
DUCTS AND A RESULTING )!1 PROBLEM "UT WITH A BASIC UNDERSTANDING
OF THE ISSUES THAT AFFECT ABSORPTION YOU CAN PROVIDE ALL THE BENEFITS
OF HUMIDIFICATION WITHOUT WORRYING ABOUT THE WET DUCT CALLBACK
"ASICS ABOUT HUMIDIFYING COMMERCIAL AND INDUSTRIAL SPACES
s 4O CONVERT A POUND OF WATER INTO VAPOR REQUIRES ABOUT
"TUS 4HIS CAN BE ACCOMPLISHED ISOTHERMALLY OR ADIABATICALLY
)SOTHERMAL HUMIDIFICATION SYSTEMS USE HEAT FROM AN EXTERNAL
SOURCE SUCH AS ELECTRICITY NATURAL GAS OR BOILER STEAM TO
CONVERT WATER TO VAPOR !DIABATIC HUMIDIFICATION SYSTEMS USE
HEAT FROM THE SURROUNDING AIR TO CONVERT WATER INTO VAPOR FOR
HUMIDIFICATION EVAPORATION
s )SOTHERMAL SYSTEMS DISPERSE PRESSURIZED STEAM INTO THE
AIR DIRECTLY FROM A BOILER OR UNFIRED STEAM GENERATOR OR
NONPRESSURIZED STEAM FROM A VAPOR GENERATOR EVAPORATIVE
HUMIDIFIER !DIABATIC SYSTEMS DISPERSE MIST OR FOG INTO THE
AIR USING PRESSURIZED WATER ANDOR PRESSURIZED AIR OR WATER
EVAPORATED FROM A WETTED MEDIA
s "OTH ISOTHERMAL AND ADIABATIC SYSTEMS DISPERSE DIRECTLY INTO
DUCTS AIR HANDLERS OR INTO OPEN SPACES CALLED AREA TYPE SYSTEMS
&IGURE !REA TYPE SYSTEMS DEFINE
ABSORPTION DISTANCE USING RISE SPREAD
AND THROW DIMENSIONS
