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EVERYTHING YOU EVER WANTED TO KNOW ABOUT
HUMIDIFICATION
By Jeff Boldt
PRESENTER
Jeff Boldt
• Director of Engineering, KJWW• Author - AEDG for Large
Hospitals• Member ASHRAE 90.1 and
189.1• 62.1 – 55 – GPC-36• PE - Mechanical• PE - Fire Protection• Nearly MS - Acoustics• [email protected]
(Search “Jeff Boldt nerd”)
WHY HUMIDIFY?
HEALTH
• Many claims of humidification promoting health
• Many based on the 1985 Sterling Study– I believe the conclusions of that study are not
supported by the details in the report
• Healthcare codes reduced minimum from 30% to 20% in most spaces (a few exceptions)
COMPUTERS
• ASHRAE expanded
the operational
ranges greatly
MATERIAL PRESERVATION
• Organic materials expand with >RH
– Not absolute humidity
– Expand more across grain
• Gym floors
• Carriage Museum
• Artwork
• Material cracking
STATIC ELECTRICITY
• Formerly a big issue in ORs
– Ether is no longer used as an anesthetic
– ORs now require 20-60% RH
• More problematic with carpet
HUMIDIFICATION ISSUES
WINDOW CONDENSATION
• Condensation
– Windows
– Inside walls
CONDENSATION PREDICTION
• Windows have a Condensation Resistance Factor (CRF)
CONDENSATION PREDICTION
• Windows
PSYCHROMETRICSPSYCHOMETRICS
MADISON
PHOENIX
SWAMPCOOLERS
File Not Saved
BAROMETRIC PRESSURE: 29.004 in. HG
PSYCHROMETRICCHARTNormal TemperatureI-P Units
860 FEET
Weather Data Location:
MADISON_DANE_CO_REGIONAL_ARPT_ISIS, WISCONSIN, USA
-10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130
DRY BULB TEMPERATURE - °F
0 5 10 15 20 25 30
35
40
45
50
55
55
60
60
EN
TH
AL
PY
- B
TU
PE
R P
OU
ND
OF
DR
Y A
IR
0
5
10
15
20
25
30
35
40
45
50
ENTH
ALP
Y -
BTU
PER P
OUND O
F DRY A
IR
SATU
RATI
ON T
EM
PERATU
RE -
°F
.05
.1
.15
.2
.25
.3
.35
.4
.45
.5
.55
.6
.65
.7
.75
.8
.85
.9
.95
1
1.05
1.1
1.15
1.2
1.25
1.3
VA
PO
R P
RE
SS
UR
E -
IN
CH
ES
OF
ME
RC
UR
Y
0
10
20
25
30
35
40
45
50
55
60
65
70
75
80
85
DE
W P
OIN
T T
EM
PE
RA
TU
RE
- °
F
Chart by: HANDS DOWN SOFTWARE, www.handsdownsoftware.com
1.00
0.95
0.90
0.85
0.80
0.75
0.70
0.65
0.60
0.55
0.50
0.45
0.400.350.300.250.20SENSIBLE HEAT RATIO = Qs / Qt
SE
NS
IBL
E H
EA
T R
AT
IO =
Qs /
Qt
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
15%
25%
2%
4%
6%
8% RELATIVE HUMIDITY
10% RELATIVE HUMIDITY20%
30%
40%
50%
60%
70%
80%
90%
-50
05
510
1015
1520
2025
25
30
30
35
35
40
40
45
45
50
50
55
5560
6065
65 70
7075
75
80
80
85 WET BULB TEM
PERATURE - °F
85
90
13.0
14.0
15.0
VO
LU
ME
- CU
.FT
. PE
R L
B. D
RY
AIR
HU
MID
ITY
RA
TIO
- G
RA
INS
OF
MO
IST
UR
E P
ER
PO
UN
D O
F D
RY
AIR
0
1.0 1.0
-
2.0
4.08.0
-8.0-4.0-2.0-1.0-0.5
-0.4
-0.3
-0.2
-0.1
0.10.
2
0.3
0.4
0.5
0.6
0.8
-2000
-1000
0
500
1000
1500
2000
3000
5000
-
SENSIBLE HEAT Qs
TOTAL HEAT Qt
ENTHALPY
HUMIDITY RATIO
h
W
File Not Saved
Chart by: HANDS DOWN SOFTWARE, www.handsdownsoftware.com
BAROMETRIC PRESSURE: 29.004 in. HG
PSYCHROMETRICCHARTNormal TemperatureI-P Units
860 FEET
Chart by: HANDS DOWN SOFTWARE, www.handsdownsoftware.com
File Not Saved
BAROMETRIC PRESSURE: 29.004 in. HG
PSYCHROMETRICCHARTNormal TemperatureI-P Units
860 FEET
Weather Data Location:
MADISON_DANE_CO_REGIONAL_ARPT_ISIS, WISCONSIN, USA
-10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130
DRY BULB TEMPERATURE - °F
0 5 10 15 20 25 30
35
40
45
50
55
55
60
60
EN
TH
AL
PY
- B
TU
PE
R P
OU
ND
OF
DR
Y A
IR
0
5
10
15
20
25
30
35
40
45
50
ENTH
ALP
Y -
BTU
PER P
OUND O
F DRY A
IR
SATU
RATI
ON T
EM
PERATU
RE -
°F
.05
.1
.15
.2
.25
.3
.35
.4
.45
.5
.55
.6
.65
.7
.75
.8
.85
.9
.95
1
1.05
1.1
1.15
1.2
1.25
1.3
VA
PO
R P
RE
SS
UR
E -
IN
CH
ES
OF
ME
RC
UR
Y
0
10
20
25
30
35
40
45
50
55
60
65
70
75
80
85
DE
W P
OIN
T T
EM
PE
RA
TU
RE
- °
F
Chart by: HANDS DOWN SOFTWARE, www.handsdownsoftware.com
1.00
0.95
0.90
0.85
0.80
0.75
0.70
0.65
0.60
0.55
0.50
0.45
0.400.350.300.250.20SENSIBLE HEAT RATIO = Qs / Qt
SE
NS
IBL
E H
EA
T R
AT
IO =
Qs /
Qt
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
15%
25%
2%
4%
6%
8% RELATIVE HUMIDITY
10% RELATIVE HUMIDITY20%
30%
40%
50%
60%
70%
80%
90%
-50
05
510
1015
1520
2025
25
30
30
35
35
40
40
45
45
50
50
55
5560
6065
65 70
7075
75
80
80
85 WET BULB TEM
PERATURE - °F
85
90
13.0
14.0
15.0
VO
LU
ME
- CU
.FT
. PE
R L
B. D
RY
AIR
HU
MID
ITY
RA
TIO
- G
RA
INS
OF
MO
IST
UR
E P
ER
PO
UN
D O
F D
RY
AIR
0
1.0 1.0
-
2.0
4.08.0
-8.0-4.0-2.0-1.0-0.5
-0.4
-0.3
-0.2
-0.1
0.10.
2
0.3
0.4
0.5
0.6
0.8
-2000
-1000
0
500
1000
1500
2000
3000
5000
-
SENSIBLE HEAT Qs
TOTAL HEAT Qt
ENTHALPY
HUMIDITY RATIO
h
W
File Not Saved
Chart by: HANDS DOWN SOFTWARE, www.handsdownsoftware.com
BAROMETRIC PRESSURE: 29.004 in. HG
PSYCHROMETRICCHARTNormal TemperatureI-P Units
860 FEET
Chart by: HANDS DOWN SOFTWARE, www.handsdownsoftware.com
HUMIDIFICATION METHODS
EVAPORATIVE (ADIABATIC)
• Pad – Residential, greenhouse, dry
climates
– Not legal in hospitals
• Spray– Commercial – mostly dry
climates
– Not legal in hospitals
• Ultrasonic & Infrared– Computer room units mostly
– Not legal in hospitals
THINK ABOUT YOUR CONDITIONS. WHICH ONE WILLWORK FOR YOU?
STEAM
• Boiler Steam– Inexpensive
– Low maintenance
– Less space needed
• Clean Steam– No potential carcinogens
– Maintenance depends on feed water
– http://www.esmagazine.com/articles/95728-humidification-options-amines-and-the-impacts-of-ashrae-standards-621-and-170
BOILER CHEMICALS
• Health Risk
• POTENTIAL carcinogens
• 62.1 = FDA boilerchemical limits
– No air monitoring
– WHEA fought hard for this
• Maintenance• Without amines,
condensate pipes rust swiftly
• Neutralizing amines protect condensate pipes– Cyclohexylamine– Morpholine– DEAE
• RO reduces blowdown, chemical costs, corrosion
Should they be used for humidification?
ENERGY SOURCES
HEAT OF THE AIR (ADIABATIC)
• Pads, sprays, ultrasonic, maybe IR
• Called “adiabatic”
• Not legal for hospitals
• Common in dry climates and computer room units
ELECTRIC
• Low first cost
• High operating cost
– Natural gas ~35% the cost of electricity
• High maintenance cost
• Difficult to control accurately except for deluxe modulating units
NATURAL GAS
• Relatively low first cost
• Maintenance depends on design
• Good option for clean steam at multiple distant locations
STEAM
• Traditional
• Jacketed
• Smaller tubes
• Need summer shutoff
• Short Dispersion
• Large diameter tubes
• No automatic shutoff needed
HOW MUCH HUMIDITY DO YOU NEED?
WISCONSIN CODE
• ASHRAE Standard 170-2008 Addendum d– 20% for most healthcare areas
• Surgery
• Delivery
• Procedure
• Endoscopy
– 30% for a few areas• Intensive Care
• NICU
• Newborn Nursery
WHAT IS THE BEST LOCATION?
• Upstream of cooling coil?
– Eliminates water in duct risk
– After HC so air is low RH
– Low velocity can be an issue
• Has anyone experienced this? Email me!
• Downstream of fan?
– High velocity = short dispersion
MY OPINION
• Between Preheat Coil and Cooling Coil
– Prevents water droplets going down ducts
– Low RH normally for good absorption
STEAM HUMIDIFIER TYPES
JACKETED BAYONET HUMIDIFIER
Need automatic shutoff valve!
SHORT DISPERSION HUMIDIFIER
DESCRIPTION
• Bayonet tubes are ~212°F
• They cause unwanted air heating
• Short absorption manifolds have large surface area and intensify the problem
• Up to 5°F of heat added
INSULATED BAYONETS
ADVANTAGES OF INSULATED BAYONETS
• Energy efficiency
• Less water waste
– Treated water waste
• Better control of discharge air temperature
• Complies with energy codes
– 90.1-2010
– IECC-2012
DISADVANTAGES OF INSULATING BAYONETS
• Higher first cost
• Can be more difficult to clean
• Must be rated for use in the airstream
• Potential wear and tear of insulation
STAINLESS STEEL SHELL WITH AIR GAP
Stainless steelshielding
¼” Air-gap
Foam strips
Cool Airflow
Hot Steam
Nortec- R = 0.66 - 70% condensate
reduction
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0 500 1000 1500 2000 2500
Loss
es
(lb
s/h
r) p
er
Lin
ear
Fo
ot
of
Tub
e
Duct Velocity (ft/min)
50°F Standard
60°F Standard
70°F Standard
80°F Standard
50°F Insulated
60°F Insulated
70°F Insulated
80°F Insulated
Stainless Steel Shell with Air Gap
ELASTOMERIC INSULATION
Elastomeric- R = 0.74- Flame Spread – 25- Smoke Spread – 45- Thickness – 0.5 in- 70% condensate
reduction
PVDF INSULATION
PVDF- R = 0.56- 1/8 inch thick- 75% reduction in
condensate- 0/0 flame/smoke
rating
THERMAL INSULATING COATING
• Ceramic spray-on coating
• Approximately 0.03” thick
• R-Value of 0.045
• Durable and easy to clean
DISPERSION TUBE HEAT LOSS
R-VALUE
• ASHRAE 90.1 6.5.2.4.3 Humidification system dispersion tube hot surfaces in the airstream of ducts or air handling units shall be insulated with a product with an insulating value of at least R-0.5.
KJWW PERSPECTIVE
• Worth the added cost for new construction
• Will save energy if implemented and maintained
• Should be considered for all projects
• Required for 90.1-2010 or later and LEED v4
• Insulation type should be evaluated for each project for cost, longevity, and R-value
CONTROL OPTIONS
• Return Air
– Slow response
– Need limits on supply RH
• Supply Air with Return RH Reset
– My favorite option
– Fast response
– No wet filters
MAINTENANCE HEADACHES
WATCH FOR IMPROPER PITCH
WATER TREATMENT
• RO reduces TDS
– 90-95% reduction in TDS (including hardness)
– Surface water vs. well water
• Madison = 18-20 grains of hardness
• TDS = hardness + other minerals (sodium)
WATER TREATMENT
• Softening
– One 2+ (calcium) replaced by two 1+ (sodium)
– “Naturally” soft water is not like softened water
WATER TREATMENT
• Legionella and Infection
– No issue for steam humidifiers
– No recorded Legionnaires from swamp coolers
