Station 4 ?? Temperatures and Moisture

Moisture MetersPinContactData Loggers

Spot Temperature MeterThermal ImagerCautions and Safety

Measure Moisture

Pin-Type makes pin holes extension pins available

Contact Type non-destructive reads ~ 3” through materials settings for different materials

Moisture Meters

Preventing Mold Growth

Control the Moisture Keep relative humidity in 30–50% rangeKeep surfaces warm No leaks inside No leaks from the outsideBlock entry of moist airControl wicking

Control Interior Moisture

Contain moisture at the source

Remove moisture with exhaust fans

Ventilate: Exchange damp indoor air with dryer outside air

De-humidification may be necessary

Relative Humidity

Saturation of the air … at a given temperature

Water holding capacity (%) of

the air

50% RH means the air is 1/2 full

90% RH means the air can only

hold 10% more water vapor (90% full)

FACT: Warm air can hold more

moisture than Cold air

Relative HumidityTemperature

Raise the temperature . . . Relative Humidity Decreases

Temperature

Relative Humidity

Relative Humidity

Temperature

Cool closet = higher relative humidity

Dew Point:Temperature at which air becomes completely saturated (100% RH)

“Wet Air” “Dry Air” Different Relative Humidity of the “Air Film”

Mold and Moisture

Materials only need to be at 85% to 90% relative humidity to support mold growth

Mirror reached dew point in Spokane on a hot summer day

Mirror temperature changed little, butmoisture in the air changed (high RH%)

Preventing Mold Growth

Control the Moisture Keep relative humidity in the 30 to 50% range

Keep surfaces warm

Important to understandcondensation

Dew Point Calculator

dpcalc.org

http://www.dpcalc.org/

30%

Surfaces at ??0 F will be damp

??

30%

Surfaces at 370 F will be damp

30%

Surfaces at ?? 0 F will be damp

??

30%

Surfaces at 460 F will be damp

45%

Surfaces at ?? 0 F will be damp

??

45%

Surfaces at 500 F will be damp

??

Surfaces at ?? 0 F will be damp

Surfaces at 550 F will be damp

??

Surfaces at 600 F will be damp

Relative Humidity MonitorRelative Humidity Monitor

Cordless Temperature and Relative Humidity Logger

33

MoistureGeneration

Rate

MoistureGeneration

RateMoistureRemoval

Rate

MoistureRemoval

Rate

Aim for 30% to 50 % RHAim for 30% to 50 % RH

Moisture Dynamics

Relative Humidity:– Saturation of the air at a given temperature . . . –% of its water holding capacity

50% RH = the air is 1/2 full90% RH = the air can only hold 10% more water vapor

RELATIVE HUMIDITY RELATIVE HUMIDITY

FACT: Warm Air Can Hold More Moisture Than Cold Air

Temperature

RelativeHumidity

RELATIVE HUMIDITY RELATIVE HUMIDITY

Raise the air temperature and lower the relative humidity

TEMP.

R.H.

RELATIVE HUMIDITY RELATIVE HUMIDITY

Lower the air temperature increases the relative humidity

TEMP. R.H.

Moisture Dynamics

Dew Point:

Temperature at which air becomes completely saturated

= 100% Relative Humidity

100% full at this temperature

Areas of High RH

COLD OUTSIDE

Buildings have Micro-climates

a/c duct, cold pipes, etc.

Dry Bulb = 72 0FWet Bulb = 60 0FRelative Humidity = 50 %Dew Point Temp = 52 0F

100 % R H ???

40 0F 70 0F100 % RH

35 % R H

40 0F 70 0F

100 % RH

Outdoors Indoors

Areas of High RH

COLD OUTSIDE

Buildings have Micro-climates

a/c duct, cold pipes, etc.

Moisture+

Asbestos

= Double Trouble

single pane glass indicates high moisture levelssingle pane glass indicates high moisture levels

Leaks

Repair Plants

Breathing

Cleaning

Dishes, etc.

Ventilation

Shower

Cooking

Laundry

Exhaust Fans

Ventilation (AC/h) VS

Indoor Relative Humidity (%)

0

20

40

60

80

100

Ventilation: Air Chances per Hour (AC/h)

I

nd

oor

Rel a

tive H

um

i dit

y

( %)

1,500 ft sq house700 F indoor temp85 % outdoor RH

300 F outside temp typical moisture load

.35 AC/h

based on G. Tsongas

Ventilation (AC/h) VS

Indoor Relative Humidity (%)

0

20

40

60

80

100

Ventilation: Air Chances per Hour (AC/h)

I

nd

oor

Rel a

tive H

um

i dit

y

( %)

1,500 ft sq house700 F indoor temp85 % outdoor RH 500 F outside temp

typical moisture load

.35 AC/h

based on G. Tsongas

Ventilation (AC/h) VS

Indoor Relative Humidity (%)

0

20

40

60

80

100

Ventilation: Air Chances per Hour (AC/h)

I

nd

oor

Rel a

tive H

um

i dit

y

( %)

1,500 ft sq house700 F indoor temp85 % outdoor RH

300 F outside temp typical moisture load 2 X moisture load

500 F outside temp typical moisture load 2 X moisture load

.35 AC/h

based on G. Tsongas

Good News for energy & comfortWhen it’s cold outside: do not need as much air exchange

When it’s mild outside: need more exchange

Drying Potential of Outside Air:

The colder the outside air, the more drying effect when this air is warmed inside

Warm, humid air has much less drying potential (can cause problems)

“Hot” household iron with half painted black ? which side is the black side?

+ 215 oF

+ 96 oF

2 pennies placed on hot household iron

Note the temperature reading of the penny painted flat black . . + 215.6 oF

note the temperature reading of the shiny iron surface

Same Thermograph…Note the temperature of the shiny penny … do you really believe + 86.6 oF ??

Want to pick it up to find out? Also note the temperature reading of the shiny iron surface

$7,500 BBQ Gas Gauge