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Published byRudolf Bruce Modified over 10 years ago
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Station 4 ?? Temperatures and Moisture Moisture Meters Pin Contact Data Loggers Spot Temperature Meter Thermal Imager Cautions and Safety
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Measure Moisture
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Pin-Type makes pin holes extension pins available Contact Type non-destructive reads ~ 3” through materials settings for different materials
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Preventing Mold Growth Control the Moisture Keep relative humidity in 30–50% range Keep surfaces warm No leaks inside No leaks from the outside Block entry of moist air Control wicking
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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
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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)
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FACT: Warm air can hold more moisture than Cold air Relative Humidity Temperature
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Raise the temperature... Relative Humidity Decreases Temperature Relative Humidity
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Relative Humidity Temperature
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Cool closet = higher relative humidity
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Dew Point: Temperature at which air becomes completely saturated (100% RH)
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“Wet Air” “Dry Air” Different Relative Humidity of the “Air Film”
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Mold and Moisture Materials only need to be at 85% to 90% relative humidity to support mold growth
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Mirror reached dew point in Spokane on a hot summer day
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Mirror temperature changed little, but moisture in the air changed (high RH%)
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Preventing Mold Growth Control the Moisture Keep relative humidity in the 30 to 50% range Keep surfaces warm
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Important to understand condensation Dew Point Calculator dpcalc.org http://www.dpcalc.org/
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30% Surfaces at ?? 0 F will be damp ??
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30% Surfaces at 37 0 F will be damp
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30% Surfaces at ?? 0 F will be damp ??
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30% Surfaces at 46 0 F will be damp
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45% Surfaces at ?? 0 F will be damp ??
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45% Surfaces at 50 0 F will be damp
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?? Surfaces at ?? 0 F will be damp
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Surfaces at 55 0 F will be damp
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??
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Surfaces at 60 0 F will be damp
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Relative Humidity Monitor
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Cordless Temperature and Relative Humidity Logger
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Moisture Generation Rate Moisture Generation Rate Moisture Removal Rate Moisture Removal Rate Aim for 30% to 50 % RH
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Moisture Dynamics Relative Humidity: – Saturation of the air at a given temperature... – % of its water holding capacity 50% RH = the air is 1/2 full 90% RH = the air can only hold 10% more water vapor
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RELATIVE HUMIDITY FACT: Warm Air Can Hold More Moisture Than Cold Air Temperature Relative Humidity
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RELATIVE HUMIDITY Raise the air temperature and lower the relative humidity TEMP. R.H.
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RELATIVE HUMIDITY Lower the air temperature increases the relative humidity TEMP. R.H.
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Moisture Dynamics Dew Point: Temperature at which air becomes completely saturated = 100% Relative Humidity 100% full at this temperature
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Areas of High RH COLD OUTSIDE Buildings have Micro-climates a/c duct, cold pipes, etc.
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Dry Bulb = 72 0 F Wet Bulb = 60 0 F Relative Humidity = 50 % Dew Point Temp = 52 0 F
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100 % R H ??? 40 0 F 70 0 F 100 % RH
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35 % R H 40 0 F70 0 F 100 % RH Outdoors Indoors
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Areas of High RH COLD OUTSIDE Buildings have Micro-climates a/c duct, cold pipes, etc.
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Moisture + Asbestos = Double Trouble
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single pane glass indicates high moisture levels single pane glass indicates high moisture levels
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Leaks Repair Plants Breathing Cleaning Dishes, etc. Ventilation Shower Cooking Laundry Exhaust Fans
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Ventilation (AC/h) VS Indoor Relative Humidity (%) Ventilation: Air Chances per Hour (AC/h) Indoor Relative Humidity (%) 1,500 ft sq house 70 0 F indoor temp 85 % outdoor RH 30 0 F outside temp typical moisture load.35 AC/h based on G. Tsongas
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Ventilation (AC/h) VS Indoor Relative Humidity (%) Ventilation: Air Chances per Hour (AC/h) Indoor Relative Humidity (%) 1,500 ft sq house 70 0 F indoor temp 85 % outdoor RH 50 0 F outside temp typical moisture load.35 AC/h based on G. Tsongas
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Ventilation (AC/h) VS Indoor Relative Humidity (%) Ventilation: Air Chances per Hour (AC/h) Indoor Relative Humidity (%) 1,500 ft sq house 70 0 F indoor temp 85 % outdoor RH 30 0 F outside temp typical moisture load 2 X moisture load 50 0 F outside temp typical moisture load 2 X moisture load.35 AC/h based on G. Tsongas
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Good News for energy & comfort When 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)
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“Hot” household iron with half painted black ? which side is the black side? + 215 o F + 96 o F
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2 pennies placed on hot household iron Note the temperature reading of the penny painted flat black.. + 215.6 o F note the temperature reading of the shiny iron surface
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Same Thermograph… Note the temperature of the shiny penny … do you really believe + 86.6 o F ?? Want to pick it up to find out? Also note the temperature reading of the shiny iron surface
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$7,500 BBQ Gas Gauge
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