Air - Humidifying with Steam - Imperial Units
The amount of steam needed to humidify 100 cfm (cubic feet per minute) of air is indicated below.
For full table - rotate the screen!
| Vapor in 100 cfm air (lb/h) | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry Temperature | Humidity (%) | |||||||||||||
| (oF) | (oC) | 100 | 85 | 80 | 75 | 70 | 65 | 60 | 55 | 50 | 45 | 40 | 35 | 30 |
| 90 | 32.2 | 12.8 | 10.9 | 10.3 | 9.6 | 9.0 | 8.3 | 7.7 | 7.1 | 6.4 | 5.8 | 5.1 | 4.5 | 3.9 |
| 88 | 31.1 | 12.1 | 10.3 | 9.7 | 9.1 | 8.5 | 7.9 | 7.3 | 6.6 | 6.1 | 5.4 | 4.8 | 4.2 | 3.6 |
| 86 | 30.0 | 11.4 | 9.7 | 9.1 | 8.5 | 8.0 | 7.4 | 6.9 | 6.3 | 5.7 | 5.1 | 4.6 | 4.0 | 3.4 |
| 85 | 29.4 | 11.0 | 9.4 | 8.8 | 8.3 | 7.7 | 7.2 | 6.6 | 6.1 | 5.5 | 5.0 | 4.4 | 3.9 | 3.3 |
| 84 | 28.9 | 10.7 | 9.1 | 8.5 | 8.0 | 7.5 | 7.0 | 6.4 | 5.9 | 5.3 | 4.8 | 4.3 | 3.7 | 3.2 |
| 83 | 28.3 | 10.4 | 8.8 | 8.3 | 7.8 | 7.3 | 6.7 | 6.2 | 5.7 | 5.2 | 4.7 | 4.2 | 3.6 | 3.1 |
| 82 | 27.8 | 10.1 | 8.6 | 8.0 | 7.6 | 7.1 | 6.5 | 6.1 | 5.5 | 5.0 | 4.5 | 4.0 | 3.5 | 3.0 |
| 81 | 27.2 | 9.8 | 8.3 | 7.8 | 7.3 | 6.8 | 6.4 | 5.9 | 5.4 | 4.9 | 4.4 | 3.9 | 3.4 | 2.9 |
| 80 | 26.7 | 9.5 | 8.0 | 7.6 | 7.1 | 6.7 | 6.2 | 5.7 | 5.2 | 4.7 | 4.3 | 3.8 | 3.3 | 2.8 |
| 79 | 26.1 | 9.2 | 7.8 | 7.3 | 6.9 | 6.4 | 6.0 | 5.5 | 5.1 | 4.6 | 4.1 | 3.7 | 3.2 | 2.7 |
| 78 | 25.6 | 8.9 | 7.6 | 7.1 | 6.7 | 6.2 | 5.8 | 5.3 | 4.9 | 4.4 | 4.0 | 3.6 | 3.1 | 2.7 |
| 77 | 25.0 | 8.6 | 7.3 | 6.9 | 6.5 | 6.1 | 5.6 | 5.2 | 4.7 | 4.3 | 3.9 | 3.5 | 3.0 | 2.6 |
| 76 | 24.4 | 8.4 | 7.1 | 6.7 | 6.3 | 5.9 | 5.5 | 5.0 | 4.6 | 4.2 | 3.8 | 3.4 | 2.9 | 2.5 |
| 75 | 23.9 | 8.1 | 6.9 | 6.5 | 6.1 | 5.7 | 5.3 | 4.9 | 4.5 | 4.1 | 3.6 | 3.2 | 2.8 | 2.4 |
| 74 | 23.3 | 7.9 | 6.7 | 6.3 | 5.9 | 5.5 | 5.1 | 4.7 | 4.3 | 3.9 | 3.5 | 3.1 | 2.7 | 2.4 |
| 73 | 22.8 | 7.6 | 6.5 | 6.1 | 5.7 | 5.3 | 4.9 | 4.6 | 4.1 | 3.8 | 3.4 | 3.1 | 2.7 | 2.3 |
| 72 | 22.2 | 7.4 | 6.3 | 5.9 | 5.5 | 5.2 | 4.8 | 4.4 | 4.1 | 3.7 | 3.3 | 2.9 | 2.6 | 2.2 |
| 71 | 21.7 | 7.1 | 6.1 | 5.7 | 5.3 | 5.0 | 4.6 | 4.3 | 3.9 | 3.6 | 3.2 | 2.9 | 2.5 | 2.1 |
| 70 | 21.1 | 6.9 | 5.9 | 5.5 | 5.4 | 4.8 | 4.5 | 4.1 | 3.8 | 3.5 | 3.1 | 2.8 | 2.4 | 2.1 |
| 69 | 20.6 | 6.7 | 5.7 | 5.4 | 5.0 | 4.7 | 4.4 | 4.0 | 3.7 | 3.4 | 3.0 | 2.7 | 2.4 | 2.0 |
| 68 | 20.0 | 6.5 | 5.5 | 5.2 | 4.9 | 4.5 | 4.2 | 3.9 | 3.5 | 3.2 | 2.9 | 2.6 | 2.3 | 1.9 |
| 67 | 19.4 | 6.2 | 5.3 | 5.0 | 4.7 | 4.4 | 4.1 | 3.7 | 3.4 | 3.1 | 2.8 | 2.5 | 2.2 | 1.9 |
| 66 | 18.9 | 6.1 | 5.2 | 4.9 | 4.5 | 4.2 | 3.9 | 3.6 | 3.3 | 3.0 | 2.7 | 2.4 | 2.1 | 1.8 |
| 65 | 18.3 | 5.9 | 5.0 | 4.7 | 4.4 | 4.1 | 3.8 | 3.5 | 3.2 | 2.9 | 2.6 | 2.3 | 2.1 | 1.8 |
| 60 | 15.6 | 5.0 | 4.2 | 4.0 | 3.7 | 3.5 | 3.2 | 3.0 | 2.7 | 2.5 | 2.2 | 2.0 | 1.7 | 1.5 |
| 55 | 12.8 | 4.2 | 3.6 | 3.4 | 3.1 | 2.9 | 2.7 | 2.5 | 2.3 | 2.1 | 1.9 | 1.7 | 1.5 | 1.3 |
| 50 | 10.0 | 3.5 | 3.0 | 2.8 | 2.6 | 2.5 | 2.3 | 2.11 | 1.9 | 1.8 | 1.6 | 1.4 | 1.2 | 1.1 |
| 45 | 7.2 | 2.9 | 2.5 | 2.4 | 2.2 | 2.1 | 1.9 | 1.8 | 1.6 | 1.5 | 1.3 | 1.2 | 1.0 | 0.89 |
| 40 | 4.4 | 2.5 | 2.1 | 2.0 | 1.8 | 1.7 | 1.6 | 1.5 | 1.3 | 1.2 | 1.1 | 1.0 | 0.86 | 0.74 |
| 30 | -1.1 | 1.7 | 1.4 | 1.3 | 1.2 | 1.2 | 1.1 | 1.0 | 0.92 | 0.83 | 0.75 | 0.67 | 0.58 | 0.50 |
| 20 | -6.7 | 1.1 | 0.91 | 0.85 | 0.80 | 0.75 | 0.70 | 0.64 | 0.59 | 0.53 | 0.48 | 0.43 | 0.37 | 0.32 |
| 10 | -12.2 | 0.67 | 0.56 | 0.53 | 0.50 | 0.47 | 0.43 | 0.40 | 0.37 | 0.33 | 0.30 | 0.26 | 0.23 | 0.20 |
| 0 | -17.8 | 0.41 | 0.35 | 0.32 | 0.31 | 0.29 | 0.26 | 0.25 | 0.22 | 0.20 | 0.19 | 0.16 | 0.13 | 0.12 |
| -10 | -23.3 | 0.25 | 0.21 | 0.2 | 0.19 | 0.17 | 0.16 | 0.15 | 0.14 | 0.12 | 0.11 | 0.10 | 0.08 | 0.08 |
| -20 | -28.9 | 0.14 | 0.12 | 0.11 | 0.11 | 0.10 | 0.10 | 0.08 | 0.08 | 0.72 | 0.06 | 0.05 | 0.05 | 0.04 |
- 100 cfm = 0.047 m3/s = 170 m3/h
- 1 lb/h = 0.4536 kg/h
Example - Humidifying Air with Steam
How much steam is needed to transform air at 30 oF with 100% humidity to air at 70 oF with 40% humidity?
- air at 30 oF and 100% humidity - steam content 1.67 lb/h (100 cfm/h air flow)
- air at 70 oF and 40% humidity - steam content 2.76 lb/h (100 cfm/h air flow)
The difference (2.76 - 1.67) = 1.09 lb/h is the amount of steam needed for 100 cfm/h air flow.
Note!
This table neglects the sensible heat required to heat cold air to final state. In the example above the heat required to heat 100 cfm dry air from 30 oF to 70 oF must be added. The heat can be added as dry heat with heating panels or similar, or in general more convenient by adding more steam.
Related Topics
• Air Psychrometrics
Moist and humid air calculations. Psychrometric charts and Mollier diagrams. Air-condition systems temperatures, absolute and relative humidities and moisture content in air.
• Steam and Condensate
Design of steam & condensate systems with properties, capacities, sizing of pipe lines, system configuration and more.
Related Documents
Air - Absolute Humidity
Absolute humidity is the actual mass of water vapor present in the air water vapor mixture.
Air - Heating, Cooling, Mixing, Humidifying or Dehumidifying Processes
Basic air changing state processes - heating, cooling, mixing, humidifying and dehumidifying by adding steam or water - psychometric diagrams and the Mollier charts.
Air - Humidifying by Adding Steam or Water
Air can be humidified by adding water or steam.
Air - Humidifying with Steam, SI units
Using steam to humidify air.
Air - Humidity Ratio
The mass of water vapor present in moist air - to the mass of dry air.
Air - Moisture Holding Capacity vs. Temperature
The moisture holding capacity of air increases with temperature.
Air - Psychrometric Chart for Standard Atmospheric Conditions - Imperial Units
Psychrometric chart to analyze air properties, including temperature, humidity, enthalpy, and dew point at barometric pressure 29.921 inches of Mercury and temperature ranging 20oF to 120oF.
Air and Steam Mixtures
Air in the steam will lower the surface temperatures in heat exchangers - and less heat will be transferred.
Humidifiers
Sprayed coils, spinning discs and steam humidifiers.
Moist Air - Density vs. Water Content and Temperature
Density of the mix of dry air and water vapor - moist humid air.
Steam Heating Air
Calculate steam heated air systems.
Steam Heating Processes - Load Calculating
Calculating the amount of steam in non-flow batch and continuous flow heating processes.
Vapor and Steam
An introduction to vapor and steam.