GAS LAWS AND FORMULAE
GAS LAWS AND FORMULAE
Gas Laws
Gas Analysis of Dry Air
Component
Nitrogen
Oxygen
Carbon Dioxide
Argon
% by Volume
78.09
20.95
0.03
0.93
% by Weight
75.52
23.15
0.05
1.28
Normal Temperature and Pressure (NTP)
Normal barometric pressure
Normal temperature
Density of dry air at NTP
101.325kPa
273.15K (0°C)
= 1.2922kg/m³
Standard Temperature and Pressure (STP)
Normal barometric pressure
Normal temperature
Density of dry air at NTP
101.325kPa
288.71K (15.56°C)
= 1.2922kg/m³
Actual vs Normal conditions & Standard
Fan inlet conditions are normally measured as Actual volume flow (e.g. Am³/h)
QActual = Actual Volume @ Fan Inlet
QNormal = Volume @ Normal Conditions
QStandard = Volume @ Standard Conditions
Ta = Inlet Temperature (°C)
B = Inlet Barometric Pressure (kPa)
Ps = Inlet Static Pressure (kPa)
Gas Laws
Gas Analysis of Dry Air
| Component | % by Volume | % by Weight |
|---|---|---|
| Nitrogen | 78.09 | 75.52 |
| Oxygen | 20.95 | 23.15 |
| Carbon Dioxide | 0.03 | 0.05 |
| Argon | 0.93 | 1.28 |
Normal Temperature and Pressure (NTP)
Normal barometric pressure 101.325kPa
Normal temperature 273.15K (0°C)
Density of dry air at NTP = 1.2922kg/m³
Standard Temperature and Pressure (STP)
Normal barometric pressure 101.325kPa
Normal temperature 288.71K (15.56°C)
Density of dry air at NTP = 1.2922kg/m³
Actual vs Normal conditions & Standard
Fan inlet conditions are normally measured as Actual volume flow (e.g. Am³/h)
QActual = Actual Volume @ Fan Inlet
QNormal = Volume @ Normal Conditions
QStandard = Volume @ Standard Conditions
Ta = Inlet Temperature (°C)
B = Inlet Barometric Pressure (kPa)
Ps = Inlet Static Pressure (kPa)
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CONTACT US
E: info@capefans.co.za
T: +27 (0)81 015 2133
FOLLOW US
EXPERTS IN FAN APPLICATION AND VENTILATION