STPD vs BTPS

STPD

Standard temperature, pressure, and dry

i.e.

• Standard temperature (0C or 273K),
• Pressure (760mmHg)
• Dry

BTPS

Body temperature, pressure, and saturated

i.e.

• Body temperature (37C)
• Pressure (760mmHg)
• Saturated
  * i.e. with water vapour=47mmHg at 37C

Conversion

To convert a gas volume from BTPS to STPD, multiply by
--> 273/310 x 713/760 = 0.8261842

Thus,

• 1 mole of perfect gas at STPD = 22.4L
• 1 mole of gas at BTPS = 27.11L

NB:

• 27.11L (BTPS) x 0.826
  ~ 22.4L (STPD)