Page 31
SP-2 User Guide
Art. No. 71022-0000 Welch Allyn Schiller ©2000
E
n
g
l
i
s
h
Calibration Details
Last Calibration
date of last calibration
BTPS
F
actor calculated BTPS (=>
B
ody
T
emperature, Ambient
P
ressure,
S
aturated with water vapor) value. This value compensates for the
difference in inhaled and exhaled humidity. The unit is set for
measuring exhaled volume (100% humidity, Temp 36.8
o
), and so
when inhaled volume is measured this factor is applied. The SP-2
uses ambient temperature to calculate the BTPS factor. This is
sufficient for accurate FIVC calculation. The formula used is as
follows:
BTPS
=
0.033
+
273.15 + 36.8
273.15 + Tu
Where:
Tu is the ambient temperature in degrees centigrade
0.033 is the equivalent to 760mmHg at 22
o
C
273.15 is degrees absolute
Calibration Factor
calculated value between measured and effective calibration air
volume.
Temperature
ambient temperature in
o
C (or
o
F) dependent on device setting.
Measured Volume
air volume measured by the system from the calibration pump.
Reference Volume
entered air volume depending on the size of the calibration pump
and times the air was pumped through the sensor; e.g. pumping 2
liters 3 times amounts to 6 liters (the recommended volume with a 2
litre pump is 4 liters and with a 3 litre pump 6 liters).
