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Chapter 22:Technical Specifications
N2O
5
Agents
Gas concentration conversion
Gas concentration is reported in units of volume percent. The concentration is defined as:
The total pressure of the gas mixture is estimated by measuring the actual atmospheric pressure in
the IRMA probe.
Effects from water vapor partial pressure on gas readings
The effects of water vapor are illustrated by the examples in the following table. The two columns to
the right show the relative error in displayed concentrations when adding or removing water vapor
from the gas mixture, and referencing the measurement to dry gas conditions at actual temperature
and pressure (ATPD) or saturated conditions at body temperature (BTPS).
Temp [C]
RH [%]
10
20
20
20
25
0
25
23
25
50
30
80
37
100
37
100
The table illustrates that the gas concentrations in the alveoli, where the breathing gas is saturated with water vapor at body
temperature (BTPS), are 6.2% lower than the corresponding concentrations in the same gas mixture after removal of all
water vapor (ATPD).
Interfering gas effects
Gas or vapour
N2O-note4)
HAL-note4)
ENF, ISO, SEV-note4)
DES-note4)
Xe (Xenon)-note4)
He (Helium)-note4)
Metered does inhaler propellants-note4)
C2H5OH (Ethanol)-note4)
C3H7OH (Isopropanol)-note4)
CH3COCH3 (Acetone)-note4)
CH4 (Methane) -note4)
CO (Carbon monoxide) -note5)
NO (Nitrogen monoxide)-note5)
O2-note 5)
Note 1 : Negligible interference, effect included in the specification " Accuracy all conditions" above.
5
The accuracy specification for IRMA AX+ is not valid if more than two agents are present in the gas mixture. If more than
two agents are present, an alarm will be set.
±(2 kPa + 5% of reading)
±(0.2 kPa + 10% of reading)
P [hPa]
H2O part.pres.
[hPa]
1013
2
1013
5
1013
0 (ATPD)
1013
7.3
1013
16
1013
42
1013
63 (BTPS)
700
63
Gas level
60 vol%
4 vol%
5 vol%
15 vol%
80 vol%
50 vol%
Not for use with metered dose inhaler propellants
0.3 vol%
0.5 vol%
1 vol%
3 vol%
1 vol%
0.02 vol%
100 vol%
errrel [%]
0
0
0
0
0
0
0
0
CO2
IRMA CO2
- note1&2)
- note1)
+8% of reading-note3)
+12% of reading-
note3)
-10% of reading-note3)
-6% of reading-note3)
- note1)
- note1)
- note1)
- note1)
- note1)
- note1)
- note1&2)
22-7
User Manual
errrel ATPD
errrel [%]
[%]
BTPS
-0.2
+6.0
-0.5
+5.7
0
+6.2
-0.7
+5.5
-1.6
+4.6
-4.1
+2.0
-6.2
0
-9.0
-2.8
Agents
N2O
IRMA
AX+
-
- note1)
- note1)
note1&2)
- note1)
- note1)
- note1)
- note 1)
- note1)
- note1)
- note 1)
- note1)
- note1)
- note1)
- note1)
- note1)
- note1)
- note1)
- note1)
- note1)
- note1)
- note1)
- note1)
- note1)
- note1)
- note1)
- note1)
- note1)
- note1)
- note1)
- note1)
- note1)
- note1)
- note1)
- note1)
-
- note1)
- note1)
note1&2)
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