AO2000
CONTINUOUS GAS ANALYZERS | OI/AO2000-EN REV. B
247
Fidas24: Conversion of concentration data
Various units for concentration data
When measuring organic carbon compounds (total C) the concentration is
indicated in various units. The most important units are:
•
mg C/m
3
(e.g. for measurements in accordance with German 17. Federal
Regulation on Emissions)
•
mg C
n
H
m
/m
3
•
ppm C
n
H
m
(e.g. for measurements in accordance with German Federal
Regulations on Air Purity, details on test gas cylinders)
•
ppm C1 (for TOC [total organic carbons] or methane CH
4
)
Examples for the conversion of units and concentration data
Conversion ppm to mg C
n
H
m
/m
3
m
3
m
n
V
weight
Molecular
ppm
/m
H
C
mg
×
=
Conversion ppm to mg C/m
3
m
3
V
12.011
atoms
C
of
Number
ppm
m
/
C
mg
×
×
=
Conversion ppm to ppm C1
atoms
C
of
Number
ppm
C1
ppm
×
=
Example 1
The analyzer module has a measuring range of 0 to 50 mg C/m
3
. As a test
gas, propane (C
3
H
8
) in N
2
or in air is used.
What is the maximum test gas concentration in ppm or mg/m
3
for the
measuring range not to be exceeded?
8
3
C
m
H
C
H
C
ppm
31.102
12.011
3
22.414
50
M
atoms
C
of
Number
V
MR
[ppm]
c
8
3
=
×
×
=
×
×
=
m
H
C
H
C
3
H
C
V
)
M
atoms
H
of
Number
M
atoms
C
of
(Number
[ppm]
c
]
[mg/m
c
8
3
8
3
×
+
×
×
=
(
)
3
8
3
3
H
C
/m
H
C
mg
61.19
22.414
1.008
8
12.011
3
31.102
]
[mg/m
c
8
3
=
×
+
×
×
=
