CLASSIFICATION OF SHIELDING GASES (ISO 14175:2008)
Short term
Main
group
Sub
group
Components in nominal percentage of volume [%]
Oxidizing
CO2
Inert
O2
1
I
2
1
2
Balance
C
R
Balance
a
Balance
a
0,5 ≤ O2 ≤ 3
Balance
a
0,5 ≤ O2 ≤ 3
Balance
a
0,5 ≤ CO2 ≤ 5
0,5 ≤ CO2 ≤ 5
3
4
0,5 ≤ CO2 ≤ 5
0
5 < CO2 ≤ 15
Balance
a
1
15 < CO2 ≤ 25
Balance
a
3 < O2 ≤ 10
Balance
a
3
0,5 ≤ CO2 ≤ 5
3 < O2 ≤ 10
Balance
a
4
5 < CO2 ≤ 15
0,5 ≤ O2 ≤ 3
Balance
a
5
5 < CO2 ≤ 15
3 < O2 ≤ 10
Balance
a
6
15 < CO2 ≤ 25
0,5 ≤ O2 ≤ 3
Balance
a
7
15 < CO2 ≤ 25
3 < O2 ≤ 10
Balance
a
1
25 < CO2 ≤ 50
Balance
a
10 < O2 ≤ 15
Balance
a
2
M3
H2
N2
100
2
M2
He
Low
reactivity
100
3
M1
Ar
Reducing
0,5 ≤ He ≤ 95
0,5 ≤ H2 ≤ 5
3
25 < CO2 ≤ 50
2 < O2 ≤ 10
Balance
a
4
5 < CO2 ≤ 25
10 < O2 ≤ 15
Balance
a
5
25 < CO2 ≤ 50
10 < O2 ≤ 15
Balance
a
1
100
2
rest
Balance
a
0,5 ≤ H2 ≤ 15
Balance
a
15 < H2 ≤ 50
Balance
a
0,5 ≤ N2 ≤ 5
Balance
a
5 < N2 ≤ 50
Balance
a
0,5 ≤ O2 ≤ 30
1
2
1
100
2
N
3
4
5
O
Z
a
b
1
0,5 ≤ H2 ≤ 10
0,5 ≤ N2 ≤ 5
0,5 ≤ H2 ≤ 50
Balance
100
Gas mixtures with components, which are not listed in the table or gas mixtures with a of the specified range.
b
For this classification Argon may be replaced partially or completely with helium.
Two gas mixtures with the same Z-classification must not be replaced against each other.
Rev. 2017-11-02
EXAMPLE
Classification
ISO 14175
For gas mixtures containing
6% carbon dioxide, 4% oxygen in argon
M25
30% helium in argon
5% hydrogen in argon
7,5% argon, 2,5% carbon dioxide in helium
0,05% oxygen in argon
ISO 14175 – M25 – ArCO – 6/4
I3
ISO 14175 – I3 – ArHe – 30
R1
ISO 14175 – R1 – ArH – 5
M12
Z
0,05% xenon (Xe), in argon
Designation
Z
ISO 14175 – M12 – HeArC – 7,5/2,5
ISO 14175 – Z – ArO – 0,05
ISO 14175 – Z – Ar+Xe – 0,05
TOLERANCES OF MIXTURES
Component gas nominal concentration [%]
Allowed tolerances
>5
± 10 % of the nominal
1 to 5
± 0,5 % absolute
<1
Not specified in ISO 14175
EXAMPLE
An addition of 25 % CO2 nominal value shall not vary more than ± 2,5 % (from 22,5 % to 27,5 %)
An addition of 2,5 % oxygen shall not vary more than ± 0,5 % (from 2,0 % to 3,0 %)
PURITIES AND DEW POINT
I
inert
99,99
Dew point at
0,101 MPa
°C
-50
M1 a
gas mix
99,9
-50
40
M2 a
gas mix
99,9
-44
80
M3 a
gas mix
99,9
-40
120
Ca
carbon dioxide
99,8
-40
120
R
reducing
99,95
-50
40
N
nitrogen
99,9
-50
40
O
oxygen
99,5
-50
40
Main groups/gas
Purity
% by volume
minimum
Moisture
ppm max.
volume
40
NOTE
For certain applications a higher purity and/or lower dew point may be recommended to avoid
possible oxidation and contamination
a
Nitrogen: 1 000 ppm maximum
Rev. 2017-11-02