Siemens ULTRAMAT 6 Series - Measurement of Hydrogen in Oxygen with Calomat 6 E

2.6 Measurement of hydrogen in oxygen with Calomat 6E
NOTICE
Explosive gas mixtures
Gas mixtures of hydrogen H
2
in oxygen O
2
are explosive in a wide range. At an atmospheric
pressure of 1000 hPa and 20 °C ambient temperature, the lower explosive limit (LEL) lies at 4 %
H
2
in O
2
, the upper explosive limit (UEL) at 95.2 % H
2
in O
2
. At an ambient temperature of 80 °C
the LEL lies at 3.8% H
2
in O
2
, the UEL lies at 95.4% H
2
in O
2
.
In general, a distinction is made between the following cases at the occurrence of explosive
gas mixtures:
• Frequently or constantly explosive - more than 1000hours/year
• Occasionally explosive - 10 to 1000hours/year
• Rarely explosive - less than 10hours/year
DANGER
Danger of explosion
Measuring explosive gas mixtures with CALOMAT 6E and CALOMAT 6F
• Non-explosive sample gases and gas mixtures below the LEL may be inserted into the
CALOMAT 6. Flame arrestors can be omitted. However, it must be guaranteed that the
sample gas in the gas path (containment system, CS) always remains below the lower
explosive limit!
• Rarely or occasionally explosive gas mixtures must only be introduced into the gas
analyzer if the inputs and outputs for sample gas have each been provided with a 󹪞ame
arrestor. The 󹪞ame arrestors must meet the safety requirements for the combustible
medium.
• Frequently or continuously explosive gas mixtures must not be introduced into the gas
analyzer.
• Gas mixtures above the upper explosive limit: Assess the introduction individually in
accordance with a separate certi󹪝cate based on on-site acceptance testing.
NOTICE
Checking leak tightness of the gas path
In case of leakages of the gas path (containment system, CS), hydrogen (H
2
) and oxygen (O
2
)
can concentrate in the gas analyzer to form an explosive mixture. Only after checking for a
suitable leak tightness of the gas path, may these gases be fed into the gas analyzer.
CALOMAT 6E rack unit
The enclosure of the gas analyzer has to be equipped with su󹪟cient openings so that a gas
exchange with the environment takes place and an explosive mixture cannot build up in the
device.
Safety instructions
2.6Measurement of hydrogen in oxygen with Calomat 6E
Series 6 and ULTRAMAT 23
22 Compact Operating Instructions, 01/2024, A5E45779144002-AB