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• Gas mixtures that are frequently or always explosive:
These must not be introduced!
• Sample gases above the upper explosive limit:
These must be individually assessed in accordance with a separate certificate based on on-
site acceptance testing using inert gas as the protective gas.
2.2.4
Further safety measures
The exhaust lines for the sample and reference gases must terminate outside the hazardous
area at a safe place. The sample gas exhaust line can also be returned to the sampling point.
When sample gases (both combustible and non-combustible) are discharged into the hazardous
area, you provide the sample gas inlet and outlet with a flame arrestor each.
When combustible media are supplied, you must interrupt the sample gas supply after switch-
off of the analyzer and pressurized enclosure or when the pressurized enclosure responds under
fault conditions.
The maximum permissible sample gas pressure in the analyzer depends on whether the
introduced gas type is combustible or non-combustible and is described in the technical
specifications under the point "Sample gas inlet conditions".
See also
Technical specifications for operation in hazardous areas (Page 62)
2.2.4.1
Analyzer versions Ex px with leakage compensation
The containment system (sample gas path in the analyzer) is rated as without release if
• the gaseous medium is not combustible,
• the gaseous medium is combustible, but the gas concentration is always below the lower
explosion limit which must be guaranteed by a safety level of at least Category 4 to
EN ISO 13849-1,
• the gaseous medium is combustible, and the differential pressure between the enclosure and
the containment system is monitored. The pressure in the enclosure must always be at least
50 Pa (recommended 5 hPa) above the pressure in the containment system and the
environment.
Monitoring of the differential pressure between the enclosure and the containment system
must be carried out at the following safety level:
– the pressure monitoring of the containment system by the system itself is at
– the differential pressure monitoring between the containment system and the protective
Compact Operating Instructions in accordance with EN 61010-1 and EN 60079-0
Compact Operating Instructions, 09/2018, A5E45779389002-01
least Category 1 to EN ISO 13849-1 (operational reliability) and the differential pressure
monitoring between the containment system and the protective gas is at least Category 1
to EN ISO 13849-1, or
gas corresponds to at least the level of Category 3 from EN ISO 13849-1 (fault tolerance,
single fault tolerant) without consideration of system-dependent safety.
Safety instructions
2.2 Analyzers in hazardous areas
17
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