Analyzer Versions Ex Px With Continuous Purging Or Ex Pz With Use Of The Containment System; Device Versions Ex Nr And Ex T; Simplified Pressurized Analyzers Ex Pz For Use In Hazardous Zone 2 And Zone 22; Oxymat 7 (Siprocess Ga700 Rack-Mounted Device Only) - Siemens SIPROCESS GA700 Compact Operating Instructions

Safety instructions
2.5 General directives for explosion protection
2.5.3.2 Analyzer versions Ex px with continuous purging or Ex pz with use of the containment
system
With gas/air mixtures above the LEL, fault tolerance of the containment system is not
guaranteed in the sense of EN 60079-2 since sample gas can be released into the pressurized
enclosure as a result of leaks (e.g. O-rings). However, this release can be assessed as limited.
The maximum quantity released is below 200 µl/min, and is guaranteed by the quality
assurance measures of the analyzer manufacturer when the analyzer is delivered.
Continuous purging of the Ex p enclosure must therefore be carried out following the pre-
purging phase. This guarantees that sample gas released by a leak is diluted to such an extent
that an explosive gas mixture cannot occur. The volume flow of the protective gas has therefore
been set to 1 l/min; this is more than 100 times the maximum quantity of sample gas released
required by the standard.
2.5.3.3

Device versions Ex nR and Ex t

Explosion hazard
For device versions with restricted breathing enclosures (Ex nR) or with dust protection by
enclosure (Ex tb):
● Only introduce sample gases with a composition below the lower explosive limit (LEL).
● The connection of combustible to occasionally explosive gas mixtures is not permissible
● The connections for the protective gas (purging gas) must be closed gas-tight!
2.5.3.4

Simplified pressurized analyzers Ex pz for use in hazardous Zone 2 and Zone 22

Combustible gases or gas/air mixtures whose composition is also occasionally above the lower
explosion limit (LEL) may not be connected to analyzers with simplified pressurized enclosures
(protection rating Ex pz).
Before you use device versions with type of protection Ex p in dust atmospheres: Make sure
that the interior of the device is dust-free.
The connection of frequently or permanently explosive gas mixtures is not permissible with
this type of explosion protection!
2.5.3.5

OXYMAT 7 (SIPROCESS GA700 rack-mounted device only)

When installing in control cabinets, suitable ventilation measures must be provided to
guarantee an air change of at least five per hour.
If the sample gases can be combustible, install suitable flame arrestors in the sample gas inlet
and sample gas outlet. If the sample gas is released into a non-hazardous area, the need for
flame arrestors at the sample gas outlet becomes obsolete.
Make sure that no higher absolute sample gas pressures occur than specified in the technical
data of the respective device version.
24
WARNING
with this type of explosion protection!
Devices in explosion-proof design
Compact Operating Instructions, 05/2015, A5E35134047-02