Siemens SIPROCESS GA700 Kompaktbetriebsanleitung Seite 170

Commissioning
6.1 Basic safety instructions
Explosive gases in the enclosure
Danger of explosion.
Explosive gases are gases with a gas concentration of more than 25% of the lower explosive
limit (LEL).
Under normal ambient conditions, the LEL is the danger threshold when handling these
gases. Special operating conditions can lower the risk potential of these gases below the
LEL. A value of 25% of the LEL is regarded as definitely safe.
Do not introduce flammable or explosive gases in the following device versions:
● Devices with restricted breathing enclosures (degree of protection Ex nR)
● Devices which are approved for use in explosive dust atmospheres (degree of protection
Unsuitable safety system for the pressurized enclosure in Zone 2
Danger of explosion in hazardous areas.
● If no combustible gases or gas/air mixtures (sample gases) are introduced into the device,
● If combustible gases or gas/air mixtures (sample gases) that are occasionally ignitable
● Purge the device with an approved safety system in accordance with the specifications in
Absence of pre-purging
Danger of explosion in hazardous areas.
An explosive atmosphere existing in a device with pressurized enclosure (type of protection
Ex p) can result in an explosion during commissioning.
● Make sure that the device is pre-purged before it is commissioned.
● Make sure that the purging time, quantity and medium are correctly observed. Refer to
Dust in pressurized enclosure "Type of protection Ex p"
An explosive dust atmosphere inside an enclosure can result in an explosion.
● In Zones 21 and 22: Remove the dust layers manually from the enclosure.
● Cleaning by pre-purging is not permitted.
64
WARNING
Ex t)
WARNING
use the type of protection "Simplified pressurized enclosure Ex pz" in Zone 2.
are introduced into the device, use the type of protection "Pressurized enclosure Ex px".
Chapter "Technical specifications (Page 79)".
WARNING
the information in Chapter "Technical specifications (Page 79)".
WARNING
Devices in explosion-proof design
Compact Operating Instructions, 05/2015, A5E35134047-02