II - DCE FEL ČVUT v Praze

Table 1-7 Safety measures
Mechanical Configuration of an Automation System with SIMATIC S7 Ex Modules
Working area Safety measures
Installations with readily flammable
gas and vapor-air mixtures, e.g.
hydrogen, city gas, acetylene and
hydrogen sulphide
Installations with gas and vapor-air
mixtures such as methane, propane,
butane and petrol (gasoline)
Installations with risk of explosion
from readily flammable dust
I/O Modules with Intrinsically-Safe Signals
C79000-G7076-C152-04
Working only allowed after implementation of special
safety measures and with written permission of plant
manager. Only non-sparking tools to be used (tool softer
than workpiece).
Sufficient to use non-sparking tools. Exception: For
materials with rust formation and aluminum coating or
similar, special protective measures required.
Remove dust deposits.
Keep working area wet and protect against dust formation.
Normal tools may be used.
Note
Working on energized electrical installations and apparatus in hazardous
industrial premises is prohibited. This also includes the disconnection of live
control lines for test purposes.
As an exception, work on intrinsically safe circuits is permitted; also, in
special cases, work on other electrical systems where the user has certified in
writing that there is no risk of explosion for the duration of the work at the
site.
If necessary, a fire permit must additionally be obtained.
Grounding and short-circuiting may only be carried out in hazardous
industrial premises when there is no risk of explosion at the point of
grounding and short-circuiting.
Use measuring instruments which are approved for the zones to test for no
voltages.
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