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SILVER M
INSTALLATION – OPERATING - MAINTENANCE
8 Explosion Protection
In order to prevent an explosion, a detonation or a fire, potentially
explosive atmospheres should be avoided wherever possible!
As a rule, a potentially explosive atmosphere must be divided into
respective categories (zones) in accordance with applicable
regulations, whereby a differentiation is made between
atmospheres, which lie inside or outside the airstream.
Equipment with special explosion protection must be deployed only
in their declared category!
8.1 Service, maintenance and repair
Service, maintenance and repair may be carried out only by
-
respectively trained personnel!
Work tasks may be carried out, either in a non-potentially
-
explosive atmosphere only, or with an avoidance of ignition
sources. For this, it must be especially regarded, that all work
materials deployed are authorised for the respective zone
Prior to opening the equipment, the system must be
-
mechanically and electrically taken out of service and secured
accordingly.
In addition, it may be required to purge the equipment with
-
fresh air, as necessary, in order to remove or dilute a
potentially explosive atmosphere. In particular, this is required
when the internal gas groups differ from the external gas
groups! This task can be automated through the control
system.
In particular, the atmospheric concentrations can change in the
-
event of a system shutdown, increasing the risk of an
explosion! In any case, all types and sources of ignition should
be avoided when performing service, maintenance and repairs.
8.2 Identification marking
Identification as to the type of atmosphere, in which the equipment
can be deployed, is located at the ventilator chamber. For this, the
identification between internal (conveyed atmosphere) and external
(installation room) will differ - the equipment may be deployed only
in agreement with the respective equipment identification.
Example: Ex II 2G IIA T3 (internal); Ex II 3G IIB T4 (external)
The individual markings have the following meaning:
Ex Ex-protection (group)
-
I
Underground operation
-
II
Above ground operation
1
Protection category 1 (Zone 0)
-
2
Protection category 2 (Zone 1)
3
Protection category 3 (Zone 2)
G
Gas, mist, steam
-
D
Dust
IIA Materials with low ignition susceptibility
-
IIB Materials with medium ignition susceptibility
IIB Materials with high ignition susceptibility
T1 450°C highest allowable surface temperature
-
T2 300°C highest allowable surface temperature
T3 200°C highest allowable surface temperature
T4 135°C highest allowable surface temperature
T5 100°C highest allowable surface temperature
T6 85°C highest allowable surface temperature
internal
in
the
-
external
outside the airstream
A warning notice is located on the equipment, which must not be
removed:
This equipment can convey a potentially explosive atmosphere!
May be opened only by specialist personnel with suitable work
materials!
As an individual module, the RAC equipment, alone, cannot
guarantee a complete and all-encompassing protection against
explosion, as the protection concept must apply to the complete
system.
The overall responsibility for explosion protection lies ultimately
with the operator or the system manufacturer.
airstream
28
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