Publicité
ZONE 2
ZONE 21
ZONE 22
3
Explosionproof switchgear combinations in
the type of protection 'nR' and 'tb'
(Equipment without built-in components that
give off arcs or sparks during normal operation)
The explosionproof switchgear combinations are
intended for use in Zone 2 (EPL Gc) explosive
gas atmospheres according to IEC/EN 60079-0
and IEC/EN 60079-15. The enclosure is
designed according to IEC/EN 60079-0 and
IEC/EN 60079-31 for use in explosive dust
atmospheres Zones 21 and 22 (EPL Db and
Dc).
Before dispatch, each enclosure is subjected to
a halftime pressure test. The test is carried out
to determine the time to change to half the initial
pressure value from 3 to 1.5 mbar. This shall not
be less than 180 seconds. Testing of enclosures
after installation is not required. For this reason,
the enclosures do not feature a test port.
The restricted breathing polyester enclosures
are subjected to ageing tests (thermal
endurance to heat and cold, impact test followed
by IP test). The test for leakage in accordance
with IEC/EN 60079-15 is not carried out until
after the IP test. The halftime value of the
polyester enclosures is substantially higher than
the requirements of the standard.
Non-explosionproof electronic components such
as, for example, access points, WLAN anten-
nas, GSM modules, can be be built into restrict-
ed breathing enclosures.
Publicité
