Brochure/Catalogue

EX basics
In which operations are ATEX-certied electronic
devices (such as signal converters, isolation
amplier, Namur switches and switching ampliers)
used?
ATEX-certied devices are used within industrial facilities
and production halls where there is the possibility that
explosive gases or dusts may be released.
Transportation and production applications which require
the use of such certied devices are listed below:
• Off-shore oil and gas drilling
• Tanker ships which carry oil, gas or chemicals
• Ships which carry potentially explosive materials
• Reneries and other oil or gas production plants
• Transportation and lling stations for oil and gas
• Petro-chemicals
What are the differences between standard devices
and intrinsically safe devices?
For electronic devices that are being used in Zone 0(20)
or 1(21), none of the components or electrical circuitry
are permitted to generate unallowable high temperatures
or sparks, whether during normal operations or during
malfunctions. In other words: “All of the circuits in
intrinsically safe electrical devices (Ex i) are safe and are not
capable of igniting explosive atmospheres“.
What is the device category?
The device Group II (hazardous areas not including underground or above-ground mining operations) is divided into device
categories 1, 2 and 3. They have the following safety levels:
Surroundings Device category Occurrence and duration of explosive
atmosphere
Ignitable materials Safety levels
Permitted errors
Groups and zones
Comparison
Group II 1 Constantly occurring
Long-term
Regularly
Gases, vapours, mist, dust Very high safety level
2 different protection classes
or
2 independent errors
Group II
Zone 0 (gas)
Zone 20 (dust)
Group II 2 Occurrence probable
over a limited time period
Gases, vapours, mist, dust High safety level
1 protection class
For which no more than one error may occur
Gruppe II
Zone 1 (gas)
Zone 21 (dust)
Group II 3 Occurrence improbable
Only for short periods
Gases, vapours, mist, dust Normal l safety level
Required protective measures
Group II
Zone 2 (gas)
Zone 22 (dust)
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Technical appendix/Glossary
W.152729490000