AO2000
CONTINUOUS GAS ANALYZERS | OI/AO2000-EN REV. B
21
Important information for the operator
Limiting the purge gas pressure
The purging system of the gas analyzer has no relief opening. Therefore, the
maximum internal pressure must be limited by the operator. The standard
EN 60079-2 requires the safe limitation of the purge gas pressure even in the
single-fault mode. The control of the purge gas pressure is therefore to be
performed in single-fault proof mode by the operator.
Purge gas outlet and sample gas outlet
In order to ensure an overpressure of 7 hPa in the purge gas path as com-
pared with the sample gas path at a minimum purge gas flow of 15 l/h, the
outlet of the sample gas and the outlet of the purge gas have to be dis-
charged against the same pressure level (atmospheric). The common dis-
charging of sample gas and purge gas (for example, into a common exhaust
gas line / flare) is not permissible, since this leads to the risk of the backflow
of flammable gases into the purge gas path.
Emergency supply of purge gas
If, in the event of failure of the primary supply, an emergency supply with an
ignition protective gas is provided (for example, in order to continue oper-
ating the gas analyzer), each supply point must be able to maintain the re-
quired pressure level or the required amount of ignition protection gas in-
dependently of each other. The two supply points may have common pipes
or lines.
Installation of the gas analyzer and the supply lines
When installing the gas analyzer as well as the supply and exhaust air lines,
the requirements according to EN 60079-2 Annex D as well as according to
EN 60079-14 must be fulfilled. The requirements listed below are an excerpt
from these standards. They are explicitly listed here because of their im-
portance for safe operation of the gas analyzer. However, this list of re-
quirements in the above standards does not exempt the operator from his
obligation to perform the installation of the gas analyzer and the associated
supply lines in accordance with relevant national and international standards
and regulations, including any additional requirements.
In particular the requirements of IEC/TR 60070-16 "Electrical apparatus for
explosive gas atmospheres. Part 16: Artificial ventilation for the protection
of analyzer(s) houses" and IEC 61285 "Industrial-process control – Safety of
analyzer houses" shall be taken into account as appropriate.
