ABB PGC5000 Series gas chromatographs
IntroductionFor a classified Ex zone 1 area, the rationale behind
this “Zone 2 by design” analyzer is that the analyzer
must remain safe when operated in an abnormal
condition. In the event of a fault, the PGC5000
provides continual protection:
• Should a failed component become ignition
capable, the pressurization system prevents the
components from being exposed to flammable
gases or vapors.
• Should a failed pressurization system expose the
internal components to flammable gases or
vapors, the analyzer’s alarm provision will alert the
user of the failure.
Neither of these single faults would present a
hazard to the potentially explosive atmosphere;
therefore, electrical power interlock is not required
for this type of pressurization protection. Enclosure
doors are not required to be interlocked so that the
electrical supply is disconnected automatically
when doors are opened. The requirement is simply
an alarm provision since there are no hazards inside
the enclosure when in normal operation.
The zone 1 certified PGC5000 analyzer offers simple
pressurization protection, commonly referred to as
Ex ‘py’ or “Y-purge”. This enclosure pressurizing
technique is made possible by ensuring that the
internal components within the analyzer are not
capable of causing an ignition in normal operation,
thus allowing for a reduction in classification within
the protected enclosures from zone 1 to zone 2.
PGC Certification
This simple pressurization technique for the
PGC5000 is considered an improvement to the
process gas chromatograph analyzer by allowing for
a continual operation without possible disruption
caused by interlocking the electrical power to the
pressurization system. When operated in a zone 1
area, the user of the PGC5000 analyzer is simply
responsible for:
• Operating the analyzer within the manufacturer’s
established parameters, as described in the
product manuals and the CE conformity
declaration’s special conditions for safe use
• Providing a reliable supply of protected air for the
enclosure purge and pressurization system
• Monitoring the alarm state of the pressurization
system in normal operation
• Responding to the alarm condition of the
pressurization system, which may require
restoring the supply of protected air or the
removal of electrical power and proper isolation
of remaining hazardous live circuits if the area is
potentially hazardous

ATEX Directive 2014/34/EU, annex II
The PGC5000 analyzer “must be so designed and
constructed as to prevent ignition sources arising,
even in the event of frequently occurring
disturbances or equipment operating faults, which
normally have to be taken into account”. The design
of the analyzer is capable of functioning within the
established operational parameters and of ensuring
a high level of protection necessary for the intended
classified Ex zone 1 area. The notified body LCIE
examined the internal components of the PGC5000
and approved the analyzer as Ex ‘py’ for a zone 1
area:
• The EC-type examination of the PGC5000 series
analyzer and the IEC Ex test report first evaluated
the internal components to Part 15 of the
harmonized conformity standard IEC60079 (Ex ‘n’)
as either being non-sparking, energy limited or
temperature limited to below the specified
temperature class (ref: certificates EC-type LCIE
09ATEX 1017X and IECEx LCI09.0010X).
• The EC-type examination of the PGC5000 series
analyzer and the IEC Ex test report then evaluated
the pressurization protection of the enclosure to
part 2 of the harmonized conformity standard
IEC60079 (Ex ‘p’) as being suitable for zone 1 area
without electrical power interlock to the
pressurization system (ref: certificates EU-type
LCIE 09ATEX 3006X and IECEx LCI09.0010X).