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Audits and Inspections
Plant and apparatus shall
be given an initial inspection, before it is
commissioned and energized.
For maintenance purposes,
the installation requires regular periodic
inspections.
Any change in area in
area classification, or movement of
equipment should be checked and recorded.
Typically, inspections
are divided into the following categories:
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Initial inspections,
which means the detailed inspection of all
electrical equipment, systems and
installations, before they are
commissioned and energized. The detailed
inspection will ensure that the equipment
is fit for purpose and safe to use.
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Detailed inspections
are performed in order to identify that
the equipment is appropriate to the
hazardous area, gas group and temperature
class, as well as check for loose
connections, damage, and loose cable
glands, missing bolts and poor
workmanship. Such defects are noted and
put on a punch list for remedial action
before the equipment is energized. Defects
are categorized as critical, major or
minor.
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Close inspections do
not normally require enclosures to be
opened, but if necessary, equipment can be
de-energized, isolated and opened.
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Visual inspections
identify defects that are apparent to the
eye.
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Periodic inspections
are normally statutory, as required by
regulations. These are normally conducted
every two years, or more frequently
depending on the operating environment and
conditions.
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Sample inspections are
conducted as a proportion of the
electrical equipment, system and
installation.
In my experience, after
an installation has been in service for five
years, a detailed inspection is necessary,
to check for hot connections, water ingress,
corrosion and loose fasteners, missing data
plates and any other conditions that normal
wear and tear, may cause an unsafe, or
non-compliant condition.
In terms of the
inspection schedules of IEC 60079-17, the
following checks are made:
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Suitability of
apparatus to area classification.
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Correct apparatus
group.
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Correct maximum surface
temperature for apparatus.
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Apparatus circuit
identification.
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Cable entry devices.
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Correct cable type.
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Bolts and fasteners.
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Unauthorized
modifications.
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Damage
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Sealing.
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Earthing and bonding.
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Insulation Resistance.
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Overload settings.
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Lamp rating and
orientation.
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Labels.
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Environmental
conditions.
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Ingress protection.
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Corrosion.
During an audit and
inspection, the as-built drawings can also
be verified and marked up.
Any other changes in
plant status such as equipment replacements,
different operating systems, changes in
processes and handling of different
chemicals can be updated as well. The audit
and inspection regime is extremely useful in
obtaining useful information about the
condition of the plant and keeping and
future planning for preventative and
maintenance purposes. For example, there
will be no major financial surprises in the
maintenance budget, unless there is a
catastrophic breakdown!
Types of Ex protection.
Exi (a) or (b) -
Intrinsically safe.
Exd Flameproof.
Exe Increased safety
ExN Non-sparking.
Exp Pressurized or
purged.
Exm Encapsulation.
Exo Oil immersion.
Exq Powder-filling.
Exs Special protection.
Documentation:
The following documents
are working documents, in order to keep
track of changes in area classification,
changes in operations, different flammable
substances, equipment replacement and
maintenance, additions and upgrades and so
on.
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Material Safety Data
Sheet. See
MSDS
example.
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Hazardous Area
Classification Drawings. See
HACD
example.
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Piping and
Instrumentation Drawings.
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Electrical Equipment
Layout Drawing.
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Electrical Single Line
Drawings.
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Register of Explosion
Protected Electrical Apparatus.
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Certificate of
Conformance by Manufacturer.
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Certificate of
Conformance by Repairer.
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Inspection Records by
Competent Person.
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Certificate of
Compliance by Master Installation
Electrician.
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Register of Portable
Electrical Equipment.
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Permit to Work.
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Calibration
Certificates.
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