Hazardous Area
Installations
Information Sheet 01/02
24 January 2002
Contents
Special installation techniques apply to the installation
of electrical equipment in hazardous areas to ensure that the
possibility of danger due to explosion is minimised.
A hazardous area is defined as one:
- In which explosive atmospheres are or may be present;
and
- Requires special precautions in respect of the use or
construction of fittings or electrical appliances.
Responsibilities
The owner is responsible for the safety of
their electrical installation (regulation 69 of the
Electricity Regulations 1997).
For hazardous area electrical installations this
responsibility includes the zoning of the hazardous area and
ensuring that all work on the installation is carried out in a
suitable manner. In practice since most electrical
installation owners will not have the expertise to deal with
hazardous area installations the appropriate expertise would
be hired in to deal with the various issues.
Electrical workers that carry out work in
hazardous areas are required to be competent or be working
under the supervision of a registered electrical worker that
is competent (regulation 25). The requirement for competency
is further reinforced in the main standard used for hazardous
area electrical installation work (AS/NZS 2381.1).
It is recommended that unless the relevant expertise and
documents (e.g. AS/NZS 2381.1, NZS 6101) are held, or the work
is to be done under supervision of an electrical worker
experienced in hazardous area electrical work, electrical
workers should avoid carrying out work involving a hazardous
area electrical installation.
Hazardous Area Zoning
Zoning is required to determine the extent of the hazardous
area. See Note 1.
From this zoning information the appropriate fittings and
electrical appliances can be selected; and the appropriate
installation methods determined.
Who Zones
Zoning would normally be carried out by a person who is
competent in this area. This would normally be a design
engineer, competent electrical inspector, or in some cases a
registered electrician. In some areas the dangerous goods or
Factories inspector may carry out the zoning.
Verification of Zoning
Presently all zonings require verification by a Territorial
Authority Inspector, normally a Dangerous Goods Inspector;
although for spray painting booths and milk powder plants
verification should be sought from a OSH Factories Inspector;
and for Natural Gas installations, the local gas authority.
The documents presently used for the zoning of hazardous
areas are:
- NZS 6101 Part 1 - Classification of Hazardous Areas,
Part 1:1988 Flammable Gas and Vapour Atmospheres.
- AS/NZS 2430.3 - Classification of Hazardous Areas,
Examples of Area Classification.
The standard contains 9 parts and is used to determine the
zoning in most common situations.
- AS/NZS 61241.1 - Electrical Apparatus in the Presence of
Combustible Dusts.
Zoning Legislation
Presently this includes the Dangerous Goods legislation and
the Factories and Commercial Premises legislation
(administered by OSH); and the Gas Act 1992 and associated
regulations administered by the Energy Safety Service,
Ministry of Consumer Affairs.
However the Hazardous Substances (Class 1 to 5
Controls) Regulations, which came into force on 1
July 2001, is running in parallel with the above legislation
and will replace it in April 2002. The Environmental Risk
Management Authority (ERMA) are the controlling agency for
these regulations although OSH, Department of Labour, will be
taking on the primary enforcement roll, with agencies such as
the Energy Safety Service (ESS) assisting.
Selection of Electrical Equipment
The selection of the type of fittings and electrical
appliances is dependent upon the zoning assigned to the area
concerned.
Once the zoning is known standard AS/NZS 2381.1:1999 (and
the standards listed within that document) should be
referenced to determine the type of electrical equipment that
can be installed for the particular zone classification.
AS/NZS 2381.1:1999 requires that all electrical fittings
and appliances used in a hazardous area:
- Be certified for compliance with the relevant Standard
(referred to in AS/NZS 2381.1) by a competent certifying
authority; and
- Bear appropriate markings.
Organisations currently recognised as competent certifying
authorities are outlined in section 2.6 of the standard.
Installation of Electrical Equipment
The construction of electrical installations is required to
be electrically safe (regulation 69). For hazardous area
electrical installations AS/NZS 2381.1 is recognised as the
means of meeting this safety requirement.
The standard outlines the technical installation
requirements for work in hazardous areas and uses AS/NZS 3000
(the joint Australian/ New Zealand Wiring Rules) to set the
base electrical installation safety requirements.
For particular explosion protection techniques (e.g.
intrinsically safe, flameproof, increased safety etc) the
requirements (additional to those in AS/NZS 2381.1) are
contained in the specific part of the AS/NZS 2381 series of
standards.
Testing, Certification and Inspection
Testing
Testing of hazardous area work associated with electrical
installations is required to be carried out in accordance with
the Electricity Regulations 1997, AS/NZS 3000:2000 and AS/NZS
2381.1.
Prescribed electrical work involving the construction of
electrical installations is required (by regulation 37 of the
Electricity Regulations 1997) to be tested prior to
connection.
Where work in hazardous areas forms part of the work
undertaken the requirements for testing contained in AS/NZS
3000 and AS/NZS 2381.1 would be required.
Certification
This is required for work carried out on electrical
installations that involves the placing or positioning, or the
replacing or repositioning of conductors (including fittings
attached to those conductors). The certification is required,
by a suitably qualified person, on a Certificate of
Compliance. See regulations 39 and 40.
Inspection
In addition to the need for testing and certification
(under regulations 37, 39 and 40) work in hazardous areas is
required to be inspected by a registered
electrical inspector. See regulation 41.
Following inspection, and the work shown to be compliant,
the inspector is required to complete the appropriate section
of the Certificate of Compliance.
Maintenance (Including Repair and Overhaul)
The requirements for maintaining fittings and electrical
appliances in hazardous areas is outlined in AS/NZS 2381.1
(Section 5)
Where fittings or electrical appliances are to be repaired
or overhauled (or modified) this is required to be carried out
in accordance with AS/NZS 3800 Electrical Equipment for
Explosive Atmospheres - Overhaul and Repair.
Very strict requirements apply to the modification of
fittings and electrical appliances used in hazardous areas
(reference needs to be made to the original certification
covering the fitting or appliance) and, in general, such
modifications would be carried out by certified workshops.
Modifications carried out by persons and organisations that
are not appropriately certified will void the original
approval certification of the equipment.
Periodic Inspection
Hazardous area electrical installations are required (by
regulation 46) to be periodically inspected for safety and
compliance (with AS/NZS 2381.1) at intervals not exceeding 4
years. The requirement for periodic inspection was introduced
in April 1993 therefore all hazardous area electrical
installations (except those less than 4 years old) should now
have at least one periodic inspection report in their
verification dossier.
Documentation
AS/NZS 2381.1 requires the owner of a hazardous area
electrical installation to keep and maintain a dossier
including information on the installation's operation,
testing, certification, inspection, maintenance, and repair.
An electrical worker working on the installation is
required to provide documentation (e.g. certification
documents for new or overhauled equipment, Certificates of
Compliance, testing results, periodic inspection reports etc)
so that the dossier can be updated.
Examples of what should be in the dossier are -
- Drawings and documentation on zoning. This should
describe the site in a three dimensional way so as to
enable the person to practically work out the zoning of
the site or be drawings that have been verified by any
official body responsible for the installation concerned;
- Inspection and test reports on the electrical
installation;
- Reports of audits/periodic inspections carried out on
the electrical installation. This is to enable a
history of the installation to be established;
- A description of any work carried out on the electrical
installation and the associated testing, certification,
and inspection documentation. The information should
include the name and registration number of the person
carrying out the work, the date the work was carried out
and the actual fittings and electrical appliances worked
on.
The dossier may be stored on site or kept at a central
location, and may be stored in an electronic form. The
operators of the site should be fully aware of the dossier and
where it is kept so as to be able to provide it when
requested.
Notes
- If the owner of an existing
electrical installation has a "dossier" as
outlined in AS/NZS 2381.1 the zoning of the hazardous area
may already be well defined.
- Electrical workers working in, or intending to work in
hazardous areas should have, as the very minimum standard
AS/NZS 2381.1 and the individual parts for the protection
techniques to be used in an electrical installation.
- General information on hazardous areas can be found in
handbook HB13-2000 published by Standards Australia.
- Standards are available from Standards New Zealand or
Standards Australia.
- The regulations mentioned in this circular can be
sighted on the Energy Safety Service website at www.ess.govt.nz
- Advice on wiring of electrical installations in
hazardous areas can be sought from the Energy Safety
Service, Ministry of Consumer Affairs, Ph 04-472 0030 or
Freefax 0508-723 336.
- Unit standards have been produced for hazardous areas
and persons can obtain training to these standards through
some training providers. The standards cover both
theoretical and practical aspects of work in hazardous
areas.
Persons with previous work experience in hazardous area
electrical installations can have this experience assessed
against the new Unit standards.
As at the date of this newsletter the Electrical Training
Company (ETCO), which has offices in the main centres, and
the Specialist Training Company in Auckland, have
indicated that they can provide training for work on
hazardous area electrical installations.
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