This unit involves the skills and knowledge required to design gas detection electrical systems and installation for a hazardous area.

It includes determining gas detection electrical system equipment parameters and evaluating these against manufacturer specifications. It also includes designing and documenting gas detection electrical system.

This unit augments formally-acquired competencies in a relevant industry. It applies to engineering design job functions at least at an engineering associate level.

Hazardous area (gas or vapour) is one in which an explosive gas atmosphere is present, or may be expected to be present, in quantities such as to require special precautions for the construction, installation and use of apparatus.

No licensing, legislative or certification requirements apply to this unit at the time of publication.

ELEMENTS

PERFORMANCE CRITERIA

Elements describe the essential outcomes.

Performance criteria describe the performance needed to demonstrate achievement of the element.

1

Determine gas detection electrical system parameters

1.1

Requirements for gas detection system are obtained or determined with relevant person/s

1.2

System parameters for gas detection are obtained and documented from consultation with relevant person/s

1.3

Explosion-protection requirement for gas detection equipment is determined from area classification documents

2

Select gas detection electrical equipment

2.1

Manufacturer specifications and operating limitations of gas equipment are obtained and analysed in accordance with workplace requirements

2.2

Manufacturer specifications and operating limitations are compared with the required workplace parameters for gas detection system

2.3

Gas detection equipment is selected on compatibility with hazardous area workplace parameters and economic considerations

3

Document gas detection equipment design

3.1

Proposed gas detection equipment design is checked in accordance with workplace procedures for compliance with relevant industry standards and hazardous area requirements

3.2

Gas system specification for gas detection equipment is documented in accordance with workplace procedures

Evidence required to demonstrate competence in this unit must be relevant to and satisfy all of the requirements of the elements and performance criteria on at least two separate occasions and include:

accessing and interpreting gas detection hazardous area workplace needs and parameters

applying relevant contingency management skills

applying relevant work health and safety (WHS)/occupational health and safety (OHS) requirements, including:

risk control measures

workplace procedures and practices

applying sustainable energy principles and practices

designing gas detection systems within a hazardous area

documenting gas detection equipment system design

following, checking and documenting workplace procedures

providing gas detection equipment selection options based on parameters for gas detection and economic considerations.

Evidence required to demonstrate competence in this unit must be relevant to and satisfy all of the requirements of the elements and performance criteria and include knowledge of:

maintenance procedures in hazardous areas that will ensure the integrity of the explosion-protection technique, including:

the purpose of a maintenance schedule

the purpose and extent of ‘close’, ‘sample’ and ‘periodic’ inspections

the features of each explosion-protection techniques that should be included in a maintenance schedule

the impact of environmental conditions on explosion-protected equipment, including corrosion and frequency of maintenance

the documentation requirements for recording the maintenance process and results

the use of standards in determining the requirements with which the design of explosion-protected apparatus shall comply

techniques for the installation and maintenance of fixed gas detection equipment, including:

use of manufacturer instruction manuals; for example, operating instructions, adjustments procedures and operational limitations

installation and maintenance of standards and/or codes of practice for gas detection equipment

location of fixed sample points or sensors, including:

optimal sensing

maintainability and ease of calibration

protection against environmental and mechanical damage

gas and vapour releases, including:

the nature of a site

natural and mechanical ventilation

common problems with fixed gas detectors

calibration and response checking

factors to consider in the evaluation and selection of portable and fixed gas detection equipment, including:

requirements for gas detection for a given situation, including:

sources for obtaining data on physical chemistry of the gas to be detected

sources for obtaining data on the conditions under which the gas may be present

processes of assessing the specifications of gas detection equipment against established requirements

detecting gases and vapours, including:

apparatus capability and users’ knowledge

propagation of gases - release of gas and vapours, ventilation, density, and temperature and location

gases to be detected and not to be detected

intended application

environmental effects

safety when monitoring for flammable gases where personnel could be present

common properties of gases and vapours - density of gases, vapours and their mixtures; effect of temperature on density; lower explosive limit (LEL) and upper explosive limit (UEL) of combustibles and toxicity

the differences between detecting gases and vapours - added complication of evaporation, condensation and temperature effects of vapours and their effect on propagation, calibration and detection, including sampling

oxygen deficiency and effects on safety, including:

chemical reaction of oxygen with solid products

chemical reaction of oxygen with gaseous products

dilution of the air by displacement by some other gas or vapour

measuring principles of catalytic sensors, electrochemical sensors, infrared sensors and semi-conductor sensors, including:

common applications

limitations and safety

interferences of other gases with the measurement

poisoning of the sensor

measuring principles of thermal conductivity sensors, flame ionisation, detectors (FID), flame temperature analysers (FTA), photo ionisation detectors (PID) and paramagnetic oxygen detectors

selection of apparatus, including:

environment

system response delay

gas to be detected with respect to measurement principles

behaviour of gas and vapour releases, including:

rate of release

density

temperature/pressure

design and installation, including:

sensor, sampling or open path

location

site

environmental conditions (adverse weather, excess temperature, vibration and other mechanical interference, hosing, airborne contaminants and corrosion)

integrity and safety, including:

redundancy

protection against loss of power supply

commissioning and scheduled maintenance, including:

sample lines

diffusion sensor screens

initial gas calibration

adjustment of alarm set points

plans and records.

Assessors must hold credentials specified within the Standards for Registered Training Organisations current at the time of assessment.

Assessment must satisfy the Principles of Assessment and Rules of Evidence and all regulatory requirements included within the Standards for Registered Training Organisations current at the time of assessment.

Assessment must occur in suitable workplace operational situations where it is appropriate to do so; where this is not appropriate, assessment must occur in suitable simulated workplace operational situations that replicate workplace conditions.

Assessment processes and techniques must be appropriate to the language, literacy and numeracy requirements of the work being performed and the needs of the candidate.

Resources for assessment must include access to:

a range of relevant exercises, case studies and/or simulations

relevant and appropriate materials, tools, facilities, equipment and personal protective equipment (PPE) currently used in industry

resources that reflect current industry practices in relation to designing gas detection systems

applicable documentation, including workplace procedures, equipment specifications, regulations, codes of practice and operation manuals.

Foundation skills essential to performance are explicit in the performance criteria of this unit of competency.

Range is restricted to essential operating conditions and any other variables essential to the work environment.

Non-essential conditions may be found in the UEE Electrotechnology Training Package Companion Volume Implementation Guide.

Electrotechnology

Hazardous