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Title / Operate and maintain main line valves in a gas network
Level / 5 / Credits / 6
Purpose / People credited with this unit standard are, in a gas network, able to: locate, identify, and interpret procedures and resource requirements for operating and maintaining main line valves; operate and maintain main line valves; and place main line valves back into serviceafter maintenance.
Classification / Gas Industry > Gas TransmissionOperations
Available grade / Achieved
Guidance Information
1This unit standard is intended for, but is not limited to, workplace assessment. The range statements relate to enterprise specific equipment, procedures, and processes.
2Evidence presented for assessment against this unit standard must be consistent with safe working practices and be in accordance with applicable manufacturer’s specifications, company procedures and legislative requirements.
3Performance of the outcomes of this unit standard must comply with the following:
Health and Safety at Work Act 2015;
Health and Safety in Employment (Pipelines) Regulations 1999;
Resource Management Act 1991;
AS/NZS 4645.1:2008 Gas distribution networks – Network management;
AS/NZS 4645.2:2008 Gas distribution networks – Steel pipe systems;
AS/NZS 4645.3:2008 Gas distribution networks – Plastic pipe systems;
AS 2885.1-2012 Pipelines – Gas and liquid petroleum Design and construction.
4References
Australian standards (AS) may be found at
Australian/New Zealand standards (AS/NZS) may be found at
5Any new, amended or replacement Acts, regulations, standards, codes of practice, guidelines, or authority requirements or conditions affecting this unit standard will take precedence for assessment purposes, pending review of this unit standard.
6Definition
Company proceduresmean the documented methods for performing work activities, and include health and safety, operational, environmental, and quality management requirements. They may refer to legislation, regulations, guidelines, standard operating procedures, manuals, codes of practice, or policy statements.
Outcomes and performance criteria
Outcome 1
Locate, identify, and interpret procedures and resource requirements for operating and maintaining main line valves ina gas network.
Performance criteria
1.1Documentation and company procedures for operating and maintaining main line valves are located and are interpreted in relation to specified job requirements.
1.2Job instructions and system specifications are confirmed.
Rangeinstructions and specifications may include – site location, work instructions, current test certificates, identification tags, equipment operating manuals, pipe and instrumentation drawings, electrical schematics, isolation procedures, plant release.
1.3Reasons for having a main line valve on a gas pipeline are explained.
Rangemay include – legislative requirements, company requirements, line rupture protection, pipeline section isolation.
1.4Types of main line valve systems and their component parts are described.
Rangemay include – main line valve, bypass valve, actuators, piping components, control systems, trip devices, indication equipment, check valves.
1.5Potential risks of incorrect application and operation of equipment and procedures, and the steps to avoid them are described.
Rangemay include – personal harm, equipment damage, loss of supply to customer, inaccurate alarms, environmental impact.
1.6Resource requirements are identified and sourced.
Rangetools, test equipment, personal protective equipment, materials, documentation, competent and authorised personnel, communication equipment.
Outcome 2
Operate and maintain main line valves ina gas network.
Performance criteria
2.1Potential risks are identified, and site emergency procedures are explained.
Rangerisks may include – flammable product, high pressure, leaks, toxic, equipment integrity, environmental.
2.2Normal operating parameters of main line valves are described.
Rangemay include – normally open, normally closed, trip set points, fail position, commissioningbypass.
2.3Main line valves and actuator systems are operated in all control modes.
Rangetrip modes –automatic, manual, low pressure.
2.4A main line valve and actuator system are bypassed, isolated, and de-pressurised.
2.5Routine maintenance is carried out on a main line valve and actuator system.
Rangemay include – main line valve, bypass valve, actuators, piping components, control systems, trip devices, indication equipment, check valves, test equipment.
2.6Components and component parts are repaired or replaced, fitted, and adjusted.
Outcome 3
Place main line valves back into service after maintenance ina gas network.
Performance criteria
3.1Communication of the intention to place the main line valve back into service is carried out with appropriate personnel.
3.2Main line valve and ancillary equipment are placed back into service, and tested for integrity and correct operation.
3.3The bypass is closed.
3.4Documentation related to monitoring and maintaining the main line valves is completed and communication to all appropriate personnel is carried out.
Planned review date / 31 December 2022Status information and last date for assessment for superseded versions
Process / Version / Date / Last Date for AssessmentRegistration / 1 / 24 January 2002 / 31 December 2018
Review / 2 / 22 May 2009 / 31 December 2020
Review / 3 / 17 August 2017 / N/A
Revision / 4 / 30 August 2018 / N/A
Consent and Moderation Requirements (CMR) reference / 0014
This CMR can be accessed at
Comments on this unit standard
Please contact MITO New Zealand Incorporated you wish to suggest changes to the content of this unit standard.
MITO New Zealand IncorporatedSSB Code 101542 / New Zealand Qualifications Authority 2018