Unodourised Gas Risk Assessment
Safety within the Queensland gas industry is regulated under the Petroleum and Gas (Production and Safety) Act 2004 (Act) and the Petroleum and Gas (Production and Safety) Regulation 2004 (Regulation).
Supplying fuel gas to a consumer, section 628 of the Act requires that the gas has the prescribed odour or where the supply is to an industrial installation, the installation must have appropriate gas detectors and shut-down system, and a risk analysis that has been carried out by an appropriately qualified person showing the supply is safe.
The Act: s628 Odour requirements-
(1) A person must not supply fuel gas to a consumer unless—
(a) the gas has the prescribed odour; or
(b) the supply is to an industrial installation with appropriate gas detectors and shut-down systems and a risk analysis has been carried out by an appropriately qualified person showing the supply is safe.
Maximum penalty—500 penalty units.
Note— If a corporation commits an offence against this provision, an executive officer of the corporation may be taken, under section 814A, to have also committed the offence.
(2) The fact that a person is supplying a consumer with fuel gas under subsection (1)(b) does not limit an inspector’s power to give the person a dangerous situation direction that requires the gas to have the prescribed odour.
(3) In this section—
appropriately qualified person means a person who—
(a) is independent of the person supplying the fuel gas; and
(b) the chief inspector considers—
(i) is appropriately qualified; and
(ii) has access to information to carry out the risk analysis.
Commonly a prescribed concentration of odourant is added to fuel gas, providing a distinctive and unpleasant odour to ensure its presence is readily detectable to a person without the use of gas detectors. Where unodourised gas is present there is an elevated level of risk, and alternative or additional controls may be required. Any risk is further elevated where the gas is supplied into a plant room, where people are required to access plant and equipment as part of their duties.
Bluefield’s Technical Report and Risk Assessment addresses the risks associated with unodourised gas and meets the requirements of the ACT to ensure the risks are as low as reasonably practical for both people and plant.
The person undertaking the assessment should consider:
1 – The use of unodourised gas would normally not be accepted where equipment is located in an enclosure unprotected by an interlocked forced ventilation and equipment shutdown facility.
2 – Gas detection and shut down systems are to be appropriately designed, installed, commissioned and operational prior to the introduction of unodourised gas to pipe work, fittings and gas devices on the site.
3 – Where pipes, fittings containing unodorised gas and gas devices are enclosed and personal are required to access the plant the following applies:
(a) – Forced ventilation through the enclosure is required with proof of ventilation airflow required prior to permitting an unodorised gas supply to the device.
(b) – Classification of Hazardous Areas (AS/NZS 60079.10.1:2009).
(c) – Activation of the gas alarm system at any level above 20% of the LEL. Activation of the alarm/monitoring system at 40% LEL shall cause the gas supply to automatically shut down, depressurise all enclosed pipe work and equipment and initiate requirements for evacuation procedures.
4 – Induction and training of relevant staff shall ensure that they are fully cognisant of the dangers of unodourised gas.
5 – Safety warning signs shall be placed at appropriate locations to warn of the presence of unodourised gas.
6 – Written procedures for commissioning, maintenance and ongoing operation of the gas supply system must reflect the unodourised nature of the gas and be made available to all relevant staff.
7 – Installer, commissioners and or maintenance personnel shall have suitable equipment and the necessary training to ensure safety in dealing with the unodourised nature of the gas during the construction, commissioning, operational and maintenance phases of the project.
8 – Maintenance, testing and recording procedures shall be established to ensure the functional integrity of the gas detection system.
9 – A scheduled system and record of manual leak surveys is to be followed, discovered leaks shall be repaired immediately and a ‘close out’ audit process implemented.