Temporary gas supply for hot work in plant areas
Hot work in an operating plant brings together ignition sources, hot surfaces, toxic products and a fuel that can spread quickly if it escapes. Welding, cutting and grinding can also ignite residue in nearby equipment, so the gas arrangement must be designed for the whole work area rather than only the torch.
A temporary gas supply for hot work is usually LPG delivered from one or more cylinders, although some sites use a temporary piped natural-gas connection. The correct arrangement depends on demand, duration, work location, available utilities and the hazards created by cylinder handling. It should be engineered, installed and commissioned by competent people, then managed through the site permit.
Australian worksites often call the container a gas bottle, and a formal job hazard analysis or JSA may sit beneath the hot work permit. The permit does not replace the design, isolation or gas-supply checks. At major industrial sites in the Pilbara, Gladstone, the Hunter Valley or Melbourne’s western suburbs, contractors, operators and gas suppliers may all control part of the arrangement, making clear ownership essential.
Define the work and the supply arrangement
Start by defining the work: hot-work locations, torch types, connected appliances, simultaneous trades, expected flow and hours of use, and whether the job continues through a shift change. Map emergency exits, process connections and adjacent activities. Check whether an approved permanent fuel-gas system already serves the area; if so, use it rather than creating a temporary supply without a sound engineering reason.
The design must comply with the site’s WHS system and the applicable law in the relevant state or territory. Use Safe Work Australia model codes where adopted, current AS/NZS standards such as AS/NZS 2980 for gas welding and allied processes, relevant LPG supply and cylinder requirements, and the manufacturer’s instructions. Electrical temporary power also needs local compliance. If gas piping or a connection to utility infrastructure is involved, obtain the approvals and qualified trades required by the local authority and gas utility.
Assign named roles before equipment arrives: the person authorising the work, the hot-work supervisor, the gas-supply competent person, the welder or operator, and an independent fire watch. Each role should have authority to stop work. For confined-space hot work, remember that a hot work permit is separate from entry into a vessel, pit or other confined space; both controls must be in place before work begins.
Control hazards before connection
A gas risk assessment should cover the quantity of fuel, release points, ventilation, ignition sources, travel paths, hot surfaces and possible accumulation. LPG is heavier than air, so low-level accumulation and poor drainage matter. Use fixed or portable gas detection with suitable alarm settings, and establish exclusion distances and access routes that will not be obstructed. Detection supplements good separation, ventilation and cylinder control; it does not justify placing cylinders inside the work area.
Position cylinders outdoors in a secure, ventilated area, normally outside any classified hazardous zone and clear of drains, pits, doors, traffic and ignition sources. Keep them upright, restrained and protected from heat, direct sunlight, damage and unauthorised access. A truck or trailer-mounted gas-bottle rack can support remote work, but it still needs separation from hot work, a safe changeover method and controls for the route between storage and the workface. Extreme heat, dust and wind common in northern and western Australia also affect cylinder condition, visibility and torch stability.
Prepare the emergency controls before commissioning: an accessible emergency isolation, suitable firefighting equipment, first aid, gas alarms, a communication method and the site emergency plan. The fire watch should remain dedicated to the task, know the escape routes and have suitable extinguishing equipment; their exact duties and duration must follow the permit and site rules. Never use a flame to find a gas leak, and do not treat an oxygen-enriched atmosphere as safe merely because the fuel-gas supply is under control.
| Supply arrangement | Where it fits | Operational strengths | Main controls |
|---|---|---|---|
| Single gas bottle | Low-volume, short-duration work with one operator | Simple arrangement and fewer exposed connections | Smallest practical cylinder, upright restraint, accessible valve, flash protection and suitable hose |
| Temporary LPG manifold | Several operators or a shift-long job | Greater capacity, controlled distribution and easier stock management | Approved outdoor manifold, cylinder restraints, emergency isolation, gas monitoring and competent cylinder changes |
| Temporary piped natural-gas connection | High demand or multiple users where suitable infrastructure exists | Stable pressure without routine cylinder handling | Design approval, pressure testing, isolation, purge or commissioning controls, utility involvement and hazardous-area assessment |
| Existing fixed fuel-gas system | Work within an area already served by an approved installation | Proven system with established controls | Formal permit, operating isolation, leak testing, gas detection and continuity of the site’s safety management system |
Install and commission the system
Install the system from an approved plan. Use cylinders, manifold, regulators, hoses and fittings rated for the fuel, pressure and duty. Fit the non-return and flashback protection required by the relevant standard and equipment instructions, and confirm that relief devices and isolation points are accessible. Keep hose runs short, supported and protected from vehicles, pedestrians, sharp edges, heat and damage. Use dedicated, inspected equipment; never improvise connections or mix incompatible hose and fittings.
Protect temporary electrical equipment used for grinders, extraction or lighting with the required Australian electrical controls, including suitable RCD/GFCI protection where applicable. Keep leads out of walkways and away from hot surfaces. Before entering a hazardous area, verify that portable electrical equipment is approved for that classification and environment. Test and tag leads and RCD/GFCI devices under the site’s inspection regime, and isolate damaged items rather than relying on visual checks alone.
Commissioning should be a documented competent-person task. Check cylinder identification, valve condition, regulator settings, hose condition, fittings and isolation sequence, then test the detection and emergency systems. Verify burner operation and flame stability in a safe location before taking the torch into the work area. A leak test must use an approved method and equipment; a naked flame is never acceptable. Record the results, cylinder quantities, test equipment details and any defects before the permit is accepted.
Run the work and respond to change
At the toolbox talk, show the crew where cylinders, isolation points, gas detectors, extinguishers and exits are located. Confirm the exclusion zone, communication signals, cylinder changeover, simultaneous-work controls and stop-work triggers. Gas monitoring must remain active for the duration specified by the risk assessment. Portable detectors should be bump-tested and function-tested before use, with calibration records current and alarms set according to the site plan.
Keep the work area controlled while the torch is operating. Separate incompatible activities, protect or isolate nearby piping that may contain residual hydrocarbons, and prevent sparks from reaching equipment that cannot be cleaned or inspected. Maintain good ventilation without directing combustion products towards the welder or other crews. Strong crosswinds at exposed Australian sites can destabilise a flame or carry it towards adjacent work, while enclosed areas can accumulate gas and smoke. Stop and reassess whenever wind, ventilation or gas readings change.
Have a clear response for leaks, alarms, fire, injury and cylinder depletion. If a safe shutdown is possible, close the upstream supply without approaching a leak or entering an unsafe area. Raise the emergency alarm and follow the site plan. Never leave a hot cylinder on the manifold or change it while under pressure; shut down, depressurise and allow equipment to cool in accordance with the procedure. Review consumption and stock before a long shift so that a cylinder change does not create a rushed or improvised connection.
Build competence and maintain assurance
Competence should cover more than operating a torch. Practical training needs to include fuel properties, cylinder identification and handling, regulator and flashback equipment, hose inspection, gas testing, permits, fire-watch duties, emergency shutdown and task-specific risk assessment. Local rules should also be refreshed through a site-specific toolbox talk. For welders, operators and permit holders, the same knowledge must be demonstrated at the actual workplace, not only acknowledged in a classroom.
Maintain a record pack containing the design, risk assessment, JSA, hot work permit, manufacturer data, safety data sheets, cylinder inventory, equipment register, inspection and test results, detector calibration, training records and emergency arrangements. Shift handover should state the number of cylinders in service, temporary connections in use and any outstanding defects or restrictions. A named owner should audit the arrangement and close corrective actions before the next shift.
HCF CATCH, the UK-based industrial training centre, supports this kind of practical development through industrial gas, process, engineering, electrical and health-and-safety training in a realistic live-process-plant environment. Its courses, apprenticeships and safety qualifications help teams connect the technical system with safe human behaviour, while facility tours and room hire support employer briefings, meetings and training events. For Australian operations, that practical standard should be paired with the local legislation, standards, permit system and emergency arrangements of the site.
A controlled temporary gas supply is built through deliberate design, competent installation, verified commissioning and active supervision on every shift. It also depends on clear interfaces between the plant operator, welding contractor, fire watch and gas supplier, with anyone authorised to stop the work when conditions change.
Organisations that want to strengthen these controls can contact HCF CATCH to discuss industrial gas and health-and-safety training, practical facility tours or suitable event space for their team. Build the competence, equipment checks and emergency response into the job before the first arc is struck.