An existing gas line can sometimes be extended or branched, but a licensed gasfitter must confirm the complete system can carry the added demand.
A nearby pipe or matching-looking fitting does not prove that a branch is suitable. The gas source, regulator and upstream shared sections also affect the decision.
What must be checked before adding a branch?
The assessment starts with the proposed appliance and follows its demand back through every part of the affected supply.
- Fuel and supply: Natural gas, metered LPG and cylinder or tank LPG have different supply conditions.
- Appliance demand: Current product information identifies the approved fuel, required inlet conditions and maximum gas use.
- Shared load: Upstream sections may supply several appliances, so the revised combined demand matters.
- Supply capacity: The meter or LPG storage, vaporisation capacity, regulator and available pressure may limit the alteration.
- Pipe route: Material, internal bore, developed length, fittings, branches and installation conditions affect capacity.
Business Queensland requires an installer to confirm adequate supply before adding an appliance. Its guidance includes meter, LPG supply and pipe-sizing checks where applicable.
This broader assessment also applies when changing an electric cooktop to gas. The appliance location alone does not determine whether the existing line has capacity.
How does a gasfitter determine pipe size?
Visible outside diameter is only one observation. It does not establish the pipe's internal bore, material, usable flow or compatibility with the existing jointing system.
The gasfitter considers available pressure, allowable pressure loss, gas properties, appliance demand and the developed route. Each shared section is assessed for the load it carries.
Proprietary multilayer systems can have different internal bores despite similar outside markings. Queensland piping guidance also warns that brands, fittings and jointing methods are not interchangeable.
Online sizing tables, burner count and appliance width cannot safely select a pipe for an unknown installation. Do not cut, tee, cap, join or test gas pipework yourself.
When is more than a new branch needed?
- Existing branch: It may be used when the source, regulator and every affected pipe section have verified capacity.
- Pipe upgrade: Shared sections may need changing when they cannot carry the revised load under the applicable requirements.
- Supply change: The meter, LPG storage, vaporisation capacity or regulator arrangement may need supplier involvement or alteration.
Concealed routes, undocumented alterations, corrosion or incompatible materials can change the expected scope. See how professionals locate concealed gas lines safely before planning access.
What shapes the quote?
A responsible quote follows the capacity and site assessment. It should explain the work needed rather than assume every extension follows one standard scope.
- the appliance, fuel configuration and revised demand
- the existing supply, regulator and shared pipe capacity
- the route, access, materials, fittings and protection required
- penetrations, cabinetry, ventilation and building coordination
- existing defects or non-compliant work found during assessment
- testing, commissioning, compliance records and surface reinstatement.
Ask which access and reinstatement tasks are included and whether another trade is required. Any supply or upstream upgrade should be explained before the changed scope is approved.
What Queensland gas-work rules apply?
Extending consumer gas piping is regulated gas-system alteration work. The person performing and certifying each stage must hold the appropriate Queensland licence or authorisation.
Completed alteration work must be tested and documented under the current process. This guide explains Queensland gas compliance certificates without assuming every installation receives a physical plate.
If you smell gas, stop treating the job as a planned extension. Avoid flames and electrical switching, leave the affected area and follow current Queensland gas-safety advice.
For a planned branch or capacity check, arrange an assessment through the gas fitter service. Provide the proposed appliance details and any existing compliance records without disturbing the pipework.