General Assist Safety Reference
Oxy / Acetylene Equipment Safety FAQ
Safe transport, storage, operation and maintenance of portable oxy-fuel equipment
Practical guidance for oxy-acetylene brazing, welding, heating and cutting equipment
This guide summarises key safety controls for portable oxy-fuel gas equipment, including oxygen, acetylene and LP Gas systems. It is based on WorkSafe Victoria guidance and references Australian Standards including AS 4332, AS 4839, AS 4603, AS 1336 and AS 1674.1.
Safety notice: Oxy-fuel equipment must only be used and maintained by trained, competent personnel. Always follow current legislation, the equipment manufacturer’s instructions and your organisation’s safe work procedures. Isolate defective equipment immediately.
1. Transporting cylinders
How should cylinders be transported on an open vehicle or trailer?
| 1 | Remove regulators before loading or transporting cylinders. |
| 2 | Close cylinder valves and fit valve-protection guards or caps where available. |
| 3 | Secure cylinders upright so they cannot tip, fall or move during transport. |
| 4 | Secure loose tools and materials that could strike or rupture a cylinder. |
| 5 | Carry suitable firefighting equipment and park in the shade where practicable. |
Do not: smoke, use naked flames or non-flameproof electrical equipment near a vehicle carrying fuel gases. Do not cover an open vehicle or trailer with a tarpaulin while carrying fuel-gas cylinders.
Can cylinders be transported in a van or enclosed compartment?
Open vehicles or trailers are preferred. Where cylinders must be carried in a van, fuel-gas cylinders must be housed in a separate airtight compartment that is permanently vented to the outside. Close the valves and leak-test the cylinders with soapy water before loading.
Never operate cylinders while they remain inside a van. Remove them to an open-air location before use.
2. Storing cylinders
What are the basic storage requirements?
- Use a well-ventilated area, preferably outdoors.
- Provide weather protection without restricting airflow.
- Secure all cylinders upright and treat empty cylinders as if they are full.
- Keep cylinders away from ignition sources, heat and flammable materials.
- Store full and empty cylinders separately.
- Protect cylinders from direct sunlight and vehicle or forklift impact.
- Restrict access to authorised personnel.
- Do not repaint cylinders, obscure labels or use cylinders that cannot be clearly identified.
How far apart must oxygen and fuel-gas cylinders be stored?
| Storage method | Requirement |
|---|---|
| Separation distance | Keep oxygen cylinders at least 3 metres from fuel-gas cylinders. |
| Fire-rated barrier | Use a firewall with a minimum 4-hour fire rating where 3-metre separation cannot be maintained. |
Required signage: Display “Danger: No Smoking, No Ignition Sources” and “Restricted Area, Authorised Personnel Only” at the storage area.
What quantities are classed as minor storage?
| Gas classification | Maximum aggregate water capacity |
|---|---|
| Class 2.1 flammable gas, including LPG and acetylene | 500 litres |
| Class 2.2 non-flammable gas, including nitrogen and argon | 2,000 litres |
| Class 2.2 with Class 5.1 subsidiary risk, including oxygen | 1,000 litres |
| Mixed gases, with no individual class exceeding its limit | 2,000 litres |
Where quantities exceed minor-storage limits, use a purpose-designed store that meets the applicable construction, ventilation, fire-protection, electrical and placarding requirements. Unmodified shipping containers are not suitable cylinder stores.
3. Use, care and handling
| Question | Safe practice |
|---|---|
| How should cylinders be moved? | Use suitable mechanical lifting or transport equipment. Do not roll cylinders horizontally, drop them or use the valve as a lifting point. |
| Can cylinders be used horizontally? | No. Cylinders must be upright and secured during use. |
| What if an acetylene cylinder was laid down? | Stand it upright for at least 12 hours before use so the acetone can redistribute. |
| Can equipment be used in poorly ventilated areas? | Provide forced ventilation where practicable, keep cylinders outside the confined or poorly ventilated area and leak-test the equipment at working pressure before use. |
| Can worm-drive or jubilee clips be used? | No. They may loosen or cut into the hose and create a gas leak. |
4. Flashback arrestors
A flashback is the burning back of a flame into the blowpipe or the ignition of an explosive mixture within a gas line. Repeated flashbacks can damage the internal hose lining and lead to equipment failure.
Common causes of flashback
- Incorrect operating pressure.
- A blocked welding or cutting tip.
- Worn or malfunctioning torch valves.
- Back-feeding from a higher-pressure line into a lower-pressure line.
- Acetylene flow exceeding the cylinder’s safe withdrawal rate.
- Incorrectly selected equipment or inadequate flow capacity.
Use flashback arrestors that comply with AS 4603 and have sufficient flow capacity for the application. Heating work may require high-flow arrestors. Incorrect arrestors can restrict flow and increase flame instability.
Where should flashback arrestors be fitted?
| Hose length | Recommended installation |
|---|---|
| 3 metres or less | Fit an arrestor to each gas line at the regulator outlet. |
| More than 3 metres | Fit two arrestors to each gas line: one at the regulator outlet and one at the blowpipe or torch connection. |
Follow the equipment supplier’s instructions. The regulator-end device should incorporate a flame arrestor, non-return valve and temperature-actuated cut-off valve. The torch-end device should incorporate a flame arrestor and non-return valve.
5. Fire protection and leak checks
- Keep a suitable dry-chemical or CO2 extinguisher attached to the cylinder trolley or immediately accessible.
- Maintain an emergency response plan for gas leaks, fire and explosion.
- Inspect hoses, regulators and connections before use.
- Leak-test connections with an approved leak-detection solution or soapy water.
- Never use a flame to test for gas leaks.
- Stop work immediately if gas is detected or equipment is damaged.
6. Inspection and maintenance
Maintenance must be completed by a technically competent person with appropriate knowledge and experience of oxy-fuel systems. Inspection should cover regulators, integral protective devices, flashback arrestors, hose assemblies, blowpipes, mixers and attachments.
| Frequency | Minimum activity |
|---|---|
| Before each use / daily | Complete a visual inspection while connecting equipment. Withdraw damaged equipment from service and conduct required leak checks. |
| Weekly | Check suitability for continued use, including threads, sealing surfaces, damage and oil or grease contamination. |
| Every 6 months | Function-test internal components and inspect hose assemblies for cracking, wear and deterioration. |
| Every 12 months | Have flashback arrestors tested for through-flow, non-return operation and leak tightness using approved purpose-built test equipment. |
| As required | Refurbish or replace faulty components in accordance with manufacturer or supplier instructions. Function-test and leak-test repaired components before return to service. |
Keep inspection and maintenance records. Inspection tags or stickers may be attached to equipment to show its current test status. Harsh conditions or rough handling may require more frequent inspections.
7. Personal protective equipment
| PPE | Requirement |
|---|---|
| Eye protection | Use compliant goggles or glasses suitable for the task. Shade 3 to 7 filters are commonly used for gas welding, cutting, resistance welding and brazing. Sunglasses are not suitable. |
| Clothing | Wear clean, well-fitting heavy cotton or wool clothing that is free from oil and grease. |
| Hands and feet | Wear leather gloves and leather safety boots to protect against sparks, hot slag and falling objects. |
| Prohibited clothing | Do not wear synthetic or readily flammable clothing, including nylon garments and some high-visibility polyester vests. |
8. Referenced standards
| AS 4332 | Storage and handling of gases in cylinders |
| AS 4839 | Safe use of portable and mobile oxy-fuel gas systems |
| AS 4603 | Flashback arresters and safety devices |
| AS 1336 | Occupational eye protection |
| AS 1674.1 | Safety in welding and allied processes |
Key safety principles
- Transport and store cylinders upright, secured and ventilated.
- Keep oxygen and fuel gases correctly segregated.
- Use compliant flashback arrestors, hoses and PPE.
- Inspect equipment routinely and maintain formal records.
- Control ignition sources, ventilation and fire-response arrangements.
Source guidance: WorkSafe Victoria, Frequently Asked Questions About Portable Oxy-Fuel Gas Equipment, Version 1, March 2007. Confirm current legal and standards requirements before relying on this article for a specific workplace or application.