Safety & Compliance · SOP
Oxy Acetylene Torch Setup, Leak Testing & Shutdown
This procedure covers the safe connection of gas cylinders, regulator attachment, leak testing with soap solution, torch lighting and adjustment, and the required shutdown sequence for oxy‑acetylene equipment.
Estimated Time
15 min
Difficulty
Intermediate
Regulation
CSA W117.2
Version
1.0
Purpose
To establish a standardized, incident‑free method for setting up an oxy‑acetylene torch system, performing leak tests on all gas‑carrying connections, and executing a complete shutdown. Adherence to this procedure eliminates the risk of flashback, regulator rupture, and uncontrolled gas leaks.
Scope
This SOP applies to all personnel authorized to use oxy‑acetylene cutting, welding, or heating equipment in workshop and field operations. It covers the complete workflow from cylinder handling through to safe shutdown. Operations involving alternate fuel gases (propylene, propane) or high‑pressure oxygen follow the same principles but require separate manufacturer instructions.
Safety Precautions
- Wear welding goggles with proper shade number (#5 or higher for cutting), gauntlet gloves, and fire‑resistant clothing. Do not roll up sleeves or wear synthetic fabrics.
- Keep a fully charged ABC fire extinguisher within 3 m of the work station. Remove all combustible materials from the immediate area.
- All cylinder valves must be closed and regulators bled down before performing any maintenance or storing the cart.
- Never use a flame to check for gas leaks. Use only a commercial leak‑detection solution or soapy water.
- Install flashback arrestors on both regulator outlets (if not integrated). Inspect monthly.
Required Tools & Materials
- Oxygen cylinder (full, green valve, CGA 540)
- Acetylene cylinder (full, red valve, CGA 300)
- Oxygen regulator (right‑hand threads) & acetylene regulator (left‑hand threads)
- Twin‑hose set (oxygen: green, acetylene: red) with flashback arrestors
- Torch handle, cutting attachment or welding tip
- Friction lighter (striker) – no matches or lighters
- Leak detection solution (soapy water in spray bottle)
- Adjustable wrench (8″)
- Cylinder cart with chains
- PPE: shade‑5 welding goggles, gauntlet gloves, FR workwear, steel‑toed boots
Procedure: Step-by-Step
1
Inspect work area and don PPE – Ensure ventilation is adequate, no flammable materials within 5 m, and a fire extinguisher is accessible. Put on welding goggles (shade 5+), gauntlet gloves, and fire‑resistant clothing.
2
Secure cylinders on cart – Chain both oxygen and acetylene cylinders upright to a dedicated cart. Verify cylinder valves are closed. Turn the oxygen valve gently counter‑clockwise to confirm it’s closed, then tighten finger‑tight.
3
Inspect regulators and hoses – Check regulator bodies for cracks, damaged gauges, or missing filters. Inspect hoses for cuts, abrasions, and brittleness. Replace any component that shows wear. Confirm flashback arrestors are present and dated.
4
Attach regulators to cylinders – Connect oxygen regulator (right‑hand thread, smooth nut) to oxygen valve; tighten with wrench. Connect acetylene regulator (left‑hand thread, notched nut) to acetylene valve; tighten with wrench. Do not use PTFE tape – seals are metal‑to‑metal.
5
Open cylinder valves and check pressures – Stand to one side. Open oxygen valve fully (all the way) to seal the valve stem. Open acetylene valve no more than ¼‑½ turn. Read high‑pressure gauges: oxygen ~13.8 MPa (2000 psi), acetylene ~1.7 MPa (250 psi). Close valves again for now.
6
Leak test all connections – Re‑open cylinder valves. Spray leak detection solution on every fitting: cylinder‑to‑regulator, regulator‑to‑hose, hose‑to‑torch, and torch tip. Bubbles indicate a leak – tighten or replace components. Do not proceed until no bubbles appear.
7
Purge hoses – With torch valves closed, open the oxygen regulator adjusting screw slightly (approx. 0.2 MPa) and open the oxygen torch valve for 2‑3 seconds to purge the hose, then close. Repeat for acetylene. This removes air and any mixed gas.
8
Light and adjust the torch flame – Open the acetylene torch valve ¼ turn. Hold the friction lighter to the tip and strike to ignite. Adjust acetylene valve until flame stops smoking. Slowly open oxygen torch valve to obtain a neutral flame (sharp inner cone, no excess feather).
9
Perform work, monitor for leaks – Keep hoses away from hot metal and sharp edges. Periodically sniff for acetylene odour and watch for soap‑bubble reappearance. If a leak develops, immediately close both cylinder valves.
10
Shut down safely – (a) Close the acetylene cylinder valve. (b) Close the oxygen cylinder valve. (c) Open both torch valves briefly to release residual pressure, then close them. (d) Back out regulator adjusting screws until finger‑loose. (e) Close cylinder valve caps (if equipped). Store hoses coiled on the cart. Never leave pressure on regulators overnight.