Gas Welding Setup — Acetylene Pressure at the Torch Select the typical acetylene pressure range desired at the welding torch for oxy-acetylene gas welding (shop practice values).

Introduction / Context:
Correct gas pressures at the torch ensure a stable neutral, carburising, or oxidising flame without dangerous flashbacks or excessive turbulence. Acetylene, in particular, is used at relatively low delivery pressures.

Given Data / Assumptions:

• Process: oxy-acetylene welding (not cutting).
• Location: torch (downstream of regulators), typical shop tip sizes.
• Units: kN/m2 (approximately kPa) ranges for acetylene.

Concept / Approach:
Acetylene is commonly delivered at low pressures to the torch, often below about 100 kN/m2 for welding applications. Excessive pressure increases the risk of backfire and can disturb flame stability. Oxygen pressures are generally higher than acetylene for a given tip size and job.

Step-by-Step Solution:
Recall safe/typical torch pressures: acetylene generally tens of kN/m2, not hundreds.Match the given ranges to this expectation.Identify 7 to 103 kN/m2 as the practical shop range for many welding tips.Select option consistent with safe operation.

Verification / Alternative check:
Manufacturer tip charts specify low acetylene pressures, rising only modestly with larger tips.

Why Other Options Are Wrong:
Higher ranges correspond to oxygen or specialized cutting conditions, not welding acetylene at the torch.

Common Pitfalls:
Confusing regulator cylinder pressures with torch delivery pressures.

Final Answer:
7 to 103 kN/m2