__________________ is the operating pressure of an acetylene regulator.

The operating pressure of an acetylene regulator is typically set to a safe range to ensure proper functioning and safety during use. Acetylene is a highly volatile gas that requires careful handling, and the pressure range of 0 to 15 psig is designed to provide an effective operating level while minimizing the risk of flashback or other hazards associated with higher pressures.

When acetylene is used with welding equipment, maintaining the pressure within this range allows for optimal combustion and effective welding without excessive turbulence or instability in the flame. Additionally, exceeding this pressure could compromise the safety of the equipment and the operator, making adherence to the prescribed limits crucial.

The other ranges, while they may apply to different gases or applications, are not appropriate for acetylene. Utilizing the correct pressure ensures the integrity of the system and promotes safe working conditions.