Acetylene manifold pressures should not exceed how many pounds per square inch?

• A. 15 psi
• B. 10 psi
• C. 20 psi
• D. 25 psi

Answer: (A)

The maximum acceptable pressure for an acetylene manifold is 15 psi. Acetylene is chemically unstable at higher pressures, and keeping the manifold pressure to 15 psi or less helps prevent decomposition and potential flare-ups or explosions. In practice, the torch mix is created with regulated, low acetylene pressure, while oxygen carries most of the energy at higher pressures. Choosing a limit of 15 psi ensures compatibility with standard regulators, hoses, and safety practices. Pressures like 20 psi or 25 psi exceed the safe limit, posing serious risk, while 10 psi is below the maximum and may still be used, but it isn’t the established upper safety bound.