Theoretical volume of oxygen required for complete combustion of 1Nm3 of acetylene, in oxy-acetylene welding is ______________ Nm3 ? February 8, 2019 – by admin Theoretical volume of oxygen required for complete combustion of 1Nm3 of acetylene, in oxy-acetylene welding is ______________ Nm3 ? A. 0.5 B. 1 C. 1/3D. 2.5