NFPA 99 requires tubing to be cut square using a sharp tubing cutter that shall be free from grease, oil or other lubricants not suitable for oxygen service. What sort of treatment is permitted of the tube ends before brazing?

• A. May be reamed
• B. May be deburred or rolled smooth
• C. May be re-cleaned
• D. None of the above

Answer: (B)

In oxygen service, tube ends must be prepared so the brazed joint can form a clean, smooth, burr-free surface. The permitted treatment is to deburr the ends or roll them smooth. Deburring removes sharp burrs from the cut edge, preventing damage to fittings and avoiding snagging or interference with the braze. Rolling smooth physically eliminates remaining burrs and creates a uniform surface without removing material excessively or introducing contaminants. This preparation minimizes debris and ensures a reliable, leak-free brazed joint.

Reaming is not the preferred method here because it can leave metal shavings that contaminate the oxygen system, and simply re-cleaning the ends doesn’t address the actual edge finish needed for brazing.