AWS Certified Welding Inspector — FundamentalsSafetyHard
A welding inspector is observing a welder preparing to cut a section of pipe that previously contained flammable liquids. Despite the pipe being drained, the inspector insists on additional safety measures before hot work begins. Which of the following is the most appropriate additional safety measure?
- ARequiring the welder to wear a full-face respirator.
- BPurging the pipe with an inert gas or water filling.
- CEstablishing a larger hot work perimeter.
- DIncreasing the size of the fire extinguisher nearby.
Show answer & explanationAnswer & explanation
Correct answer: B. Purging the pipe with an inert gas or water filling.
Pipes that contained flammable liquids can still have residual vapors. Purging with inert gas (like nitrogen) or completely filling with water displaces these vapors, eliminating the risk of explosion or fire during hot work.
Why the other options are wrong
- A. A respirator protects against fumes, but not against an internal explosion risk from flammable vapors.
- C. A larger perimeter is for external fire spread, not internal pipe explosion from residual flammables.
- D. While good practice, increasing extinguisher size does not address the internal hazard of flammable vapors.
Hot Work on Flammable Containers
Before performing hot work on containers that held flammable materials, they must be thoroughly cleaned, purged with inert gas, or filled with water to eliminate residual vapors and prevent explosion.
- Flammable liquids leave explosive vapors.
- Cleaning alone may not be sufficient.
- Inert gas purging or water filling are effective methods.
Memory trick: Purge the Pipe, Prevent the Pop!