AWS Welding Inspection and Testing Certification Practice Test

How long should acetylene cylinders that have been on their sides stand upright before use?

1. Two hours

2. Four hours

3. Six hours

4. Eight hours

The correct answer is: Four hours

Acetylene cylinders contain a solvent that absorbs acetylene gas. When these cylinders are positioned on their sides, the solvent can potentially enter the cylinder valve and mix with the acetylene gas. This can lead to unsafe conditions when the gas is used. To ensure that any solvent has returned to its proper position at the bottom of the cylinder, it is recommended that the cylinder stand upright for a period of four hours before use. This time frame allows for the solvent to settle back, minimizing the risk of solvent being released during gas use, which could create hazardous situations. While the other durations may seem reasonable, four hours is the standard safety guideline established by industry best practices to ensure safe handling and operation of acetylene cylinders. This guideline should be followed to maintain safety protocols for anyone using these gas cylinders in welding and cutting applications.