AWS Welding Inspection and Testing Certification Practice Test

When is it acceptable to use oxygen instead of compressed air during welding?

1. Only when specialized equipment is used.

2. Only in emergencies and under strict conditions.

3. It is never acceptable.

4. When directed by a supervisor.

The correct answer is: Only in emergencies and under strict conditions.

Using oxygen instead of compressed air during welding is a practice that should be approached with great caution. The correct context for allowing the use of oxygen is primarily in emergencies and under strict conditions. This stems from the fact that oxygen supports combustion far more vigorously than ambient air, which consists largely of nitrogen. In emergency situations, such as when a quick response is needed to escalate a process safely or to clear an obstruction, oxygen can sometimes be used to accelerate the cutting or welding process. However, it is vital that this is done under strict conditions to avoid any unintended fires or explosions. This implies a controlled environment with the appropriate safety protocols in place, training in proper usage, and the right type of applications where the benefits outweigh the risks. Using oxygen outside of emergencies or in non-regulated conditions is potentially hazardous, leading to uncontrollable fires or explosions due to the enhanced combustion rates. Therefore, while other choices suggest scenarios like using specialized equipment, never using it, or following a supervisor's directive, the nuances of safe and effective welding operations emphasize that if oxygen is used, it must be in a crisis and with established safety procedures in mind.