NFPA-99 Practice Exam

What type of nitrogen is recommended for purging during brazing?

1. Wet nitrogen

2. Compressed air

3. Oil-free, dry nitrogen

4. Industrial nitrogen

The correct answer is: Oil-free, dry nitrogen

The recommended type of nitrogen for purging during brazing is oil-free, dry nitrogen. Utilizing this specific type of nitrogen is essential because it effectively prevents oxidation of the metal surfaces being brazed. When moisture and oil are present, they can lead to undesirable reactions that compromise the quality of the brazed joint. Dry nitrogen ensures that there is no moisture content that could cause corrosion or weaken the integrity of the braze. Furthermore, oil-free nitrogen eliminates any risk of contaminants that might interfere with the brazing process, ensuring a clean environment that promotes strong, durable joints. Other options, such as wet nitrogen or compressed air, could introduce moisture or contaminants that are detrimental to the brazing process. Industrial nitrogen may not guarantee that it is oil-free and dry, thus it might not meet the specific purity requirements needed for high-quality brazing applications. This highlights the importance of using oil-free, dry nitrogen to achieve optimal results in brazing.