Gas Heat ESCO Practice Exam

When installing a copper elbow on an LP gas line, what substance should be used?

1. 5% silver solder

2. 10% silver solder

3. 15% silver solder

4. 20% silver solder

The correct answer is: 15% silver solder

The correct choice involves using a solder that contains sufficient silver content which is crucial for ensuring a strong and durable joint. In the case of LP gas lines, it's important to use a solder with a good balance of strength and ductility. A 15% silver solder is recommended for its high resistance to corrosion and ability to withstand the conditions found in LP gas systems. It provides a reliable seal that prevents leaks, ensuring the safety and integrity of the gas line. While lower percentages of silver solder may be adequate in some situations, they may not provide the same level of performance and safety required for gas applications. Utilizing a solder with too low a silver content might lead to weaker joints, which can be a significant safety hazard in gas installations. Higher contents of silver beyond 15% can be unnecessary and more expensive, without offering commensurate benefits for this specific application. Therefore, using 15% silver solder strikes a balance between performance and cost, making it the appropriate choice for installing a copper elbow on an LP gas line.