MCC-NH Gas Fitters Practice Exam

Why are threaded joints generally limited to certain pipe sizes?

1. To prevent leaks and enhance safety

2. To save manufacturing costs

3. Because they are less durable

4. Due to aesthetic concerns

The correct answer is: To prevent leaks and enhance safety

Threaded joints are generally limited to specific pipe sizes primarily to prevent leaks and enhance safety. As pipe sizes increase, the potential for improper threading and alignment issues also grows, which can lead to compromised joints and increased risks of failure under pressure. Smaller pipes are more manageable for threading, and the tight tolerance required for a secure joint is more feasible with these sizes. The integrity of larger threaded joints can be difficult to maintain, making them less reliable for high-pressure applications. In larger diameters, welding or flanging becomes more common as these methods provide a more robust and leak-proof connection. Therefore, the choice to limit threaded joints to certain sizes is fundamentally tied to ensuring safety and reliability in gas fittings. Concerns such as manufacturing costs, durability, or aesthetic considerations are secondary to the critical focus on maintaining a secure and safe system that prevents leaks.