Final answer:
The correct answer is Schedule 80 (Option B). Schedule 80 PVC and CPVC pipes have thicker walls compared to other schedules, making them suitable for threading since the thicker walls can handle the process and maintain a strong and reliable connection.
Step-by-step explanation:
The student is asking about the types of PVC (polyvinyl chloride) and CPVC (chlorinated polyvinyl chloride) pipes that can be threaded. In the context of this question and the information provided, it's important to consider that these different types of pipes are categorized according to “schedules”, which relate to the wall thickness of the pipes. When we talk about threading pipes, we refer to the process of cutting grooves into the end of the pipe so that it can connect with other pipes using threads.
Based on industry standards, Schedule 80 is the type of PVC and CPVC pipe that is durable enough to be threaded. Pipes with thinner walls, like Schedule 40, are not suitable for threading because they may not have adequate strength to maintain the integrity of the connection. Thicker walled pipes, namely Schedule 80, are used in applications where higher pressures are present and therefore, they are designed to withstand the process of threading.
To answer the student's question, the only schedule of PVC and CPVC pipe that can be threaded is Schedule 80 (Option B). The reference to the 4-inch, 8-inch, and 16-inch pipes, as well as Table 7.15 Comparing Pipes: Economies of Scale in the Chemical Industry, may relate to the economics of using different sizes and schedules of pipe, but specifically, for the purpose of threading, Schedule 80 is the suitable choice. It offers a good balance between economic efficiency and the necessary strength for industrial applications where the piping must be able to be threaded and handle higher internal pressures.