Final answer:
The acceptable joints for PEX-AL-PEX are compression fittings and crimped fittings. Soldered joints are not suitable due to the material's inability to withstand high heat without damage. The correct answer is option 2) Compression fittings and 3) Crimped fittings
Step-by-step explanation:
The question pertains to the types of acceptable joints for PEX-AL-PEX, which is a type of multilayer composite piping used in various plumbing and heating applications. PEX-AL-PEX stands for cross-linked polyethylene-aluminum-cross-linked polyethylene, and it combines the benefits of plastic and metal pipes.
One of the advantages of PEX-AL-PEX is that it doesn't require soldering, a bonus in applications where a torch can't be used, but it also presents limitations on the methods that can be used for making connections.
The acceptable joints for PEX-AL-PEX are not soldered joints due to the presence of plastic components which can be damaged by the high heat. Instead, compression fittings and crimped fittings are commonly used with PEX-AL-PEX. Compression fittings rely on a nut and ferrule to compress the PEX-AL-PEX onto a fitting, creating a watertight seal. On the other hand, crimped fittings involve a metal or plastic ring that is compressed onto the pipe and the fitting using a special crimping tool, which again ensures a secure and leak-proof connection.