What component must be used to close each outlet after installation?

To ensure the integrity of the gas system after installation, it is essential to use a cap or plug to close each outlet. This is crucial for several reasons. First, using a cap or plug effectively seals the outlet, preventing gas leaks that could result from unsealed openings in a gas system. Additionally, it protects the outlet from contaminants such as dirt, debris, and moisture, which can adversely affect the performance and safety of the gas installation.

A cap or plug is designed for this specific purpose and meets the standards set by safety regulations, providing a reliable closure that maintains the system's integrity. In comparison, while sealants can be used in certain applications, they are not typically the primary means for sealing gas outlet fittings. A cover may not provide the secure closure needed for safety and might not be suitable for gas applications. A cap only option does not convey that a plug would also be an acceptable method of closure, which is integral to understanding the requirements. Thus, the use of a cap or plug is the recommended practice for closing outlet ends in gas installations.