Devices connected to openings in tanks are known as:

Devices connected to openings in tanks are referred to as container appurtenances. This terminology encompasses various fittings and accessories that are designed to facilitate the safe and efficient operations related to the storage and handling of materials within the tanks. Container appurtenances can include vents, gauging devices, and other fittings that are essential for maintaining the integrity and functionality of the tank.

This term is specifically used in the context of tanks because it not only describes the physical connections but also implies a relationship with the overall operation and safety of the tank system. The design and installation of these appurtenances are critical, as they must adhere to safety standards to prevent leaks or failures that could lead to environmental hazards or safety risks.

Other options, while related, do not accurately capture the specific nature of the devices that connect to tank openings. Safety devices may refer to equipment that ensures the safety of operations but do not specifically denote the connecting aspect. Connecting fittings suggest a broader category that may include various types of connections but does not focus solely on tank openings. Containment valves are particular devices that serve a specific purpose related to leak prevention but are not a term that encompasses all devices connected to tank openings. Therefore, container appurtenances is the most appropriate term in