Which two equipment items are generally not required to be cleaned for oxygen service?

The selection of BC (buoyancy compensator) and dry suit valves as not generally requiring cleaning for oxygen service is based on the understanding of their use and the role they play in a diving setup. These components typically do not come into direct contact with high-pressure oxygen in the same manner as regulators, tanks, hoses, and masks. Regulators and tanks, which directly handle large volumes of oxygen, require thorough cleaning to prevent contamination that could lead to fire hazards. Hoses and masks also require special attention since they are part of the direct breath pathway and deal with high concentrations of oxygen.

In contrast, BC and dry suit valves primarily manage buoyancy and water ingress, respectively, and are typically not exposed to the same level of risk concerning oxygen service. This allows them to be maintained with standard cleaning practices rather than the stringent requirements set for components directly involved in oxygen delivery. Understanding the specific application and interaction of diving gear with oxygen service is crucial for safe diving operations.