Final answer:
The essential component required on every air tank is a draincock. The draincock is crucial for the removal of condensation and contaminants, maintaining the system's integrity.
Step-by-step explanation:
The component that is a requirement on every air tank is a draincock.
A draincock is used to remove any condensation and contaminants that have settled at the bottom of the air tank. This is essential to maintaining the air system's integrity and preventing corrosion or damage to the tank and other components supplied with air. While safety valves, pressure protection valves, and air dryers are significant components for the overall safety and efficiency of pneumatic systems, the draincock is often the only component that every air tank must have to ensure proper maintenance and operation.