A safe manufacturing environment must include a healthy respect for the sometimes dangerous interactions between human and machinery. This is reflected in the fact that once simple devices such as safety-related valves have evolved and advanced to an amazing level of sophistication.
In pneumantic and hydraulic circuits where the primary concern is the removal of pneumatic or hydraulic energy from a device or system, additional dump or exhaust valves typically are incorporated specifically for this function. Just how critical this valve function is within the circuit, meaning the hazard level, is determined by a risk assessment of the machine.