What is a safety valve also called? (List of names/terms)

In different contexts, safety valves have many other names. Some of these names emphasize their function, while others describe how they work.

Here are some common names:

1. Alternative names in industrial and mechanical fields

In factories or among maintenance workers, you might hear these names:
Relief Valve (PRV): Although there are subtle differences in professional terminology, many people use them interchangeably in everyday conversation, simply calling them "relief valves."
Pop-off Valve: This is a very descriptive name. Because many safety valves suddenly "pop" open with a crisp sound when the pressure is too high, they are called "pop-off valves."
Overflow Valve: In hydraulic systems or oil circuits, if there is excess pressure, the liquid is allowed to "flow away," and people usually call it an overflow valve.
Exhaust Valve / Vent Valve: If this valve is specifically used to release excess gas (such as on a boiler), workers often casually call it an exhaust valve.

2. Alternative names in legal and policy fields

In court or legal documents, "safety valve" also has specific names:
"Safety Valve" Provision: The legal community directly uses this term to refer to special rules that can bypass "mandatory minimum sentences."
Sentence Reduction Exemption: Many people colloquially refer to it as a "sentence reduction green light," meaning it gives first-time offenders who behave well and are non-violent a chance to serve less time in prison.
Mandatory Minimum Sentence Exception: This is a more formal term, emphasizing that it is an exception that breaks those "rigid rules."

3. Names in everyday life and metaphors

In daily life, this term is also often used as a metaphor:
Stress Reliever / Emotional Outlet: When we say something is a "safety valve" in life, it means a channel that allows us to release stress and prevent us from breaking down.
Safety Lock / Lifeline: Describing it as the last line of defense, invisible in normal times, but life-saving at critical moments.
Pressure Relief Valve: For example, "exercise is a pressure relief valve for stress," where the usage is exactly the same as a safety valve.