safety valve

American  

noun

1. a device that, when actuated by a gas or vapor pressure above a predetermined level, opens and allows the gas or vapor to escape until its pressure is reduced to a pressure equal to or below that of the predetermined level.

2. a harmless outlet for emotion, tension, etc.

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safety valve British  

noun

1. a valve in a pressure vessel that allows fluid to escape when a predetermined level of pressure has been reached

2. a harmless outlet for emotion, energy, tension, etc

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Etymology

Origin of safety valve

First recorded in 1805–15

Example Sentences

Dot plots and macro projections serve as a pressure safety valve where disagreement can be hashed out, without harming the consistency of the policy message.

From Barron's

The safety valves are drained, reserves are lower — and your money-market fund is the first domino.

From MarketWatch

The control room sent a message to the emergency response center requesting more batteries so they could open the safety valves and vent the extra steam.

From Literature

Banks have more regularly tapped a Fed lending facility designed as a safety valve that lets them exchange securities for reserves, offering another sign of reserves becoming less ample.

From The Wall Street Journal

In that incident, the board’s investigation found multiple safety failures, including a severely eroded safety valve that allowed flammable gases to dangerously seep into unwanted areas.

From Los Angeles Times