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 • Dec. 12, 2025

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 • Oct. 28, 2025

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 • Oct. 4, 2025

The garment sector, which employs 750,000 people, has been a crucial social safety valve, giving steady incomes to Cambodia's poorest.

From BBC • Apr. 9, 2025

Others use an espresso pot, which uses steam to drive water up through the grounds: the pot is a pressurized steam system, which is why it requires a safety valve.

From "The Invention of Science" by David Wootton