Without the safety valves of emigration to Europe, which is getting harder, and families' willingness to support those out of work, Morocco would look far less stable.

ECONOMIST: The king is seeking to embrace moderate Islamists

The college spread has elevated the function of slot receivers, who often work the middle of the field as safety valves whom the quarterback can target if pressured.

WSJ: Tom Brady, Drew Brees and Aaron Rodgers: The NFL's Mount Passmore

The Renewable Fuels Standard builds in "safety valves" in the event of extreme economic harm in states or regions or if the ethanol industry does not produce an adequate supply.

WSJ: Review & Outlook: Ethanol vs. the World

The passive feature means they rely less on electrically driven pumps and valves, for safety, and more on systems designed to shut down plants safely in emergencies and to prevent operator error.

WSJ: Nuclear Industry Likely to Reassess Safety Systems

America and operates a number of service centers, supply branches and sales offices through which it markets pipes, valves, fittings, safety and other maintenance products.

FORBES: Pronounce It 'Shlum-Bur-Zhay' And Value It At $106

The AP1000 has half the valves, 35% fewer safety-grade pumps, 80% less pipe and 85% less cable than existing plants.

FORBES: Magazine Article

But the girls used one-way valves throughout the device as a safety measure.

FORBES: Teens Create A Way To Use Urine As Fuel