escape valve vs safety valve

escape valve and safety valve both are nouns.

Word	Noun	Adjective	Verb	Adverb
escape valve	Yes	No	No	No
safety valve	Yes	No	No	No

As nouns, escape valve and safety valve are synonyms defined as:

escape valve and safety valve: a valve in a container in which pressure can build up (as a steam boiler); it opens automatically when the pressure reaches a dangerous level

Other synonyms of escape valve include escape, escape cock, relief valve.

escape valve (noun)	safety valve (noun)
a valve in a container in which pressure can build up (as a steam boiler); it opens automatically when the pressure reaches a dangerous level	a valve in a container in which pressure can build up (as a steam boiler); it opens automatically when the pressure reaches a dangerous level