safety curtain
From Longman Dictionary of Contemporary EnglishRelated topics: Theatresafety curtainˈsafety ˌcurtain noun [countable] APTa thick curtain at the front of a theatre stage that prevents fire from spreadingExamples from the Corpussafety curtain• As he disappears behind a safety curtain of blue smoke he starts to say something, but he coughs on the smoke.