OPEN-ENDED • DICCIONARIO INGLES.COM • Definition of Open-ended

... mixture lying within the explosive limits, when an explosion will occur. Again, if a gaseous mixture containing less of its combustible constituent than is necessary to attain the lower explosive limit escapes from an open-ended pipe and a light is applied to it, the mixture will not burn as a useful compact flame (if, indeed, it fires at all); if the mixture contains more of its combustible constituent than is required to attain the upper explosive limit, that mixture will burn quietly ...

— Acetylene, The Principles Of Its Generation And Use • F. H. Leeds and W. J. Atkinson Butterfield