A pressure vessel for containing liquids and/or gases under pressure, said pressure vessel comprising: a polymeric liner comprising a hollow body having a cylindrical wall extending from a first end to an opposing end of said liner , said cylindrical wall having an inner surface and an outer surface , said hollow body including a corrugated section having circumferential corrugations providing alternating ridges and valleys arranged from one end to an opposing end of said corrugated section , each of said corrugations comprising a curved mountain region having a ridge , a curved valley between adjacent spaced apart mountain regions , and a side wall joining each successive mountain region and valley , said outer surface of said ridge defining an outer diameter (OD) of the corrugated section , air space between said outer surface of adjacent side walls defining an annular cavity, a distance between successive ridges defines a period (T) of said corrugations , a distance between said inner surface and said outer surface of said liner at said ridge defines a mountain wall thickness (Tm), a distance between said inner surface and said outer surface of said liner at a midpoint of said valley defines a valley wall thickness (Tv), and a radial distance between said outer surface at said ridge and said outer surface at said valley defines an amplitude (A) of said corrugations ; and an outer composite shell comprising resin and fiber surrounding an outer periphery of said liner ; characterized in that : wherein said mountain wall thickness Tm is greater than said valley wall thickness Tv and said amplitude A is between about 0.65 times said period T and about 0.75 times said period T of said corrugations . a polymeric liner comprising a hollow body having a cylindrical wall extending from a first end to an opposing end of said liner , said cylindrical wall having an inner surface and an outer surface , said hollow body including a corrugated section having circumferential corrugations providing alternating ridges and valleys arranged from one end to an opposing end of said corrugated section , each of said corrugations comprising a curved mountain region having a ridge , a curved valley between adjacent spaced apart mountain regions , and a side wall joining each successive mountain region and valley , said outer surface of said ridge defining an outer diameter (OD) of the corrugated section , air space between said outer surface of adjacent side walls defining an annular cavity, a distance between successive ridges defines a period (T) of said corrugations , a distance between said inner surface and said outer surface of said liner at said ridge defines a mountain wall thickness (Tm), a distance between said inner surface and said outer surface of said liner at a midpoint of said valley defines a valley wall thickness (Tv), and a radial distance between said outer surface at said ridge and said outer surface at said valley defines an amplitude (A) of said corrugations ; and an outer composite shell comprising resin and fiber surrounding an outer periphery of said liner ; characterized in that : wherein said mountain wall thickness Tm is greater than said valley wall thickness Tv and said amplitude A is between about 0.65 times said period T and about 0.75 times said period T of said corrugations . <EOS>