A method of fabricating a conduit comprises steps of attaching a first tubular outboard ply to a first inner collar portion of a first collar with a third weld and attaching the first tubular outboard ply to a second inner collar portion of a second collar with a fifth weld. The method also comprises steps of interconnecting the first inner collar portion and a first outer collar portion of the first collar with a first weld, interconnecting the second inner collar portion and a second outer collar portion of the second collar with a sixth weld, attaching a trimmed first corrugated-inboard-ply end of a corrugated inboard ply to the first outer collar portion with a second weld, attaching a trimmed second corrugated-inboard-ply end of a corrugated inboard ply to the second outer collar portion with a fourth weld, and communicatively coupling a first sensor with an interstitial space.