Abstract: A method for forming helically wound pipe from an elongated sheet of material having a longitudinal axis wherein markings are provided perpendicular to said longitudinal axis adjacent the edges of the elongated sheet of material at predetermined spaced intervals. The elongated sheet is fed in a direction parallel to its axis and wound helically to form a helically wound pipe having adjoining revolutions while maintaining the distance, parallel to said longitudinal axis, between successive indicia adjacent the edge of one revolution and the indicia adjacent the edge of the adjoining revolution constant.

Abstract: A removable deck for an interstitial space between stories of a building has joist saddles adapted to be permanently secured to building truss members in the interstitial space, each saddle having a socket into which the end of a joist may be dropped. The joists are channel type members of a length equal to the space between trusses. Each joist has an upturned flange at its top and the deck members, of a chosen length to extend across selected number of joists, have slots across their bottoms for close engagement with the upturned flange of the joist. The joists have a strip of rubber-like material along their upper surfaces and the upturned flange has dimple-like projections spaced therealong for holding sidewise movement of the deck members to a minimum. Each deck member is of inverted channel shape, the upper surface of which is longitudinally slitted to provide good air circulation.