Pipes that are manufactured from a steel strip, of appropriate width and thickness. The welding processes can vary; electric resistance welding (E.R.W.), high frequency welding (H.F.I.) or submerged arc welding (S.A.W.).
Pipes for fire protection systems are longitudinally welded HSW type. Spiral welded pipes are only used for large diameters that are not commonly used in fire protection systems.
- Welded pipe is produced by forming a cylinder from flat steel sheets
coming from a hot strip mill. The welded seam is either parallel to the tube axis or in a spiral direction about the tube centreline. By varying the spacing between the rolls bend radius can change to manufacture different pipe diameters.
- Existing pipe Standards for welded steel pipe for fire protection systems are: EN 10217-1, EN 10255 W, ASTM A53 W, ASTM A795 W, ASTM A135.