Welders qualification: For welding on principal stress carrying parts or parts subject to vibration, the welding procedures and welders qualifications shall conform to EN ISO 3834, Part 5: 2005 or similar standards approved by the Engineer. EN 13445 or ASME Boiler and Pressure Vessel Code, Sections VIII and IX. Non-destructive tests: Non-destructive tests of the materials shall include ultrasonic tests, radiographic tests, magnetic particle tests and dye penetrant tests as specified. Unless otherwise specified, the requirements of EN 13445 part 4 and 5, as an alternative CCH 70-3 or Section VIII and IX of the ASME Boiler and Pressure Vessel Code shall apply: Magnetic Particle Inspection Ultrasonic Inspection Liquid Penetrant Inspection Welding Tests at Works and at Site Inspection and testing after welding, the compliance with relevant acceptance criteria shall be checked: by visual inspection; by non-destructive testing; by destructive testing; form, shape and dimensions of the construction; results and records of post-weld operations (e.g. post-weld heat treatment, ageing) The ISO documents to which it is required to conform to fulfil the quality requirements are specified in ISO 3834-5:2005, Table 8, for arc welding, electron beam welding, laser beam welding and gas welding, and in ISO 3834-5:2005, Table 10, for other fusion welding processes. Acceptance criteria shall be as given in EN 1289 (PT), EN 1291 (MT), EN 1712 (UT) or as agreed with the Engineer. The welding properties shall be demonstrated by the Contractor as required by the Engineer. For penstocks and circular steel linings 10% of all pipes of each quality and thickness shall be tested as follows: For longitudinal joints two test plates (tablets) shall be fixed to the ends of the rolled plates which are to be joined and welded together as a continuous prolongation of the longitudinal weld. The tablet base material and plate thickness, filler material, flux and any heat treatment shall be identical for the plates proper and the test tablets. The tablet size, etc., is subject to the Engineer's approval. Samples shall be cut from the test tablets for testing as follows: Two elongation specimens with parallel side faces, cut normal to the directions of weld for testing

of tensile strength, elongation at rupture, position of rupture (in the weld, in the heat affected zone (HAZ), or in the base material).

One elongation test shall be performed with reduced section at the weld, for testing of yield strength and tensile strength of the weld deposit material itself. The specimen is to be cut from

along the weld seam if possible. Two bending tests are to be performed, executed with tension on both faces of the weld seam, mandrel diameter =2.5 a (a =thickness of specimen).Three ISO V-notch impact tests (at ODC or temperature as agreed), each with notch normal to direction of weld, are to be performed as follows: Two with notch in HAZ One with notch in the first weld pass No impact test shall be accepted if the impact strength is less than 27 J or as given in the relevant standards. The welded joint shall prove to have a quality and property not inferior to that of the base material. Surface Treatment and Painting: The coating and painting shall be carried out in accordance with ISO 12944, "Corrosion protection of steel constructions by protective paint systems", or other equivalent standard. Surface preparation, blasting, cleaning: For removing rust and mill scale, blasting shall be carried out down to clean bare metal, according to ISO 8501-1, grade Sa 2.5. The average surface roughness after blasting shall not exceed 50 microns. Cleaning of Welds Erection welds and their heat affected zones made during the erection of constructions, which have already been blast-cleaned and painted shall, unless otherwise agreed, be blast j cleaned to Sa. 2.5.