Page 196 - Water Standards
P. 196

ties and diffusible hydrogen content shall meet the require⁃
                     ments of GB 5117, GB 5118, and GB 983.
                3  Datum points and measuring tools shall meet the following re⁃
           quirements:
                  1) Datum points and installation control points which are used
                     in the elevation and axis survey shall all be obvious, firm
                     and easy to use. The survey department shall explain and
                     provide the sketch of point positions to the installation de⁃
                     partment on site.
                  2) The accuracy of steel rulers and measuring apparatus used
                     in installing metal structures shall meet the following re⁃
                     quirements: The steel ruler accuracy shall be 1 / 10000;
                     the measuring apparatus shall use J2 Theodolites and S3
                     Level Gauges. The measuring tools and instruments used
                     in the metal structure installation shall be sent to a legal
                     calibration department and checked before use.
                4  The connection of metal structures shall meet the following re⁃
           quirements:
                  1) The requirements of the important welding joints of the
                     metal structures such as onsite splicing weld joints of sec⁃
                     tional sluice gates, onsite longitudinal joints and circular
                     seams of penstocks shall be the same as those for similar
                     weld joints in manufacturing and shall comply with the
                     corresponding standards.
                  2) For permanent bolted connections, the manufacture of bolt
                     holes and bolts, as well as bolt tightening shall meet the
                     relevant requirements of DL/ T 5018.
                5   Anticorrosion metal structures shall meet the following re⁃
           quirements:
                  1) Surface pre⁃treating, paint coating and thermal spraying of
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