5.3　Waterwalls

5.3.1　The assembly of waterwalls shall be carried out in the firm assembly frame.

5.3.2　The allowable deviation for the waterwalls assembly components shall meet the requirements of Table 5.3.2.

Table 5.3.2　Allowable deviation for the assembly and erection of waterwalls（mm）

5.3.3　The allowable deviation for the assembly and erection of buckstays shall meet the requirements of Table 5.3.3.

Table 5.3.3　Allowable deviation for the assembly and erection of buckstays（mm）

5.3.4　The hoisting points for the waterwalls assembly shall reasonably be selected and the appropriate reinforcement measures may be taken.No any permanent deformation shall be generated during the transportation and lifting.

5.3.5　The spiral waterwalls should be spliced in the ground completely.The splicing seams shall keep the appropriate pre-contraction value.The reference line for the hanging belts（vertical overlapping boards）shall be located accurately.

5.3.6　During the erection of spiral waterwalls，the delamination alignment and location shall be carried out.The delamination alignment and location of the hanging belts（vertical overlapping boards）shall be carried out in time.

5.3.7　During the erection of spiral waterwalls，the spiral angle deviation shall be controlled within 0.5°.

5.3.8　The sealing and welding shall be carried out according to the manufacturer's drawing requirements.Moreover，inspection shall be carried out to the welds to find whether the welds is lack of weld or solder wrong.For the dense-phase zone of the circulating fluidized bed boiler or the positions required in the manufacturer's technical documents，the sealing weld for theses parts shall be inspected by penetrating method.

5.3.9　The butt seam welding for the sleeves and waterwalls in the wall pipes in the tower type boiler and the butt joint wall pipes shall be carried out synchronously.The welds between the sleeves and wall pipes shall meet the manufacturer's drawing requirements.