5.4　Superheater，Reheater，Economizer and Desuperheater

5.4.1　Prior to the erection of the serpentuators of superheater，reheater，the economizer and so on is carried out，the header shall be aligned and fixed first.

5.4.2　The allowable deviation for the assembly and erection of superheater and reheater components shall meet the requirements of Table 5.4.2.

Table 5.4.2　Allowable deviation for the assembly and erection of superheater and reheater components（mm）

5.4.3　The allowable deviation for the assembly and erection of economizer components shall meet the requirements of Table 5.4.3.

Table 5.4.3　Allowable deviation for the assembly and erection of economizer components（mm）

5.4.4　The distances between the furnace arch，the horizontal flue and the upper serpentuator bottom location shall be no less than the value of design.

5.4.5　The expansion clearance shall be provided in the joints according to the drawing requirements for the wear-resistant devices in the heating surface.Moreover，the flue gas flowing shall not be interfered.

5.4.6　The allowable deviation in flatness of the tube arrays in the ceiling superheater shall be 10mm.The spacing between tubes shall be uniform.

5.4.7　For the erection of the wall enclosed superheater assembly，the related provisions in Article 5.3 in this Part shall be implemented.

5.4.8　Prior to the erection of the spray type attemperator，inspection shall be carried out and the erection direction shall be confirmed.

5.4.9　The erection of the boiler connecting pipes and accessories shall meet the following requirements:

1　Prior to the erection of the boiler connecting pipes，the pipe end seals shall be disassembled.It shall be confirmed that no sundries exist inside the pipes.The pipe butt joint shall meet the requirements of DL 5190.5 Technical Specification for Thermal Power Erection and Construction-Part 5:Piping and System.

2　The boiler connecting pipes shall be in free expansion and the expansion for the equipment in the heating surface shall not be hindered.

3　The erection of supports and hangers of boiler connecting pipes shall meet the following requirements:

1）The comprehensive inspection shall be carried out prior to the erection.The sizes shall be correct，and the components shall be complete without deformation or other defects.

2）The supports and hangers，which are designed to put into operation under the normal temperature，shall not perforate into the insulation layer of pipes.

3）The motion parts and support parts for pipe supports and hangers shall be in good contact.The supports and hangers shall allow free expansion of the pipe.

4）For any hanger frame with the offset design requirements，the erection shall be carried out strictly according to the offset quantity of the design drawing.If there is no specific requirement in the design，the offset shall be carried out in accordance with the piping system overall expansion quantity.

5）The adjustment of the hangers shall be carried out before hydrostatic test.The nuts shall be locked according to the drawing requirements after the final adjustment.Welding or striking arc shall not be carried out on the hangers.