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1 Scope This standard specified the basic technical requirements for stress calculation of steam/water pipes in the thermal power plant. This standard is applicable to the stress calculation of steam/water Pipes in the thermal power plants which are being newly built, undergoing expansion or being rebuilt as well as in the thermal plants which take the low carbon steels, low alloy steels and high chrome steels as their piping materials. The stress calculation of the oil/gas media pipes and the non-nuclear pipes of the nuclear power station can refer to this standard. 2 Normative References The clauses in the following documents become parts of this standard by quotation of it. For those quoted documents with dates, all their subsequent modifications (not including the errata contents) or revisions are not applicable to this standard. However, parties having reached an agreement on this standard are encouraged to study whether the latest revisions of these documents are applicable or not. But for those quoted documents without dates, the latest revisions are applicable to this standard. DL/T 5054 Technical regulations for steam/water pipes design in the thermal power plant SY/T 5037 The low pressure fluid transferring pipes using spiral seam to cover up the arc welding steel pipes. ASME B31.1-2004 Power pipes 3 General Principles 3.0.1 The main tasks of piping stress calculation are to check the primary stress generated under the functions of internal pressure, deadweight and other external loads and the secondary stress generated under the functions of thermal expansion, cold shrinkage and displacement if restricted; to judge the security, economy and rationality of the pipes, as well as to judge the thrust and moment generated by the pipes within the range of these equipments' security bearance. 3.0.2 The thermal expansion stress of the pipes should be checked according to the stress range in cold/hot conditions. And the thrust and moment of the pipes to the equipments should be checked respectively according to the likely maximum value in the cold and working conditions. 3.0.3 Appropriate cold tightening could reduce the hot stress at the initial operation of the pipes and the hot thrust of the pipes to the ends, as well as reduce the local overstrains of the piping system. And the cold tightening has relationship with the check stress range. 3.0.4 When carrying out the flexibility analysis of the pipes, it can be assumed that the whole piping system is elastomers. |