1 Scope
This specification specifies the flexibility design methods, calculation parameters and evaluation standard of non-buried carbon steel, alloy steel and stainless steel piping in petrochemical industry.
This specification is applicable to the flexibility design of non-buried carbon steel, alloy steel and stainless steel pipelines in petrochemical industry.
2 Normative references
The following documents are indispensable for the application of this specification. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB 3087 Seamless steel tubes for low and medium pressure boiler
GB/T 3091 Welded steel pipes for low pressure liquid delivery
GB 5310 Seamless steel tubes and pipes for high pressure boiler
GB 6479 Seamless steel tubes for high-pressure for chemical fertilizer equipment
GB/T 8163 Seamless steel pipes for liquid service
GB 9948 Seamless steel tubes for petroleum cracking
GB/T 12771 Welded stainless steel pipes for fluid transport
GB/T 14976 Seamless stainless steel pipes for fluid transport
SH/T 3039 General seismic design rule of non-buried pipe for petrochemical industry
API Std 610 Centrifugal pumps for petroleum, petrochemical and natural gas industries
API Std 617 Axial and centrifugal compressors and expander-compressors for petroleum, chemical and gas industry services
ASMEB 16.5 Pipe flanges and flanged fittings
ASMEB 16.9 Factory-made wrought buttwelding fittings
ASMEB 16.11 Forged fittings, socket-welding and threaded
ASMEB 31.3 Process piping
NEMA SM 23 Steam turbines for mechanical drive service
3 General requirements
3.1 The piping system shall be sufficiently flexible under various operating conditions, and shall not cause the following problems due to thermal expansion, additional displacement of endpoints, improper piping support settings, etc.:
a) excessive piping stress or metal fatigue, which causes piping damage;
b) leakage at the piping connection;
c) excessive piping thrust and/or torque, which causes excessive stress or deformation of the equipment connected to it, therefore affecting the normal operation of the equipment;
d) excessive piping thrust and/or torque, which causes damage to the piping support and hanger.
3.2 In the design of piping flexibility, the following additional displacements of the piping endpoints shall be taken into account:
a) the additional displacement imposed on the connecting pipeline by the static equipment due to thermal expansion;
b) the additional displacement imposed on the connecting pipeline by the rotating machine due to thermal expansion;
c) the additional displacement imposed on the connecting pipeline by the heating furnace;
d) the additional displacement imposed on the connecting pipeline by the foundation settlement of equipment such as storage tanks;
e) the additional displacement imposed on the branch pipe by the main pipe when the branch pipe is not analyzed together with the main pipe.
3.3 For complex piping systems, fixed points may be used to divide them into several simpler piping systems, and then analysis and calculation may be performed.
3.4 When determining the location of the fixed points of the pipeline, the pipelines with the two fixed points shall be able to meet the flexibility requirements.
3.5 The flexibility should be increased by changing the piping direction in the piping design. When limited by conditions, compensator may be used to increase flexibility.
3.6 Stuffing box compensator shall not be used for toxic or combustible medium pipelines.
3.7 When using the Π-shaped compensator, the Π-shaped compensator should be installed in the middle of the two fixed points of the pipeline.
3.8 Cold spring shall not be used for the pipeline connected with the rotating machine.
3.9 When cold spring is adopted for the pipeline, two-thirds of the effective coefficient of cold spring should be taken.
3.10 In the design of piping flexibility, the friction influence of the support shall be taken into account, and the friction coefficient shall be selected according to those specified in Table 3.10.
Foreword II
1 Scope
2 Normative references
3 General requirements
4 Analysis methods and range
5 Calculation parameters
6 Evaluation standard
Annex A (Informative) Steel mean coefficient of linear thermal expansion and total linear thermal expansion
Annex B (Informative) Elastic modulus of steel
Annex C (Informative) Allowable stress of common steel pipe
Annex D (Normative) Flexibility and stress intensification factors
Explanation of wording in this specification
