1 General Provisions
1.0.1 This code is formulated with the view to standardizing the design of stream/water piping of fossil-fired power plant and ensuring safe, full-capacity, economical and continuous operation of fossil-fired power plant.
1.0.2 This code is applicable to the design of steam/water metal piping within the scope of fossil-fired power plant, it is not applicable to the design of water supply and drainage piping, fire-fighting water piping and large-caliber thin-wall exhaust piping of direct air-cooled unit.
1.0.3 The design of stream/water piping of fossil-fired power plant shall comply with this code and the requirements of relevant current standards of the nation.
2 Terminologies and Symbols
2.1 Terminologies
2.1.1 Piping
It consists of piping components and pipe supports and hangers, etc. and is used for conveying, distributing, mixing, separating, discharging, measuring or controlling fluid flow.
2.1.2 Piping components
Elements used to connect or assemble piping, including pipes, pipe fittings, flanges, gaskets, fasteners, valves, filter screen and compensator, etc.
2.1.3 Pipe or tube
The piping component with round cross section and used for conveying fluid.
2.1.4 Pipe fittings
A category of piping components, including bend or elbow, tee, stub tube, reducer and end cap, etc.
2.1.5 Pipe supports and hangers
The generic term of various assemblies or devices bearing piping load, restraining piping displacement and controlling piping vibration, and transferring load to support structures, but excluding the civil structures.
2.1.6 Guides
The device used to guide piping to displace along the predetermined direction instead of other directions. The guiding device used for horizontal piping may also bear the dead load of piping.
2.1.7 Restraints
The device used to restrain or partially restrict the displacement of piping system in a certain or several directions at the hanging and supporting point. Generally, it doesn't bear the dead load of piping.
2.1.8 Vibration reducing device brace
The device used for controlling low-frequency and high-amplitude shaking or high-frequency and low-amplitude vibration of piping, but having certain restriction on thermal expansion or cold shrinkage of piping system.
2.1.9 Snubbers
The device used for bearing seismic load or impact load of piping, controlling high-speed vibration displacement of piping system, meanwhile allowing free expansion and contraction of piping system.
2.1.10 Set pressure
The preset pressure of safety valve started under operating conditions, it is the gauge pressure measured at valve inlet. Under this pressure, the force generated by medium pressure under specified operating conditions to open valve is balanced to the force that keeps valve clack on valve seat.
2.1.11 Relieving pressure
The static pressure at the inlet of safety valve when the safety valve clack reaches specified opening height, which is also known as full opening pressure. It is equal to the set pressure plus the pressure increment exceeding the set pressure, which is generally expressed in the percentage of the set pressure.
2.1.12 Reseating pressure
The static pressure at the inlet of safety valve when the valve lift is zero and medium stops flowing out due to recontact of valve clack and valve seat, with the fall of system pressure after safety valve relieves.
2.1.13 Blowdown
The difference between set pressure and reseating pressure of relief valve, which is generally expressed in the percentage of the set pressure.
2.1.14 Rupture disk device
The pressure relief device that is composed of such assemblies as rupture disk (or rupture disk assemblies) and clamp holder or support ring. The rupture disk will act, crack or fall off immediately and then discharge the pressure medium when the pressure difference between both sides of the rupture disk reaches the preset value at the preset temperature.
2.1.15 Steady pressure pipe blowing scheme of boiler
The pipe blowing mode of boiler where the pressure of boiler vaporization system is constant during pipe blowing. It is a relatively steady state process to boiler system, during this process, boiler maintains energy balance between input energy and energy output and the mass balance between water supply quantity and evaporation capacity.
2.1.16 Energy storage reduced pressure pipe blowing scheme of boiler
It is a kind of pipe blowing mode using the heat storage of boiler as well as the additional vaporization capacity generated during fast pressure drop process of boiler to obtain relatively large steam flow in short time, so as to achieve pipe blowing by relying on the effective pipe blowing time and accumulation where the blowing coefficient is larger than 1 during pipe blowing.
2.1.17 Target and target holder assembly
Target is the test metal plate produced according to the material and dimension specified by relevant standards and used for inspecting the cleanliness of the pipe blown. Target holder assembly is the device used for fixing target.
2.1.18 Collector
Collector is also known as slag trap, which is the device collecting the relatively large sundries previously blown from the steam piping during pipe blowing, so as to prevent the sundries from being blown into reheater.
2.1.19 Blowing control valve
The main valve used for controlling blowing steam, it is an important part affecting the blowing procedure.
2.1.20 Temporary parts
The generic term of parts replacing the valve core of main steam valve, temporary medium-pressure steam valve and high-pressure bypass valve and parts such as piping temporary baffle, etc.
2.1.21 Temporary pipe
It includes the temporary connecting piping between the original systems and the temporary pipe exhausting blowing steam to the atmosphere.
2.2 Symbols
1 General Provisions
2 Terminologies and Symbols
2.1 Terminologies
2.2 Symbols
3 Basic Requirements
3.1 Design Condition
3.2 Design Parameter
3.3 Hydrostatic Test
3.4 Material
3.5 Welding
4 Selection of Piping Components
4.1 General Requirements
4.2 Pipe
4.3 Bend and Elbow
4.4 Flange and Accessories
4.5 Reducer
4.6 Branch Connection
4.7 End Caps
4.8 Valves
4.9 Valve Actuating Gear
4.10 Blind and Orifice
4.11 Compensator
5 Calculation of Piping Components
5.1 Selection of Pipe Diameter
5.2 Calculation of Thickness of Straight Pipe Wall
5.3 Calculation of the Minimum Wall Thickness of Bends and Elbows
5.4 Reinforcement of Branch Connections
5.5 Reducer
5.6 Calculation of End Caps and Throttle Orifice
5.7 Flange and Accessory
5.8 Metal Bellows Compensator
5.9 Control Valve
5.10 Torsion of Valve Actuating Gear
6 Piping Layout
6.1 Layout of Piping
6.2 Layout of Piping Components
6.3 Compensation of Piping
6.4 Cold Springing of Piping
7 Hydraulic Calculation
7.1 General Requirements
7.2 Pressure Loss of Water Piping
7.3 Pressure Loss of Steam Piping with Little Change of Medium Specific Volume
7.4 Pressure Loss of Steam Piping with Big Change of Medium Specific Volume
7.5 Calculation of Orifice Pressure Loss and Bore Diameter
7.6 Hydraulic Calculation of Two-Phase Fluid Piping
8 Design of Supports and Hangers
8.1 General Requirements
8.2 Spacing of Supports and Hangers
8.3 Supports and Hangers Loads
8.4 Selection of Spring
8.5 Structure Strength Calculation of Supports and Hangers
9 Design of Drain, Water Discharge, Venting and Boiler Blowdown Systems
9.1 General Requirements
9.2 Drain, Water Discharge and Venting Systems for Piping and Equipment
9.3 Drain System to Prevent Water Damage to Steam Turbines
9.4 Blowdown, Drain and Water Discharge Systems of Boilers
9.5 Selection of Pipes and Accessories
9.6 Layout
10 Design of Auxiliary Equipment Cooling Water System
10.1 General Requirements
10.2 Design of System
10.3 Design of Layout
11 Overpressure Protection Design of Piping System
11.1 General Requirements
11.2 Selection of Overpressure Protection Device
11.3 Layout of Safety Valve and Venting Piping
11.4 Calculation of Safety Valve and Venting Piping
11.5 Selection Calculation of Safety Valve
12 Design of Steam-blowing System
12.1 General Requirements
12.2 Design of System
12.3 Selection of Temporary Pipe and Accessories
12.4 Design of Layout
12.5 Design of Supports and Hangers
Appendix A Performance of Common Material
Appendix B Dimensional Tolerance of Piping
Appendix C Data of Piping Compensation
Appendix D Data of Piping Hydraulic Calculation
Appendix E Load Approximate Calculation of Supports and Hangers
Appendix F Calculation of Wind Load and Seismic Load
Explanation of Wording in This Code
List of Quoted Standards 错误!未定义书签。
