This standard specifies the basic requirements of materials, design, fabrication, erection, inspection, test, safety protection, insulation and corrosion resistance of piping with steam, water as well as flammable, explosive, toxic and corrosive liquid or gas as the medium within the battery limit of thermal power plants. Reference shall be made to GB/T 20801 for piping with flammable, explosive, toxic and corrosive liquid or gas as medium.
This standard is not applicable to the following piping:
a) boiler body piping;
b) nuclear power plant piping;
c) piping for heating, ventilation and air conditioning as well as those with non-circular cross section;
d) piping for various towers, building frames, storage vessels, mechanical equipment and instruments.
This standard does not include the material requirements of nonmetal piping.
See Figures 1 and 2 for the boundary between the piping specified in this standard and those within the boiler body.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB 150-2011 (all parts) Pressure vessel
GB/T 229 Metallic materials - Charpy pendulum impact test method
GB/T 231.1 Metallic materials - Brinell hardness test - Part 1: Test method
GB/T 700-2006 Carbon structural steels
GB 713-2014 Steel plates for boilers and pressure vessels
GB/T 1048 Pipework components - Definition and selection of PN
GB 3087 Seamless steel tubes for low and medium pressure boiler
GB/T 3091 Welded steel pipes for low pressure liquid transmission
GB/T 3274 Hot-rolled plates, sheets and strips of carbon structural steels and high strength low alloy structural steels
GB/T 4622.2-2008 Dimensions for spiral wound gaskets for pipe flanges
GB 5310 Seamless steel tubes and pipes for high pressure boiler
For the purposes of this document, the following terms and definitions apply.
3.1
piping
piping that consists of pipe components, pipe supports and hangers, etc., which is used to transport, distribute, mix, separate, discharge, measure or control fluid flow
3.2
piping system
a group of piping formed by connecting one or more piping divided according to fluid and design conditions
3.3
piping component
components used to connect or assemble into piping, including pipe, pipe fitting, flange, gasket, fastener, valve, filter mesh and compensator
3.4
pipe or tube
piping component with circular cross section for conveying fluid
3.5
pipe fitting
a category of piping component, including bend or elbow, tee, branch, reducer and seal head
3.6
piping assembly
assembly composed of such pipes, pipe fittings, elbows and flanges as are separately numbered according to piping design
3.7
manufacture
production process of products such as piping component and piping supports and hangers
3.8
fabrication
process of connecting pipe fittings and pipes into piping assembly through working procedures such as cutting, groove preparation, bending, forming, welding, heat treatment, etc. in a shop or in the field before piping erection
3.9
erection
process of putting a piping system in place completely according to the regulations of piping design
3.10
test
a method for confirming the quality characteristics of products stipulated jointly by the owner and the manufacturing, fabricating and erection units according to the standards or regulations, including hydraulic test, air tightness test, etc.
3.11
verification
process of document confirmation of the received piping components and supports and hangers by the power piping manufacturing unit or erection unit
3.12
receiving acceptance
process of confirmation of the received piping components and supports and hangers by the power piping manufacturing unit or erection unit through verification and/or inspection
3.13
branch connection
structure leading branch from the main pipe, including integrally reinforced tee fittings and branch connection without reinforced welded structures
3.14
liquid collecting pocket (drain leg)
device for collecting condensed water set at the low point of gas or steam piping
3.15
sway brace
device for controlling low-frequency and high-amplitude sloshing or high-frequency and low-amplitude vibration of piping
3.16
snubber
device for bearing seismic load or impact load of piping, controlling high-speed vibration displacement of piping system, and allowing piping system to expand and contract freely with the change of temperature
3.17
stress intensification factor
ratio of the maximum bending stress produced by bending pipe, elbow, reducer and tee fitting under the action of bending moment to that produced by straight pipe bearing the same bending moment, or ratio of the fatigue strength of straight pipe to that of bending pipe, elbow, reducer and tee fitting under the action of the same alternating bending moment
3.18
cold spring
elastic deformation applied to the piping in advance when erecting the piping to produce the expected initial displacement and stress, thereby reduce the stress in initial hot state as well as the acting force and moment of the pipe end in initial hot state
3.19
flexibility
ability of the piping to absorb displacement deformation caused by thermal expansion, cold contraction and others through its own deformation
3.20
hot displacement
change of position of the piping system at the supporting and hanging point between cold and hot states
Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 Grading of piping 5 Materials 6 Design and calculation 7 Fabrication and erection 8 Inspections and tests 9 Safety protection 10 Insulation and anti-corrosion Annex A (Normative) Allowable stress of materials Annex B (Informative) Physical properties of commonly used materials Annex C (Normative) Flexibility factors and stress intensification factors Annex D (Informative) Common data for fabrication and erection Annex E (Normative) Assembly deviations for piping prefabrication Annex F (Normative) Calculations for safety relief devices
