Standard No.:	GB/T 20801.1-2025
English Name:	Pressure piping code - Part 1: Industrial piping
Chinese Name:	压力管道规范 第1部分：工业管道
Professional Classification:	GB    National Standard
Source Content Issued by:	SAMR, SAC
Issued on:	2025-10-31
Implemented on:	2026-5-1
Status:	to be valid
Superseding:	GB/T 20801.1-2020 Pressure piping code—Industrial piping—Part 1:General GB/T 20801.2-2020 Pressure piping code - Industrial piping - Part 2: Materials GB/T 20801.3-2020 Pressure piping code - Industrial piping - Part 3: Design and calculation GB/T 20801.4-2020 Pressure piping code - Industrial piping - Part 4: Fabrication and assembly GB/T 20801.5-2020 Pressure piping code - Industrial piping - Part 5: Inspection and testing GB/T 20801.6-2020 Pressure piping code - Industrial piping - Part 6: Safeguarding
Target Language:	English
File Format:	PDF
Word Count:	136000 words
Translation Price(USD):	3990.0
Delivery:	via email in 1~8 business day

GB/T 20801.1-2025 Pressure piping code - Part 1: Industrial piping English Foreword This document is drafted in accordance with the rules given in GB/T 1.1-2020 Directives for standardization - Part 1: Rules for the structure and drafting of standardizing documents. This document is part 1 of GB/T 20801 Pressure piping code. GB/T 20801 has issued the following parts: —— Part 1: Industrial piping. This document replaces and integrates the following six standards: —— GB/T 20801.1-2020 Pressure piping code - Industrial piping - Part 1: General; —— GB/T 20801.2-2020 Pressure piping code - Industrial piping - Part 2: Materials; —— GB/T 20801.3-2020 Pressure piping code- Industrial piping - Part 3: Design and calculation; —— GB/T 20801.4-2020 Pressure piping code - Industrial piping - Part 4: Fabrication and assembly; —— GB/T 20801.5-2020 Pressure piping code - Industrial piping - Part 5: Inspection and testing; —— GB/T 20801.6-2020 Pressure piping code - Industrial piping - Part 6: Safeguarding. In addition to structural adjustments and editorial changes, the following main technical changes have been made with respect to GB/T 20801.1-2020, GB/T 20801.2-2020, GB/T 20801.3-2020, GB/T 20801.4-2020, GB/T 20801.5-2020, and GB/T 20801.6-2020: a) Modified the scope of this document (see Clause 1 hereof, and Clause 1 of GB/T 20801.1-2020); b) Added terms "pressure piping elements", "leakage hazardous medium", "low hazardous media", "maximum allowable accumulation pressure" and their definitions (see 3.7, 3.15, 3.17, and 3.71 hereof); c) Modified the definitions of terms "piping components", "low temperature and low stress service", "lower temperature and lower stress service", "tack weld cover fillet weld", and "interpass temperature" (see 3.6, 3.18, 3.19, 3.49, and 3.51 hereof; 3.5 of GB/T 20801.1-2020; 3.1 and 3.2 of GB/T 20801.2-2020; 3.10 and 3.17 of GB/T 20801.4-2020); d) Modified the pressure piping classification of this document (see Clause 4 hereof, and Clause 4 of GB/T 20801.1-2020); e) Modified the use restriction requirements of carbon structural steel (see 5.3.3 hereof, and 6.2 of GB/T 20801.2-2020); f) Modified the figure and table for "Minimum service temperature of carbon steel (including carbon manganese steel) exempted from impact test" (see Figure 1 and Table 1 hereof, and Figure 1 and Table 1 of GB/T 20801.2-2020); g) Modified the table of "Restrictions on the use of carbon steel, pipeline steels and austenitic stainless steel pipes and their butt-welded pipe fittings" (see Table 3 hereof, and Table 3 of GB/T 20801.2-2020); h) Added non-destructive testing requirements for butt welds of welding piping components when used in elevated temperature fluid service (see 5.4.2.5 hereof); i) Modified the restrictions on the use of materials under low temperature conditions (see 5.5 hereof, and Clause 8 of GB/T 20801.2-2020); j) Modified the content of material marking (see 5.6.1.2 hereof, and 9.1.2 of GB/T 20801.2-2020); k) Added the requirements for the rating value of separator valves when connecting piping in different fluid service (see 6.1.1.1.4 hereof); l) Modified the allowable stress criteria for metal materials and bolt materials (see Table 13 and Table 14 hereof, and Table 1 and Table 2 of GB/T 20801.3-2020); m) Modified the requirements for butt-welded pipe fittings of Grade GC1 in severe cyclic conditions (see 6.3.2.4 hereof, 5.1.2.4 of GB/T 20801.3-2020); n) Added the requirements for half-pipe joints for straight pipe connections (see 6.3.7.5 hereof); o) Modified the selection requirements for flange types in GC1 piping (see 6.3.8.3 hereof, and 5.1.8.10 of GB/T 20801.3-2020); p) Modified additional requirements for flat welded flanges and loose sleeve flanges (see 6.3.8.4 hereof, and 5.1.8.3 of GB/T 20801.3-2020); q) Modified the dimensions of sockets and flanges (see Table 21 hereof, and Tables 9 and 10 of GB/T 20801.3-2020); r) Modified the relevant requirements for the attachment joint of tapered pipe thread (NPT) (see 6.4.5.2 hereof, and 5.2.5.2 of GB/T 20801.3-2020); s) Modified the selection method of sustained force and moment coefficient (see 6.7.5.2 hereof, and 7.5.2 of GB/T 20801.3-2020); t) Modified the calculation formulas for displacement stress range coefficient and equivalent cycle number, and the relationship diagram between stress range coefficient and displacement cycle equivalent number (see 6.7.5.5.3 and Figure 13 hereof, and 7.5.5.3 and Figure 12 of GB/T 20801.3-2020); u) Modified the technical requirements for piping factory pre-fabrication products (see 7.1.5 hereof, and 10.1.1 of GB/T 20801.4-2020); v) Modified the requirement for material monitoring quantity (see 7.2.3 hereof, and 5.3 of GB/T 20801.4-2020); w) Added the erection requirements for ferrule-type pipe joints, zirconium and zirconium alloy piping [see 7.7.4.1 f), and 7.8.6 hereof]; x) Modified the erection requirements for safety protection devices such as rupture discs, flame arresters, and emergency shut-off valves (see 7.7.10 hereof, and 10.9.4 and 10.9.5 of GB/T 20801.4-2020); y) Modified the pressure piping examination level (see 8.3.1 hereof, and 6.1 of GB/T 20801.5-2020); z) Added non-destructive testing methods and related technical requirements for phased array testing and X-ray computer-aided imaging testing (see 8.3.3.1 hereof); aa) Modified the description about "fillet weld" and the related remarks of "branch pipe connection" in the table "Examination methods and proportions of welded joints" (see Table 42 hereof, and Table 1 of GB/T 20801.5-2020); ab) Added the requirement that air pressure test and air tightness test with design pressure greater than 1.6 MPa needs to be agreed by the parties (see 8.6.1.4 a) and 8.6.2.3 hereof); ac) Modified the technical requirements for sensitivity leakage test (see 8.6.2.2 hereof, 9.2.1 of GB/T 20801.5-2020); ad) Added the basic principles and requirements for safety protection design (see 9.1 hereof); ae) Added the setting principles for safety relief device (see 9.2.1.5 hereof); af) Modified Annex A (normative) "Classification of media toxicity, flammability and corrosiveness in pressure piping” (see Annex A hereto, and Annex A to GB/T 20801.1-2020); ag) Modified Annex B (Normative) "Material grade and allowable stress" (see Annex B hereto, and Annex A to GB/T 20801.2-2020); ah) Modified Annex M (Normative) "Flexibility factor and stress increase factor" has been (see Annex M hereto, and Annex G to GB/T 20801.3-2020). Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights. This document was proposed by and is under the jurisdiction of SAC/TC 262 National Technical Committee on Boilers and Pressure Vessels of Standardization Administration of China. The previous editions of this document are as follows: —— GB/T 20801.1-2006, GB/T 20801.2-2006, GB/T 20801.3-2006, GB/T 20801.4-2006, GB/T 20801.5-2006, and GB/T 20801.6-2006; —— GB/T 20801.1-2020, GB/T 20801.2-2020, GB/T 20801.3-2020, GB/T 20801.4-2020, GB/T 20801.5-2020, and GB/T 20801.6-2020; —— This edition is the second revision. Pressure piping code - Part 1: Industrial piping 1 Scope 1.1 This document specifies the basic requirements for materials, design, fabrication, erection, inspection, testing and safety protection of industrial pressure piping. 1.2 The industrial pressure piping referred to in this document (hereinafter referred to as "pressure piping") includes the pressure piping for process devices, auxiliary devices and utility works within the battery limit. This document is applicable to pressure piping under the following conditions: a) Process piping and refrigeration piping within the scope of the Special Equipment Catalog: Pressure piping with the maximum working pressure greater than or equal to 0.1MPa (gauge pressure) and a nominal diameter greater than or equal to 50mm, for which the medium may be gas, liquefied gas, steam or flammable, explosive, toxic and corrosive liquid with the maximum working temperature greater than or equal to the standard boiling point. Piping with a nominal diameter less than 150 mm and a maximum operating pressure less than 1.6 MPa (gauge pressure) conveying non-toxic, non-flammable, non-corrosive gases (excluding liquefied gases, steam, and oxygen) is excluded. b) Piping (excluding piping listed in 1.3, a) and b) and in 1.4] that meet the following conditions: 1) Piping for conveying low-hazard (non-toxic, non-combustible, non-corrosive) liquids; 2) Piping with a nominal diameter of less than 150mm and a maximum working pressure of less than 1.6 MPa (gauge pressure) for conveying low-hazard (non-toxic, non-flammable, non-corrosive) gas (excluding liquefied gas, steam and oxygen); 3) Piping with a nominal diameter less than 50 mm; 4) Piping with maximum operating pressure greater than atmospheric pressure and less than 0.1 MPa (gauge pressure); 5) Vacuum piping. Note: piping outside the scope of the Special Equipment Catalog listed in 1.2 b). 1.3 This document does not include the following scope: a) Piping with a maximum working pressure greater than 42 MPa (gauge pressure); b) Non-metallic piping or its lining layer; c) Special requirements for reconstruction, examination, inspection, test, maintenance and repair of in-service pressure piping; 1.4 The exclusions of this document are as follows: a) Piping for military equipment and nuclear facilities; b) Piping for offshore facilities and in mine shafts; c) Piping for exploration and excavation devices for petroleum, natural gas, terrestrial heat, etc.; d) Piping for mobile equipment such as railway locomotives, automobiles, ships and aerospace vehicles; e) Type GA long-distance piping; f) Type GB utility piping; g) Type GCD Class power piping; h) Internal piping for boilers, pressure vessels and heating furnaces as well as external piping orifices of equipment; i) Piping integral to equipment. Note: Piping integral to equipment refers to internal piping and external piping connections of equipment such as pumps and compressors (excluding pipes connecting multiple stages on-site), steam turbines, gas turbines, internal combustion engines, packaged refrigeration units, quick-freezing devices, and other fluid conveying or processing equipment. 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/T 150 (all parts) Pressure vessels GB/T 150.3-2024 Pressure vessels - Part 3: Design GB/T 196 General purpose metric screw threads - Basic dimensions GB/T 197 General purpose metric screw threads - Tolerances GB/T 229 Metallic materials - Charpy pendulum impact test method GB/T 567.1 Bursting disc safety devices - Part 1: Basic requirement GB/T 567.2 Bursting disc safety devices - Part 2: Application,selection and installation GB/T 567.3 Bursting disc safety devices - Part 3: Classification and mounting dimensions GB/T 567.4 Bursting disc safety devices - Part 4: Type test GB/T 700 Carbon structural steels GB/T 985.1 Recommended joint preparation for gas welding, manual metal arc welding, gas-shield arc welding and beam welding GB/T 985.2 Recommended joint preparation for submerged arc welding GB/T 985.3 Recommended joint preparation for gas-shield arc welding on aluminium and its alloys GB/T 985.4 Recommended joint preparation for welding on clad steels GB/T 1031 Geometrical product specifications(GPS) - Surface texture: Profile method - Surface roughness parameters and their values GB/T 1047 Pipework components - Definition and selection of nominal size GB/T 1048 Pipework components - Definition and selection of nominal pressure GB/T 1220 Stainless steel bars GB/T 1348 Spheroidal graphite iron castings GB/T 2882 Nickel and nickel alloys tube GB/T 3077 Alloy structure steels GB/T 3087 Seamless steel tubes and pipes for low and medium pressure boiler GB/T 3091 Welded steel pipes for low pressure fluid delivery GB/T 3098.1 Mechanical properties of fasteners - Bolts,screws and studs GB/T 3098.6 Mechanical properties of fasteners - Stainless steel bolts,screws and studs GB/T 3420 Gray iron castigs for pipe fittings GB/T 3422 Cast-iron pressure pipe made by continuous casting process GB/T 3624 Titanium and titanium alloy seamless tubes GB/T 3733 24° cone connectors - Straight thread GB/T 3734 24° cone connectors - Male GB/T 3735 24° cone connectors - Straight thread long GB/T 3736 24° cone connectors - Male long GB/T 3737 24° cone connectors - Union GB/T 3738 24° cone connectors - Straight thread elbow GB/T 3739 24° cone connectors - Male elbow GB/T 3740 24° cone connectors - Union elbow GB/T 3741 24° cone connectors - Straight thread tee GB/T 3742 24° cone connectors - Male tee GB/T 3743 24° cone connectors - Straight thread run tee GB/T 3744 24° cone connectors - Male run tee GB/T 3745 24° cone connectors - Union tee GB/T 3746 24° cone connectors - Union cross GB/T 3747 24° cone connectors - Weld male GB/T 3748 24° cone connectors - Bulkhead union GB/T 3749 24° cone connectors - Bulkhead union elbow GB/T 3750 24° cone connectors - Angle swivel screw connector GB/T 3751 24° cone connectors - Connector for pressure gauge GB/T 3752 24° cone connectors - Adjustable elbow GB/T 3753 24° cone connectors - Adjustable tee GB/T 3754 24° cone connectors - Swivel elbow with O-ring GB/T 3755 24° cone connectors - Branch tee with O-ring GB/T 3756 24° cone connectors - Swivel stud straight adapter with O-ring with stud end GB/T 3757 24° cone connectors - Weld-in bulkhead straight connector GB/T 3758 24° cone connectors - Weld-on nipple GB/T 3759 24° cone connectors - Nut GB/T 3760 24° cone connectors - Plug with O-ring GB/T 3763 24° cone connectors and flared couplings - Hexagon thin nut GB/T 3764 24° cone connectors - Ferrule GB/T 3765 24° cone connectors - Specification GB/T 4334 Corrosion of metals and alloys - Test methods for intergranular corrosion of austenitic and ferritic-austenitic (duplex) stainless steels GB/T 4437.1 Aluminium and aluminium alloys extruded tubes - Part 1:Seamless tubes GB/T 4622.1 Spiral wound gaskets for pipe flanges - Part 1: PN designated GB/T 4622.2 Spiral wound gaskets for pipe flanges - Part 2: Class designated GB/T 4732 (all parts) Pressure vessels design by analysis GB/T 4732.3-2024 Pressure vessel design by analysis - Part 3: Formulae method GB/T 5310 Seamless steel tubes and pipes for high pressure boiler GB/T 5625 Flared couplings - Straight thread GB/T 5626 Flared couplings - Male GB/T 5627 Flared couplings - Male long GB/T 5628 Flared couplings - Union GB/T 5629 Flared couplings - Male elbow GB/T 5630 Flared couplings - Union elbow GB/T 5631 Flared couplings - Straight thread elbow GB/T 5632 Flared couplings - Swivel elbow GB/T 5633 Flared couplings - Straight thread branch tee GB/T 5634 Flared couplings - Swivel run tee GB/T 5635 Flared couplings - Male branch tee GB/T 5637 Flared couplings - Straight thread run tee GB/T 5638 Flared couplings - Swivel branch tee GB/T 5639 Flared couplings - Union tee GB/T 5641 Flared couplings - Union cross GB/T 5642 Flared couplings - Weld male GB/T 5643 Flared couplings - Bulkhead union GB/T 5644 Flared couplings - Bulkhead union elbow GB/T 5645 Flared couplings - Connector for pressure gauge GB/T 5646 Flared couplings - Sleeve GB/T 5647 Flared couplings - Style A nut GB/T 5648 Flared couplings - Style B nut GB/T 5649 Flared couplings - Lock nut and lockup washer GB/T 5650 Flared couplings - Inverted flare bolts GB/T 5651 Flared couplings - Seat insert GB/T 5652 Flared couplings - Flared end GB/T 5653 Flared couplings - Specification GB/T 5782 Hexagon head bolts GB 5908 Flame arrester GB/T 6170 Hexagon nuts,style 1 GB/T 6175 Hexagon nuts,style 2 GB/T 6479 Seamless steel tubes for high - pressure chemical fertilizer equipments GB/T 6614 Titanium and titanium alloy castings GB/T 6893 Aluminium and aluminium alloys cold drawn (rolled) tubes GB/T 7306.1 Pipe threads with 55 degree thread angle where pressure - tight joints are made on the threads - Part1: Parallel internal and taper external threads GB/T 7306.2 Pipe threads with 55 degree threads angle where pressure - tight joints are made on the threads - Part 2: Taper internal and threads GB/T 8163 Seamless steel pipes for liquid service GB/T 8464 Cast iron,copper and stainless steel valves with screwed connections GB/T 9065.1 Hydraulic hose fittings - Part 1: Hose fittings with O-ring face seal ends GB/T 9065.2 Connections for hydraulic fluid power - Hose fittings - Part 2: 24°cone connectors GB/T 9065.5 Connections for hydraulic fluid power and general use - Hose fittings - Part 5: Hose fittings with 37°degree flared ends GB/T 9124.1 Spiral wound gaskets for pipe flanges - Part 1: PN designated GB/T 9124.2 Steel pipe flanges - Part 2: Class designated GB/T 9125.1 Fasteners for steel pipe flange joints - Part 1: PN designated GB/T 9125.2 Fasteners for steel pipe flange joints - Part 2: Class designated GB/T 9126.1 Non-metallic flat gaskets for pipe flanges - Part 1: PN designated GB/T 9126.2 Non-metallic flat gaskets for pipe flanges - Part 2: Class designated GB/T 9128.1 Metallic ring joint gaskets for steel pipe flanges - Part 1: PN designated GB/T 9128.2 Metallic ring joint gaskets for steel pipe flanges - Part 2: Class designated GB/T 9439 Grey iron castings GB/T 9440 Malleable iron castings GB/T 9711 Petroleum and natural gas industries - Steel pipe for pipeline transportation systems GB/T 9948 Seamless steel tubes and pipes for petrochemical and chemical facilities GB/T 12220 Induatrial valves - Marking GB/T 12221 Metal valves - Face to face, end to end, centre to face and centre to end dimensions GB/T 12224 General requirements for industrial steel valves GB/T 12228 General purpose industrial valves - Technical specification for carbon steel forgings GB/T 12229 General purpose Industrial valves - Technical specification for carbon steel castings GB/T 12230 General purpose industrial valves - Specification of stainless steel castings GB/T 12232 General purpose industrial valves - Flanged iron gate valves GB/T 12233 General purpose industrial valves - Casting iron globe valves and lift check valves GB/T 12234 Bolted bonnet steel gate valves for petroleum and natural gas industries GB/T 12235 Steel globe valves and lift check valve for petroleum, petrochemical and allied industries GB/T 12236 Steel swing check valve for petroleum, petrochemical and allied industries GB/T 12237 Steel ball valves for petroleum , petrochemical and allied industries GB/T 12238 Flanged and wafer resilient seal butterfly valves GB/T 12239 Industrial valves - Diaphragm valves made of metallic materials GB/T 12240 Iron plug valves GB/T 12241 Safety valves - General requirements GB/T 12242 Pressure relief devices - Performance test code GB/T 12243 Spring loaded safety valves GB/T 12246 Pilot operated pressure reducing valves GB/T 12459 Steel buttwelding piping fittings - Types and parameters GB/T 12459-2017 Steel buttwelding pipe fittings - Types and parameter GB/T 12771 Welded stainless steel pipes for fluid transport GB/T 12777 General specification for metal bellows expansion joints GB/T 13295 Ductile iron pipes, fitting and accessories for water or gas applications GB/T 13401 Steel buttwelding piping fittings - Technical specification GB/T 13402 Large diameter steel pipe flanges GB/T 13403 Gaskets for large-diameter steel pipe flanges GB/T 13793 Steel pipes with a longitudinal electric(resistance)weld GB/T 13927 Industrial valves - Pressure testing GB/T 13932 Cast iron swing check valves GB/T 14382 Tee strainers for fluids for pipes GB/T 14383 Forged fittings, socket-welding and threaded GB/T 14976 Seamless stainless steel pipes for fluid transport GB/T 15605 Guide for pressure venting of dust explosions GB/T 15706 Safety of machinery - General principles for design - Risk assessment and risk reduction GB/T 16253 Steel castings for pressure purposes GB/T 17116.1 Pipe supports and hangers - Part 1: Technical specification GB/T 17116.1-2018 Pipe supports and hangers - Part 1: Technical specification GB/T 17116.2 Pipe supports and hangers - Part 2: Pipe attachments GB/T 17116.3 Pipe supports and hangers Part 3: Middle connection attachments and building structure attachments GB/T 17185 Steel flanged fittings GB/T 17186.1 Calculation methods for the pipe flange joints - Part 1:Calculation method satisfies both strength and rigidity requirements GB/T 17241.1 Cast iron pipe flanges - Part 1:PN designated GB/T 17241.2 Cast iron pipe flanges - Part 2: Class designated GB/T 17395 Dimensions, shapes, masses and tolerances of steel tubes GB/T 18615 Non-alloyed and stainless steel fittings for corrugated flexible metallic hoses GB/T 18984 Seamless steel tubes for low - temperature - service piping GB/T 19326 Forged branch outlet fittings GB/T 19675.1 Reinforced flexible graphite gaskets for pipe flanges - Part 1: PN designated GB/T 19675.2 Reinforced flexible graphite gaskets for pipe flanges - Part 2 :Class designated GB/T 21832.2 Welded austenitic-ferritic (duplex)stainless steel tubes and pipes - Part 2: Pipes for fluid transport GB/T 21833.2 Seamless austenitic-ferritic (duplex) stainless steel tubes and pipes - Part 2: Pipes for fluid service GB/T 21833.2-2020 Seamless austenitic-ferritic (duplex) stainless steel tubes and pipes - Part 2: Pipes for fluid service GB/T 25137 Titanium and titanium alloy forgings GB/T 26030 Nickel and nickel alloys forgings GB/T 26057 Titanium and titanium alloy welded tube GB/T 26058 Extruded tube of titanium and titanium alloys GB/T 26120 Pipework - Stainless steel threaded fittings GB/T 26480 Valve inspection and testing GB/T 26481 Industrial valves test for fugitive emissions GB/T 27684 Seamless and welded fittings for titanium and titanium alloy GB/T 28708 Specification for size selection of seamless and welded steel pipe used in piping engineering GB/T 29168.1 Petroleum and natural gas industries - Induction bends, fittings and flanges for pipeline transportation systems - Part 1: Induction bends GB/T 29168.2 Petroleum and natural gas industries - Bends, fittings and flanges for pipeline transportation systems - Part 2: Fittings GB/T 29168.3 Petroleum and natural gas industries - Induction bends, fittings and flanges for pipeline transportation systems - Part 3: Flanges GB 30000 (all parts) Specification for classification and labelling of chemicals GB/T 30059 Seamless corrosion - resisting alloy tubes for heat-exchanger GB/T 31032 Welding and acceptance standard for steel pipings and pipelines GB/T 32294 Forged unions, socket-welding and threaded GB/T 32964 Welded stainless steel pipes for liquefied natural gas GB/T 32970 Longitudinal submerged-arc welded steel pipe for high pressure service at high temperatures GB/T 38343 Technical specification for flange joints installation GB/T 38512 Aluminum and aluminum alloy tubes for the pressure vessel GB/T 39245.1 Grooved metal gaskets with covering layers for pipe flanges - Part 1: PN designated GB/T 39245.2 Grooved metal gaskets with covering layers for pipe flanges - Part 2: Class designated GB/T 40079 Classification system and qualification procedures for fugitive emission type testing of valves GB/T 42594 Guidelines for classification on hazard of medium in pressure equipment GB/T 42594-2023 Guidelines for classification on hazard of medium in pressure equipment GB/T 43913 Steel swage (d) nipples GB 50057 Code for design protection of structures against lightning GB 50236 Code for construction of field equipment industrial pipe welding engineering HG/T 3651 Unalloyed titanium and titanium alloy butt - welding seamless pipe fittings HG/T 20537.3 Chemical apparatus of austenitic stainless steel welded pipe technical requirements HG/T 20537.4 Chemical apparatus of austenitic stainless steel welded pipe technology requirements of large diameter HG/T 20592 Steel pipe flanges (PN designated) HG/T 20606 Non-metallic flat gaskets for use with steel pipe flanges (PN designated) HG/T 20607 PTFE envelope gaskets for use with steel pipe flanges (PN designated) HG/T 20609 Metal jacketed gaskets for use with steel pipe flanges (PN designated) HG/T 20610 Spiral wound gaskets for use with steel pipe flanges (PN designated) HG/T 20611 Covered serrated metal gaskets for use with steel pipe flanges (PN designated) HG/T 20612 Metallic ring joint gaskets for use with steel pipe flanges (PN designated) HG/T 20613 Bolting for use with steel pipe flanges (PN designated) HG/T 20614 Specification for selection of steel pipe flanges,gaskets and bolting(PN designated) HG/T 20615 Steel pipe flanges (Class designated) HG/T 20623 Large diameter steel pipe flanges (PN designated) HG/T 20627 Non-metallic flat gaskets for use with steel pipe flanges(Class designated) HG/T 20628 PTFE envelope gaskets for use with steel pipe flanges(Class designated) HG/T 20630 Metal jacketed gaskets for use with steel pipe flanges(Class designated) HG/T 20631 Spiral wound gaskets for use with steel pipe flanges(Class designated) HG/T 20632 Covered serrated metal gaskets for use with steel pipe flanges(Class designated) HG/T 20633 Metallic ring joint gaskets for use with steel pipe flanges(Class designated) HG/T 20634 Bolting for use with steel pipe flanges(Class designated) HG/T 20635 Specification for selection of steel pipe flanges,gaskets and bolting (Class designated) HG/T 21547 Paddle blank,Paddle spacer,Figure - 8 blank for piping system JB/T 2768 Components of valves - High pressure pipes,fittings and end - to - end dimensions of valves JB/T 2769 Components of valves - High pressure threaded flanges JB/T 2772 Components of valves - High pressure Blanks JB/T 2776 Components of valves - High pressure lens gaskets JB/T 2778 Components of valves - Temperature karking of hing pressure pipes and fasteners JB/T 3223 Welding consumables quality management procedures JB/T 6439 Methods of magnetic examination for valves JB/T 6440 Methods of radiographic examination for steel castings valves JB/T 6899 Firetest for valves JB/T 6902-2008 Methods for liquid penetrant examination of valves JB/T 6903-2008 Methods for ultrasonic examination of steel gorgings for valves JB/T 7248 Technical specification for low temperature service steel casting for valves JB/T 7747 Needle valve JB/T 7927 Valve cast steel visual quality requirements JB/T 7927-2024 Valve cast steel visual quality requirements JB/T 8527 Metallic sealing butterfly valve JB/T 8937 Wafer type check valve NB/T 11268 Specification for pressure retaining steel casting of boiler NB/T 47008 Carbon and alloy steel forgings for pressure equipment NB/T 47009 Alloy steel forgings for low temperature pressure equipment NB/T 47010 Stainless and heat-resisting steel forgings for pressure equipment NB/T 47013.1 Nondestructive testing of pressure equipments - Part 1: General requirements NB/T 47013.2 Nondestructive testing of pressure equipments - Part 2: Radiographic testing NB/T 47013.3 Nondestructive testing of pressure equipments - Part 3: Ultrasonic testing NB/T 47013.4 Nondestructive testing of pressure equipments - Part 4: Magnetic particle testing NB/T 47013.5 Nondestructive testing of pressure equipments - Part 5: Penetrant testing NB/T 47013.7 Nondestructive testing of pressure equipments - Part 7: Visual examination NB/T 47013.8-2012 Nondestructive testing of pressure equipments - Part 8: Leak Testing NB/T 47013.10 Nondestructive testing of pressure equipments - Part 10: Ultrasonic time of flight diffraction technique NB/T 47013.11 Nondestructive testing of pressure equipments Part 11: Digital radiographic testing NB/T 47013.14 Nondestyuctive testing of pressure equipments Part14: Computed radiographic testing NB/T 47013.15 Nondestructive testing of pressure equipments Part15: Phased-array ultrasonic testing NB/T 47014 Welding procedure qualification for pressure equipments Welding specification for pressure vessels Mechanical proper tests of product welded test coupons for pressure equipments NB/T 47028 Nickel and nickel alloy forgings for pressure vessels NB/T 47029 Aluminium and aluminium alloy forgings for pressure vessels NB/T 47047 Nickel-nickel alloy seamless tube and pipe for pressure equipments SH/T 3405 Series of steel pipe size in petrochemical industry SH/T 3408 Specification for steel butt-welding pipe fittings in petrochemical engineering SH/T 3410 Forged steel socket-welded and threaded fittings in petrochemical industry SH/T 3411 Specification for selection, inspection and acceptance of strainer for pump in petrochemical industry SH/T 3412 Standard for selection,inspection and acceptance of metallic hose for piping in petrochemical industry SH/T 3413 Specification for selection, inspection and acceptance of pipeline flame arresters for petroleum gas in petrochemical industry SH/T 3419 Steel swaged nipples in petrochemical industry SH/T 3425 Steel line blanks in petrochemical engineering SY/T 5037 Submerged arc-welded steel pipe for common fluid service pipeline TSG ZF001 Safety Technical Supervision Regulation for Safety Valves TSG ZF003 Safety Technical Supervision Regulations for Bursting Disc Devices TSG Z6002 Examination Rules for Welding Operators of Special Equipment YB/T 4173 Seamless forged and bored steel pipes with heavy wall for high-temperature service ISO 15848-1 Industrial valves - Measurement, test and qualification procedures for fugitive emissions - Part 1: Classification system and qualification procedures for type testing of valves ISO 23251 Petroleum, petrochemical and natural gas industries - Pressure-relieving and depressuring systems ISO/IEC 80079-49 Explosive atmospheres - Part 49: Flame arresters - Performance requirements, test methods and limits for use 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 piping system assembled by piping components for conveying, distributing, mixing, separating, discharging, metering or stopping fluid flow Note: Besides the piping components, it also includes pipe-supporting elements, but does not include supporting structures, such as building frame, pipe support, pipe gallery and base (pipe pier or foundation), etc. 3.2 nominal pressure parameter composed of letters PN or class and dimensionless numbers for representing the pressure grade of piping component 3.3 nominal diameter parameter composed of letters DN and dimensionless integer numbers for representing the specification of piping component 3.4 pipe; tube sealed hollow continuous body for conveying fluid or transferring fluid pressure 3.5 fittings general term for elbows, tees, quads, elbows, reducers, pipe caps, flanged joints, unions, etc. 3.6 piping components component for connecting or assembly into a sealed pressure piping system Note: Piping components includes pressure piping elements, safety accessories, non-ferrous metal (non-ferrous metal alloy) fittings, casting fittings, flexible joints, pressure-resistant hoses, fasteners, low-temperature insulation pipes, directly buried jacketed pipes, sight glasses and throttling devices (such as orifice plates) in pipelines, etc. 3.7 pressure piping elements general term for pipe, fittings, valves, flanges, compensators, sealing elements and special components Note 1: Element combination device refers to the device combining pipes, fittings, valves, flanges, compensators and sealing elements with certain functions, including gas regulator, temperature and pressure reducing device, flame arrester, flowmeter (housing) and factory prefabricated pipe spools. Note 2: Flowmeter (housing) refers to a housing made from tubes, plate coils, castings, forgings, flanges, pipe fittings, etc., through machining or welding, that withstands the internal medium pressure of the flowmeter. Note 3: Factory prefabricated pipe spools refer to pipe element products where the manufacturer welds or flange-connects pressure piping elements into an integral assembly according to construction design drawings within the factory for shipment as a whole, including: manifolds, filters, separators, drip legs (drip pots), dirt traps, mixers, buffers, pig launchers/receivers, insulated joints, loading arms, etc., excluding pipe prefabrication performed at the construction site. Note 4: Special components include anti-corrosion piping components and component combination devices. 3.8 safety accessories general term for safety valves, bursting disc devices and emergency stop valves. 3.9 attachment joint attachment joint between piping components, the first attachment joint (welds, flanges, seals, fasteners, etc.) between pipe and equipment or device, and attachment joint between pipe and non-pressure components 3.10 pipe-supporting elements elements used to transfer piping loads to the structure, including the dead weight of piping, weight of the conveyed fluid, loads caused by operating pressure and temperature difference, and the loads caused by vibration, wind, earthquake, snow load, impact and displacement strain Note 1: Pipe-supporting element is classified into two types, i.e. fixed parts and structural accessories. Note 2: Fixed parts include suspended fixed parts such as suspender, spring hanger, diagonal draw bar, counter weight, elastic bolt, bracing piece, chain, guide rail, as well as load-supporting fixed parts such as saddle, base, roller, bracket and sliding support. Note 3: Structural accessories refer to the components attached to piping by welding, bolt connection or clamping methods, such as lifting lugs, pipe hanger, snap ring, pipe clamp, U-clamp and clamping plate. 3.11 pipe supports and hangers general term for structures (excluding supporting structures) used to bear piping loads or constrain piping displacements 3.12 acute toxicity toxicity index of chemicals (medium) causing human death by one-time contact. Note: The hazard degree is classified according to the median lethal dose of LD50 (oral and dermal) or LC50 (inhalation for 4h); see Annex A for details. 3.13 flammable gases gases with a certain explosive (flammable) range when mixed with air at 20 °C and under a standard pressure of 101.3 kPa Note: The classification of flammable gases involved in pressure piping is detailed in Annex A. 3.14 flammable liquids liquids (including liquefied hydrocarbons) with a certain flash point, which are classified according to their flash point and boiling point Note: The classification of flammable liquids involved in pressure piping is detailed in Annex A. 3.15 leakage hazardous medium toxic and flammable media listed in 1) and 2) of 4.1 a) of this document (including also media with design pressure less than or equal to 4.0 MPa) and media of carcinogenic category 1 specified in GB/T 42594 3.16 gas in addition to the definition in 3.13, the "gas" involved in this document also includes steam, liquefied gas, liquids with the maximum working temperature greater than or equal to the standard boiling point, and two-phase or multi-phase gaseous fluid medium 3.17 low hazardous medium fluid media less toxic, flammable and corrosive than those specified in A.2.2, A.2.3, A.2.4, A.2.5.1 and A.2.5.2 Note: It is a "non-toxic, non-flammable and non-corrosive" fluid medium. 3.18 low temperature and low stress service working conditions that need to meet the following conditions at the same time: a) The maximum working pressure at low temperature is not more than 30% of the maximum allowable working pressure at normal temperatures; b) The maximum working stress at low temperature is not greater than 30% of the allowable stress of the material at room temperature, and is not greater than 50 MPa; c) The local stress caused by impact load, hot (cold) impact and differences in linear expansion coefficients of dissimilar metals shall be less than 10% of the allowable stress of the material at room temperature under the design conditions. Note 1: The maximum working stress of a straight pipe (determined by the primary overall membrane tensile stress) is the greater of the following two values: 1) Circumferential tensile stress generated by pressure; 2) The sum of the axial tensile stress caused by pressure, piping durable load and displacement (when calculating the displacement stress, the stress increase factor is not included). Note 2: The maximum working pressure or maximum working stress of flat cover, blind plate, flange, valve and fittings shall be determined by one of the following conditions: 1) Pressure-temperature rating value specified by the standard on piping components; 2) Maximum permissible working pressure determined by type test; 3) The obtained value corresponding to a straight pipe or calculated by using the formula given in Clause 6. 3.19 lower temperature and lower stress service working conditions that need to meet the following conditions at the same time: a) The maximum working pressure at low temperature is not greater than 80% of the maximum allowable working pressure at normal temperature; b) The maximum working stress at low temperature is not greater than 80% of the allowable stress of the material at room temperature; c) The local stress caused by impact load, hot (cold) impact and differences in linear expansion coefficients of dissimilar metals should be less than 10% of the allowable stress of the material at room temperature under the design conditions. Note 1: The maximum working stress of a straight pipe (determined by the primary overall film tensile stress) is the greater of the following two values: 1) Circumferential tensile stress generated by pressure; 2) The sum of the axial tensile stress caused by pressure, piping durable load and displacement (when calculating the displacement stress, the stress increase factor is not included). Note 2: The maximum working pressure or maximum working stress of flat cover, blind plate, flange, valve and fittings shall be determined by one of the following conditions: 1) Pressure-temperature rating value specified by piping components Standard; 2) Maximum permissible working pressure determined by type test; 3) The obtained value corresponding to a straight pipe or calculated by using the formula given in Clause 6. 3.20 electric-resistance welded pipe; ERW continuous butt welded pipe (coil) under pressure, using itself as the current circuit, and heated by resistance 3.21 electric-fusion welded pipe; EFW longitudinally butt-welded pipe on the preformed blank by automatic or electrode arc welding 3.22 plate welded pipe electric-fusion welded pipe, with one or two longitudinal straight welds, preformed into a tubular shape from a flat plate 3.23 inspection certificate a form of material quality certificate, which is an inspection document. It is recorded with the inspection result obtained by the following process: independent authorized departments or personnel other than the production department of the manufacturer inspect and test the delivered products in batches (or by sampling) according to the requirements of the standards and the provisions of the contract, and indicate the results on such document Note: The inspection certificate of the manufacturer shall take effect after signed and approved by the inspection department of the manufacturer independent of the production department. As required by laws and regulations or the development unit (or using unit), a statutory or third-party inspection and testing institution shall issue a supervision and inspection certificate. 3.24 severe cyclic conditions working conditions under which one of the following circumstances occurs: a) The displacement stress range SE [calculated using formula (39)] in pipes, pipework components or joints in the piping system exceeds 0.8 times the allowable stress range SA [calculated using formula (34) or formula (35)], and the equivalent cycle number N [calculated by formula (37)] exceeds 7,000; b) Other working conditions with the same effect [the displacement stress range SE is close to the allowable stress range SA, and the allowable stress range reduction factor f (calculated using formula (36) or obtained by looking up Figure 13) is close to 1.0] determined by the designer according to experience. 3.25 general carbon structural steels carbon steel with product specification level not superior to Grade A specified in GB/T 700 3.26 pipeline steels carbon manganese steel with a high yield ratio, used for pipelines Note: They include seamless steel pipes, electric-resistance welded pipe, plate welded pipe, induction bent pipes, butt welded pipe fittings, and flange forgings with a steel grade not lower than L290/X42 specified in GB/T 9711, GB/T 29168.1, GB/T 29168.2 and GB/T 29168.3. 3.27 product specification level; PSL level to characterize the quality of pipeline steel products specified in GB/T 9711, with the numbers after the abbreviation representing different quality grades 3.28 piping system piping determined by the same design conditions and connected with each other 3.29 elevated temperature fluid service working condition that the working temperature of the material is in the allowable stress temperature range that is determined by the long-term strength of the material 3.30 fluid service comprehensive term related to piping system application, which comprehensively considers fluid properties, operating conditions and other factors, and constitutes the basis of piping system design 3.31 branch connection fitting integral reinforcing fitting that connects the branch pipe to the main pipe through butt welding, socket welding and threaded connection Note: Such as branch pipe socket and half coupling. 3.32 rating value pressure value of piping components specified in the standard 3.33 schedule number numerical code of pipe wall thickness series 3.34 displacement strain in the pipe components, the strain caused by the displacement of piping constraint points and the additional displacement of end points as well as the strain caused by temperature changes 3.35 displacement stress stress caused by displacement strain in piping components 3.36 structural attachments; attachment of support on piping general name of the support and hanger parts directly connected with the piping or its insulation layer by welding, bolting or clamping 3.37 design minimum temperature minimum temperature of components in expected working conditions, based on which the special design requirements and material evaluation requirements are determined 3.38 creep strength enhanced ferritic steels; CSEF Cr-Mo ferritic steel with creep rupture strength improved through precipitation strengthening and grain refining Note: They generally include 2.25 Cr-1.6W-V-Cb, 9Cr-1Mo-V, 9Cr-1Mo-1W-Cb, 9Cr-2W and 12Cr-2W chromium molybdenum ferritic steels. 3.39 volatile organic compounds; VOC organic compound participating in photochemical reaction in atmosphere or any organic liquid that emits organic compounds into the atmosphere and meets one of the following conditions: a) The true vapor pressure of volatile organic liquid is larger than 0.3kPa at 20℃; b) At 20℃, in the mixture of air and organic compounds, the total mass fraction of pure organic compounds with true vapor pressure greater than 0.3 kPa is equal to or higher than 20%, see GB 31570 and GB 31571. 3.40 fabrication preparation work ahead of assembly in piping Note: It includes cutting, threading, grooving, forming, bending, welding and connecting components into assemblies, which may be done in workshop or on site. 3.41 assembly process of connecting two or more piping components together (including piping prefabrication) by bolts, welding, bonding, threading, brazing, soldering or sealing elements according to the design documents 3.42 erection process of completely fixing a piping system on the designated position and bracket according to the design documents Note: It includes all on-site fabrication, assembly, checking and test of the system according to the specification requirements. 3.43 isometric drawing diagram that each piping is drawn as a 3D view of piping represented by a single line according to the drawing method of axonometric projection 3.44 piping factory pre-fabrication process of manufacturing piping products by processing, inspection, assembly, welding, heat treatment, piping, testing, marking, cleaning, painting and protection of piping components or pipe-supporting elements in the factory (workshop). Note: It includes production processes of factory prefabricated pipe spools, piping of modular structure, piping of skid-mounted equipment system, etc. 3.45 hot bending process of fabricating the bend when the temperature is higher than the critical point AC1 of metal 3.46 cold bending process of fabricating the bend when the temperature is lower than the critical point AC1 of metal 3.47 pipe-segments to be prefabricated pipe-segment, which is determined and can be processed in advance, selected according to the isometric diagram before the piping is fabricated and processed 3.48 pipe-segments for dimension adjustment pipe-segment, which is determined and can be processed after measuring the erection dimension, selected according to the isometric diagram before the piping is fabricated and processed 3.49 tack weld cover fillet weld short weld to be welded for assembling and locating weldment joints before the final weld is completed 3.50 weldment assembly made by welding all components of a member Note: The weldment includes two parts, namely base metal and welded joint. 3.51 interpass temperature temperature to be maintained by the adjacent weld pass and the base metal before the next weld pass is welded in multi-layer multi-pass welding 3.52 final closure point the last connection port to be assembled between two fixed positions in a piping system Note: The final closure point of the piping may be connected by welding (butt joint, welded connector) or flange connection. 3.53 misalignment at the final closure point deviation of the final closure point of the piping when it is assembled without external force, which may be decomposed into the misalignment deviation values in the transverse direction (X and Y axes) and the axial direction (Z-axis). Transverse (X and Y axes) deviation value indicates the deviation degree of the center lines of the end faces of two connected pipe segments; axial (Z-axis) deviation value indicates the gap between the parallel sections at the ends of two connected pipe segments 3.54 length of assembly pipe length of the assembly pipe segment in a direction (X, Y, or Z axis) Note: It represents the sum of the cumulative length of pipe segments in the piping system extending from the closure point to both ends in the other two directions (transverse or axial) between the two closest fixed positions. 3.55 inspection compliance review process conducted by the development unit (or using unit) or an inspection body independent of the piping builder to verify whether the product or piping construction meets the requirements of code and engineering design 3.56 inspector full-time personnel engaged in inspection work at the development unit (or using unit) or the inspection body 3.57 examination process of manufacturing plant as well as fabrication, construction and erection units fulfilling quality control responsibilities by carrying out necessary inspection and test on materials, components, processing, fabrication and erection to verify whether the product or piping construction meets the requirements of relevant standards and engineering design 3.58 examination personal full-time staff of manufacturing plant as well as fabrication, construction and erection units engaging in examination work, who shall be the staff independent of the manufacturing, fabrication and erection departments 3.59 safety protection device mechanical (physical) protection device that works in case of failure of automatic control instrument and manual intervention when analyzing according to the safety protection layer Note: Safety protection devices are the last barrier to prevent accidents or reduce accident losses, including safety relief devices, flame arresters, fire emergency block valve and mechanical interlocking devices. 3.60 safety relief device device opened by the inlet static pressure or the inlet and outlet static pressure difference to release fluid so as to prevent the pressure in the system from exceeding the preset safety value in case of non-fire or fire accident Note: It includes safety valve, rupture disk device and buckling pin relief valve. 3.61 safety valve valve acted by a spring or controlled by pilot valve Note: When the static pressure at the inlet (for ordinary valves, the static pressure difference between the inlet and outlet) exceeds the set pressure, it can release the fluid so as to prevent the pressure in the system from exceeding the preset safety value, and automatically stop releasing when the pressure drops to the re-seating pressure Safety valves have ordinary, balanced and pilot types.