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GB/T 20801 consists of the following six parts under the general title of Pressure piping code - Industrial piping:
——Part 1: General;
——Part 2: Materials;
——Part 3: Design and calculation;
——Part 4: Fabrication and assembly;
——Part 5: Inspection and testing;
——Part 6: Safeguarding.
This is part 1 of GB/T 20801.
This part is developed in accordance with the rules given in GB/T 1.1- 2009.
This part replaces GB/T 20801.1-2006 Pressure piping code Industrial piping - Part 1: General. In addition to editorial changes, the following main technical changes have been made with respect to GB/T 20801.1-2006:
——the application scope of this standard is modified according to Special Equipment Catalog [see 1.3 a); 1.3.1 of Edition 2006];
——the application scope of this standard is modified with exclusive method [see 1.3 b); 1.3.2 of Edition 2006];
——the non-application scope and exclusion scope of this standard are modified (see 1.4 and 1.5; 1.4 and 1.5 of Edition 2006);
——the definition of piping component is modified (see 3.5; 3.5 of Edition 2006);
——the relevant definitions of medium hazard are modified (see 3.9, 3.10 and 3.11; 3.10 and 3.11 of Edition 2006);
——the relevant definition of “gas” is added (see 3.12);
——the classification for Grades GC1, GC2 and GC3 pressure piping is modified according to relevant administrative licensing (see 4.1 and 4.2; 4.1, 4.2 and 4.3 of Edition 2006);
——the "classification for toxicity and inflammability of medium in pressure piping" is added (see Annex A).
This part was proposed by and is under the jurisdiction of the National Technical Committee on Boilers and Pressure Vessels of Standardization Administration of China (SAC/TC 262).
The previous edition replaced by this part is as follows:
——GB/T 20801.1-2006.
Pressure piping code - Industrial piping - Part 1: General
1 Scope
1.1 GB/T 20801 specifies the basic requirements for the design, fabrication, assembly, inspection, testing and safeguarding of industrial metal pressure piping.
1.2 This part of GB/T 20801 specifies the basic requirements for pressure piping, such as application scope and piping grading.
1.3 The industrial metal pressure piping (hereinafter referred to as “pressure piping”) in this part includes the pressure piping for process devices, auxiliary devices and utility works within the battery limit.
This part is applicable to the piping with the following conditions:
a) The 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. The piping and equipment piping with a nominal diameter less than 150mm and the maximum working pressure less than 1.6MPa (gauge pressure) for conveying non-toxic, nonflammable and non-corrosive gases is excluded.
b) Pressure piping other than those listed in 1.5.
1.4 The exclusion scope of this part is as follows:
a) special requirements for reconstruction, examination, inspection, test, maintenance and repair of in-service pressure piping;
b) piping with a nominal pressure greater than PN420;
c) non-metal piping or lining layers thereof.
1.5 The non-application scope of this part is as follows:
a) piping of military equipment and nuclear facilities;
b) piping of exploration and excavation devices for petroleum, natural gas, terrestrial heat, etc.;
c) pressure piping of mobile equipment such as railway locomotives, automobiles, ships and aerospace vehicles;
d) Type GA long-distance piping;
e) Type GB utility piping;
f) Type GCD power piping;
g) internal piping of boilers, pressure vessels and heating furnaces as well as external piping orifices of equipment;
h) piping with a design pressure less than 0.1MPa (gauge pressure) and not less than atmospheric pressure for conveying non-toxic, non-flammable and non-corrosive fluids.
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 20801.2 pressure piping code - Industrial piping - Part 2: Materials
GB/T 20801.3 Pressure piping code - Industrial piping - Part 3: Design and calculation
GB/T 20801.4 Pressure piping code - Industrial piping - Part 4: Fabrication and assembly
GB/T 20801.5 Pressure piping code - Industrial piping - Part 5: Inspection and testing
GB/T 20801.6 Pressure piping code - Industrial piping - Part 6: Safeguarding
GB 30000 (All parts) Rules for classification and labeling of chemicals
GB 50016-2014 Code for fire protection design of buildings
GB 50160-2008 Fire prevention code of petrochemical enterprise design
Catalogue of hazardous chemicals (2015)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 20801.2, GB/T 20801.3, GB/T 20801.4, GB/T 20801.5, GB/T 20801.6 and the following 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; PN
parameter composed of letters PN and dimensionless integer numbers for representing the pressure grade of piping component
3.3
nominal diameter; DN
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
piping component
mechanical element for connecting or assembling into pressure-tight piping system
Note: it includes pressure piping elements (pipes, fittings, valves, flanges, compensators, sealing elements and special elements), safety accessories (safety valves, rupture disk devices and emergency cut-off valves), as well as fasteners, back-fire relief valves, expansion joints, flexible connectors, pressure hoses, filters, instruments in pipelines (such as pore plates) and separators.
3.6
pipe-supporting element
elements used to transfer piping loads to pipe support 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
Notes:
1 Pipe-supporting element is classified into two types, i.e. fixed parts and structural accessories.
2 Fixed parts include suspended fixed parts such as suspender, spring hanger, diagonal draw bar, counter weight, elastic bolt, bracing piece, chain, guide rail and supporting structure, as well as load-supporting fixed parts such as saddle, base, roller, bracket and sliding support.
3 Structural accessories refer to the elements 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.
3.7
fitting
a category of piping component, generally including elbow, tee, cross, bend pipe, reducer, pipe cap, stub ends, union, etc.
3.8
pipe support
structure used to support piping
Notes:
1 The piping transfers the load and thrust to the pipe support through the supporting element.
2 The pipe support consists of columns, beams or frames of steel structure or reinforced concrete structure, which may be fixed on the foundation independently or on the equipment or wall.
3 It may be classified into single-column type, double-column type and cantilever type based on the type.
3.9
acute toxicity
toxicity index of chemicals (medium) causing human death by one-time contact. 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
3.10
flammable gas
gases with a certain explosive (flammable) range after being mixed with air at 20℃ and 101.3kPa standard pressure
3.11
flammable liquid
liquids (including liquefied hydrocarbon) with a certain flash point, which are classified based on the flash point and boiling point. See Annex A for details
3.12
gas
in addition to the definition in 3.10, the "gas" involved in GB/T 20801 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
4 Grading of pressure piping
4.1 The "pressure piping" listed in 1.3 a) is classified into Grade GC1 and Grade GC2 based on the hazard degree and safety level:
a) pressure piping meeting one of the following conditions shall be classified as Grade GC1:
1) Pressure piping for conveying medium of Category 1 acute toxicity medium, gas medium of Category 2 acute toxicity and liquid medium of Category 2 acute toxicity with working temperature greater than its standard boiling point specified in Catalogue of hazardous chemicals (2015).
2) Pressure piping with design pressure greater than or equal to 4.0MPa for conveying Categories A and B flammable gases or Category A flammable liquid (including liquefied hydrocarbon) specified in GB 50160-2008 and GB 50016-2014.
3) Pressure piping with design pressure greater than or equal to 10.0MPa or greater than or equal to 4.0MPa and design temperature greater than or equal to 400℃ for conveying the fluids other than the medium mentioned above.
b) pressure piping (including refrigeration piping) meeting the following conditions shall be classified as Grade GC2:
Pressure piping with medium toxicity or flammability hazard and hazard degree, design pressure and design temperature lower than those (Grade GC1) specified in 4.1 a).
4.2 Pressure piping listed in 1.3 b) and meeting the following conditions shall be classified as Grade GC3:
Pressure piping with a design pressure less than or equal to 1.0MPa and a design temperature greater than -20℃ but not greater than 185℃ for conveying non-toxic, nonflammable and non-corrosive liquid medium.
Note: Grade GC3 piping is not applicable to the pressure piping listed in 1.3 a).
4.3 Where the mixed medium with different toxicities or flammable hazards and hazard degrees are conveyed, the grade of pressure piping shall be determined by the owner or designer according to those specified in Annex A.
5 Basic requirements
5.1 The materials of pressure piping shall meet those specified in GB/T 20801.2.
5.2 The design and calculation of pressure piping shall meet those specified in GB/T 20801.3.
5.3 The fabrication and assembly of pressure piping shall meet those specified in GB/T 20801.4.
5.4 The inspection and testing of pressure piping shall meet those specified in GB/T 20801.5.
5.5 The safeguarding of pressure piping shall meet those specified in GB/T 20801.6.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Grading of pressure piping
5 Basic requirements
Annex A (Normative) Classification of toxicity and inflammability of medium in pressure piping
