1. General
1.0.1 This code is prepared for improving the design level of industrial metallic pipeworks and ensuring their design quality.
1.0.2 This code is applicable for the design of industrial metallic pipings serving at a nominal pressure below or equal to 42MPa and those with non-metallic lines.
1.0.3 This code is not applicable for the design of:
10.3.1 Pipings for a whole set of equipment or machine designed by the manufacturer;
1.0.3.2 Pipings in power sector;
1.0.3.3 Long-distance delivering pipings;
1.0.3.4 Pipings in mine;
1.0.3.5 Pipings for heating, ventilating, and air conditioning, as well as pipings with a noncircular section;
1.0.3.6 Underground or indoor water supply and drainage pipings, and fire extinguishing purpose water supply pipings;
1.0.3.7 Pipings for foam, carbon dioxide, or other type fire extinguishing systems;
1.0.3.8 Urban public pipings.
1.0.4 The pressure used in this code shall be gauge pressure unless otherwise specified.
1.0.5 In addition to this code, the design of any industrial metallic piping shall meet the requirements in national current standards concerned.
2. Terms and Symbols
2.1 Terms
2.1.1 category A1 fluid
for the purpose of this code, highly toxic fluid that can seriously poison the individual who absorbs or is exposed to the fluid and cannot be cured even he/she is out of exposure, in case a small amount of the fluid leaks out during transportation. The fluid is corresponding to the (extremely hazardous) Level I toxic substance stipulated in the current national standard GB 5044 Classification of Health Hazard Levels From Occupational Exposure to Toxic Substances
2.1.2 category A2 fluid
toxic fluid that can poison the individual who is exposed to it to different extents, but can be cured after being out of exposure. The fluid is corresponding to the (high, moderately, or lightly hazardous) Level II toxic substance or below stipulated in the current national standard GB 5044 Classification of health hazard levels from occupational exposure to toxic substances
2.1.3 category B fluid
for the purpose of this code, fluid that may be gas or liquid that can generate a gas by flash evaporation in the circumstance or under the operation condition and can be ignited and continuously burn in air
2.1.4 category D fluid
incombustible and nontoxic fluid that is used in the case of the design pressure below or equal to 1.0MPa and design temperature between –20 and 186℃
2.1.5 category C fluid
incombustible and nontoxic fluid excluding Category D fluid
2.1.6 piping
facility that consists of piping components, pipe supports and hangers, and others, and is used to deliver, distribute, mix, separate, drain, measure, or control flow of fluid
2.1.7 piping system
set of pipings connecting each other and classified according to the category of fluid and the design condition
2.1.8 piping components
components used to connect or assemble into a piping, including pipes, pipe fittings, flanges, gaskets, fasteners, valves, and piping specialties
2.1.9 piping specialties
non-standard ordinary piping components, which are specially manufactured according to the engineering design condition, including expansion joints, compensators, special valves, rupture disks, fire arrestors, filters, flexible connectors, hoses, etc.
2.1.10 minter bends
welded bend made of pipes or steel sheets, spliced from pipe sections of mitre weldings not perpendicular to the longitudinal axis of the pipes
2.1.11 branch connections
structure leading branch(es) from the main pipe, including integrally -reinforced pipe fittings and the branch connections with or without reinforced welded structure
2.1.12 raised face
a kind of seal face of flange, with the bulgy flat seal face within the internal side of the bolthole, designated as RF
2.1.13 full face
a kind of seal face of flange, with flat seal face all within the outer diameter, designated as FF
2.1.14 liquid collecting pocket (drip leg)
condensate-collecting purpose pocket-like device setting at the low point of a gas or vapor piping
2.1.15 pipe supports and hangers
generic name used to entitle various structures supporting pipings or restricting displacement of pipings as a whole, excluding civil structures
2.1.16 anchors
support that can make a piping system produce neither linear displacement nor angular displacement at a supporting point, and may bear various loads on the piping in different directions
2.1.17 sliding support
support with sliding supporting face, which may restrict vertically downward displacement of a piping, but does not restrict horizontal displacement of the piping for thermal expansion or contraction, and bears the vertical load including of the deadweight of the piping
2.1.18 rigid hangers
pipe support structure with a hinged hanging rod, which may restrict vertically downward displacement of a piping, but does not restrict horizontal displacement of the piping for thermal expansion or contraction, and bears the vertical load including of the deadweight of the piping
2.1.19 guides
support that may prevent rotation caused by a moment of force or a torsional moment, guide one or more direction(s), but the piping still may move in the given axial direction. When it is used in a horizontal piping, the guide bears the vertical load including of the deadweight of the piping in addition to the above-mentioned function. Usually, the structure of a guide has a restricting function in one or two axial direction(s)
2.1.20 restraints
support that can restrict the displacement, which may be linear or angular displacement in one or more direction(s), of the piping in the designated direction at a point. The restraint with a prescriptive displacement value is called the setting value restraint
2.1.21 vibrating eliminators
device that can control high-frequent and low-amplitude vibration or low-frequent and high-amplitude shake of a piping system, but does not restrain its thermal expansion or contraction
2.1.22 snubbers (dampers)
device that can control instantaneous impact load upon a piping or high-speed vibration displacement of a piping system, but does not restrain their thermal expansion or contraction
2.1.23 severe cyclic condition
condition under which the maximum displacement stress range, σE, calculated for a piping exceeds 0.8 times of the allowable displacement stress range, that is 0.8[σ]A, and the number of equivalent cycles, N, is larger than 7,000 or designed condition resulting equivalent effect
2.1.24 stress intensification factor
ratio of the maximum bending stress leading fatigue failure of a component of a non-straight piping for the sake of a bending moment to the maximum bending stress leading fatigue failure of a component of a straight piping with the same diameter and thickness at the same bending moment, which are divided into two types, in-plane and out-plane, according to different planes the bending moment and the component are in
2.1.25 displacement stress range
stress calculated from the displacement caused by thermal expansion of a piping. The one calculated from the full compensation value from the lowest temperature to the highest temperature is called the calculated maximum displacement stress rang
2.1.26 externally imposed displacements
displacement of the calculated piping system imposed from the end of the piping system due to thermal expansion of the equipment or other connected piping, or another displacement
2.1.27 cold spring
a process that an elastic deformation is imposed upon the piping prior to its installation to produce an anticipated displacement and stress, and reduce the acting force and the moment on the piping end under the initial thermal condition
2.1.28 flexibility factor
extent to which the flexibility of a piping component increases as it bears a moment relative to a straight piping. That is, in a piping component, the ratio of the angular deformation of the component per unit length generated under action of a given moment to the angular deformation of a straight piping with the same diameter and thickness, under action of the same moment
2.1.29 utility piping
pipings for utility fluids in various operations of a plant or device relative to process piping
2.1.30 piping and instrument diagram
P&ID or PID for short, where the designations indicating the piping system, and instrument and gauges connected, and the identification codes for different pipings are shown, in addition to equipment and apparatus
2.2 Symbols
A——The reinforced area needed for opening on a main pipe.
A1——The redundant metallic area of a main pipe within the reinforced range, excluding both the calculated thickness and the additional thickness used to bear internal and external pressures.
A2——The redundant metal area of a branch within the reinforced range, excluding both the calculated thickness and the additional thickness used to bear internal and external pressures.
A3——The area of the fillet weld within the reinforced rang.
A4——The area of the additional reinforcing plate within the reinforced rang.
A5——The redundant metallic area of an extruded branch within the reinforced range, excluding both the calculated thickness and the additional thickness used to bear internal and external pressures.
Ak——The impact power upon a material.
B——The effective width of a reinforced zone.
Clt——The allowance for the possibly attenuated (minus deviation) of a branch in the thickness.
Clm——The allowance for the possibly attenuated (minus deviation) of a main pipe in the thickness.
Clr——The allowance for the possibly attenuated (minus deviation) of a reinforcing plate in the thickness.
C——The sum of all thickness allowances.
C1——The allowance for the possibly attenuated in the thickness, including minus deviations caused by processing, fluting, depth of thread, and material thickness.
C2——The allowance for corrosion or abrasion.
Cf——The correction factor.
Ch——The tolerance factor in piping pressure loss.
Cp——The specific heat at constant pressure.
Cs——The cold spring ratio, namely the ratio of cold spring value and full compensation value.
Cv——The specific heat at constant volume.
C.S.C.(L.C.)——Lock in closed state (not allow to open without approval).
C.S.O.(L.O.)——Lock in opened state (not allow to close without approval).
d——The inner diameter of a branch after deducting the allowance in thickness.
do——The nominal diameter of a branch.
d1——The major diameter of the diagonal cut joint on a main pipe after deducting the allowance in thickness.
dG——The inner diameter of the gasket for a female or face flange, or average diameter of a ring groove gasket.
dX——The inner diameter of an extruded branch after deducting the allowance in thickness.
DN——The nominal diameter of a pipe or pipe fitting.
Di——The inner diameter of a pipe or pipe fitting.
DiL——The inner diameter of the larger end of a reducer.
DiS——The inner diameter of the smaller end of a reducer.
Do——The outer diameter of a pipe or pipe fitting.
DOL——The outer diameter of the larger end of a reducer.
DOS——The outer diameter of the small end of a reducer.
Dr——The outer diameter of a reinforcing plate.
Ec——The quality factor of a casting.
Ej——The weld joint factor.
Eh——The elastic modulus of a piping material at the highest or lowest temperature.
E20——The elastic modulus of a piping material at the installation temperature.
FH——The working load.
fr——The ratio between the allowable stresses of the materials for the reinforcing plate and the main pipe.
fs——The changing factor of load.
f——The reduction factor of the displacement stress range of a piping.
g——The acceleration of gravity.
h——The dimension factor.
h1——The normally reinforced effective height at the outer side of a main pipe.
h2——The effective reinforced height for a branch.
h3——The inward dented depth of a flat cap.
hx——The height of a extruded branch.
i——The stress intensification factor.
ii——The stress intensification factor in a plane.
io——The stress intensification factor out of a plane.
is——The gradient of a piping.
k——The adiabatic index of a gas.
K——The flexibility factor.
K1——The factor related to the structure of a flat cap.
K2——The empirical value for a minter bend.
K3——The reinforcing factor for an extruded branch.
KR——The resistance factor.
Ks——The stiffness of a spring.
KT——The allowable stress factor.
L——The length of a piping.
Le——The equivalent length of valves and pipe fittings.
Lf——The shorter edge length of the end section of a minter bend.
Ls——The spacing between supports or hangers.
LST——The length of the reinforced section of a straight pipe connected to the larger end of a reducer.
LSS——The length of the reinforced section of a straight pipe connected to the smaller end of a reducer.
M——The molecular weight of a gas.
MA——The resultant moment from action of the deadweight and other continuous external load on the section of the piping.
MB——The resultant moment from action of the accidental load caused by the counterforce of the safety valve or relief valve, transient change of flow and pressure in a piping, wind force, or earthquake on the section of the piping.
ME——The equivalent resultant moment of thermal expansion.
M’E——The resultant moment in which the stress intensification factor is not counted.
Mi——The bending moment from thermal expansion in the plane.
MO——The bending moment from thermal expansion out of the plane.
Mt——The twisting moment from thermal expansion.
MX——The moment in the direction of X- coordinate axis.
MY——The moment in the direction of Y- coordinate axis.
MZ——The moment in the direction of Z- coordinate axis.
n——The ordinal.
N——The equivalent number of full displacement cycles in the estimated service life of a piping system.
NE——The cyclic number related to the calculated maximum displacement stress range, σE.
Nj——The cyclic number related to the displacement stress range, σj calculated for a value less than the full displacement.
P——The design pressure.
PA——The allowable stress at the design temperature.
Pm——The maximum allowable inner pressure of a minter bend.
PN——The nominal pressure.
PT——The test pressure.
QL——The stress intensification factor for connection of the larger end of a reducer with a straight pipe.
QS——The stress intensification factor for connection of the smaller end of a reducer with a straight pipe.
R——The curvature radius of a circular arc bend.
Rl——The curvature radius of a minter bend.
Rc——The force and moment acted by a piping on the equipment or the end point at the installation temperature in the initial period of operation.
Rcl——The force and moment acted by a piping on the equipment or the end point at the installation temperature after self-recovery
RE——The force and moment acted by a piping on the end point that is calculated based on E20 and full compensation
Rh——The force and moment acted by a piping on the equipment or the end point at the highest or lowest temperature in the initial period of operation.
Rm——The average radius of the main pipe.
r——The fillet radius in the flat cap.
ro——The average radius of a pipe or pipe fitting.
r1, r2, r3——The transitional radius of the reinforced position of the branch.
rj——The ratio of the displacement stress range, σj calculated for a value less than the full displacement to the calculated maximum displacement stress range, σE.
rm——The average radius of a branch.
rp——The outer radius of the reinforced position of a branch.
rx——The curvature radius at the corner of the outer profile in the plane of the axes of a main pipe and its branch.
S——The spacing at the central line of the miter section of a minter bend.
T——The gas temperature.
T1——The thickness of a butt weldment at the thinner side.
T2——The thickness of a butt weldment at the thicker side.
Tc——The thickness of a tee at the round corner (the intersection position of the main pipe and the branch).
Tt——The calculated thickness of the main pipe.
Ttn——The nominal thickness of the main pipe.
t——The thickness of the end of a half coupling.
tb——The effective thickness of a branch at the reinforced position.
tc——The calculated effective thickness of a fillet weld.
teb——The effective thickness of the branch of a tee.
tFn——The nominal thickness of a pipe fitting.
tL——The nominal thickness of a reducer.
tL1——The nominal thickness of a reducer at the larger end.
tL2——The nominal thickness of a reducer at the smaller end.
tLC——The calculated thickness of a reducer at the conic position.
tLL——The calculated thickness of a reducer at the larger end.
tLS——The calculated thickness of a reducer at the smaller end.
tm——The calculated thickness of a blind flange.
tp——The calculated thickness of a flat cap.
tpd——The design thickness of a flat cap or blind flange
tr——The nominal thickness of a reinforcing plate.
ts——The calculated thickness of a straight pipe.
tsd——The design thickness of a straight pipe.
tse——The effective thickness of a straight pipe.
tsn——The nominal thickness of a straight pipe.
tt——The calculated thickness of a branch.
ttn——The nominal thickness of a branch.
tX——The effective thickness for extruding a branch on the outer surface of the main pipe after reducing the allowance for thickness.
tw——The dimension of a sockolet.
v——The average flow velocity.
vc——The sound velocity or the critical flow velocity of a gas.
W——The cross section factor.
WB——The net section factor of a reduced tee branch.
Wo——The mass flow rate.
X——The dimension of the fillet leg weld inside a flange.
Xmin——The minimum dimension of a fillet weld leg.
Y——The factor.
Ys——The bending deflection of a piping due to its deadweight.
α——The angle by which the direction of a welding seam on a minter bend changes (the included angle between the two adjacent miter lines).
α1——The included angle between the axes of the branch and the main pipe.
α0——The average linear expansion factor of a metallic material.
β——The included angle between the bevel edge and the axial line of a reducer.
θ——A half of the angle by which the direction of a welding seam on a minter bend changes (a half of the included angle between the two adjacent miter lines).
θn——The transitional angle at the reinforced position of a branch.
δ——The maximum calculated elongation of fiber.
δave——The average value of the unfitness of a butt joint.
δmax——The maximum value of the unfitness of a butt joint.
δ1——The nominal thickness of a parent metal.
δ2——The effective thickness of a coating metal after reducing the allowance.
Δ——The vertical thermal displacement of a piping.
ΔPf——The pressure loss due to friction on a straight piping.
ΔPk——The local pressure loss due to friction.
ΔPt——Total pressure loss of a piping.
η——The factor related to the structure of a flat cap.
ρ——The density of a fluid.
λ——The friction factor of a fluid.
σb——The lower limit value of the tensile strength of a material at standard temperature-pressure.
——The tensile strength of a material at the design temperature.
——The average value of the creep rupture strengths of a material at the design temperature for 100 thousand hrs in a creep test.
σE——The calculated maximum displacement stress range.
σj——The displacement stress range calculated for a value less than the full displacement.
σL——The sum of the longitudinal stresses produced by pressure, gravity, and other continuous load in the piping.
——The creep limit of a material at a creep rate of 1% at the design temperature for 100 thousand hrs in a creep test.
σs(σ0.2)——The yield point of a material at the standard normal temperature (or 0.2% yield strength).
(σt0.2)——The yield point of a material at the design temperature (or 0.2% yield strength).
σT——The hoop stress of a component under the test condition.
[σ]T——The allowable stress of a material at the test temperature.
[σ]t——The allowable stress of a material at the design temperature.
[σ]o——The allowable stress of an integrally clad metallic material at the design temperature.
[σ]1——The allowable stress of the parent metal at the design temperature.
[σ]2——The allowable stress of the coating metal at the design temperature.
[σ]A——The allowable displacement stress rang.
[σ]c——The allowable stress of a metallic material in cold status (at the estimated lowest temperature) in the analyzed displacement cycle.
[σ]h——The allowable stress of a metallic material in hot status (at the estimated highest temperature) in the analyzed displacement cycle.
[σ]x——The allowable stress of a material at the calculated temperature adopted when the thickness of a component is determined.
[σ]tRP——The allowable stress of the material used for a reinforcing plate at the design temperature.
[σ]tM——The allowable stress of the material used for a main piping at the design temperature.
3. Design Condition and Design Reference
3.1 Design Condition
3.1.1 The piping shall be designed according to the process conditions, such as pressure, temperature, characteristics of the fluid and others, taking the circumstance and various load conditions in account.
3.1.2 Determination of the design pressure shall meet the following requirements:
3.1.2.1 The design pressure of a piping and each component of it shall not be less than the pressure occurred when a severest condition appears due to coupling of an internal pressure or an external pressure with temperature in operation. The severest condition shall be taken as a parameter for calculation of the largest thickness of the piping component is required, and of the highest nominal pressure in the strength calculation. But, the above-said design pressure shall not include the non-recurrently fluctuant value of pressure allowed in this clause.
3.1.2.2 For any of the following pipings in special conditions, the design pressure value shall be compared with the result selected as 3.1.2.1, whichever is larger.
(1) For the piping used to deliver the fluid with a lower gasifying temperature, such as cryogen and liquefied hydrocarbons, the design pressure shall not be less than the highest pressure possibly reached when the fluid in it is gasified at the highest ambient temperature in the case of closure of the valve or the fluid not in flow;
(2) The design pressure of the discharge piping of a centrifugal pump shall not be less than the sum of the suction pressure and the pressure equivalent to the delivery head;
(3) For the piping that is equipped with no pressure-relieving device, or isolated from a pressure-relieving device, its design pressure shall not be less than the maximum pressure the fluid in it may reach.
3.1.2.3 A vacuum piping shall be designed according to the external pressure it may bear, if equipped with a safety control device, its design pressure shall be 1.25 times of the difference between the internal and external pressures, or 0.1MPa, whichever is lower; if there is no safety control device, its design pressure shall be 0.1MPa.
3.1.2.4 The design pressure of a piping with the pressure-relieving device shall not be less than the pressure under which the pressure-relieving device opens.
3.1.3 Determination of the design temperature shall meet the following requirements:
3.1.3.1 The design temperature of each piping component shall not be less than the temperature corresponding to the required maximum thickness or the maximum nominal pressure specified in 3.1.2.1 hereof. The determination of the design temperature shall also take into the account of the influence of such factors as fluid temperature, environment temperature, solar radiation and heated or cooled fluid temperature.
The designed minimum temperature shall be the minimum working temperature of piping components, and this temperature shall not be less than the lower limit of service temperature of materials. The lower limit of the service temperature of common materials shall meet the requirements of Annex A in this code.
3.1.3.2 For the piping heated by its tracer or jacketed pipe, the externally heating temperature or the temperature of the fluid inside the piping shall be taken as the design temperature, whichever is higher.
3.1.3.3 For the piping without thermo-insulating layer, different piping components may be designed with different temperatures, and their design temperatures shall meet the following requirements:
(1) In the case of a fluid temperature below 65℃, the design temperature of a piping component may be the same as that of the fluid;
(2) In the case of a fluid temperature equal to or over 65℃, the design temperature of a piping component shall not be less than the following value, unless calculated as heat transfer or there is a lower average wall temperature determined by the test:
95% of the fluid temperature for valves, pipes, flange spools, welded pipe fittings, and other piping components with the similar thickness;
90% of the fluid temperature for flanges, including those on the pipe fittings and valves, but excluding loose flanges;
85% of the fluid temperature for loose flanges;
80% of the fluid temperature for the fasteners for flanges.
3.1.3.4 The design temperature of a piping with external thermo-insulation shall be determined as 3.1.3.1 and 3.1.3.2. Other temperatures may be adopted if there is a calculated, tested, or measured result available.
3.1.3.5 The design temperature of a piping with internal thermo-insulation shall be determined based on heat transfer calculation or test.
3.1.3.6 For a piping with a non-metallic material liner, its design temperature shall be equal to the highest working temperature of the fluid. When there is no external thermo-insulating layer, the design temperature of the external metal may be determined by heat transfer calculation, or test, or as 3.1.3.3.
3.1.4 Effective measures shall be taken to cope with the following environmental influences:
3.1.4.1 For cooling of gas or vapor in a piping, its pressure drop value shall be determined. In case of vacuum in piping, the piping shall be able to withstand the external pressure at low temperature, or effective preventive measure shall be taken to destroy the vacuum.
3.1.4.2 A piping component shall be able to withstand or eliminate the increasing pressure due to thermal expansion of the static fluid; otherwise, effective preventive measure shall be taken.
3.1.4.3 In case of the piping temperature below 0℃, proper measures shall be taken to prevent the external surfaces of shutoff valves, control valves, pressure-relieving devices, and the moving parts of other piping components from freezing.
3.1.5 A piping shall be able to withstand the following dynamic loads:
3.1.5.1 A piping shall be able to withstand impact loads caused by hydraulic impact, strike of liquid or solid, and others.
3.1.5.2 An outdoor above ground piping shall be able to withstand wind load.
3.1.5.3 The piping located in an earthquake region shall be able to withstand the horizontal force caused by earthquake, and shall conform to the requirements in the national current aseismatic standards concerned.
3.1.5.4 The piping arrangement and support shall be such designed to eliminate the influence of harmful vibration caused by impact, pressure fluctuation, resonance of machines, and wind load on the pipings.
3.1.5.5 The piping arrangement and support shall be such designed that they can withstand the counterforce caused by pressure reduction and discharge of the fluid.
3.1.6 The static loads born by piping shall include fixed loads and live loads. Live loads shall include the gravity of the delivered fluid or of the fluid for test, the gravity of ice, and/or snow in a cold region, and other temporary live loads. Fixed loads shall include the deadweights of piping components and thermo-insulating materials, and other permanent loads born by the piping.
3.1.7 The influence of the following thermal expansion or contraction shall be analyzed in design:
3.1.7.1 The force and moment from thermal expansion or contraction acted upon the restrained or fixed piping.
3.1.7.2 The stress in and load upon the piping wall due to galloping temperature change, or uneven temperature distribution on the piping wall.
3.1.7.3 For the clad or lined piping consists of two different materials, the load caused by the difference between the parent layer material and the coating layer material in their thermal expansion properties, and the load caused by difference between the internal and external pipes in a jacketed piping in their temperatures.
3.1.8 Fatigue failure caused by pressure cycling load, temperature cycling load, and/or other cyclic alternating loads upon the piping shall be avoided in the design.
3.1.9 The displacements of pipe supports and connected equipment shall be considered in the design, including those caused by the thermal expansion of equipment or supports, setting of ground, flow of tidewater, wind load and others.
3.1.10 For welding, heat treatment, processing and shaping, bending, and low temperature operation, as well as chilling action generated by sudden pressure reduction of light volatile fluid, the deterioration of tenacity of the material used shall be ensured within the allowable limit.
3.1.11 When the working temperature of a fluid is below -191℃, either an external coating layer shall be determined or corresponding measures shall be taken according to the possibility that air can condense and oxygen can be concentrated during the selection of the materials for the piping, including thermo-insulating material.
3.2 Design Reference
3.2.1 The pressure-temperature rated values of a piping component shall conform to the following requirements:
3.2.1.1 Unless otherwise herein stipulated, the nominal pressure and the corresponding working pressure-temperature rated value of piping components shall comply with the national current standard. When selecting piping component, the rated value specified in the standard for this component shall not be less than the design pressure and the design temperature of piping.
Unless otherwise stipulated, the allowable pressure at the design temperature for components only indicated with nominal pressure may be calculated according to following equation:
Contents
1. General Stipulations
2. Nomenclature and Symbols
2.1 Nomenclature
2.2 Symbols
3. Design Condition and Design Reference
3.1 Design Condition
3.2 Reference
4. Materials
4.1 General Stipulations
4.2 Service Temperature of Metallic Materials
4.3 Requirement for the Low Temperature Toughness Test of a Metallic Material
4.4 Requirements for Application of Materials
5.1 General Stipulation
5.2 Pipes
5.3 Bends and Miter Bends
5.4 Piping and Branch Connection
5.5 Valves
5.6 Flanges
5.7 Gaskets
5.8 Fasteners
5.9 Requirements for selection of the connection structure of piping components
5.10 Piping Specialties
5.11 Piping Components with the Non-metallic Liner
6. Calculation of Pressure-resistance Strength of Metallic Piping Components
6.1 General Stipulations
6.2 Straight Pipe
6.3 Miter Bends
6.4 Reinforcement of Branch Connections
6.5 Non-standard Reducer
6.6 Flat Cover
6.7 Special Flange and Blinding Flange
7. Determination of Pipe Diameter and Calculation of Pressure Loss
7.1 Determination of Pipe Diameter
7.2 Pressure Loss in Mono-phase Flow Piping
7.3 Pressure Loss of Dual-phase Fluid of Gas-liquid Flow in Piping
8. Layout of Piping
8.1 Piping on Ground
I. General stipulations
II. Net overhead height and net distance between pipes
III General requirement for layout
IV. Requirement for layout of category B fluid piping
V. Layout of valves
VI. Setting of discharging gas at high point and discharging liquid at low point
VII. Position of vents
8.2 Piping in Ditch
8.3 Underground Buried Piping
9. Expansion and Flexibility of Metallic Piping
9.1 General Stipulations
9.2 Scope and Approach for Calculating Piping Flexibility
9.3 Basic Requirement for Flexibility Calculation of Piping
9.4 Displacement stress of Piping
9.5 Force from the Piping Acts upon Equipment or End Point
10. Supporting and Hanger Rack of Piping
10.1 General Stipulations
10.2 Layout and Maximum Space between Supports and hangers
10.3 Load of Supports and Hangers
10.4 Materials and Permitted Stress
10.5 Design and Selection of Support and Hanger Structure
11. Requirement by Designing upon Components Fabrication, Piping Construction and Inspection
11.1 General Stipulations
11.2 Welding of Metals
11.3 Heat Treatment of Metals
11.4 Inspection
11.5 Pressure Test
11.6 Other Requirements
12. Heat Insulation, Acoustical Insulation, Noise Elimination and Anticorrosion
12.1 Heat Insulation
12.2 Acoustical Insulation and Noise Elimination
12.3 Anti Corrosion and Painting
13. Supplementary Stipulations for Piping Delivering Category A1 Fluid and Category A2 Fluid
13.1 Supplementary Stipulations for Piping Delivering Category A1 Fluid
13.2 Supplementary Stipulations for Piping Delivering Category A2 Fluid
14. Safety Stipulations for Piping System
14.1 General Stipulations
14.2 Over Pressure Protection
14.3 Valves
14.4 Blind Flanges
14.5 Drainage
14.6 Other requirements
Appendix A Allowable Stress for Metal Piping Material
Appendix B Physical Properties of Metal Materials
Appendix C Range of Application Temperature for Non-Metal Lining Materials
Appendix D Stipulations for the Thickness of Steel Pipe and Steel-Made Fittings
Appendix E Flexibility Factor and Stress Intensification Factor
Appendix F Distance Between the Outdoor Underground Pipings and the Railways, Roads and Buildings
Appendix G Stipulations for Pipe Heat Treatment
Appendix H Welding Structures of Piping
Appendix J Non-Destructive Inspection of Piping
Appendix K Description of the Wording in this code
Appendix L Specification on the Test of Heat Insulating Material Used for Austenitic Stainless Steel
Additional Descriptions
1. General
1.0.1 This code is prepared for improving the design level of industrial metallic pipeworks and ensuring their design quality.
1.0.2 This code is applicable for the design of industrial metallic pipings serving at a nominal pressure below or equal to 42MPa and those with non-metallic lines.
1.0.3 This code is not applicable for the design of:
10.3.1 Pipings for a whole set of equipment or machine designed by the manufacturer;
1.0.3.2 Pipings in power sector;
1.0.3.3 Long-distance delivering pipings;
1.0.3.4 Pipings in mine;
1.0.3.5 Pipings for heating, ventilating, and air conditioning, as well as pipings with a noncircular section;
1.0.3.6 Underground or indoor water supply and drainage pipings, and fire extinguishing purpose water supply pipings;
1.0.3.7 Pipings for foam, carbon dioxide, or other type fire extinguishing systems;
1.0.3.8 Urban public pipings.
1.0.4 The pressure used in this code shall be gauge pressure unless otherwise specified.
1.0.5 In addition to this code, the design of any industrial metallic piping shall meet the requirements in national current standards concerned.
2. Terms and Symbols
2.1 Terms
2.1.1 category A1 fluid
for the purpose of this code, highly toxic fluid that can seriously poison the individual who absorbs or is exposed to the fluid and cannot be cured even he/she is out of exposure, in case a small amount of the fluid leaks out during transportation. The fluid is corresponding to the (extremely hazardous) Level I toxic substance stipulated in the current national standard GB 5044 Classification of Health Hazard Levels From Occupational Exposure to Toxic Substances
2.1.2 category A2 fluid
toxic fluid that can poison the individual who is exposed to it to different extents, but can be cured after being out of exposure. The fluid is corresponding to the (high, moderately, or lightly hazardous) Level II toxic substance or below stipulated in the current national standard GB 5044 Classification of health hazard levels from occupational exposure to toxic substances
2.1.3 category B fluid
for the purpose of this code, fluid that may be gas or liquid that can generate a gas by flash evaporation in the circumstance or under the operation condition and can be ignited and continuously burn in air
2.1.4 category D fluid
incombustible and nontoxic fluid that is used in the case of the design pressure below or equal to 1.0MPa and design temperature between –20 and 186℃
2.1.5 category C fluid
incombustible and nontoxic fluid excluding Category D fluid
2.1.6 piping
facility that consists of piping components, pipe supports and hangers, and others, and is used to deliver, distribute, mix, separate, drain, measure, or control flow of fluid
2.1.7 piping system
set of pipings connecting each other and classified according to the category of fluid and the design condition
2.1.8 piping components
components used to connect or assemble into a piping, including pipes, pipe fittings, flanges, gaskets, fasteners, valves, and piping specialties
2.1.9 piping specialties
non-standard ordinary piping components, which are specially manufactured according to the engineering design condition, including expansion joints, compensators, special valves, rupture disks, fire arrestors, filters, flexible connectors, hoses, etc.
2.1.10 minter bends
welded bend made of pipes or steel sheets, spliced from pipe sections of mitre weldings not perpendicular to the longitudinal axis of the pipes
2.1.11 branch connections
structure leading branch(es) from the main pipe, including integrally -reinforced pipe fittings and the branch connections with or without reinforced welded structure
2.1.12 raised face
a kind of seal face of flange, with the bulgy flat seal face within the internal side of the bolthole, designated as RF
2.1.13 full face
a kind of seal face of flange, with flat seal face all within the outer diameter, designated as FF
2.1.14 liquid collecting pocket (drip leg)
condensate-collecting purpose pocket-like device setting at the low point of a gas or vapor piping
2.1.15 pipe supports and hangers
generic name used to entitle various structures supporting pipings or restricting displacement of pipings as a whole, excluding civil structures
2.1.16 anchors
support that can make a piping system produce neither linear displacement nor angular displacement at a supporting point, and may bear various loads on the piping in different directions
2.1.17 sliding support
support with sliding supporting face, which may restrict vertically downward displacement of a piping, but does not restrict horizontal displacement of the piping for thermal expansion or contraction, and bears the vertical load including of the deadweight of the piping
2.1.18 rigid hangers
pipe support structure with a hinged hanging rod, which may restrict vertically downward displacement of a piping, but does not restrict horizontal displacement of the piping for thermal expansion or contraction, and bears the vertical load including of the deadweight of the piping
2.1.19 guides
support that may prevent rotation caused by a moment of force or a torsional moment, guide one or more direction(s), but the piping still may move in the given axial direction. When it is used in a horizontal piping, the guide bears the vertical load including of the deadweight of the piping in addition to the above-mentioned function. Usually, the structure of a guide has a restricting function in one or two axial direction(s)
2.1.20 restraints
support that can restrict the displacement, which may be linear or angular displacement in one or more direction(s), of the piping in the designated direction at a point. The restraint with a prescriptive displacement value is called the setting value restraint
2.1.21 vibrating eliminators
device that can control high-frequent and low-amplitude vibration or low-frequent and high-amplitude shake of a piping system, but does not restrain its thermal expansion or contraction
2.1.22 snubbers (dampers)
device that can control instantaneous impact load upon a piping or high-speed vibration displacement of a piping system, but does not restrain their thermal expansion or contraction
2.1.23 severe cyclic condition
condition under which the maximum displacement stress range, σE, calculated for a piping exceeds 0.8 times of the allowable displacement stress range, that is 0.8[σ]A, and the number of equivalent cycles, N, is larger than 7,000 or designed condition resulting equivalent effect
2.1.24 stress intensification factor
ratio of the maximum bending stress leading fatigue failure of a component of a non-straight piping for the sake of a bending moment to the maximum bending stress leading fatigue failure of a component of a straight piping with the same diameter and thickness at the same bending moment, which are divided into two types, in-plane and out-plane, according to different planes the bending moment and the component are in
2.1.25 displacement stress range
stress calculated from the displacement caused by thermal expansion of a piping. The one calculated from the full compensation value from the lowest temperature to the highest temperature is called the calculated maximum displacement stress rang
2.1.26 externally imposed displacements
displacement of the calculated piping system imposed from the end of the piping system due to thermal expansion of the equipment or other connected piping, or another displacement
2.1.27 cold spring
a process that an elastic deformation is imposed upon the piping prior to its installation to produce an anticipated displacement and stress, and reduce the acting force and the moment on the piping end under the initial thermal condition
2.1.28 flexibility factor
extent to which the flexibility of a piping component increases as it bears a moment relative to a straight piping. That is, in a piping component, the ratio of the angular deformation of the component per unit length generated under action of a given moment to the angular deformation of a straight piping with the same diameter and thickness, under action of the same moment
2.1.29 utility piping
pipings for utility fluids in various operations of a plant or device relative to process piping
2.1.30 piping and instrument diagram
P&ID or PID for short, where the designations indicating the piping system, and instrument and gauges connected, and the identification codes for different pipings are shown, in addition to equipment and apparatus
2.2 Symbols
A——The reinforced area needed for opening on a main pipe.
A1——The redundant metallic area of a main pipe within the reinforced range, excluding both the calculated thickness and the additional thickness used to bear internal and external pressures.
A2——The redundant metal area of a branch within the reinforced range, excluding both the calculated thickness and the additional thickness used to bear internal and external pressures.
A3——The area of the fillet weld within the reinforced rang.
A4——The area of the additional reinforcing plate within the reinforced rang.
A5——The redundant metallic area of an extruded branch within the reinforced range, excluding both the calculated thickness and the additional thickness used to bear internal and external pressures.
Ak——The impact power upon a material.
B——The effective width of a reinforced zone.
Clt——The allowance for the possibly attenuated (minus deviation) of a branch in the thickness.
Clm——The allowance for the possibly attenuated (minus deviation) of a main pipe in the thickness.
Clr——The allowance for the possibly attenuated (minus deviation) of a reinforcing plate in the thickness.
C——The sum of all thickness allowances.
C1——The allowance for the possibly attenuated in the thickness, including minus deviations caused by processing, fluting, depth of thread, and material thickness.
C2——The allowance for corrosion or abrasion.
Cf——The correction factor.
Ch——The tolerance factor in piping pressure loss.
Cp——The specific heat at constant pressure.
Cs——The cold spring ratio, namely the ratio of cold spring value and full compensation value.
Cv——The specific heat at constant volume.
C.S.C.(L.C.)——Lock in closed state (not allow to open without approval).
C.S.O.(L.O.)——Lock in opened state (not allow to close without approval).
d——The inner diameter of a branch after deducting the allowance in thickness.
do——The nominal diameter of a branch.
d1——The major diameter of the diagonal cut joint on a main pipe after deducting the allowance in thickness.
dG——The inner diameter of the gasket for a female or face flange, or average diameter of a ring groove gasket.
dX——The inner diameter of an extruded branch after deducting the allowance in thickness.
DN——The nominal diameter of a pipe or pipe fitting.
Di——The inner diameter of a pipe or pipe fitting.
DiL——The inner diameter of the larger end of a reducer.
DiS——The inner diameter of the smaller end of a reducer.
Do——The outer diameter of a pipe or pipe fitting.
DOL——The outer diameter of the larger end of a reducer.
DOS——The outer diameter of the small end of a reducer.
Dr——The outer diameter of a reinforcing plate.
Ec——The quality factor of a casting.
Ej——The weld joint factor.
Eh——The elastic modulus of a piping material at the highest or lowest temperature.
E20——The elastic modulus of a piping material at the installation temperature.
FH——The working load.
fr——The ratio between the allowable stresses of the materials for the reinforcing plate and the main pipe.
fs——The changing factor of load.
f——The reduction factor of the displacement stress range of a piping.
g——The acceleration of gravity.
h——The dimension factor.
h1——The normally reinforced effective height at the outer side of a main pipe.
h2——The effective reinforced height for a branch.
h3——The inward dented depth of a flat cap.
hx——The height of a extruded branch.
i——The stress intensification factor.
ii——The stress intensification factor in a plane.
io——The stress intensification factor out of a plane.
is——The gradient of a piping.
k——The adiabatic index of a gas.
K——The flexibility factor.
K1——The factor related to the structure of a flat cap.
K2——The empirical value for a minter bend.
K3——The reinforcing factor for an extruded branch.
KR——The resistance factor.
Ks——The stiffness of a spring.
KT——The allowable stress factor.
L——The length of a piping.
Le——The equivalent length of valves and pipe fittings.
Lf——The shorter edge length of the end section of a minter bend.
Ls——The spacing between supports or hangers.
LST——The length of the reinforced section of a straight pipe connected to the larger end of a reducer.
LSS——The length of the reinforced section of a straight pipe connected to the smaller end of a reducer.
M——The molecular weight of a gas.
MA——The resultant moment from action of the deadweight and other continuous external load on the section of the piping.
MB——The resultant moment from action of the accidental load caused by the counterforce of the safety valve or relief valve, transient change of flow and pressure in a piping, wind force, or earthquake on the section of the piping.
ME——The equivalent resultant moment of thermal expansion.
M’E——The resultant moment in which the stress intensification factor is not counted.
Mi——The bending moment from thermal expansion in the plane.
MO——The bending moment from thermal expansion out of the plane.
Mt——The twisting moment from thermal expansion.
MX——The moment in the direction of X- coordinate axis.
MY——The moment in the direction of Y- coordinate axis.
MZ——The moment in the direction of Z- coordinate axis.
n——The ordinal.
N——The equivalent number of full displacement cycles in the estimated service life of a piping system.
NE——The cyclic number related to the calculated maximum displacement stress range, σE.
Nj——The cyclic number related to the displacement stress range, σj calculated for a value less than the full displacement.
P——The design pressure.
PA——The allowable stress at the design temperature.
Pm——The maximum allowable inner pressure of a minter bend.
PN——The nominal pressure.
PT——The test pressure.
QL——The stress intensification factor for connection of the larger end of a reducer with a straight pipe.
QS——The stress intensification factor for connection of the smaller end of a reducer with a straight pipe.
R——The curvature radius of a circular arc bend.
Rl——The curvature radius of a minter bend.
Rc——The force and moment acted by a piping on the equipment or the end point at the installation temperature in the initial period of operation.
Rcl——The force and moment acted by a piping on the equipment or the end point at the installation temperature after self-recovery
RE——The force and moment acted by a piping on the end point that is calculated based on E20 and full compensation
Rh——The force and moment acted by a piping on the equipment or the end point at the highest or lowest temperature in the initial period of operation.
Rm——The average radius of the main pipe.
r——The fillet radius in the flat cap.
ro——The average radius of a pipe or pipe fitting.
r1, r2, r3——The transitional radius of the reinforced position of the branch.
rj——The ratio of the displacement stress range, σj calculated for a value less than the full displacement to the calculated maximum displacement stress range, σE.
rm——The average radius of a branch.
rp——The outer radius of the reinforced position of a branch.
rx——The curvature radius at the corner of the outer profile in the plane of the axes of a main pipe and its branch.
S——The spacing at the central line of the miter section of a minter bend.
T——The gas temperature.
T1——The thickness of a butt weldment at the thinner side.
T2——The thickness of a butt weldment at the thicker side.
Tc——The thickness of a tee at the round corner (the intersection position of the main pipe and the branch).
Tt——The calculated thickness of the main pipe.
Ttn——The nominal thickness of the main pipe.
t——The thickness of the end of a half coupling.
tb——The effective thickness of a branch at the reinforced position.
tc——The calculated effective thickness of a fillet weld.
teb——The effective thickness of the branch of a tee.
tFn——The nominal thickness of a pipe fitting.
tL——The nominal thickness of a reducer.
tL1——The nominal thickness of a reducer at the larger end.
tL2——The nominal thickness of a reducer at the smaller end.
tLC——The calculated thickness of a reducer at the conic position.
tLL——The calculated thickness of a reducer at the larger end.
tLS——The calculated thickness of a reducer at the smaller end.
tm——The calculated thickness of a blind flange.
tp——The calculated thickness of a flat cap.
tpd——The design thickness of a flat cap or blind flange
tr——The nominal thickness of a reinforcing plate.
ts——The calculated thickness of a straight pipe.
tsd——The design thickness of a straight pipe.
tse——The effective thickness of a straight pipe.
tsn——The nominal thickness of a straight pipe.
tt——The calculated thickness of a branch.
ttn——The nominal thickness of a branch.
tX——The effective thickness for extruding a branch on the outer surface of the main pipe after reducing the allowance for thickness.
tw——The dimension of a sockolet.
v——The average flow velocity.
vc——The sound velocity or the critical flow velocity of a gas.
W——The cross section factor.
WB——The net section factor of a reduced tee branch.
Wo——The mass flow rate.
X——The dimension of the fillet leg weld inside a flange.
Xmin——The minimum dimension of a fillet weld leg.
Y——The factor.
Ys——The bending deflection of a piping due to its deadweight.
α——The angle by which the direction of a welding seam on a minter bend changes (the included angle between the two adjacent miter lines).
α1——The included angle between the axes of the branch and the main pipe.
α0——The average linear expansion factor of a metallic material.
β——The included angle between the bevel edge and the axial line of a reducer.
θ——A half of the angle by which the direction of a welding seam on a minter bend changes (a half of the included angle between the two adjacent miter lines).
θn——The transitional angle at the reinforced position of a branch.
δ——The maximum calculated elongation of fiber.
δave——The average value of the unfitness of a butt joint.
δmax——The maximum value of the unfitness of a butt joint.
δ1——The nominal thickness of a parent metal.
δ2——The effective thickness of a coating metal after reducing the allowance.
Δ——The vertical thermal displacement of a piping.
ΔPf——The pressure loss due to friction on a straight piping.
ΔPk——The local pressure loss due to friction.
ΔPt——Total pressure loss of a piping.
η——The factor related to the structure of a flat cap.
ρ——The density of a fluid.
λ——The friction factor of a fluid.
σb——The lower limit value of the tensile strength of a material at standard temperature-pressure.
——The tensile strength of a material at the design temperature.
——The average value of the creep rupture strengths of a material at the design temperature for 100 thousand hrs in a creep test.
σE——The calculated maximum displacement stress range.
σj——The displacement stress range calculated for a value less than the full displacement.
σL——The sum of the longitudinal stresses produced by pressure, gravity, and other continuous load in the piping.
——The creep limit of a material at a creep rate of 1% at the design temperature for 100 thousand hrs in a creep test.
σs(σ0.2)——The yield point of a material at the standard normal temperature (or 0.2% yield strength).
(σt0.2)——The yield point of a material at the design temperature (or 0.2% yield strength).
σT——The hoop stress of a component under the test condition.
[σ]T——The allowable stress of a material at the test temperature.
[σ]t——The allowable stress of a material at the design temperature.
[σ]o——The allowable stress of an integrally clad metallic material at the design temperature.
[σ]1——The allowable stress of the parent metal at the design temperature.
[σ]2——The allowable stress of the coating metal at the design temperature.
[σ]A——The allowable displacement stress rang.
[σ]c——The allowable stress of a metallic material in cold status (at the estimated lowest temperature) in the analyzed displacement cycle.
[σ]h——The allowable stress of a metallic material in hot status (at the estimated highest temperature) in the analyzed displacement cycle.
[σ]x——The allowable stress of a material at the calculated temperature adopted when the thickness of a component is determined.
[σ]tRP——The allowable stress of the material used for a reinforcing plate at the design temperature.
[σ]tM——The allowable stress of the material used for a main piping at the design temperature.
3. Design Condition and Design Reference
3.1 Design Condition
3.1.1 The piping shall be designed according to the process conditions, such as pressure, temperature, characteristics of the fluid and others, taking the circumstance and various load conditions in account.
3.1.2 Determination of the design pressure shall meet the following requirements:
3.1.2.1 The design pressure of a piping and each component of it shall not be less than the pressure occurred when a severest condition appears due to coupling of an internal pressure or an external pressure with temperature in operation. The severest condition shall be taken as a parameter for calculation of the largest thickness of the piping component is required, and of the highest nominal pressure in the strength calculation. But, the above-said design pressure shall not include the non-recurrently fluctuant value of pressure allowed in this clause.
3.1.2.2 For any of the following pipings in special conditions, the design pressure value shall be compared with the result selected as 3.1.2.1, whichever is larger.
(1) For the piping used to deliver the fluid with a lower gasifying temperature, such as cryogen and liquefied hydrocarbons, the design pressure shall not be less than the highest pressure possibly reached when the fluid in it is gasified at the highest ambient temperature in the case of closure of the valve or the fluid not in flow;
(2) The design pressure of the discharge piping of a centrifugal pump shall not be less than the sum of the suction pressure and the pressure equivalent to the delivery head;
(3) For the piping that is equipped with no pressure-relieving device, or isolated from a pressure-relieving device, its design pressure shall not be less than the maximum pressure the fluid in it may reach.
3.1.2.3 A vacuum piping shall be designed according to the external pressure it may bear, if equipped with a safety control device, its design pressure shall be 1.25 times of the difference between the internal and external pressures, or 0.1MPa, whichever is lower; if there is no safety control device, its design pressure shall be 0.1MPa.
3.1.2.4 The design pressure of a piping with the pressure-relieving device shall not be less than the pressure under which the pressure-relieving device opens.
3.1.3 Determination of the design temperature shall meet the following requirements:
3.1.3.1 The design temperature of each piping component shall not be less than the temperature corresponding to the required maximum thickness or the maximum nominal pressure specified in 3.1.2.1 hereof. The determination of the design temperature shall also take into the account of the influence of such factors as fluid temperature, environment temperature, solar radiation and heated or cooled fluid temperature.
The designed minimum temperature shall be the minimum working temperature of piping components, and this temperature shall not be less than the lower limit of service temperature of materials. The lower limit of the service temperature of common materials shall meet the requirements of Annex A in this code.
3.1.3.2 For the piping heated by its tracer or jacketed pipe, the externally heating temperature or the temperature of the fluid inside the piping shall be taken as the design temperature, whichever is higher.
3.1.3.3 For the piping without thermo-insulating layer, different piping components may be designed with different temperatures, and their design temperatures shall meet the following requirements:
(1) In the case of a fluid temperature below 65℃, the design temperature of a piping component may be the same as that of the fluid;
(2) In the case of a fluid temperature equal to or over 65℃, the design temperature of a piping component shall not be less than the following value, unless calculated as heat transfer or there is a lower average wall temperature determined by the test:
95% of the fluid temperature for valves, pipes, flange spools, welded pipe fittings, and other piping components with the similar thickness;
90% of the fluid temperature for flanges, including those on the pipe fittings and valves, but excluding loose flanges;
85% of the fluid temperature for loose flanges;
80% of the fluid temperature for the fasteners for flanges.
3.1.3.4 The design temperature of a piping with external thermo-insulation shall be determined as 3.1.3.1 and 3.1.3.2. Other temperatures may be adopted if there is a calculated, tested, or measured result available.
3.1.3.5 The design temperature of a piping with internal thermo-insulation shall be determined based on heat transfer calculation or test.
3.1.3.6 For a piping with a non-metallic material liner, its design temperature shall be equal to the highest working temperature of the fluid. When there is no external thermo-insulating layer, the design temperature of the external metal may be determined by heat transfer calculation, or test, or as 3.1.3.3.
3.1.4 Effective measures shall be taken to cope with the following environmental influences:
3.1.4.1 For cooling of gas or vapor in a piping, its pressure drop value shall be determined. In case of vacuum in piping, the piping shall be able to withstand the external pressure at low temperature, or effective preventive measure shall be taken to destroy the vacuum.
3.1.4.2 A piping component shall be able to withstand or eliminate the increasing pressure due to thermal expansion of the static fluid; otherwise, effective preventive measure shall be taken.
3.1.4.3 In case of the piping temperature below 0℃, proper measures shall be taken to prevent the external surfaces of shutoff valves, control valves, pressure-relieving devices, and the moving parts of other piping components from freezing.
3.1.5 A piping shall be able to withstand the following dynamic loads:
3.1.5.1 A piping shall be able to withstand impact loads caused by hydraulic impact, strike of liquid or solid, and others.
3.1.5.2 An outdoor above ground piping shall be able to withstand wind load.
3.1.5.3 The piping located in an earthquake region shall be able to withstand the horizontal force caused by earthquake, and shall conform to the requirements in the national current aseismatic standards concerned.
3.1.5.4 The piping arrangement and support shall be such designed to eliminate the influence of harmful vibration caused by impact, pressure fluctuation, resonance of machines, and wind load on the pipings.
3.1.5.5 The piping arrangement and support shall be such designed that they can withstand the counterforce caused by pressure reduction and discharge of the fluid.
3.1.6 The static loads born by piping shall include fixed loads and live loads. Live loads shall include the gravity of the delivered fluid or of the fluid for test, the gravity of ice, and/or snow in a cold region, and other temporary live loads. Fixed loads shall include the deadweights of piping components and thermo-insulating materials, and other permanent loads born by the piping.
3.1.7 The influence of the following thermal expansion or contraction shall be analyzed in design:
3.1.7.1 The force and moment from thermal expansion or contraction acted upon the restrained or fixed piping.
3.1.7.2 The stress in and load upon the piping wall due to galloping temperature change, or uneven temperature distribution on the piping wall.
3.1.7.3 For the clad or lined piping consists of two different materials, the load caused by the difference between the parent layer material and the coating layer material in their thermal expansion properties, and the load caused by difference between the internal and external pipes in a jacketed piping in their temperatures.
3.1.8 Fatigue failure caused by pressure cycling load, temperature cycling load, and/or other cyclic alternating loads upon the piping shall be avoided in the design.
3.1.9 The displacements of pipe supports and connected equipment shall be considered in the design, including those caused by the thermal expansion of equipment or supports, setting of ground, flow of tidewater, wind load and others.
3.1.10 For welding, heat treatment, processing and shaping, bending, and low temperature operation, as well as chilling action generated by sudden pressure reduction of light volatile fluid, the deterioration of tenacity of the material used shall be ensured within the allowable limit.
3.1.11 When the working temperature of a fluid is below -191℃, either an external coating layer shall be determined or corresponding measures shall be taken according to the possibility that air can condense and oxygen can be concentrated during the selection of the materials for the piping, including thermo-insulating material.
3.2 Design Reference
3.2.1 The pressure-temperature rated values of a piping component shall conform to the following requirements:
3.2.1.1 Unless otherwise herein stipulated, the nominal pressure and the corresponding working pressure-temperature rated value of piping components shall comply with the national current standard. When selecting piping component, the rated value specified in the standard for this component shall not be less than the design pressure and the design temperature of piping.
Unless otherwise stipulated, the allowable pressure at the design temperature for components only indicated with nominal pressure may be calculated according to following equation:
Contents of GB 50316-2000(2008)
Contents
1. General Stipulations
2. Nomenclature and Symbols
2.1 Nomenclature
2.2 Symbols
3. Design Condition and Design Reference
3.1 Design Condition
3.2 Reference
4. Materials
4.1 General Stipulations
4.2 Service Temperature of Metallic Materials
4.3 Requirement for the Low Temperature Toughness Test of a Metallic Material
4.4 Requirements for Application of Materials
5.1 General Stipulation
5.2 Pipes
5.3 Bends and Miter Bends
5.4 Piping and Branch Connection
5.5 Valves
5.6 Flanges
5.7 Gaskets
5.8 Fasteners
5.9 Requirements for selection of the connection structure of piping components
5.10 Piping Specialties
5.11 Piping Components with the Non-metallic Liner
6. Calculation of Pressure-resistance Strength of Metallic Piping Components
6.1 General Stipulations
6.2 Straight Pipe
6.3 Miter Bends
6.4 Reinforcement of Branch Connections
6.5 Non-standard Reducer
6.6 Flat Cover
6.7 Special Flange and Blinding Flange
7. Determination of Pipe Diameter and Calculation of Pressure Loss
7.1 Determination of Pipe Diameter
7.2 Pressure Loss in Mono-phase Flow Piping
7.3 Pressure Loss of Dual-phase Fluid of Gas-liquid Flow in Piping
8. Layout of Piping
8.1 Piping on Ground
I. General stipulations
II. Net overhead height and net distance between pipes
III General requirement for layout
IV. Requirement for layout of category B fluid piping
V. Layout of valves
VI. Setting of discharging gas at high point and discharging liquid at low point
VII. Position of vents
8.2 Piping in Ditch
8.3 Underground Buried Piping
9. Expansion and Flexibility of Metallic Piping
9.1 General Stipulations
9.2 Scope and Approach for Calculating Piping Flexibility
9.3 Basic Requirement for Flexibility Calculation of Piping
9.4 Displacement stress of Piping
9.5 Force from the Piping Acts upon Equipment or End Point
10. Supporting and Hanger Rack of Piping
10.1 General Stipulations
10.2 Layout and Maximum Space between Supports and hangers
10.3 Load of Supports and Hangers
10.4 Materials and Permitted Stress
10.5 Design and Selection of Support and Hanger Structure
11. Requirement by Designing upon Components Fabrication, Piping Construction and Inspection
11.1 General Stipulations
11.2 Welding of Metals
11.3 Heat Treatment of Metals
11.4 Inspection
11.5 Pressure Test
11.6 Other Requirements
12. Heat Insulation, Acoustical Insulation, Noise Elimination and Anticorrosion
12.1 Heat Insulation
12.2 Acoustical Insulation and Noise Elimination
12.3 Anti Corrosion and Painting
13. Supplementary Stipulations for Piping Delivering Category A1 Fluid and Category A2 Fluid
13.1 Supplementary Stipulations for Piping Delivering Category A1 Fluid
13.2 Supplementary Stipulations for Piping Delivering Category A2 Fluid
14. Safety Stipulations for Piping System
14.1 General Stipulations
14.2 Over Pressure Protection
14.3 Valves
14.4 Blind Flanges
14.5 Drainage
14.6 Other requirements
Appendix A Allowable Stress for Metal Piping Material
Appendix B Physical Properties of Metal Materials
Appendix C Range of Application Temperature for Non-Metal Lining Materials
Appendix D Stipulations for the Thickness of Steel Pipe and Steel-Made Fittings
Appendix E Flexibility Factor and Stress Intensification Factor
Appendix F Distance Between the Outdoor Underground Pipings and the Railways, Roads and Buildings
Appendix G Stipulations for Pipe Heat Treatment
Appendix H Welding Structures of Piping
Appendix J Non-Destructive Inspection of Piping
Appendix K Description of the Wording in this code
Appendix L Specification on the Test of Heat Insulating Material Used for Austenitic Stainless Steel
Additional Descriptions