This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard 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).
Technical specification for flange joints installation
1 Scope
This standard specifies the method for determining the bolt mounting load of circular bolted flange joints with gaskets, as well as the additional requirements for the selection of flange joints (flanges, gaskets and fasteners), and their technical requirements for installation preparation, assembling, bolt tightening, inspection, recording and marking, etc.
This standard is applicable to the flange joints of the following "pressure equipment" with leakage control requirements:
a) that specified in TSG D0001 and other relevant technical specifications and regulations for safety;
b) that specified in GB/T 20801 and other corresponding product standards or engineering specifications;
c) that required by user or design.
Note: For the purposes of this standard, the "pressure equipment" includes boilers, pressure vessels (including fixed pressure vessels, mobile pressure vessels and gas cylinders), pressure piping, pumps, valves, etc.
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 150.3 Pressure vessels - Part 3: Design
GB/T 17186.1-2015 Calculation methods for the pipe flange joints - Part 1: Calculation method satisfies both strength and rigidity requirements
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
HG/T 20592~20635 Steel pipe flanges, gaskets and bolting
EN 13555 Flanges and their joints - Gasket parameters and test procedures relevant to the design rules for gasketed circular flange connections
3 Symbols
For the purposes of this document, the following symbols apply.
Aa——the gasket contact area, that is, the direct contact area between gasket and flange sealing face (for the octagonal gasket, it is calculated according to the projected area of the gasket), mm2;
Ab——the sectional area of bolt at the root diameter of thread or at the minimum diameter of unthreaded part, whichever is smaller, mm2;
Am——the total sectional area of flange joint bolts, Am=nAb, mm2;
AG——the gasket sealing area, that is, gasket contact area calculated based on effective sealing width of the gasket, AG=2πGb, mm2;
b——the effective sealing width of gasket (determined according to GB/T 150.3 or GB/T 17186.1), mm;
C——the diameter of bolt circle, mm;
D——the outer diameter of gasket contact surface, mm;
d——the nominal diameter of bolts, mm;
FE——the equivalent force generated by additional load of flange joint except internal pressure under operating conditions, FE=FZ+(4MZ/G), N;
FP——the static pressure at the end of flange joint caused by internal pressure under operating conditions, FP=0.785G2P, N;
FZ——the additional axial tension force (equivalent force generated by applied axial force and applied bending moment, determined according to GB/T 20801.3) applied to the flange joint except internal pressure under operating conditions, N;
G——the diameter where the gasket pressing force acts, G=D-2b, mm;
hG——the radial distance from the bolt circle to the position where the gasket pressing force acts, hG=(C-G)/2, mm;
K——the torque coefficient;
L0.1——the sealing class (determined according to EN 13555), with a corresponding leakage rate of 0.1 mg/(s•m) (calculated based on the perimeter of the middle diameter of the gasket sealing face);
MA——the flange moment caused by bolt mounting load under installation conditions, MA=WAhG, N•mm;
MZ——the additional axial torque of flange joint except internal pressure under operating conditions, N•mm;
——the gasket sealing parameters, dimensionless;
n——the number of bolts for flange joints;
PQR——the creep relaxation coefficient of gasket at operating temperature (determined according to EN 13555);
P——the operating pressure, MPa;
QA——the average compressive stress of gasket contact surface under installation conditions, QA=WA/Aa, MPa;
Qmax——the maximum crushing stress of gasket (determined according to EN 13555), MPa;
——the minimum sealing stress of gasket required when the leakage rate is not greater than L0.1 under operating conditions, MPa;
Qs——the average sealing stress on the gasket mating face, with the internal pressure and additional load deducted, under operating conditions, MPa;
RJ——the bolt load relaxation coefficient under operating conditions, that is, the ratio of residual bolt load to bolt mounting load;
SB——the bolt mounting stress, MPa;
SBmax——the maximum bolt mounting stress, MPa;
SBmin——the minimum bolt mounting stress, MPa;
SBT——the bolt mounting target stress, MPa;
T——the bolt mounting torque, T=KW0d/1000, N•m;
WA——the total bolt mounting loads of flange joints under installation conditions, WA=SBAm, N;
W0——the single bolt mounting load of flange joints under installation conditions, W0=SBAb, N.
4 Determination for bolt mounting loads of flange joints
4.1 General requirements
Flange joints shall be subjected to strength and stiffness evaluation under design and installation conditions according to 4.2 and 4.3 respectively, and sealing performance evaluation under operating conditions according to 4.4; bolt mounting loads shall be determined accordingly.
4.2 Strength and stiffness evaluation of flange joints under design conditions
4.2.1 The compressive strength evaluation for standard pipe flanges and equipment flange joints (flanges-gaskets-fasteners) shall meet the pressure-temperature ratings specified in the corresponding standards and their selection requirements. When standard pipe flange joints are subjected to external axial force and external bending moment, the compressive strength and stiffness shall be evaluated according to the corresponding requirements of GB/T 20801.3.
4.2.2 The compressive strength and stiffness of non-standard flange joints shall be evaluated according to the corresponding requirements of GB/T 17186.1 or GB/T 150.3.
4.3 Strength and stiffness evaluation of flange joints under installation conditions
4.3.1 Bolts
4.3.1.1 Under installation conditions, bolt mounting stress, SB, shall not exceed 70% of the yield strength of bolt material (at mounting temperature). The actual bolt mounting stress (including mounting load deviation) shall not exceed 90% of the yield strength of bolt material (at mounting temperature).
4.3.1.2 The high-strength bolt mounting target stress, SBT, is 350 Mpa; the medium-strength bolt mounting target stress, SBT, is 280 Mpa. The medium-strength bolt mounting target stress may be 350 Mpa where necessary, but measures shall be taken to control the bolts from yielding during mounting and use.
4.3.2 Gasket
4.3.2.1 Under installation conditions, the total bolt mounting loads (WA) is equal to the compressive load on the gasket contact surface (Aa). The compressive stress of gasket contact surface (QA) shall not be greater than the maximum crushing stress of gasket (Qmax), as shown in Equation (1):
Foreword i 1 Scope 2 Normative references 3 Symbols 4 Determination for bolt mounting loads of flange joints 5 Additional requirements for selection of flanges, gaskets and fasteners 6 Installation 7 Inspection, test and marking 8 Records Annex A (Informative) Calculation of flange mounting stress Annex B (Informative) Maximum bolt mounting load of standard pipe flange joints Annex C (Informative) Recommended surface roughness of flange sealing face Annex D (Informative) Examples of flange joints installation inspection record Annex E (Informative) Calculation of bolt mounting torque by friction coefficient Bibliography
Foreword
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard 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).
Technical specification for flange joints installation
1 Scope
This standard specifies the method for determining the bolt mounting load of circular bolted flange joints with gaskets, as well as the additional requirements for the selection of flange joints (flanges, gaskets and fasteners), and their technical requirements for installation preparation, assembling, bolt tightening, inspection, recording and marking, etc.
This standard is applicable to the flange joints of the following "pressure equipment" with leakage control requirements:
a) that specified in TSG D0001 and other relevant technical specifications and regulations for safety;
b) that specified in GB/T 20801 and other corresponding product standards or engineering specifications;
c) that required by user or design.
Note: For the purposes of this standard, the "pressure equipment" includes boilers, pressure vessels (including fixed pressure vessels, mobile pressure vessels and gas cylinders), pressure piping, pumps, valves, etc.
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 150.3 Pressure vessels - Part 3: Design
GB/T 17186.1-2015 Calculation methods for the pipe flange joints - Part 1: Calculation method satisfies both strength and rigidity requirements
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
HG/T 20592~20635 Steel pipe flanges, gaskets and bolting
EN 13555 Flanges and their joints - Gasket parameters and test procedures relevant to the design rules for gasketed circular flange connections
3 Symbols
For the purposes of this document, the following symbols apply.
Aa——the gasket contact area, that is, the direct contact area between gasket and flange sealing face (for the octagonal gasket, it is calculated according to the projected area of the gasket), mm2;
Ab——the sectional area of bolt at the root diameter of thread or at the minimum diameter of unthreaded part, whichever is smaller, mm2;
Am——the total sectional area of flange joint bolts, Am=nAb, mm2;
AG——the gasket sealing area, that is, gasket contact area calculated based on effective sealing width of the gasket, AG=2πGb, mm2;
b——the effective sealing width of gasket (determined according to GB/T 150.3 or GB/T 17186.1), mm;
C——the diameter of bolt circle, mm;
D——the outer diameter of gasket contact surface, mm;
d——the nominal diameter of bolts, mm;
FE——the equivalent force generated by additional load of flange joint except internal pressure under operating conditions, FE=FZ+(4MZ/G), N;
FP——the static pressure at the end of flange joint caused by internal pressure under operating conditions, FP=0.785G2P, N;
FZ——the additional axial tension force (equivalent force generated by applied axial force and applied bending moment, determined according to GB/T 20801.3) applied to the flange joint except internal pressure under operating conditions, N;
G——the diameter where the gasket pressing force acts, G=D-2b, mm;
hG——the radial distance from the bolt circle to the position where the gasket pressing force acts, hG=(C-G)/2, mm;
K——the torque coefficient;
L0.1——the sealing class (determined according to EN 13555), with a corresponding leakage rate of 0.1 mg/(s•m) (calculated based on the perimeter of the middle diameter of the gasket sealing face);
MA——the flange moment caused by bolt mounting load under installation conditions, MA=WAhG, N•mm;
MZ——the additional axial torque of flange joint except internal pressure under operating conditions, N•mm;
——the gasket sealing parameters, dimensionless;
n——the number of bolts for flange joints;
PQR——the creep relaxation coefficient of gasket at operating temperature (determined according to EN 13555);
P——the operating pressure, MPa;
QA——the average compressive stress of gasket contact surface under installation conditions, QA=WA/Aa, MPa;
Qmax——the maximum crushing stress of gasket (determined according to EN 13555), MPa;
——the minimum sealing stress of gasket required when the leakage rate is not greater than L0.1 under operating conditions, MPa;
Qs——the average sealing stress on the gasket mating face, with the internal pressure and additional load deducted, under operating conditions, MPa;
RJ——the bolt load relaxation coefficient under operating conditions, that is, the ratio of residual bolt load to bolt mounting load;
SB——the bolt mounting stress, MPa;
SBmax——the maximum bolt mounting stress, MPa;
SBmin——the minimum bolt mounting stress, MPa;
SBT——the bolt mounting target stress, MPa;
T——the bolt mounting torque, T=KW0d/1000, N•m;
WA——the total bolt mounting loads of flange joints under installation conditions, WA=SBAm, N;
W0——the single bolt mounting load of flange joints under installation conditions, W0=SBAb, N.
4 Determination for bolt mounting loads of flange joints
4.1 General requirements
Flange joints shall be subjected to strength and stiffness evaluation under design and installation conditions according to 4.2 and 4.3 respectively, and sealing performance evaluation under operating conditions according to 4.4; bolt mounting loads shall be determined accordingly.
4.2 Strength and stiffness evaluation of flange joints under design conditions
4.2.1 The compressive strength evaluation for standard pipe flanges and equipment flange joints (flanges-gaskets-fasteners) shall meet the pressure-temperature ratings specified in the corresponding standards and their selection requirements. When standard pipe flange joints are subjected to external axial force and external bending moment, the compressive strength and stiffness shall be evaluated according to the corresponding requirements of GB/T 20801.3.
4.2.2 The compressive strength and stiffness of non-standard flange joints shall be evaluated according to the corresponding requirements of GB/T 17186.1 or GB/T 150.3.
4.3 Strength and stiffness evaluation of flange joints under installation conditions
4.3.1 Bolts
4.3.1.1 Under installation conditions, bolt mounting stress, SB, shall not exceed 70% of the yield strength of bolt material (at mounting temperature). The actual bolt mounting stress (including mounting load deviation) shall not exceed 90% of the yield strength of bolt material (at mounting temperature).
4.3.1.2 The high-strength bolt mounting target stress, SBT, is 350 Mpa; the medium-strength bolt mounting target stress, SBT, is 280 Mpa. The medium-strength bolt mounting target stress may be 350 Mpa where necessary, but measures shall be taken to control the bolts from yielding during mounting and use.
4.3.2 Gasket
4.3.2.1 Under installation conditions, the total bolt mounting loads (WA) is equal to the compressive load on the gasket contact surface (Aa). The compressive stress of gasket contact surface (QA) shall not be greater than the maximum crushing stress of gasket (Qmax), as shown in Equation (1):
Contents of GB/T 38343-2019
Foreword i
1 Scope
2 Normative references
3 Symbols
4 Determination for bolt mounting loads of flange joints
5 Additional requirements for selection of flanges, gaskets and fasteners
6 Installation
7 Inspection, test and marking
8 Records
Annex A (Informative) Calculation of flange mounting stress
Annex B (Informative) Maximum bolt mounting load of standard pipe flange joints
Annex C (Informative) Recommended surface roughness of flange sealing face
Annex D (Informative) Examples of flange joints installation inspection record
Annex E (Informative) Calculation of bolt mounting torque by friction coefficient
Bibliography
