Steel Horizontal Vessels on Saddle Supports
1 Scope
This standard covers the requirements on design, manufacturing, test and acceptance inspection of steel horizontal vessels (hereafter called horizontal vessel).
This standard is applicable to the horizontal vessel with the designed pressure no more than 35MPa and supported by two symmetric saddle pedestals under even load.
This standard is not applicable to the following horizontal vessels:
a) The horizontal vessels heated directly by flame or under nuclear radiation;
b) The horizontal vessels handled frequently;
c) The horizontal vessels to which fatigue analysis is required;
d) The horizontal vessels with clamping cover.
2 Referenced Regulatory Documents
The clauses of the following standards become a part of this standard through being referenced. For all the reference indicated with the date, all their afterwards amendments (excluding amendment on text error) or revisions shall not be effective to this standard. However, the parties reaching agreement based on this standard are encouraged to study whether the latest versions of such documents are adoptable. For all the reference without being indicated with the date, their newest versions shall be effective to this standard.
GB 150 Steel Pressure Vessel
GB/T 700-1988 Carbon Structural Steel
GB/T 1804-2000 Ordinary Tolerance and Tolerance without the Indication of Its Linearity or Angle or Size
GB/T 1591-1994 Low-Alloy High-Strength Structural Steel
GB 50017-2003 Regulation for Design of Structural Steel
JB/T 4712 Saddle Pedestal
JB 4733-1996 Explosion Stainless Steel Composite Steel Plate for Pressure Vessel
JB/T 4735-1997 Wielded Ordinary-Pressure Steel Vessel
Regulation for Technical Supervision on Pressure Vessel Safety (Issued by the former National Administration of Quality and Technical Supervision in 1999)
3 Terminology and Definition
The following terminology and definitions are applicable to this standard.
3.1 Pressure
Unless otherwise indicated, pressure refers to gauge pressure.
3.2 Operating pressure
Operating pressure refers to the possible maximum pressure on top of horizontal vessel under normal operating conditions.
3.3 Design pressure
Design pressure refers to the maximum pressure on top of horizontal vessel as designed. It works as the basis for design load together with the corresponding design temperature, and shall not be lower than the operating pressure.
3.4 Calculating pressure
Calculating pressure refers to the pressure used to determine the thickness of components under the corresponding design temperature.
3.5 Test pressure
Test pressure refers to the pressure on top of horizontal vessel during pressure experiment.
3.6 Design temperature
Design temperature refers to the designed temperature (average temperature on metal part section) of metal part of horizontal vessel under normal operating conditions. It works as the basis for design load together with the design pressure.
3.7 Test temperature
Test temperature refers to the temperature of housing metal of horizontal vessel during pressure experiment.
3.8 Thickness
3.9 Calculated thickness
Calculated thickness refers to the thickness calculated according to the formulas in chapters of GB 150 or JB/T 4735 or this standard. If necessary, the thickness needed by other loads shall also be calculated.
3.10 Design thickness
Design thickness refers to the sum of calculated thickness and corrosion margin.
3.11 Nominal thickness
Nominal thickness refers to the thickness calculated from the design thickness plus minus deviation of steels thickness and then convert the sum into the standard specification f steels.
3.12 Effective thickness
Effective thickness refers to the nominal thickness deducted by corrosion margin and minus deviation of steels thickness.
4 General Principles
4.1 Except meeting the requirements of this standard in design, manufacturing, test and acceptance inspection, the horizontal vessel applicable to this standard shall also follow the related national regulations, rules and standards.
4.2 Definition of Vessels
4.2.1 Connection between horizontal vessels and external pipes
a) The first loop joint slope end side connected by wielding;
b) The first screw joint end side connected by screwing;
c) The first flange seal side connected by flange;
d) The first seal side connected by specific connection or pipe.
4.2.2 The bearing seal, flat cap and fasteners of horizontal vessel connected by pipe.
4.2.3 Wielding joint between non-bearing component and horizontal vessel.
The components other than joints, such as saddle support and supporting loop shall also meet the requirements of this standard and other related standards.
4.2.4 The over-pressure releasing device connected to horizontal vessel directly shall meet the related specifications in GB 150. The accessories including the instruments on horizontal vessels shall also be adopted in accordance with related standards.
4.3 Qualifications and Responsibilities
4.3.1 Qualifications
4.3.1.1 The designers and manufacturers of horizontal vessels shall have acquired the optimized quality management system.
4.3.1.2 The designers of horizontal pressure vessels shall have the required permit on designing pressure vessels, and the manufacturers shall have the required permit on manufacturing pressure vessels.
4.3.1.3 The manufacturing and inspection personnel of horizontal pressure vessels shall have the qualifications meeting the requirements of JB/T 4735.
4.3.2 Responsibilities
4.3.2.1 Responsibilities of designers
a) The designers shall be responsible for the correctness and integrity of designing documents;
b) The designing documents shall include the designing calculation and designing drawings at least;
c) The general design drawings of horizontal pressure vessels shall carry the stamp indicating the qualification of pressure vessel design.
4.3.2.2 Responsibilities of manufacturers
4.3.2.2.1 The manufacturers shall manufacture the products in accordance with the design drawings.
4.3.2.2.2 During the manufacturing and after its manufacturing completion of horizontal pressure vessels, the inspection department of the manufacturers shall carry out various inspections and tests according to the specifications of this standard and the drawings, prepare the test reports, and be responsible for the correctness and integrity of reports.
4.3.2.2.3 The manufacturers shall archive the following technical documents for each set of horizontal vessels they manufacture, and such documents shall be maintained for at least 7 years.
a) Manufacturing process drawings or cards;
b) Certificates of materials and bills of material;
c) The records of wielding and heat treatment process;
d) The records on items that are adoptable to manufacturers as allowed by the standard;
e) The inspection records during manufacturing and after manufacturing completion;
f) Drawings after manufacturing completion.
4.3.2.2.4 After the inspection institution confirms that the quality of vessel meets this standard and the drawings, the manufacturer shall fill up the product quality certificate and hand it over to the user.
4.4 General Specifications on Design
4.4.1 Determination of design pressure
4.4.1.1 The value of design pressure shall be no less than the operating pressure.
4.4.1.2 If the horizontal vessel is equipped with overpressure release device, the design pressure shall be determined according to the specifications in Appendix B of GB 150.
4.4.1.3 For the horizontal vessels holding liquefied air or liquefied gas, the design pressure shall meet the requirements in the Regulation for Technical Supervision on Pressure Vessel Safety.
4.4.1.4 The design pressure of horizontal vacuum vessel shall take into consideration of its external pressure. When it is equipped with safety controlling device (such as vacuum release valve), the design pressure shall 1.25 times the difference between the external and internal pressures or 0.1MPa, whichever is lower; when no safety controlling device is installed, it shall be 0.1MPa.
4.4.2 Determination of design temperature
4.4.2.1 The design pressure shall be no less than the maximum possible temperature of component metal during operation. For the metal temperature below 0℃, the design temperature shall be no more than the minimum possible temperature of component metal. The nameplate shall indicate the design temperature.
4.4.2.2 When the components of horizontal vessel have different metal temperature during operation, the design temperature of each component may be determined separately.
4.4.2.3 The design temperature of low-temperature horizontal vessel shall be determined according to Appendix C of GB150.
4.4.2.4 The metal temperature of components may be calculated from the heat conduction, or measured from similar vessel that is already in use, or determined according to the temperature of internal mediate when the metal temperature is close to the mediate temperature.
4.4.3 The horizontal vessels with different working conditions shall be designed according to the most severe working conditions, and the drawings or technical documents indicate the operating pressure and operation temperature under different working conditions.
4.4.4 Load
The below loads and their combinations shall be taken into consideration during designing:
a) Pressure;
b) Liquid static pressure;
c) Gravity of horizontal vessel itself (including its internal parts) and the gravity of interior materials during normal working conditions or during test;
d) The concentrated or even gravity of accessories, platforms, heat insulation materials and interlinings;
e) Load in case of earthquake;
f) Counteracting force of pedestal;
g) The friction on pedestal and other forces caused by thermal expansion;
If necessary, the following loads shall also be considered:
h) The forces from the connecting pipes and other components;
i) Impact load including dramatic fluctuation of pressure;
j) Counter-impact force, such as the counter force caused by fluid;
k) Effect of fluctuation of pressure and temperature;
l) Forces during hoisting.
4.4.5 Thickness surplus C
The thickness surplus shall be determined according to the equation 4-1:
C=C1+C2 (4-1)
Where C——Thickness surplus, mm;
C1——Minus deviation of steels thickness, mm;
C2——Corrosion margin, mm.
4.4.5.1 Minus deviation of steels thickness C1
The minus deviation of thickness of steel plates or pipes shall meets the requirements in related standards for steels. In case the minus deviation of steels thickness is no more than 0.25mm, and is in no more than 6% of the nominal thickness, the minus deviation during calculation may be omitted.
4.4.5.2 Corrosion margin C2
To avoid the decrease of thickness of vessel components due to corrosion and mechanical abrasion, the corrosion margin shall be taken into consideration. The specific stipulations are as follows:
a) For the components with corrosion or abrasion, the corrosion margin shall be determined according to the design life span and the corrosion rate of metal materials caused by mediates;
In case the components of horizontal vessel have different degree of corrosion, different corrosion margins may be adopted;
c) For the horizontal vessels manufactured from carbon steel or low-alloy steels, the corrosion margin shall be no less than 1mm.
4.4.6 After the processing of reel of horizontal vessel is accomplished, the minimum thickness excluding the corrosion margin shall meet the following requirements:
a) For the horizontal vessels manufactured from carbon steel or low-alloy steels, it shall be no less than 3mm;
b) For the horizontal vessels manufactured from high-alloy steels, it shall be no less than 2mm.
4.5 Allowable Stress
4.5.1 The allowable stress of bearing components and bolt materials of horizontal pressure vessels under different temperatures shall be determined according to GB 150, with the Table 4-1 (for the steels other than bolts) and Table 4-2 (for the bolt materials) as the basis. The allowable stress of materials used on horizontal pressure vessels shall be in accordance with JB/T 4735.
Table 4-1 Basis of Determining the Allowable Stress (I)
Contents
1 Scope
2 Referenced Regulatory Documents
3 Terminology and Definition
4 General Principles
5 Materials
6 Structure
7 Strength Calculation
8 Manufacture, Inspection and Acceptance
Appendix A (Informative Supplement) Check Calculation for Strength and Stability of Horizontal Vessel with Additional Load Applied
JB/T 4731-2005 Standard Interpretation
