- 1 -  
ICS 23.020.30  
 
 
 
 
 
National Standard  
of the People's Republic of China  
 
 
GB 150.1 - 20xx  
Replaces Part of GB 150 - 1998  
 
 
 
Pressure Vessels  
Part 1: General Requirements  
 
 
 
 
  
(Draft for approval)  
 
 
 
 Issue Date: 20XX – XX – XX Implementation Date: XX 0XX – XX –
XX 
 
 
 
Issued by the General Administration of Quality Supervision, Inspection and 
Quarantine of the People's Republic of China  
 
 
- 2 - Table of contents  
 
 
Foreword...............................................  
 
Introduction........................ ...................  
 
1 Scope..................................................  
 
2 Normative references..........................  
 
3 Terms and symbols..............................  
 
4 General requirements...........................  
 
 
 
 
Appendix A (Normative  annex)  Conformity declaration..................................................  
 
Appendix B (Normative annex)  Excessive pressure relief device.......................................  
 
Appendix C (Normative annex)  Determination of vessel design pressure by confirmatory burst test  
 
Appendix D (Normative annex)  Comparative  empirical design method.............................  
 
Appendix E (Normative annex)  Local structure stress analysis and evaluation...................  
 
Appendix F (Normative annex)  Risk asses sment report.........................................................  
 
Appendix G (Normative annex)  Standard Proposal /Inquiry form.........................................  - 3 -  
Foreword  
 
 
GB 150 Pressure Vessels consists of the following four parts:  
----Part 1: General requirements  
----Part 2: Materials  
----Part 3: Designs;  
----Part 4: Fabrication, inspection and testing, and acceptance.  
 
This part is Part 1 of GB 150. The draft procedure of this Part is in accordance with the provisions 
specified in GB /T 1.1  – 2009 Directives for standardisation.  
 
This p art replaces some part contents of GB 150 – 1998 Steel pressure vessels (Chapter 1 ~ Chapter 
3, Appendix B and Appendix C), compares with GB 150 – 1998, the main technical change are as 
below:  
 
a) Expanded the ap plicable scope of the Standard.  
---- By means of reference standards,  it is applicable to pressure vessels made of metal materials;  
---- Under the premise of meet ing the design guidelines of this Standard, it specifies design methods 
to deal with circumsta nces exceeding standard scopes;  
---- It specifies the basis Standards for all kinds  of structure vessels;  
 
b) Amended the requirements on the qualifications and responsibilities of the vessel 
construction participants.  
---- Specifies the storing  period for the design documents;  
---- Added the responsibilities of the user or desi gn-trustor in providing the written design 
conditions at  the design stage;  
---- Specifies the responsibilities of the inspectors from inspection institution on the report 
confirmation a nd testimony of the confirmatory burst test.  
 
c) Amended the safety factors for determining allowable stress.  
---- Adjusted the safety factor of tensile strength from 3.0 to 2.7;  
---- Adjusted the safety factor of yield strength of carbon steels and low -alloy  steels from 1.6 to 1.5.  
---- For austenitic stainless steel , one  can use Rp1.0 to determine the allowable stress.  
 
d) Added conformity declarations to meet the basic safety requirements prescribed in the safety 
technical regulations for special equipment.  
 
e) Added implementation details of the design methods in addition to adoptive standards and 
regulations.  
 
f) Added the requirements o f the risk evaluation at  the design stage for pressure vessels and its 
implementation details.  
  
This Standard was proposed and fo rmulated by China Standardisation Committee on Boilers and 
Pressure Vessels (CSCBPV).  
 - 4 - The organisation responsible for the drafting of this Standard is :  
China Special Equipment Inspection and Research Institution (CSEI).  
 
The organisations participated i n the drafting of this Standard are:  
Bureau of Safety Supervision of Special Equipment of AQSIQ;  
Zhejiang University;  
Hefei General Machinery Research Institute;  
SINOPEC Engineering Incorporation;  
East China University of Science and Technology;  
Lanpec Te chnologies Limited.  
 
The main drafters of this Standard are: Shou Binan, Chen Gang, Zheng JinYang, Chen XueDong, 
Yang GuoYi, Xie TieJun, Li ShiYu, Xu Feng, Wang XiaoLei, Li Jun, Qiu QingYu, Zhang YanFeng, 
Wu QuanLong.  
 
This Standard replaces the previous v ersions: GB 150 – 1989, GB 150 – 1998.  
 
The China Standardisation Committee on Boiler and Pressure Vessels (CSCBPV) is responsible for 
the interpretation of this Standard.  
 - 5 -  
Introduction  
 
The China Standardisation Committee on Boilers and Pressure Vessels (CSCBPV) (hereinafter 
refereed to as the Committee) is approved and established by the Standardisation Administration of 
the Peopl e's Republic of China (SAC) in accordance with the Standardisation Law of PRC China. 
The Committee is a national technical wor k organisation which is specialised in boilers, pressure 
vessels and pressure piping, and is responsible for the technical jurisdiction and standardisation 
work of the above mentioned field. The Committee is under direct jurisdiction management of the 
SAC for its National Standard professional work, and under jurisdiction management of the 
National Energy Administration for its Industrial Standard professional work.  
 
This Standard is one of the major common technical standards which is formulated and centra lised 
by the Committee for pressure vessels, so as to regulate all technical requirements relevant to the 
design, fabrication, inspection and acceptance of all pressure vessels constructed or used in China.  
 
The technical terms of this Standard includ e all mandatory requirements, all specific restrictive 
provisions as well as all recommended terms which should be followed during the construction 
process (that is the works on the design, fabrication, inspection and acceptance) of pressure vessels. 
Among these, the implementation of the recommended terms is  not compulsory. As it is neither 
necessary nor possible for this  standard to include all technical details of the construction process of 
pressure vessels within the applicable scope of th e Standard, under the premise of meeting the basic 
safety requirements specified by regulations, any technical contents which are not speci fically 
mentioned in this Standard should not be prohibited. This Standard must not be used as a technical 
manual for the construction of any specific pressure vessel, it also can not be used to replace 
training, engineering experience and project evaluation. Engineering evaluation is defined as any 
technical evaluation made by technicians with professional knowledge and deep understandin g of 
the application of specifications in connection with specific products. However the engineering 
evaluation should be consistent with the relevant technical requirements of this Standard, shall not 
violate the mandatory requirements and the restrictive  provisions of this Standard.  
 
This Standard does not preclude  any advanced technical methods adopted during the actual 
engineering designs and construction. However, the engineers who adopted the advanced technical 
methods should be able to make reliable  judgments, to ensure that the technical methods meet the 
provisions of this Standard, particularly the relevant mandatory design regulations (Such as strength 
or stability design formula etc.).   
 
The technical methods and technology requirements specified  in this Standard are not involved with 
any Patent. However, the project application of this Standard may involve some particular patents;  
the user of this Standard shall bear the responsibilities associated with the patent rights.   
 
This Standard neither requires nor prohibits the designers  to use computer programs to achieve the 
analysis  or design of the pressure vessels, however, if a computer program is employed to conduct 
the analysis or design, then  – as well as  meeting the requirements of this Standa rd – the following 
should also be confirmed :  
 
1) The technology consistency assumed in the adopted programs;  
2) The adaptability of the design contents from the adopted programs;  
3) The correctness of any input parameters and output results of the adopted programs  used in 
the project designs.   - 6 -  
The Committee adopted a proposal review system to amend this S tandard. Any units or individuals 
have the right to propose suggestions towards the amendment  of this Standards;  the proposed 
amendment suggestions should be fill ed in  on the “Standard Proposal/Inquiry form” (See Appendix 
G) to submit to the Committee. The Committee carries out examination to the contents of the 
“Standard Proposal/Inquiry form”, and according to the results of the examination, records the 
adopted t echnical content into the next version of the Standard.  
 
The Committee only gives  an interpretation of the technical clauses of this Standard. Any query 
should be submitted to the Secretariat of the Committee in writing, and must  provide all required 
infor mation. Queries which are not directly related to the Standard terms or queries which cannot  be 
understood should be treated as in the category of technical advisory . The Committee has the right 
to refuse to answer or provide any paid technical services st ated in the agreement.  
 
The Committee is responsible for the public ising work of this Standard. The Committee will not 
bear any responsibility for any consequences occurred  from misunderstanding or ambiguity 
meaning of this Standard during its public ising of other institutions which have not obtained a 
written author isation or approval  from the Committee.  - 7 -  
 
           
Pressure Vessels  
Part 1: General requirements  
 
 
 
 1  Scope  
1.1 This Standard specifies the general requirements for materials, design, fabrica tion, inspection and 
acceptance of pressure vessels. It applies to the construction of metal pressure vessels (hereinafter 
refereed to as the Pressure Vessels)  
 
1.2 Applicable design pressure of this Standard  
1.2.1 For steel Pressure Vessels shall not exc eed 35MPa.  
1.2.2 For other metal Pressure Vessels shall be determined by according to the corresponding 
reference Standards.  
 
1.3 Applicable design temperature range of this Standard  
1.3.1 Design temperature range: -269oC ~ 900oC. 
1.3.2 For steel Pressure  Vessels shall not exceed the allowable operating temperature range of the 
materials listed in GB 150.2.  
1.3.3 For other metal Pressure Vessels, shall be determined by according to the allowable operating 
temperature range of the materials listed in the re ference Standards of this Part.  
 
1.4 The structure forms and construction requirements of this Standard applicable steel Pressure 
Vessels shall be in accordance with the corresponding provisions of this Part and GB 150.2 ~ GB 
150.4; Pressure Vessels with s pecific structures and made of aluminium, titanium, copper, nickel 
and nickel alloy, as well as z irconium, apart from meeting the relevant requirements of this 
Standard, should also meet the following corresponding requirements:  
a) The applicable scope and co nstruction requirements of tubular heat exchangers shall meet 
the requirements set out in  GB 151.  
b) The applicable scope and construction requirements of steel spherical tanks shall meet the 
requirements set out in  GB 12337.  
c) The applicable scope and construc tion requirements of horizontal Pressure Vessels shall 
meet the requirements set out in  GB 4731.  
d) The applicable scope and construction requirements of tower Pressure Vessels shall meet the 
requirements set out in  JB/T 4710.  
e) The applicable scope and constru ction requirements of aluminium welded Pressure Vessels 
shall meet the requirements set out in  JB/T 4734.  
f) The applicable scope and construction requirements of titanium welded Pressure Vessels 
shall meet the requirements set out in  JB/T 4745.  
g) The applicabl e scope and construction requirements of copper welded Pressure Vessels shall 
meet the requirements set out in  JB/T 4755.  
h) The applicable scope and construction requirements of nickel and nickel alloy welded 
Pressure Vessels shall meet the requirements set out in  JB/T 4756.  
i) The applicable scope and construction requirements of zirconium Pressure Vessels shall - 8 - meet the requirements set out in  NB/T 47011.  
 
1.5 The following Pressure Vessels are not within the applicable scope of this Standard  
a) Pressure Vessels with design pressure lower than 0.1MPa and vacuum  degree lower than 
0.02MPa;  
b) Vessels under the jurisdiction of the Technical Supervision Regulation for Safety o f 
Transportable Pressure Vessels;  
c) Among equipment, the pressure chambers (such as pump casing, o uter casing of 
compressors, outer casing of turbines, hydraulic cylinders etc.) which can be its own system 
or as components in swivelling or reciprocating movement machinery ; 
d) Vessels with possible failure risk of neutron radiation damage which exist in nu clear power 
plants.  
e) Vessels heated by direct flame;  
f) Vessels with inner diameter (for non -circular sections, refers to the maximum geometric 
dimensions of the inner boundaries of the sections, such as: diagonals of rectangles and 
major axes of ellipses) les s than 150mm;  
g) Glass -lined vessels or vessels which are specified with other national standards or industrial 
standards in refrigeration  and air -conditioning industry.  
 
1.6 Vessel define scope  
1.6.1 Vessels connected with external pipelines;  
a) The groove end face of the first girth joint of the welded connection;  
b) The end face of the first threaded connection joint;  
c) The first flange sealing surface of  the flange connection;  
d) The first sealing surface of any special purpose connector or pipe;  
 
1.6.2 The pressure heads,  flat heads and fasters of connection pipe s, manholes and hand -holes etc.  
 
1.6.3 The connection welding seam between non -pressure components and pressure components  
 
1.6.4 Non -pressure components such as racks or skirt supports etc. which are directl y connected to 
the vessels.  
 
1.6.5 Excessive -pressure relief devices of vessels (see Appendix B).  
 
1.7 For Pressure Vessels or pressure components, where its structure dimensions cannot  be 
determined in accordance with GB 150.3, the designs of such Pressur e Vessels or components may 
be conducted using the following methods:  
a) Confirmatory  test analysis, such as the test stress analysis and the confirmatory hydraulic 
test, the specific requirements shall meet the requirements set out in Appendix C;  
b) Use compara ble structures which have been in operations to carry out comparative  empirical 
design , the specific requirements shall be in line with the provisions  in Appendix D;  
c) Use stress analysis which comprises finite element method to conduct calculations and 
evaluations, the specific requirements shall meet the requirements set out in Appendix E.  
 2  Normative References  
The following documents are absolutely essential to the application of this Standard. For dated 
reference documents, only the dated ve rsions apply t o this Standard; f or undated reference 
documents, the latest versions (including all amendments) apply to this Standard.  
 - 9 - GB 150.2 Pressure vessels Part 2: Materials  
 
GB150.3 Pressure vessels Part 3: Design  
 
GB 150.4 Pressure vessels Part 4: Fabrication, inspection and testing, and acceptance  
 
GB 151 Tubular heat exchangers  
 
GB 567 (All parts) Bursting disc safety devices  
 
GB/T 12241 Safety valves – General requirements  
 
GB 12337 Steel spherical tanks  
 
GB/T XXXX Terminologies for pressure vessels - basic t erms  
 
JB 4708 Welding procedure qualifications for steel pressure vessels  
 
JB/T 4709 Welding specifications for steel pressure vessels  
 
JB/T 4710 Steel vertical vessels supported by skirt  
 
JB/T 4711 Coating and packing for transport of pressure vessels  
 
JB/T 4730 (All parts) Non -destructive testing for pressure equipment  
 
JB/T 4731 Steel horizontal vessels on saddle support  
 
JB 4732 Steel pressure vessels – designed by analysis  (confirmed 2005)  
 
JB/T 4734 Aluminium welded vessels  
 
JB/T 4745 Titanium welded vessels  
 
JB/T 4755 Copper pressure vessels  
 
JB/T 4756 Nickel and nickel alloy pressure vessels  
 
NB/T 47002 (All parts) Explosion welded clad plate for pressure vessels  
 
NB/T 47011 Zirconium pressure vessels  
 
TSG R0004 Technical Supervision Regulation for S afety of Stationary Pressure Vessels  
 
TSG R1001 Design appraisal regulations for pressure vessels and pressure pipes  
 3  Terms and symbols  
3.1 Terms and definitions  
The terms and definitions specified in GB/T XXXX and below apply to this Standard.  - 10 - 3.1.1 Press ure 
The force vertically applied onto the unit surface area of Pressure Vessels. In this Standard, pressure 
shall be refereed to as gauge pressure unless specifically indicated.  
 
3.1.2 Operating pressure  
Under normal operating conditions, the achievable ma ximum pressure at the top of Pressure 
Vessels.  
 
3.1.3 Design pressure  
The set maximum pressure at vessel top, together with the corresponding design temperature to be 
used as the basic design loading conditions of Pressure Vessels, its value shall not be l ower than the 
operating pressure.  
 
3.1.4 Calculation pressure  
Under the corresponding design temperature, the pressure used to determine the thickness of the 
components, including additional loads such as fluid column hydrostatic pressure etc.  
 
3.1.5 Test  pressure  
When conducting pressure test or leak test, the pressure at the vessel top.  
 
3.1.6 Maximum allowable working pressure (MAWP)  
Under a specified corresponding temperature, the maximum pressure allowed to be  borne  by the 
vessel top. This pressure i s calculated on the basis of the effective thickness of a pressure 
component of a pressure vessel, taken all loads borne by this component into consideration, the 
value should be the minimum value.  
 
Note: when the design documentation of a pressure vessel did not specify its maximum allowable 
working pressure, then the design pressure of this vessel can be considered as the maximum 
allowable working pressure.  
 
3.1.7 Design temperature  
When a vessel is under normal operating conditions, the set metal tempera ture of its components 
(the average temperature along the metal section surface of the components). The design 
temperature and design pressure are both used as the design load conditions.  
 
3.1.8 Test temperature  
When conducting pressure test or leak test, the metal temperature of the shell of the pressure vessel.  
 
3.1.9 Minimum design metal temperature  
In cases of  design, the expected minimum value of the metal temperature of each component under 
any possible condition for the duration of the vessel operati ng process.  
 
3.1.10 Required thickness  
The thickness calculated according to the corresponding formula of this Standard. When necessary , 
it should include the thickness (see 4.3.2) required by other loads. For components subjected to 
external pressure, th e required thickness shall be referred to as the minimum thickness which can 
meet the requirement of stability.  
 
3.1.11 Design thickness  - 11 - The sum of the required thickness and corrosion allowance.  
 
3.1.12 Nominal thickness  
The thickness which comes from the  round up the sum of the design thickness and the negative 
deviation of the material thickness to the standard specification of the material.  
 
3.1.13 Effective thickness  
The nominal thickness minus the corrosion allowance and the negative deviation of the material 
thickness.  
 
3.1.14 Minimum required fabrication thickness  
The minimum thickness ensures the design requirements after the fabrication of the pressure 
components.  
 
3.1.15 Low -temperature pressure vessel  
Pressure Vessels made of carbon steel, low -alloy steel, duplex stainless steel and ferritic stainless 
steel with design temperature lower than -20oC, and austenitic stainless steel vessels with design 
temperature lower than -196oC. 
 
3.2 Symbols  
 
C ____Additional thickness, mm;  
C1____Negative deviatio n of the material thickness, according to 4.4.6.1, mm;  
C2____Corrosion allowance, according to 4.4.6.2, mm;  
Di_____The inner diameter of a cylinder or a sphere shell, mm;  
Et______The elasticity modulus of materials under design temperature, MPa ; 
p_______De sign pressure, MPa ; 
pT______The minimum value of the test pressure, MPa ; 
Ro______The external radius of a cylinder, mm;  
Rm_____The lower limit of the standard tensile strength of materials, MPa ; 
ReL (R p0.2, Rp1.0) ____The yield strength of materials under standard room temperature (or 0.2%, 
1.0% non -proportional extension strength), MPa ; 
Rt
eL(Rt
p0.2, Rt
p1.0) ____The yield strength of materials under design temperature (or 0.2%, 1.0% non -
proportional extension strength), MPa ; 
Rt
D _______Under design temperat ure, and after the materials have experienced 100  000 hours 
fracture, the average value of the rupture strength, MPa ; 
Rt
n _______Under design temperature for 100 000 hours, the average creep limit when the creep 
rates of the material is 1%, MPa ; 
T_____The  stress of the pressure components under test pressure, MPa ; 
[]_____The allowable stress of the component materials of  pressure vessels under pressure test 
temperature, MPa ; 
[]t_____The allowable stress of the component materials of a pressure vessel und er design 
temperature, MPa ; 
[]t1 ____The allowable stress of the base material under design temperature, MPa ; 
[]t2_____The allowable stress of the coating material under design temperature, MPa ; 
[]tcr_____The allowable axial compressive stress of a cyli nder under design temperature, Moa;  
1 ____the nominal thickness of the base material, mm;  
2_____the thickness of the coating material, corrosion allowance is exclusive, mm;  
e____The effective thickness of a cylinder or a spherical shell, mm;  
____the co efficient of a welded joint.  - 12 -  
4 General requirements  
 
4.1 General rules  
4.1.1 The design, fabrication, inspection and acceptance of Pressure Vessels, apart from meeting the 
provisions of all Parts of this Standard, also shall comply with the State issued r elevant laws, 
regulations and safety technical codes.  
 
4.1.2 The units which design and manufacture Pressure Vessels should establish a sound quality 
management system and conduct effective operations.  
 
4.1.3 The design and manufacturing of Pressure Vessel s which are within the jurisdiction of the 
Technical Supervision Regulation for Safety of Stationary Pressure Vessels should accept 
supervisions from the safety supervision institution of special equipment.  
 
4.1.4 The category of Pressure Vessels shall be determined in accordance with the regulations of the  
Technical Supervision Regulation for Safety of Stationary Pressure Vessels.  
 
4.2 Qualification and responsibility  
 
4.2.1 Qualifications  
 
a) The design units of Pressure Vessels within the jurisdiction of th e Technical Supervision 
Regulation for Safety of Stationary Pressure Vessels should hold the corresponding special 
equipment designing license;  
 
b) The manufacturer of Pressure Vessels within the jurisdiction of the Technical Supervision 
Regulation for Safety  of Stationary Pressure Vessels should hold the corresponding special 
equipment manufacturing license;  
 
4.2.2 Responsibilities  
 
4.2.2.1 The responsibilities of the user or the design -trustor  
The design -trustor or the vessel user should submit the design s pecifications (UDS – User's Design 
Specification) of the pressure vessels to the design units in formal writing, the following contents 
should be included in the design specification:  
a) The main standards and regulations which the vessel design is based on;  
b) Operating parameters (including the operating pressure, operating temperature range, liquid 
level and the load of the connection pipes etc.);  
c) The operation location and the natural conditions of the location of the pressure vessels 
(including the environme nt temperature, seismic fortification intensity, wind load and snow 
load etc.);  
d) Components and characteristics  of the medium ; 
e) Expected service life;  
f) The geometric parameters and nozzle position;  
g) Other necessary conditions required by the design.  
 
4.2.2.2 T he responsibilities of the design units  
a) The design units are responsible for the correctness and integrity of the design 
documentation;  - 13 - b) The design documentation should at least include the strength calculation notes, the design 
drawings, the manufacture te chnical conditions, the risk assessment report (when it is 
required by the relevant regulations or design -trustor),  installation instructions and 
maintenance manual are also included when necessary;  
c) The general design diagram of the pressure vessels which are within the jurisdiction scope 
of the Technical Supervision Regulation for Safety of Stationary Pressure Vessels should be 
stamped with the official stamp of design license for special equipments.  
d) The risk assessment report issued by the design units to  the vessel users should comply with 
the requirements in Appendix F;  
e) The design units should keep all of the vessel design documentation within the expected 
service life of the pressure vessels.  
 
4.2.2.3 The responsibilities of the manufacturer  
a) The manufac turer of the pressure vessels should conduct the manufacturing process in 
accordance with the requirements specified in the design documentation, if any modification 
of the original design is required, the manufacturer should obtain a modification permissi on 
from the original design unit in writing, and record the modified sections in detail;  
b) Before manufacturing, the manufacturer should draw up complete quality plans, the contents 
of the plan should include at least the control point of the manufacturing t echnology, the 
inspection items and compliance quota of the pressure vessels or components;  
c) During the manufacturing process and after the completion of the manufacture, the 
inspection department of the manufacturer must comply with  the regulations of this  
Standard, drawing up specifications and quality plans to conduct all type s of inspections and 
tests to the pressure vessels, issuing relevant reports and be ing responsible for the 
correctness and integrity of the report.  
d) After the inspection prove s to be qualified, the manufacturer should issue a product quality 
certificate;  
e) The manufacturer should keep the following technical documentation within the expected 
service life of each vessel product produced by them:  
1) Quality quota;  
2) Manufacturing technology dra wings or manufacturing technology card;  
3) Product quality certificate;  
4) The documentations on welding technology and heat treatment technology of the 
pressure vessels.  
5) In the Standard, the records of inspections and test items which are within the 
permissible  selection for the manufacturer;  
6) During the manufacturing process and after the completion of the pressure vessel 
manufacturing, all records of inspections, checking and tests.  
7) The original design diagrams and project completion drawings of the pressure 
vessels.  
 
4.3 General provisions of the design  
4.3.1 The design units (designers) of the pressure vessels should carry out the designs strictly in 
accordance with the vessel design specifications provided by the user or the design -trustor, and 
should take a ll possible failure modes which may be occur during the operation of the pressure 
vessels into consideration, and put forward measures to prevent vessel failures. The calculations on 
the strength, rigidity and stability of the pressure components of the pr essure vessels should meet  
the provisions specified in GB 150.3 or the reference standards.  
 
With regard to pressure vessels bearing cyclic loading and have successful operation experiences, - 14 - after obtaining approval from the technical leader of the design unit, can be designed in accordance 
with this Standard, and be added fatigue analysis and evaluation by according to the Appendix C of 
JB 4732, meanwhile should meet the relevant manufacturing requirements.  
 
4.3.2 Loading  
The following loading should be ta ken into consideration during designing.  
a) External pressure, internal pressure or the maximum pressure difference;  
b) Fluid column hydrostatic pressure, when the fluid column hydrostatic pressure  is 5% lower 
than the design pressure, it can be overlooked;  
 
The following loading should also be considered when it is necessary:  
c) The self -weight of a pressure vessel (including internal pieces and fillers etc), as well as the 
gravity load of the inside contained medium under normal working conditions or the status 
of pressure test;  
d) The gravity loads of the subsidiary equipment and the insulation materials, linings, pipe line, 
ladders and terraces etc.  
e) Wind load, earthquake load and snow load;  
f) The reaction forces of the bearings, base rings, skirt support as well as oth er types of 
supporting items;  
g) The forces of the connecting pipes and other components;  
h) The forces caused by the differences of temperature gradient or thermal expansion;  
i) The impact loads, including impact load caused by rapid fluctuations, and the reaction  
forces caused by fluid impact;  
j) The force during transporting or lifting.  
 
4.3.3 When determining the design pressure or calculation pressure,  the following  should  be 
consider ed: 
a) When a  pressure vessel is equipped with an excessive pressure relief device, the design 
pressure of such pressure vessel should be determined in accordance with the provisions in 
Appendix B;  
b) With regard to vessels containing liquefied gases, if the pressure vessels are equipped with 
reliable cold facilities, then within the specifi ed load coefficient range, the design pressure 
should be determined on the basis of maximum achievable temperature of the contained 
medium under working conditions, otherwise shall be determined in accordance with the 
relevant regulations;  
c) With regard to e xternal pressure vessels (such as vacuum vessels, vessels positioned under 
liquid or vessels buried underground), when determining the calculation pressure, should 
consider the possible maximum pressure difference between the internal pressure and the 
external pressure under normal working conditions;  
d) When determining the wall thickness of a vacuum vessel, the design pressure should be 
considered on the basis of external pressure bearing by the vessel. In case s where  a safety 
control device (such as vacuum relief valve) is equipped, the design pressure should be the 
1.25 times of the maximum difference between the internal and external pressures or 
0.1MPa , whichever is lower ; if there is not a safety control device equipped, then it should - 15 - be determin ed as 0.1MPa;  
e) For pressure vessels which consist of two or more pressure chambers, such as jacketed 
pressure vessels, the design pressure of each pressure chamber should be determined 
separately. When determining the calculation pressure of any common component, the 
maximum pressure difference between two adjacent chambers should be considered.  
4.3.4 Determination of the design temperature  
a) The design temperature must not be lower than the achievable maximum temperature of the 
component metal under working conditio ns. With regard to the metal temperature under 
0oC, the design temperature must not be higher than the achievable minimum temperature of 
the component metal;  
b) When the metal temperatures of each part of a pressure vessel under working conditions are 
differe nt, can set up the design temperature of each part separately:  
c) The metal temperatures of the components can be determined by the following methods:  
1) From heat transfer calculation;  
2) Measured on the same type of vessels which have been in use;  
3) Determined on t he basis of the vessel contained medium temperature and combine with 
the external conditions;  
d) When determining the minimum design metal temperature, one should give full 
consideration to the effects of the atmospheric environmental low temperature conditio ns to 
the metal temperature of the vessel walls.  The atmospheric environmental low temperature 
refers to the minimum value of the average minimum temperature (refers to the sum of the 
minimum temperatures on each day of that month divide d by the number of days of that 
month) over the years.  
4.3.5 For pressure vessels with different working conditions, the vessels should be designed in 
accordance with the harshest working condition, the combination of different working conditions 
should also be taken into co nsideration when necessary, and the drawings or corresponding 
technical documents, should clearly indicate the values of pressure and temperature under each 
design condition and working condition.  
 
4.3.6 Additional thickness  
The additional thickness should  be determined according to formula (1):  
  C = C1 + C2.......................(1)  
 
4.3.6.1 The negative deviation of material thickness  
The negative deviation of the thickness of sheet materials or tube materials should be determined in 
accordance with the material Standards.  
 
4.3.6.2 Corrosion allowance  
In order for the pressure components of pressure vessels to prevent any weakening and thinning 
from corrosions or mechanical wearing, the corrosion allowance should be taking into 
consideration, the specific  provisions are as below:  
a) For components bearing even corrosion or wearing, the corrosion allowance of such 
components should be determined in accordance with the expected service life of the 
pressure vessels and the corrosion speed rate (and erosion speed  rate) of the medium to the 
metal materials;  
 - 16 - b) When the corrosion level of each component of pressure vessels are different, then different 
corrosion allowance should be adopted;  
 
c) For pressure vessels made of carbon steel or low -alloy steel and with compres sed air or 
water vapour as the medium, its corrosion allowance shall not be lower than 1mm.  
 
4.3.7 The minimum thickness of vessel walls after forming shall not include the corrosion 
allowance:  
a) For vessels made of carbon steel or low -alloy steel, shall not  be less than 3mm;  
b) For high -alloy steel vessels, usually not less than 2mm.  
 
4.3.8 The nominal thickness and the minimum required fabrication thickness of a vessel component 
should usually be indicated on the design drawings.  
 
4.4 Allowable stress  
4.4.1 Th e allowable stress of the materials in this Standard should be selected in accordance with 
GB 150.2 and corresponding reference standards. According to the specifications in Table 1 to 
determine the allowable stress of steel materials (bolt materials not i nclusive), according to the 
specifications in Table 2 to determine the allowable stress of the steel bolt materials.  
 
Table 1 Allowable stress value of steel materials (bolt materials not inclusive)  
 
Material  Allowable stress  
Take the minimum value from fo llowing, MPa  
Carbon steel, low -alloy steel  Rm
2.7,ReL
1.5,ReLt
1.5,RDt
1.5,Rnt
1.0 
High -alloy steel  Rm
2.7,ReL(Rp0.2)
1.5,ReLt(Rp0.2)
1.5,RDt
1.5,Rnt
1.0 
Titanium and titanium -alloy  Rm
2.7,Rp0.2
1.5,Rp0.2
1.5,RDt
1.5,Rnt
1.0 
Nickel and nickel -alloy  Rm
2.7,Rp0.2
1.5,Rp0.2
1.5,RDt
1.5,Rnt
1.0 
Aluminium and aluminium -alloy  Rm
3.0,Rp0.2
1.5,Rp0.2
1.5 
Copper and copper -alloy  Rm
3.0,Rp0.2
1.5,Rp0.2
1.5 
Note 1: For any austenitic high -alloy steel pressure component, when its design temperature is 
lowe r than the creep range, and if any micro -scale permanent deformation is permitted, then the 
allowable stress can be appropriately increased to 0.9Rt
p0.2, but not exceeds R p0.2/1.5. This rule 
does not apply to flanges or situations where any micro -scale def ormation can result in leakage or 
malfunctions.  
Note 2: If any reference standard permits to adopt R p1.0 or Rt
p1.0, then this value can be used to 
calculate the allowable stress;  
Note 3: According to the expected service life to select the limit value of t he rupture strength such 
as 1.0x105hours, 1.5x105hours, 2.0x105hours etc..  
 
 
Table 2 Allowable stress of steel bolt materials  - 17 - Material  Bolt diameter, mm  Heat treatment status  Allowable stress  
Take the maximum value from the 
following values, MPa  
 M22  ReLt
2.7 Carbon S teel 
M24 ~ M48  Hot rolling, 
Normal ising 
ReLt
2.5 
 M22  ReLt(Rp0.2t)
3.5 
M24 ~ M48  ReLt(Rp0.2t)
3.0  Low-alloy steel, 
high-alloy 
martensitic steel  
 M52  Quenching and 
tempering  
ReLt(Rp0.2t)
2.7 
 M22  ReLt(Rp0.2t)
1.6 High -alloy 
austenitic steel  
M24 ~ M48  Solid solution  
ReLt(Rp0.2t)
1.5  RDt
1.5 
 
 
4.4.2 When the design temperature is lower than 20oC, select the allowable stress at 20oC. 
 
4.4.3 Allowable stress of clad steel plates  
For clad steel plates with its integration rate between the coating clad layer and the base reach  to or 
above  Grade B2 plates prescribed in Standard NB/T 47002, during the design calculation, if the 
strength of the coating clad layer is required to be included, then its allowable stress under the 
design temperature should be determined by according to  Formula (2):  
 
  []t=[]1t1+[]2t2
1+2  ….......................(2)  
 
4.4.4 When earthquake load or wind load is combined with other loads listed in 4.3.2, then the 
design stress of the components should not be permitted to exceed 1.2  times the allowable stress, its 
combination requirements should be specified in accordance with corresponding standards.  
 
4.4.5 Allowable axial compressive stress of cylinders  
a) On the basis of the external radius R 0 of the cylinder and its effective thickness e, calculate 
the A value by according to Formula (3):  
 
   A=0.094 e/R0..........................(3)  
 
b) On the basis of the cylinder material, select the corresponding stress coefficient curve of 
external pressure (GB 150.3 Chapter  4), according to its temperature line to obtain the B 
value, within the elastic range (the straight line in the diagram or at its left side), the B value 
can be calculated by according to Formula (4):  
 
  B=2AEt/3 ........... ..........(4)  
 - 18 - c) The allowable axial compressive stress [ ]t
er shall be the B value, and not greater than [ ]t. 
 
4.5 Classification and coefficient of weld joints  
4.5.1 Classification of weld joints  
4.5.1.1 The weld joints between the pressure components of pressure vessels are classed as A, B, C 
and D four cate gories, such as shown in Diagram 1.  
a) The vertical weld joint (the vertical joints of multi -layer weld -shrunk vessels are not 
included) between the cylinder (including connection pipe) and the conical shell, the girth 
weld joint between the spherical head an d the cylinder, all weld joints between all types of 
the convex heads and flat heads, or the butt connection joints between the embedded 
connecting pipes or sockets and the vessel wall body, are all belong to Category A weld 
joints;  
 
b) The girth joints of th e vessel wall body, the joints between the small ends of the corn heads 
and the connection pipes, the joints between the long neck flanges and vessel wall body or 
connection pipes, the butt connection joint between the flat cover or tube plate and the 
cylinder as well as the butt girth joints between the connection pipes, all belong to Category 
B weld joints, but the weld joints which have been classed in Category A are not included.  
 
c) The non -butt connection joints between spherical -heads, flat covers, tube  plates and 
cylinders, the joints between flanges and vessel wall body or connection pipes, the overlap 
joints between the inner heads and the cylinders, as well as  the vertical joints of multi -layer 
weld -shrunk vessels, are all belong to Category C weld j oints, but the weld joints which are 
classed in Category A and Category B are not included.  
 
d) The joints between the connection pipes (including manhole cylinders), sockets, 
reinforcement pad and the vessel wall body belong to Category D weld joints, but th e weld 
joints which are classed in Category A, B, C are not included.  
 
4.5.1.2 The connection joints which connecting non -pressure components and pressure components 
belong to Category E weld joints, as shown in Diagram 1.  
 
 
- 19 -                                        Diagram 1 Classification of weld joints  
4.5.2 Coefficient of weld joints  
4.5.2.1 The coefficient of a weld joint  should be determined on the basis of the welding form of 
the butt joints and the length ratio of the non -destructive testing.  
4.5.2.2 The coefficient s of weld joint s for steel pressure vessels are specified as below:  
a) Double -sided welding butt joints and full welding butt joints which are equivalent to double -
sided welding  
1) Overall non -destructive testing,  =1.0;  
2) Local area non -destructive testing,  = 0.85.  
 
b) Single -sided welding butt joints (along all length of the welding seam, sealed with base 
metal pa d) 
1) Overall non -destructive testing,  = 0.9;  
2) Local area non -destructive testing,  = 0.8.  
 
4.5.2.3 The coefficients of weld joints for other metal materials shall correspond to  the provisions in 
corresponding reference standards.  
 
4.6 Pressure tests   
4.6.1 General requirements  
4.6.1.1 Pressure tests including: hydrostatic test, gas pressure test, gas and hydrostatic combined 
test. 
4.6.1.2 Pressure vessels are subjected to pressure tests after being produced, the type and 
requirements of the test, and the t est pressure should be clearly indicated in the drawings.  
4.6.1.3 The h ydrostatic test is us ually used as the pressure test;  the test liquid should meet  the 
requirements specified in GB 150.4 or relevant reference standards.  
4.6.1.4 Pressure vessels not su itable for  the hydrostatic test can be tested with gas pressure test or 
gas and hydrostatic combined test. Pressure vessels subject to gas pressure test or gas and 
hydrostatic combined test should meet the requirements specified in GB 150.4 or relevant ref erence 
standards.  
4.6.1.5 When a gas and hydrostatic combined test is adopted, the test liquid and test gas should 
meet the requirements in 4.6.1.3 and 4.6.1.4 respectively, the test pressure should be in line with the 
provisions  of the gas pressure test.  
4.6.1.6 Where external pressure vessels should be conducted pressure test with internal pressure, the 
test pressure should be according to 4.6.2.3.  
4.6.1.7 For any multi -cavity pressure vessel which consists of two or more than two pressure 
chambers, the t est pressure of each pressure chamber should be determined by according to its test 
pressure, and each pressure chamber is subjected to pressure test respectively.  
a) Check the stabilities of the common components under the test pressure.  
b) If the stability req uirement can not be met, then a leak test should be conducted first. When 
the leak test has been successful, a pressure test can be conducted. When conducting the 
pressure test, inside of the adjacent pressure chambers should be maintained a certain 
pressu re, to make sure that during the whole testing process (including the pressure boost, 
pressure maintaining and pressure relief) at any one moment, the pressure difference of each 
pressure chamber does not exceed the allowable pressure difference, this requ irement and 
the allowable pressure difference shall be indicated in the drawings.  
c) If the test pressure of any cavity is required to be increased, then the provisions in 4.6.3 
should be met.  
 
4.6.2 Pressure of pressure test  - 20 - 4.6.2.1 The minimum value of pres sure tests meet  the provisions in 4.6.2.2 and 4.6.2.3, and take 
into account the following : 
a) When a vertical vessel is horizon tally positioned to conduct a hydrostatic test, the test 
pressure should include the fluid column hydrostatic pressure  from  when th e pressure vessel 
was tested at its upright position;  
b) Under working conditions, if the fluid column hydrostatic pressure of the medium contained 
inside of the pressure vessel is greater than the fluid column hydrostatic pressure of the 
hydrostatic  test, th en one should consider increas ing the test pressure.  
4.6.2.2 Internal pressure vessels  
a) Hydrostatic test:  
 
 .................................(5)  
b) Gas pressure test or gas and hydrostatic combined test:  
...................................(5)  
Note 1: If a maximum  allowable working pressure is indicated on the nameplate of the pressure 
vessel, then in the formula the design pressure p should be replaced by the maximum allowable 
working pressure;  
Note 2: If the materials of the main pressure components of a pre ssure vessel, such as the cylinder, 
head, connection pipes, equipment flange (or hand -hole flange) as well as the fasteners  of this 
pressure vessel are differe nt, then the minimum ratio value []/[]t of each component material 
should be selected.  
4.6.2.3 External pressure vessels  
a) Hydrostatic test:  
 
 .........................(7)  
b) Gas pressure test or gas and hydrostatic combined test:  
 ..............(8)  
 
4.6.3 S tress check for pressure tests  
If a test pressure which is greater than the ones prescribed in 4.6.2.2 and 4.6.2.3 is used, then before 
conducting the pressure test,  the stress level of each pressure component under the test condition 
should be checked, su ch as for the shell components, should check the maximum overall film stress 
T. 
 
a) When conducting the hydrostatic test, then T  0.9 R eL;  
b) When conducting the gas pressure test or gas and hydrostatic combined test, then 
T  0.8 ReL; 
 
In the formula: R eL is the yield strength (or 0.2% non -proportional extension strength) of the shell - 21 - material at the test temperature.  
 
4.6.4 Relieve of pressure testing  
For pressure vessels which cannot  be conducted with pressure tests as mentioned above, under the 
premise of ensuring the safe operation of the pressure vessels, the design unit shou ld put forward 
safety measures to relieve the pressure tests, after obtaining approval from the technical director of 
the design unit, the decision should be clearly indicated in the drawings.   
 
4.7 Leak tests  
4.7.1 Leak tests including air tightness testi ng and ammonia leak test, halogen leak test and helium 
leak test.  
4.7.2 For pressure vessels contain ing a  medium with toxicity level classed as extreme toxic, highly 
toxic or not allowed to have any slight quantity leakages, then a leak test should be cond ucted after 
qualified pressure test.  
Note: the toxicity level of the medium should be determined in accordance with the relevant 
regulations of the Technical Supervision Regulation for Safety of Stationary Pressure Vessels.  
4.7.3 The design unit should sub mit methods and technical requirements for the leak tests of the 
pressure vessels.  
 
4.7.4 Where a leak test is required, the test pressure, test medium and the corresponding test 
requirements should be indicated in the drawings and the design documents.   
 
4.7.5 The test pressure of the air tightness test should be equal to the design pressure.  
 
4.8 The structural design requirements of weld joints  
4.8.1 For steel pressure vessels, the structural designs of the weld joints should meet  the 
requirements speci fied in Appendix D of GB 150.3.  
4.8.2 For other metal pressure vessels, the structural designs of the weld joints should meet  the 
requirements specified in the reference standards.  
 
4.9 Excessive pressure relief device  
Pressure vessels within the applicati on scope of this Standard, if there is any excessive pressure 
happens during the operation process, then an excessive pressure relief device should be fitted in 
accordance with Appendix B.  - 22 - Appendix A  
 
(Normative annex)  
 
Conformity Declaration  
 
A.1 The form ulation of all Parts of this Standard has followed the general safety requirements 
specified in the State issued safety regulations for pressure vessels, the design criteria, material 
requirements, technical requirements on the manufacturing and inspection , as well as the acceptance 
criteria of the pressure vessels are in line with the corresponding regulations in the Technical 
Supervision Regulation for Safety of Stationary Pressure Vessels. All Parts of this Standard are 
harmon ised standards, that is all pressure vessels which are constructed according to all Parts of this 
Standard,  are able to meet the general safety requirements which are stated in the Technical 
Supervision Regulation for Safety of Stationary Pressure Vessels.  
 
 - 23 - Appendix B  
(Normative ann ex) 
Excessive pressure relief device  
B.1 Scope  
B.1.1  During pressure vessel operation, i f any excessive pressure occurs , then an  excessive pressure 
relief device (hereinafter referred to as the “Relief Device”) should be provided in accordance with 
the req uirements of this Appendix.  
B.1.2 This Appendix applies to Relief Devices fitted on pressure vessels, including safety valves, 
bursting disc safety devices, assemblies of safety valves and bursting disc safety devices. Relief 
Devices fitted on the connecti on pipeline of pressure vessels may consult this Appendix.  
B.1.3 This Appendix does not apply to pressure vessels that during operation the pressure may 
rapidly increase, and its reaction speed reaches to the detonation state.  
Note: Detonation (detonatio n) means that the burning speed of the substance is fast enough to reach 
to 1000m per second or faster, which produces absolutely different phenomenon from usual 
deflagration.  
B.2 Definition  
B.2.1 Actuating pressure  
In this Appendix, the actuating pressur e refers to the set -pressure of the safety valves or the design 
burst pressure of the rupture disc.  
B.2.2 Set pressure  
Under operating conditions, the set pressure for the safety valve to open, it is the gauge pressure 
measured at the valve inlet. Under t his pressure and specified operating conditions, the force created 
by the medium pressure that can open the valve and at the same time make  the force maintained on 
the valve seat balance with each other.  
B.2.3 Design burst pressure  
The set up of the desig n burst pressure is in line with  the working conditions of the pressure vessels 
and the corresponding technical safety specifications, it is the burst pressure value of the bursting 
disc under the design burst temperature.  
B.2.4 Marked burst pressure  - 24 - It is marked on the nameplate of the bursting disc, under a specified design (or licensed test) burst 
temperature, when conducting sampling burst test to a same batch of bursting discs, the arithmetic al 
mean value of the actual measured burst pressure.  
B.2.5  Manufacturing range  
The allowable distribution range of the differences between the marked burst pressure and the 
relative design burst pressure of the same batch of bursting discs. When a bursting disc takes zero 
manufacturing range, then the marked burs t pressure shall be the design burst pressure.  
B.2.6 Minimum marked burst pressure  
The algebraic  sum of the design burst pressure and the deviation under the manufacturing range.  
B.3 General provisions  
B.3.1 When a pressure vessel is equipped with Relief  Devices, generally the design pressure of the 
vessel is treated as the initial pressure of the excessive pressure limit.  
When the maximum allowable working pressure is marked in the design drawings and nameplates, 
the maximum allowable working pressure of  the pressure vessel can be used to substitute the design 
pressure, the following are the same.  
B.3.2 When vessels are equipped with Relief Devices,  the actuating pressure of the Relief Device 
and the Excessive Pressure Limit should meet the following req uirements.  
B.3.2.1 When a pressure vessel is equipped with only one Relief Device, then the actuating pressure 
of the Relief Device should not exceed the design pressure, and the Excessive Pressure Limit should 
not exceed 10% of the design pressure or 20 KPa, whichever is greater .  
B.3.2.2 When a pressure vessel is equipped with multiple Relief Devices, then the actuating 
pressure of one of the Relief Devices should not exceed the design pressure, the actuating pressures 
of other Relief Devices can be increa sed to 1.05 times of the design pressure; the Excessive 
Pressure Limit should not exceed 16% of the design pressure or 30 KPa, whichever is greater .  
B.3.2.3 When considering the situations where the a pressure vessel may be encountered with fire 
disaster o r come close to any unexpected external heat sources which may lead to danger, then the 
Excessive Pressure Limit of  the pressure vessel should not exceed 21% of the design pressure; such 
as if the Relief Devices mentioned in  B.3.2.1 or B.3.2.2 cannot  meet this requirement on Excessive 
Pressure Limit, then an auxiliary relief device should be installed, to assist the actuating pressure of 
the Relief Device will not exceed 1.1 times of the design pressure.  
B.3.3 Any one of the following circumstances, can be regar ded as one pressure vessel, in which case 
only one Relief Device is required to be fitted at the dangerous place (on the pressure vessel or on a 
pipeline), however when calculating the discharge capacity of the Relief Device, the connection 
pipeline be tween pressure vessels should be included:  - 25 - a) Pressure vessels connected to pressure sources but  where  the pressure vessels do not 
generate any pressure by themselves, and the design pressure of  such pressure vessels have 
reached to the pressure of the pressu re source;  
b) The design pressures over a few  pressure vessels are the same or slightly different, the 
connecting between the pressure vessels are conducted by connection pipes with large 
enough openings, and there is no block valve  fitted between the pressu re vessels, or a block 
valve is used but sufficient measures are adopted to ensure that the block valve is fully 
opened and sealed during normal operation of the pressure vessels.  
B.3.4 In the case of the pressure inside of a pressure vessel happens to be lower than the 
atmospheric pressure, and when this pressure vessel cannot  withstand this negative pressure 
conditions, then a Relief Device used to prevent  negative pressure should be fitted.  
B.3.5 Pressure vessels such as heat exchangers, if any high tem perature medium happens to leak to  
low temperature medium and generate steam, then a Relief Device should be fitted at the low 
temperature area.  
B.3.6 When a pressure vessel is required to fit Relief Devices and there are no special requirements, 
then the safety valves should be preferred.  
B.3.7 When one of the following conditions is met, then the safety devices of the bursting discs 
should be employed:  
a) Rapid increase of the pressure (such as increasing the chemical reaction, chemical explosion 
and the d eflagration etc. of the molecular weight).  
b) Has hig her sealing demands;  
c) The substances contained in the pressure vessel will lead to safety valve failure.  
d) Other situations where the safety valves cannot  be applied.  
B.3.8 In order to minim ise the expensive media, toxic media, or other hazardous media leaking out 
through the safety valves, or in order to prevent corrosive gases from the discharge pipeline getting 
into the inside of the safety valves, the safety valves and the safe ty devices of the bursting di scs can 
be used in series.  
B.3.9 Pressure vessels which are in one of the following conditions, then one or more safety devices 
for the bursting discs and the safety valves should be used in parallel:  
a) To prevent the rapid increase of the pressure in abnor mal working conditions;  
b) As an auxiliary relief device, when considering encountering with fire disaster or near 
unexpected external heat source, which requires the discharge area  to be increased .  - 26 - B.3.10 For pressure vessels used to contain explosive media  or toxic media with the toxi city level is 
extreme, highly or moderately hazardous, a conduit should be fitted at the outlet of the Relief 
Devices, to lead the discharged media to a safe location, and carry out proper dealing method, to 
prevent the dischar ged media getting directly into the Atmosphere.  
B.4 Safety valves  
B.4.1 Safety valves are used for clean, low viscosity media which do not contain any solid particles.  
B.4.2 Safety valves cannot  be independently used in circumstances  with rapid increase of  pressure.  
B.4.3 Safety valves cannot  be independently used in circumstances where the valve seat and valve 
sealing surface are glued by media or where the media may generate crystals, however the safety 
device of a bursting disc can be linked to the side of the safety valve inlet to put into combined 
function.  
B.4.4 The common type of the safety valves is  a spring loaded safety valve, with full lift safety 
valves and low lift safety valves two types. Full lift safety valves are suitable for discharging med ia 
such as  gases, steam and liquefied gas, low lift valves are generally used to discharge liquid media. 
Self-active non -direct loaded safety valves (pilot safety valves) can also be used.  
B.4.5 The nominal diameter of any safety valve used for liquid sho uld be at least 15mm.  
B.4.6 The set -pressure deviation of any safety valve should not exceed ± 3% of the set pressure or 
the greater value of ± 0.015MPa.  
B.4.7 When a safety valve is equipped, the design pressure of a pressure vessel should be 
determined through  the following steps:  
a) Use the working pressure p w of the pressure vessel to determine the set -pressure of the 
safety valve p z, usually the p z = (1.05 ~ 1.1) p w; when p z <0.18MPa, the ratio value of  pz to 
pw can be appropriately increased;  
b) The desig n pressure p of the pressure vessel is equal to or slightly greater than the set -
pressure p z, ie p  p z.  
B.4.8 The relevant technical requirements of safety valves should be in accordance with GB / T 
12241.  
B.5 Bursting disc safety device  
B.5.1 A burstin g disc safety device is primarily formed by a bursting disc and a holder. Common 
shapes of bursting discs are conventional domed,  reverse domed and flat.  
B.5.2 Bursting disc safety devices are suitable for situations where pressure is rapidly increased, 
also can be linked with safety valves to protect the performance of the safety valves.  - 27 - B.5.3 Bursting disc safety devices may  not be independently used in situations where the toxic level 
of medium emission is extreme toxicity, with high degree of hazard or  explosive a nd liquefied 
petroleum gas etc.  On these occasions the safety devices can be used in tandem with safety valves.  
B.5.4 When used to discharge liquid medium, a bursting disc safety device which is suitable for 
media with fully liquid state should  be selected.  
B.5.5 When pressure vessels are equipped with bursting disc safety devices, then the design 
pressure of such pressure vessels are determined by the following steps.  
a) According to different  types of domed metallic bursting discs to determine t he minimum 
marked burst pressure p smin of busting discs,  see Table B.1 for the recommended p smin 
values;  
Table B.1 Minimum marked burst pressure P smin  
Bursting disc shape  Loading characters  Psmin, MPa  
Simple conventional domed  Static load   1.43p w 
Slotte d lined conventional 
domed  Static load   1.25p w 
Conventional domed  Pulsating load   1.7p w 
Reverse domed  Static load, pulsating load   1.1p w 
Note: If the designers have mature experience or reliable data, then they do not have to follow the 
specification s in Table B.1.  
b) Select the manufacturing range for the bursting discs, see Table B.2 for the manufacturing 
range of the bursting di scs. 
c) Calculate the design burst pressure p b of the bursting discs, p b is equal  to the Psmin plus the 
lower limit (absolute v alue) of the manufacturing range of the selected bursting disc;  
d) Determine the design pr essure p of the pressure vessel;  p should not be smaller than the sum 
of the p b and the upper limit of the manufacturing range of the selected bursting disc.  
Table B.2 M anufacturing range of bursting discs  
Full range  ½ range  ¼ range  Zero range  Bursting 
disc 
classific
ation  Design 
burst 
pressure  Upper 
limit  
(Positive
) Lower 
limit  
(negative)  Upper 
limit  
(positive)  Lower 
limit  
(negative)  Upper 
limit  
(Positive)  Lower 
limit   
(negative)  Upper 
limit  Lower 
limit  
>0.30~0.40  0.045  0.025  0.025  0.015  0.010  0.010  0 0 
>0.40~0.70  0.065  0.035  0.030  0.020  0.020  0.010  0 0 
>0.70~1.00  0.085  0.045  0.040  0.020  0.020  0.010  0 0 Convent
ional  
domed  
>1.00~1.40  0.110  0.065  0.060  0.040  0.040  0.020  0 0 - 28 - >1.40~2.50  0.160  0.085  0.080  0.040  0.040  0.020  0 0 
>2.50~3.50  0.210  0.105  0.100  0.050  0.040  0.025  0 0 
> 3.50  6.00%  3.00%  3.00%  1.50%  1.50%  0.80%  0 0 
Reverse 
domed   0.1 0 10.00%  0 5.00%  - - 0 0 
Note: with regard to conventional domed bur sting discs, when the design burst pressure is lower 
than 0.3MPa, the manufacturer and the user (or design unit) may decide a wider manufacturing 
range which is acceptable by both parties through consultation.  
B.5.6 Materials for bursting disc safety devi ce  
B.5.6.1 The materials for bursting disc safety devices is not restricted by the material nameplates in 
GB 150.2, the bursting disc materials should be compatible  with the medium, and should be 
determined on the basis of the application conditions of th e bursting disk and by consultations of 
the supplier and the user. See Table B.3 for the common materials used for bursting discs and their 
maximum applicable temperature.  
Table B.3 The maximum applicable temperature of bursting discs  
Bursting disc materia l Maximum applicable temperature, oC 
Pure aluminium  100 
Pure silver  120 
Pure nickel  400 
Austenitic stainless steel  400 
Nickel -copper alloy (Monel)  430 
Nickel -chromium alloy  480 
Nickel chromium molybdenum alloy (Hastelloy)  480 
Graphite  200 
Note: w hen the surface of any bursting disc is covered with sealing film or protecting film, the 
effect from the cover materials to the maximum applicable temperature should be taken into 
consideration.  
B.5.6.2 For bursting disc safety devices used with corrosiv e medium or in corrosive environments, 
and has the possibilities of leading to early efficiency lost of the bursting disc safety devices, the 
surfaces of the bursting discs should be conducted with anti -corrosion measures such as plating, 
coating or lining . 
B.5.6.3 For the holders, the common materials are pressure vessel materials such as carbon steel, 
austenitic stainless steel, nickel -copper alloy and nickel -iron-chromium alloy etc. The properties of 
the materials should be compatible  with the media.  
B.5.7 The selection and relevant technical requirements of bursting disc safety devices should 
comply with  the provisions in GB 567.  - 29 - B.6 Combined installation of safety valves and bursting disc safety devices  
B.6.1 If a bursting disc safety device is series c onnected on the inlet side of a safety valve, when the 
bursting disc bursts, there should be no debris allowed. The area b etween the bursting disc safety 
device and the safety valve should be fitted with a pressure gauge, an exhaust outlet and an alarm 
indicator etc.  
B.6.2 If a bursting disc safety device is series connected on the outlet side of a safety valve, then the 
safety valve should adopt special structure type (such as balance safety valve) to ensure that when 
accumulated backpressure arises betwee n the safety valve and the bursting disc safety device, the 
safety valve can still open under the set  pressure. Meanwhile, the cavity between the bursting disc 
safety device and the safety valve should be equipped with exhaust outlet or fluid discharge por t. 
B.6.3 When a safety valve and a bursting disc safety device are connected as series combination, 
then the actuating pressure of each individual relief device and the excessive pressure limit of the 
pressure vessel should meet the requirements in B.3.2.1 . 
B.6.4 When a safety valve and a bursting disc safety device are connected as a parallel combination, 
then the actuating pressure of the relief device and the excessive pressure limit of the pressure 
vessel should meet the requirements in B.3.2.2, in whic h the actuating pressure of the safety valve 
should not exceed its design pressure, the actuating pressure of the bursting disc should not exceed 
1.05 times its design pressure.  
B.7 Calculation of required discharge  capacity  for pressure vessels  
B.7.1 Symb ols 
At -------- Heat area of vessel, m2; 
Horizon tal vessels with hemispherical heads, A t = 3.14D oL; 
Horizontal elliptical head vessels, A t = 3.14Do (L + 0.3D o); 
Vertical vessels: A t = 3.14D oh1; 
Spherical vessels, A t = 1.57D o2, or take higher value of the ex ternal surface area from the ground up 
to 7.5 m high.  
Do-----The external diameter of a pressure vessel, m;  
d------- The inner diameter of the feeding tube of a pressure vessel, mm;  
F------- Coefficient.  
When a pressure vessel is positioned underground  and i s covered with sand and soil, then F = 0.6;  - 30 - When a pressure vessel is positioned on the ground, F = 1.0;  
When a pressure vessel is positioned under a spraying device with speed higher than 10L/m2.min, F 
= 0.6;  
H------- Input heat, kJ/h;  
h1------ The maximum liquid level, m;  
L------- The total length of a pressure vessel, m;  
q-------- The latent heat of vapor isation of the liquid under relief pressure, kj/kg;  
v------- The flow rate in the feeding tube of a pressure vessel, m/s;  
t------- The saturation temperature of the medium under relief pressure, oC; 
Ws------ The required discharge  capacity of a pressure vessel, kg/h;  
--------- The thickness of the insulation layer of a pressure vessel, m;  
------- The thermal conductivity of the insulation material under normal a tmospheric temperature, 
kJ/m·h· oC; 
------ The medium density under discharge conditions (set temperature and set pressure), kg/m3; 
B.7.2 The required discharge  capacity of pressure vessels containing compressed gases or water 
steam  
a) The safe discharge  capa city of pressure vessels such as compressor tanks or steam tanks, 
take the maximum production (vapor) capacity produced within a unit time by the 
compressor  and the steam generator respectively.  
b) The required discharge  capacity of gas tanks, should be deter mined by according to formula 
(B.1):  
  
 ......................(B.1)  
B.7.3 When a heat exchanger generates steam, its required discharge  capacity should be determined 
by according to formula (B.2):  
  
 .........................(B.2)  - 31 - B.7.4 The required discharge  capacity of pressure vessels containing liquefied gases  
B.7.4.1 For a pressure vessel where its medium is flammable liquefied gas or its medium is non -
flammable liquefied gas but the pressure vessel is positioned in a working condition wher e possible 
fire can arise, then the required discharge  capacity of such vessel should be separately calculated as 
the vessel is equipped with or without thermal insulation layer:  
a) If without thermal insulation layer, the safe discharge  capacity should be 
determined by according to formula (B.3):  
..............................(B.3)  
b) If with complete thermal insulation layer (for example, in a fire disaster situation , 
the insulation layer cannot  be damaged), the required discharge  capacity should be 
determined  by according to formula (B.4):  
…............(B.4)  
B.7.4.2  For a pressure vessel where its medium is non -flammable liquefied gas, when the vessel is 
placed and working in a non -fire danger environment, the safe discharge  capacity of this vessel 
shall be a s the vessel is equipped with or without a thermal insulation layer, and calculated by 
formula (B.3) or (B.4) respectively, take a value which is not lower than 30% of the calculated 
value.  
B.7.5 For a pressure vessel where its gas volume can be increased by chemical reaction, its required 
discharge  capacity should be determined by the possible maximum capacity generated by the 
chemical reactions inside of the vessel and the reaction time length.  
B.8 Calculation of discharge area of relief device  
B.8.1 Appl icable scope  
This section applies to the calculation of the discharge area when single -phase media goes through 
relief devices. When the medium is in liquid state, then during discharge there will not be any flash 
evaporation happening.  
B.8.2 Symbols  
A------the minimum discharge area of safety valves or bursting discs, mm2; 
C------- the coefficient of gas characteristics, can consult to Table B.4 or calculate using the 
following formula:  - 32 -   
  
K------- the discharge coefficient of a relief device;  
For safety val ves, K shall be the rated discharge coefficient (the rated discharge coefficient is 
usually provided by the manufacturer of the safety valve)  
For bursting discs, K is the coefficient which is related to the shape of the inlet pipe line of the 
bursting disc device;  it can be determined by consulting Table B.5, but should  still meet the 
following conditions from a) to d):  
a) Emit directly to the atmosphere;  
b) The distance from the bursting disc safety device to the vessel body should not exceed 8 
times  the pipe dia meter;  
c) The length of the discharge pipe of the bursting disc safety device shall not exceed 5 times  
the pipe diameter;  
d) The nominal diameter of the upper and lower pipes of the bursting disc safety device shall 
not be smaller than the nominal diameter of th e discharge opening of the bursting disc safety 
device.  
When the shape of the inlet pipeline is not easy to determine or does not meet the requirements 
stated in a) to d), then K= 0.62; with regard to liquid medium, take K as 0.62 or according to 
regulatio ns specified in relative safety technical codes:  
k------ the adiabatic exponent, see Table B.6;  
M------ The molar mass of the gas, kg/kmol;  
po------ The pressure at the outlet side of the relief device (absolute pressure), MPa ; 
pf---------- The relief pressure  (absolute pressure) of the relief device, including the design pressure 
and excessive pressure limit two parts, MPa ; 
p------------ The difference between the internal pressure and the external pressure when the relief 
device is discharging, MPa ; 
R-----------  The common gas constant, J/kmol.K, R = 8314;  
Re---------- The Reynolds Number, 
 ; - 33 - Tf------- The discharge temperatur e of the relief device, K;  
W---------- The discharge capacity of the relief device, kg/h;  
Ws--------- the required discharge capacity of  pressure vessel, kg/h;  
z---------- The compressibility factor of the gas, see Diagram B.1, For air, Z = 1.0;  
---------- The correction coefficient of fluid dynamic viscosity, see Diagram B.2, when the viscosity 
of any fluid is not greater than the viscosity of water, then  = 1.0;  
------ The fluid dynamic viscosity, Pa.s;  
--------- The medium density under the relief conditio n (set temperature and set pressure), kg/m3; 
B.8.3 Calculation of the discharge area of individual relief device  
B.8.3.1 Gas  
a) Critical condition, that is when 
 , 
then  
 .....................................................................(B.5)  
b) Subcritical c ondition, that is when 
 , 
then 
 ........................(B.6)  
B.8.3.2 Saturated steam  
The steam content in saturated steam shall not be lower than 98%, the overheating shall not exceed 
11oC. 
a) when p f  10MPa,  - 34 - then 
 ....................................................................................(B.7)  
b) when 10 MPa  < p f  22MPa,  
then 
 ...............................................(B.8)  
B.8.3.3 Liquid  
              
 ................................... .................(B.9)  
For viscous liquid, the calculation of its discharge area should be as below:  
a) Assume it was non -viscous liquid, take  = 1.0 and use formula (B.9) to calculate the initial 
discharge area and the corresponding diameter, and round up t o the nominal diameter and 
corresponding discharge area nearest to the product series specifications.  
b) On the basis of the calculated and rounded up discharge area value from step a), according 
to formula (B.9) and  = 1.0 to calculate the discharge  capacit y W;  
c) On the basis of the discharge capacity W calculated from step b), as well as the calculated 
and rounded up discharge area value from step a), according to formula Re=0.3134W
A 
to calculate the Reynolds number; determine the   value from Diagram B.2, and on the basis 
of this   value and according to formula (B.9) to re -calculate the discharge capacity W.  
d) If W Ws, then this diameter (area) shall be the required value; if W < W s, then use the 
discharge  area corresponding to the  nominal diameter of one size up product to replace the 
calculated and rounded up discharge area value from step a), and repeat the calculations 
from step b) to step c), until W Ws. 
B.8.4 The actual discharge area of the selected safety relief device shal l not be smaller than the  
minimum discharge area A calculated from B.8.3.  
Table B.4 Coefficient C of gas characteristics C  
k C k C k C k C 
1.00 315 1.20 337 1.40 356 1.60 372 
1.02 318 1.22 339 1.42 358 1.62 374 
1.04 320 1.24 341 1.44 359 1.64 376 - 35 - 1.06 322 1.26 343 1.46 361 1.66 377 
1.08 324 1.28 345 1.48 363 1.68 379 
1.10 327 1.30 347 1.50 365 1.70 380 
1.12 329 1.32 349 1.52 366 2.00 400 
1.14 331 1.34 351 1.54 368 2.20 412 
1.16 333 1.36 352 1.56 369 - - 
1.18 335 1.38 354 1.58 371 - - 
 
Table B.5 D ischarge coefficient of bursting disc safety device  
Serial No.  Schematic diagram of 
connection pipe  Shape of connection 
pipe Discharge coefficient  
k 
1  Plug-in type connection 
pipe 0.68 
2  Flat connection pipe  0.73 
3  Transitional round 
corner connec tion pipe  0.8 
 
Table B.6 Properties of some gases  
Gas Molecular 
formula  Molar mass M  
kg/ kmol  Adiabatic 
exponent Pe  
MPa  
(0.013MPa, 
under 15oC) Critical 
pressure Pe  
MPa  (absolute 
pressure)  Critical 
temperature  
Te, K  
- 36 - Air - 28.97  1.40 3.769  132.45  
Nitrogen  N2 28.01  1.40 3.394  126.05  
Oxygen  O2 32.00  1.40 5.036  154.35  
Hydrogen  H2 2.02 1.41 1.297  33.25  
Chlorine  Cl2 70.91  1.35 7.711  417.15  
Carbon 
monoxide  CO 28.01  1.40 3.546  134.15  
Carbon dioxide  CO 2 44.01  1.30 7.397  304.25  
Ammonia  NH 3 17.03  1.31 11.298  405.55  
Hydrogen 
chloride  HC1  36.46  1.41 8.268  324.55  
Hydrogen 
sulph ide H2S 34.08  1.32 9.008  373.55  
Nitrous oxide  N2O 44.01  1.30 7.265  309.65  
Sulph ur 
dioxide  SO 2 64.06  1.29 7.873  430.35  
Methane  CH 4 16.04  1.31 4.641  190.65  
Acetylene  C2H2 26.02  1.26 6.282 309.15  
Ethylene  C2H4 28.05  1.25 5.157  282.85  
Ethane  C2H6 30.05  1.22 4.945  305.25  
Propylene  C3H6 42.08  1.15 4.560  365.45  
Propane  C3H8 44.10  1.13 4.357  368.75  
Butane  C4H10 58.12  1.11 3.648  426.15  
Isobutane  CH(CH 3)3 58.12  1.11 3.749  407.15  - 37 -  
Reduced pressure  
 
Reduced Temperature Tr = Medium relieving temperature (K) / Medium critical temperature (K)  
Reduced pressure Pr = Medium relieving pressure ( MPa ) /Medium critical pressure ( MPa )  
- 38 - Diagram B.1 Gas compressibility coefficient  
 
 
Diagram B.2 Correct ion coefficient () of fluid dynamic viscosity  
B.9 Installation of the relief devices  
B.9.1 The relief devices should be installed on the vessel body or on the connection pipeline of the 
pressure vessel where it is easy to install, inspect and maintain. Th e valve body of the safety valve 
should be installed at the top of the pressure vessel or pipeline and should be positioned straight up.  
B.9.2 The relief devices should be installed at a location near to the stressor of the pressure vessel. 
If a relief dev ice is used for gas medium, then it should be installed at gas -phase space (including 
the gas -phase space which is above the liquid) or on the pipeline connected to such space; if the 
relief device is used for liquid medium, then it should be installed und er the normal surface of the 
liquid.  
B.9.3 The cross -section area of all pipes and tubes between the pressure vessel and the relief 
devices should not be smaller than the discharge area of the relief device ; its connection pipe should 
be short and straight , to avoid generating too much pressure loss. If two or more than two relief 
devices (spare safety valves are not included) are installed on one connection port, then the cross -
section area of the inlet of this connection port should be at least equal to t he total sum of the cross -
section areas of the inlets of all these relief devices.  
B.9.4 Between the pressure vessel and the relief device, usually not suitable to install an 
intermediate block valve. For pressure vessels requiring continuous operation, be tween the pressure 
vessel and its relief devices, can install a block valve speci fically for maintenance use. During the 
- 39 - normal operation of the pressure vessel, the block valve should be in a fully open state and is lead 
sealed.  
B.9.5 The supporting struc ture of the relief devices should have sufficient strength (or stiffness), to 
ensure it can bear the force generated during the discharging process of the discharge device.  
B.10 Discharge pipe  
B.10.1 Discharge pipe should be designed in a vertical directio n, its port diameter should not be 
smaller than the outlet diameter of the relief device. If multiple relief devices use a single  discharge 
head pipe, then the cross -section area of the head pipe should not be smaller than the total sum of 
the cross -sectio n areas of the outlets of relief devices.  
B.10.2 If in the discharge pipes there may be some flammable medium to be discharged, then 
measures such as flame arrester etc. should be installed in accordance with relevant regulations and 
requirements, to prev ent the danger of tempering.  
B.10.3 Discharge holes should be set at the appropriate  locations of the discharge pipes, to avoid 
rain, snow and condensate etc to build up in the discharge pipes.  
B.10.4 During the process of installing the discharge pipeline  of the bursting disc safety devices, the 
centerline of the discharge pipeline should be aligned with the center line of the bursting disc safety 
device, to avoid the bursting discs bearing uneven forces.  - 40 - Appendix C  
(Normative annex)  
Determination of vesse l design pressure by confirmatory burst test  
C.1 General provisions  
C.1.1 This Appendix specifies the primary requirements by using confirmatory burst test to 
determine the design pressure of pressure vessels.  
C.1.2 This Appendix applies to pressure vesse ls or pressure  components for which the structure 
design calculations are unable to be carried out by according to GB 150.3. For  a pressure 
component whose  required thickness can be correctly calculated by according to GB 150.3, the 
structural strength des ign should meet the requirements in GB 150.3,  and must not use methods 
specified in this Appendix.  
C.1.3 Pressure vessels and test vessels (or components and test components) should meet the 
following requirements:  
a) Same design structure and shapes;  
b) Same ma terials, that is the corresponding material standards, nameplates and heat treatment 
status should be consistent ; 
c) Same nominal  thickness and structural dimensions. For structures with same section 
measurement, its length shall not be longer than the confir matory  test item;  
d) Same heat treatment requirements;  
e) The manufacturing deviation should meet the requirements in GB 150.4.  
C.1.4 If only some of the pressure components of a pressure vessel, have a  maximum allowable 
working pressure determined by using conf irmatory burst tests, then the design pressure of this 
pressure vessel should be determined by according to the requirements of all pressure components.  
C.1.5 This Appendix does not apply to the design of pressure vessels used to contain media whe n 
the toxicity level is extremely toxic or highly toxic.  
C.2 Administration and responsibilities  
C.2.1 The manufacturing of the test item for the confirmatory burst test should be completed by the 
manufacturer of this vessel or pressure components, the test should be conducted by the 
manufacturer of this vessel or pressure components or an entrusted third party.  - 41 - C.2.2 The conducting process of this confirmatory burst test should give full consideration to the 
safety of the test personnel and the test sites, the safe ty measures on the test procedures and test 
sites should be approved by the technical leader of the unit conducting the test.  
C.2.3 Consult the supervision and inspection requirements of the pressure tests for vessels, the 
entire test process should accept  the testimony of the personnel from the inspection institution, the 
confirmatory burst test report should be signed and confirmed by the personnel of inspection 
institution.  
C.2.4 Technical review  
C.2.4.1 The technical documentation about using confirmato ry burst tests to determine the design 
pressure of a vessel or the maximum allowable working pressure of pressure components are 
subjected to technical reviews in accordance with Article 1.9 of the Technical Supervision 
Regulation for Safety of Stationary Pressure Vessels.  
C.2.4.2 Requirements of technical documentation  
C.2.4.2.1 The documentation on the design and manufacturing of the test item should contain at 
least the following contents:  
a) The structural and design drawing of the test item;  
b) The material quality certificates;  
c) The technology documents of manufacturing process;  
d) The inspection record;  
e) Other rel evant  documents.  
C.2.4.2.2 The confirmatory burst test report should include at least the following contents:  
a) The test and experimental equipment;  
b) The test procedures;  
c) The report of the test process;  
d) The test conclusion.  
C.3 Test requirements  
C.3.1 Confirmatory burst test usually uses water as the test medium, the test medium and 
temperature should be in line with the provisions  in GB 150.4.  - 42 - C.3.2 Before  conducting confirmatory burst test to the test vessel, the pressure of the pressure test 
shall not exceed 1.25 times of the expected design pressure.  
C.3.3 The pressure increase for the confirmatory burst test should be carried out slowly, first should 
gradually increase the pressure to 0.5 times of the expected design pressure, after maintaining the 
pressure and observing then gradually increase the pressure as 1/10 of the expected design pressure, 
until the pressure has reached to the expected design pre ssure, after conducting at least 10 minutes 
of pressure maintaining and observing, then continuously increase the pressure as 1/10 of expected 
design pressure to the burst stopping point or set stopping point.  
C.3.4 The confirmatory burst test can choose suitable pressure as the stopping point, it will be valid 
as far as the design pressure calculated by using this stopping point pressure meets the requirement 
of expected design pressure.  
C.4 Determination of design pressure  
C.4.1 The maximum allowable wor king pressure under the test temperature  
a) When using C.4.4 to determine  Rmave, use the formula (C.1) to calculate the maximum allowable 
working pressure p'' under the test temperature, otherwise use formula (C.2) to calculate:  
    
 ...................... ......................(C.1)  
      
        ................................(C.2)  
In which:  
p'' ----- The maximum allowable  working pressure  in test temperature, MPa ; 
pb ------  The pressure of the burst test or the pressure of the test stopping point, MPa ; 
 --------  The coefficient of welded joint;  
Rm ------  The lower limit of the standard tensile strength  of the material;  
Rmave --------  The average tensile strength of the test item in room temperature, MPa , determined by 
according to C.4.4.  
Rmh -------  The upper limit of the standard tensile strength of the material, MPa ; 
b) After considering the corrosion allowance, the maximum allowable working pressure p' at test 
temperature should be determined by according to formula  (C.3):  - 43 -                 
 ............ ................................(C.3)  
In which:  
p' ------  After considering the corrosion allowance, the maximum allowable working pressure in test 
temperature, MPa ; 
t ------  The material thickness at the place where the strength is weakest, mm;  
C2 ---- The corrosion allowance, mm;  
n ------ The structure and shape factor. For cylinders, spherical -shells, and conicals  with half vertex 
angle of   60o etc., as well as when the bending stress of pressure  components not exceeding 2/3 
of the total stress, n=1; for flat surface or semi -flat surface , such as flat cover plates, flanges or 
conicals  with half vertex   > 60o etc, as well as when the bending stress of pressure components 
exceeds 2/3 of the total stress, n=2.  
C.4.2 The maximum allowable working pressure at  design temperature  
The maximum  allowable working pressure pmax at design temp erature should be calculated us ing 
formula (C.4):  
    
 ........................................(C.4)  
in which:  
pmax ----- the maximum allowable working pressure at design temperature, MPa ; 
[]t --------  the allowable stress of the material at design temperature, MPa ; 
[] ---------  the allowable stress of the material at test temperature, MPa ; 
C.4.3  Use the maximum allowable working pressure calculated from C.4.1 and C.4.2 as the basis to 
determine the design pressure p of the pressure vessel.  
C.4.4 Determination of the average tensile strength R mave of the test sample  
C.4.4.1 The test sample should be cut from material which is same as the material of the test vessel 
by mechanical methods.  
C.4.4.2 Take the average value of tensile strength from three samples as the average tensile strength.  - 44 - Appendix D  
(Normative annex)  
Comparative  empirical design method  
D.1 General provisions  
D.1.1 This Appendix specifies the general requirements for using the comparative  empirical design 
method.  
D.1.2 This Appendix applies to the comparative  empirical design of pressure vessels  where  the 
comparative  empirical designed pressure vessels and the reference pressure vessel have the same or 
similar structures and  design conditions.  
D.1.3 Pressure vessels meet the following requirements can use the comparative empirical design 
method set in this Appendix:  
a) Pressure vessels cannot  be designed by according to GB 150.3;  
b) The lower limit of the standard tensile strength  of the materials is lower than 540MPa;  
c) Pressure vessels contain medium with toxicity level as moderate hazard.  
D.1.4 The design unit should obtain the user approved testimony documents and design documents 
about the safe use of the reference pressure vess el.  
D.1.5 Designing by this method should follow  Article 1.9 of  the Technical Supervision Regulation 
for Safety of Stationary Pressure Vessels to pass the technology assessment.  
D.2 Requirements on using experiences  
D.2.1 The reference pressure vessel sh ould be a vessel  has been in actual operation , and its safe 
operation period must not be less than 5 years . 
D.2.2 The actual operating conditions of the reference pressure vessel must not be less than 80% of 
its design conditions.  
D.3 Design conditions  
D.3.1 The same structure and same medium as the reference pressure vessel.  
D.3.2 The design temperature must not be higher than the design temperature of the reference 
pressure vessel; for pressure vessels with design temperature is below 0oC, then the desi gn - 45 - temperature of such pressure vessels shall not be lower than the design temperature of the reference 
pressure vessel.  
D.3.3 The design pressure shall not exceed the design pressure of the reference pressure vessel.  
D.4 Structures  
D.4.1 Comparative  emp irical designed pressure vessels should have the same or similar structures 
as the reference pressure vessel, the structure similarity ratio of the main structure dimensions are 
within the range of 0.85 to 1.15.  
D.4.2 Under the premise of ensuring the ope rating functions of the comparative  empirical designed 
pressure vessel, should also considering structural optim isation, reducing the effect from the 
secondary stress and peak stress caused by the discontinuity of the overall structure and local 
structure.  
D.5 Materials  
D.5.1 The mechanical properties of the materials of the comparative empirical designed pressure 
vessel at the design temperature must not be less than the corresponding requirements for the 
materials of the reference pressure vessel.  
D.5.2 The corrosion resistance of the materials of the comparative empirical designed pressure 
vessel  shall not be lower than the corresponding requirements for the materials of the reference 
pressure vessel.  
D.6 Design  
D.6.1 The comparative empirical design of the pressure vessels should meet the above 
requirements, the structure size can be determined with structurally similar principles.  
D.6.2 The design unit should provide the design specifications.  
D.6.3 Pressure vessels which are subjected to fatigue analy sis by according to section 3.10.2 and 
section 3.10.3  of JB 4732, when carry out the comparative empirical design of such vessels by 
according to the requirements of this Appendix, the contents of the fatigue analysis of such pressure 
vessels should be add ed into the design specifications.  - 46 - Appendix E  
(Normative annex)  
Local structure stress analysis and evaluation  
E.1 General provisions  
E.1.1 This Appendix specifies the basic requirements for the local structure of  pressure vessels 
using stress analysis (a ccording to GB 150 to design the overall pressure vessel) as the design basis.  
E.1.2 This Appendix applies only to the local structures of vessels where the design calculations are 
impossible  to carry out by according to GB 150.3.  
E.2 Design management  
E.2.1 The design units and designers who carry out stress analysis to the local structures of pressure 
vessels by according to this Appendix are not required to hold analysis and design qualifications.  
E.2.2 The design  unit should be responsible for the accur acy of the local structure analysis, the 
analysis report should be used as the corresponding strength calculation note of the local structure.  
E.3 Requirements for strength evaluation  
E.3.1 The evaluation methods for stress classification and stress analy sis results should be in line 
with the provisions  in JB 4732.  
E.3.2 The determination of the design stress intensity of materials should be in accordance with the 
allowable stress of the corresponding material in GB 150.2.  
E.4 The requirements on fabricati on, inspection and acceptance of  the local structures should be in 
accordance with the corresponding provisions in JB 4732.  - 47 - Appendix F  
(Normative annex)  
Risk Assessment Report  
F.1 General provisions  
F.1.1 This Appendix specifies the general requirements fo r the risk assessment report.  
F.1.2 The vessel designers should be according to relevant laws and regulations or the requirements 
of the entrustor, to draw up a Risk Assessment Report for the expected service status of the vessels.  
F.1.3 The designers sho uld give full consideration to the possible failure modes under a variety of 
working conditions, put forward security measures on the issues such as material selection, 
structural design, manufacturing and inspection requirements and other aspects, to prev ent any  
possible failure.  
F.1.4 The designers should provide the vessel users with any required information to draw up 
emergency plans for vessel incidents.  
F.2 Principles and procedures of report formulation  
F.2.1 At the design stage, the risk assessmen t is mainly aimed at hazard identification and risk 
control.  
F.2.2 At the design stage, the risk assessment shall be conducted according to the following 
procedures:  
a) On the basis of the user design conditions and other design input information, to determin e 
the various use conditions of the vessel.   
b) On the basis of the medium, operating conditions and environmental factors in various use 
conditions to carry out hazard identification, to determine any possible hazards and 
consequences;  
c) Contrary to all hazard s and corresponding failure modes, to explain all security measures 
and evidences should be taken;  
d) With regard to all possible failure modes, provide required information to draw up 
emergency plans.  
e) Form a complete risk assessment report . 
F.3 Contents of risk assessment report  - 48 - A risk assessment report should at least include:  
a) The basic design parameters of pressure vessel: pressure, temperature, materials, media 
properties and external loads, etc.;  
b) Description of the operating conditions.  
c) Possible hazards  under all operating and the design conditions, such as: explosions, leakage, 
breakage, deformation, etc.;  
d) For the failure modes have been specified in standards, illustrate the terms of that standard;  
e) For the failure modes have not been specified in sta ndards, illustrating the selection basis of 
the design loads, safety factors and the corresponding calculation methods;  
f) Measures on how to deal with small amount leakages and large amount emissions of media 
and explosive situations;  
g) According to possible  injury situation of surrounding personnel, specifies appropriate 
personnel protective equipment and measures;  
h) The risk assessment report should have consistent signatures as the design drawings.  - 49 - Appendix G  
(Informative annex)  
Standard Proposal /Inquiries          Total No. of  
Standard proposal           Standard inquiries  Name of the Standard   
Unit  Name   
Contact address   Post code   
Phone No./Fax No.   Email   
Terms of the Standard     
Proposal/ inquiry contents (additional pages are permitted)  
 
Technical basis and relevant information (additional pages are permitted)  
 
Additional explanation  
Official unit stamp or proposal(inquiry) 
personnel signature:  Submi ssion  date:  
                _____Year_____Month______Date  
China Standardisation Committee on Boilers and Pressure Vessels (CSCBPV)  
Address:  D. 3rd Floor, Xiyuan Building No.2, Heping Jie, Chaoyang District, Beijing  
Post code: 100013