GB/T 35974.1-2018 English PDF (GBT35974.1-2018)
GB/T 35974.1-2018 English PDF (GBT35974.1-2018)
GB/T 35974.1-2018: Plastics and plastic lining pressure vessels -- Part 1: General requirements
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.120; 83.140
Plastics and Plastic Lining Pressure Vessels -
Part 1: General Requirements
ISSUED ON: FEBRUARY 6, 2018
IMPLEMENTED ON: SEPTEMBER 1, 2018
Issued by: General Administration of Quality Supervision, Inspection and Quarantine;
Standardization Administration of the People’s Republic of
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 6
3 Terms and Definitions ... 6
4 Basic Requirements ... 9
5 Basic Requirements ... 9
6 Design Requirements ... 11
7 Fabrication, Inspection and Testing ... 15
Appendix A (Normative) Photoaging Life ... 18
Plastics and Plastic Lining Pressure Vessels -
Part 1: General Requirements
1.1 Basic Scope
This Part of GB/T 35974 specifies the terms and definitions; general requirements of materials, design, fabrication, inspection and testing for plastics and plastic lining pressure vessels.
NOTE: if it is not particularly indicated, all parts of GB/T 35974 may use the following abbreviations:
---Plastics and plastic lining pressure vessels: “vessels” for short;
---Plastic pressure vessels: “plastics vessels” for short;
---Plastics vessels with plastic lining: “lining vessels” for short.
This Part is not applicable to movable vessels.
This Part is not applicable to plastics vessels, whose medium is flammable, explosive and toxic gas; moderately toxic liquid stipulated in HG/T 20660.
This Part is applicable to vessels fabricated by the following thermoplastic plastics: a) Plastics vessels: rigid polyvinyl chloride (PVC-U), chlorinated polyvinyl chloride (PVC-C), polyethylene (PE), polypropylene (PP), Acrylonitrile-butadiene- styrene (ABS);
b) Lining vessels: rigid polyvinyl chloride (PVC-U), chlorinated polyvinyl chloride (PVC-C), polyethylene (PE), polytetrafluoroethylene (PTFE),
tetrafluoroethylene/ethylene copolymer (ETFE), polyvinylidene fluoride (PVDF). 1.3 Design Pressure
This Part is applicable to vessels of the following design pressure:
a) Plastics vessels: design pressure is 0 MPa ~ 0.25 MPa; nominal diameter is not more than 4 m;
b) Lining vessels: design pressure is 0.1 MPa ~ 2.5 MPa; gauge pressure is less than 0.1 MPa; it may be taken as a reference in implementation.
2 Normative References
The following documents are indispensable to the application of this Standard. In terms of references with a specified date, only versions with a specified date are applicable to this Standard. In terms of references without a specified date, the latest version (including all the modifications) is applicable to this Standard.
GB/T 1040.2 Plastics - Determination of Tensile Properties - Part 2: Test Conditions for Molding and Extrusion Plastics
GB/T 16422.2 Plastics - Methods of Exposure to Laboratory Light Sources - Part 2: Xenon-arc Sources
GB/T 26501 General Technical Specification for Pressure Vessels Lined with Fluoroplastics
GB/T 26929 Terminology for Pressure Vessels
GB/T 35974.2 Plastics and Plastic Lining Pressure Vessels - Part 2: Materials GB/T 35974.3 Plastics and Plastic Lining Pressure Vessels - Part 3: Design GB/T 35974.4 Plastics and Plastic Lining Pressure Vessels - Part 4: Fabrication, Inspection and Testing for Plastic Pressure Vessels
GB/T 35974.5 Plastics and Plastic Lining Pressure Vessels - Part 5: Fabrication, Inspection and Testing for Pressure Vessels with Plastic Lining
HG/T 3915 Reacting Caldron Lined with Fluoroplastics
HG/T 20660 Standard for Classification on Hazards of Toxicity and Explosion of Chemical Mediums in Pressure Vessel
3 Terms and Definitions
What is defined in GB/T 26929, and the following terms and definitions are applicable to this document. In order to make it convenient for application, certain terms and definitions in GB/T 26929 are repeatedly listed.
3.1 Stationary Pressure Vessel
Stationary pressure vessel refers to pressure vessel, which is installed in a fixed position.
NOTE: in terms of pressure vessels, which are merely moved and used in devices or field areas for a certain specific purpose, they shall also be constructed in accordance when vessel is under normal operating condition.
NOTE: design temperature and design pressure are considered as conditions of design load.
3.8 Calculating Pressure
Calculating pressure refers to the pressure used to determine component thickness at corresponding design temperature.
NOTE: it includes additional loads, for example, liquid column static pressure. 3.9 Test Pressure
Test pressure refers to the pressure of the top of vessel during pressure resistance test or leakage test.
[GB/T 26929-2011, Definition 2.3.3]
3.10 Operating Temperature; working temperature
Operation temperature/working temperature refers to the temperature of materials inside the vessel under the stipulated normal operating condition.
NOTE 1: in domestic and overseas technical documents of the pressure vessel industry, “operating temperature/working temperature” refers to the temperature of materials.
NOTE 2: in a vessel, the temperature of materials in different parts might differ; if necessary, operating temperature/working temperature of various parts needs to be respectively pointed out.
NOTE 3: sometimes operating temperature/working temperature is also known as operating temperature.
[GB/T 26929-2011, Definition 2.4.1]
3.11 Required Thickness
Required thickness refers to the thickness obtained through formula calculation in design.
NOTE: when needed, required thickness of other loads shall also count. In terms of external pressure component, it refers to the minimum thickness which satisfies the requirement of stability.
3.12 Reserved Thickness
Reserved thickness refers to the additional thickness that plastics vessel needs to technology.
5.1.3 The organization fabricating vessels shall inspect the quality certificate of the selected materials; the item indicators shall comply with corresponding stipulations in material standards.
5.1.4 The organization fabricating vessels shall have the capability of determining materials’ reliability under corrosive environment; if necessary, conduct testing and verification.
5.2 Technical Requirements
5.2.1 In materials’ technical requirements, there shall be one of the following items, or a combination of the following items:
a) Weather resistance;
b) Corrosion resistance;
d) Tensile yield stress;
e) Elongation at break;
f) Tensile modulus of elasticity;
g) Vicat softening temperature;
h) Charpy notched impact strength;
j) Longitudinal retraction rate;
k) Falling impact performance;
l) Hydrostatic strength;
m) Oxidation induction time;
n) Melt mass flow rate;
o) Bending strength;
p) Dimensional change rate;
q) Thermal shrinkage rate.
5.2.2 Indicators of material technical requirements shall comply with the stipulations in 6.1.2 Vessel design organizations (designers) shall design vessels in accordance with the vessel design conditions provided by users or design clients. During the design, they shall consider the strength, stability and corrosion resistance of pressure components that might emerge, and all the failure modes that might emerge during the usage; propose measures to prevent from such failures. The design conditions that design organizations obtain from users or design clients shall at least include the following content:
a) Main standards and specifications that vessel design complies with;
b) Operating conditions;
c) Place of using pressure vessel; its natural conditions;
d) Medium components and characteristics;
e) Expected service life;
f) Geometric parameters and nozzle orientation;
g) Other necessary conditions that design needs.
6.1.3 When different operating conditions exist in various constituent parts of vessel, the design shall comply with the most rigorous operating conditions. If necessary, a combination of different operating conditions shall be considered. In addition, various operating conditions, and pressure and temperature value under the design conditions shall be indicated in drawings or corresponding technical documents.
6.1.4 The designed service life of vessel shall be determined in accordance with users’ requirements and the practical operating conditions. Generally speaking, it shall be not less than 10 a.
6.1.5 The welded joint coefficient of different plastic materials and processes is 0.4 ~ 0.5. Commonly used welded joint coefficient shall be selected in accordance with the stipulations in GB/T 35974.3.
6.1.6 The design of plastics vessel mainly includes:
a) Internal pressure cylinder design;
b) Head design;
c) Design of Flange and its connection;
d) Opening reinforcement design;
e) Welding structural design.
6.1.7 The design of lining vessel mainly includes:
the lowest temperature that vessel materials might reach.
b) Vessel’s design temperature shall be determined in accordance with the following methods:
1) Determine on the same type of vessels that are already put into use; 2) Determine in accordance with medium temperature in the vessel, and a combination of external conditions.
6.5 Design (calculating) Thickness
6.5.1 Material design (calculating) thickness of plastics vessel shall be calculated in accordance with relevant stipulations in GB/T 35974.3.
6.5.2 The minimum wall thickness of lining vessel shall comply with the stipulations in GB/T 35974.3.
6.5.3 Under the operating conditions where photoaging exists, in accordance with the designed service life, the reserved thickness shall be increased. Reserved thickness shall be calculated in accordance with Formula (1).
C2---reserved thickness, expressed in (mm);
y---materials’ photoaging life, calculated in accordance with Appendix A, expressed in (a);
---calculating thickness, expressed in (mm).
6.6 Plastics Vessel
6.6.1 The design of plastics vessel, such as internal pressure cylinder, head, Flange and its connection, opening reinforcement and welding structure, shall comply with the stipulations in GB/T 35974.3.
6.6.2 The support, safety and protection of plastics vessel shall comply with the stipulations in GB/T 35974.3.
6.7 Lining Vessel
6.7.1 The design of lining vessel, such as metal shell and lining, shall comply with the stipulations in GB/T 35974.3.
6.7.2 The support, safety and protection of lining vessel shall comply with the 7.1.2 Fabrication organizations shall provide fabrication materials to users or fabrication clients; the content mainly includes:
a) Vessel’s original design drawings and completion drawings;
b) Vessel’s quality certificate;
c) Vessel characteristics (including design pressure, maximum allowable operating pressure, test pressure, design temperature and operating medium); d) Vessel’s usage instruction.
7.1.3 Materials for vessel fabrication shall receive acceptance check in accordance with the stipulations in GB/T 35974.4 and GB/T 35974.5. Moreover, if they comply with the requirements, they may be put into use. If necessary, during the fabrication process, materials shall be re-inspected in accordance with the stipulations in GB/T 35974.4 and GB/T 35974.5.
7.2 Processing Procedures
7.2.1 Processing procedures adopted in vessel fabrication shall pass corresponding procedure evaluation, and comply with the requirements.
7.2.2 Plastics vessel shall be fabricated in accordance with the processing procedures stipulated in GB/T 35974.4, such as: welding, rotational molding, extrusion and extrusion winding.
7.2.3 Lining vessel shall be fabricated in accordance with the processing procedures stipulated in GB/T 35974.5, such as: welding, rotational molding and winding sintering. 7.3 Inspection and Testing
During vessel fabrication, the various fabrication stages shall be inspected in accordance with the items stipulated in quality plan and processing procedures. 7.3.2 Testing
22.214.171.124 After vessel fabrication is completed, vessels shall be tested. 126.96.36.199 Test items of plastics vessels are: appearance, dimension, minimum wall thickness, pressure resistance test, air tightness test and ultra-leakage detection. Indicator requirements shall comply with the stipulations in GB/T 35974.4. 188.8.131.52 Test items of lining vessels are: appearance, minimum wall thickness of lining, pressure resistance test, leakage test, electric spark test, thermal expansion and contraction test, and negative pressure resistance test. Indicator requirements shall