GB/T 37842-2019 English PDF (GBT37842-2019)

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GB/T 37842-2019: Ball valves of thermoplastics materials
GB/T 37842-2019
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 83.140.30
G 33
Ball valves of thermoplastics materials
热塑性塑料球阀
(ISO 16135:2006, Industrial valves - Ball valves of thermoplastics materials,
MOD)
ISSUED ON: AUGUST 30, 2019
IMPLEMENTED ON: MARCH 01, 2020
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3 
1 Scope ... 6 
2 Normative references ... 6 
3 Terms, definitions and symbols ... 7 
4 Materials ... 12 
5 Design ... 13 
6 Requirements ... 16 
7 Test method ... 20 
8 Inspection rules ... 21 
9 Marking, packaging, transportation and storage ... 23 
Appendix A (Informative) Type selection of multi-way ball valve ... 25 
Appendix B (Informative) Comparison between nominal outer diameter dn and
nominal diameter DN ... 30 
Appendix C (Informative) Purchasing Information ... 31 
References ... 33 
Ball valves of thermoplastics materials
1 Scope
This standard specifies the terms, definitions and symbols, materials, design,
requirements, test methods, inspection rules, signs, packaging, transportation
and storage of ball valves of thermoplastics materials (hereinafter referred to
as ball valves).
According to the different materials of ball valves, this standard has a
temperature range of -40 °C ~ +120 °C.
The nominal outer diameter range is dn16 mm ~ dn180 mm.
The nominal pressure range is PN 0.6 MPa ~ PN 2.5 MPa.
The range of pipe series is S2 ~ S12.5.
Note: It is the responsibility of the purchaser to select this product appropriately
according to its specific application needs and in conjunction with relevant
regulations, standards or specifications.
2 Normative references
The following documents are essential to the application of this document. For
the dated documents, only the versions with the dates indicated are applicable
to this document; for the undated documents, only the latest version (including
all the amendments) are applicable to this standard.
GB/T 2828.1-2012 Sampling procedures for inspection by attributes -Part 1:
Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot
inspection (AQL) (ISO 2859-1:1999, IDT)
GB/T 2918-2018 Plastics - Standard atmospheres for conditioning and
testing (ISO 291:2008, MOD)
GB/T 7306.1-2000 Pipe threads with 55 degree thread angle where
pressure-tight joints are made on the threads - Part 1: Parallel internal and
taper external threads (eqv ISO 7-1:1994)
GB/T 7306.2-2000 Pipe threads with 55 degree thread angle where
pressure-tight joints are made on the threads - Part 2: Taper internal and
external threads (eqv ISO 7-1:1994)
GB/T 8806-2008 Plastics piping systems - Plastics components -
Determination of dimensions (ISO 3126:2005, IDT)
GB/T 12223-2005 Part-turn valve actuator attachments (ISO 5211:2001,
MOD)
GB/T 17219 Safety evaluation standard for drinking water delivery and
distribution equipment and protective materials
GB/T 19278-2018 General terms and their definitions of thermoplastic pipes,
fittings and valves
GB/T 21300-2007 Plastics pipes and fittings - Determination of opacity (ISO
7686:2005, IDT)
GB/T 27726-2011 Thermoplastics valves - Pressure test methods and
requirements (ISO 9393-1:2004, MOD)
GB/T 28494-2012 Globe valves of thermoplastics materials (ISO
21787:2006, MOD)
GB/T 30832-2014 Valves - Test method of flow coefficient and flow
resistance coefficient
ISO 10931:2005 Plastics piping systems for industrial applications - Poly
(vinylidene fluoride) (PVDF) - Specifications for components and the system
ISO 15493:2003 Plastics piping systems for industrial applications -
Acrylonitrile-butadiene-styrene (ABS), unplasticized poly (vinyl chloride)
(PVC-U) and chlorinated poly (vinyl chloride) (PVC-C) -Specifications for
components and the system - Metric series
ISO 15494:2015 Plastics piping systems for industrial applications -
Polybutene (PB), polyethylene (PE), polyethylene of raised temperature
resistance (PE-RT), crosslinked polyethylene(PE-X), polypropylene (PP) -
Metric series for specifications for components and the system
3 Terms, definitions and symbols
The terms and definitions as defined in GB/T 19278-2018 as well as the
following terms and definitions apply to this document.
3.1 Terms and definitions related to geometric dimensions
3.1.1
Nominal size
S: Pipe series
4 Materials
4.1 Shell material
4.1.1 The polyvinylidene fluoride (PVDF), acrylonitrile-butadiene-styrene (ABS),
unplasticized polyvinyl chloride (PVC-U), chlorinated polyvinyl chloride,
bonnets/bonnets (PVC-C), polybutene (PB), polyethylene (PE), heat-resistant
polyethylene (PE-RT), cross-linked polyethylene (PEX), polypropylene (PP)
used in the production of valve body and bonnet shall comply with the
requirements of ISO 10931:2005, ISO 15493:2003, ISO 15494:2015.
4.1.2 For the materials selected for the valve body and bonnet, the raw material
supplier shall provide a raw material creep failure curve report that meets the
requirements of the predicted strength reference curve.
4.1.3 When selecting polyphenylene ether (PPO/PPE), polyphenylsulfone
(PPSU), polyamide (PA) or other materials, the supplier shall provide the raw
material creep failure curve report and temperature derating factor fr.
4.2 Materials of other components of ball valve
The selection of materials for other components such as seals, stems, balls
shall ensure that the performance of the ball valve meets the requirements
specified in Chapter 6; these materials shall not adversely affect the
performance of the ball valve.
4.3 Pressure-temperature reduction
4.3.1 The maximum allowable operating pressure MOP of the ball valve is
related to the operating temperature, the characteristics of the valve body
material, the structural design. The maximum allowable operating pressure
MOP of the ball valve shall be determined by the derating factor fr, which can
be calculated according to formula (2):
Where:
MOP - The maximum allowable operating pressure, in megapascals (MPa);
fr - The derating factor;
PN - Nominal pressure, in megapascals (MPa).
4.3.2 When the designed service life is 25 years and the delivered fluid has no
a) Two-way ball valve:
- Two-way ball valve, which is suitable for two-way fluid flow and isolation;
- One-way ball valve; the flow direction shall be marked with an arrow on
the outside of the shell.
b) Multi-way ball valve:
- Suitable for commutation/allocation of fluids; it is also suitable for
isolating one or more channels of it.
c) Ball:
- The ball is driven by the stem to rotate; it is positioned by friction at any
position at the end or in the middle; the fluid pressure cannot rotate it.
d) Stem:
- It is fixed in the valve body; the seal between it and the valve body shall
meet the requirements of 6.7;
- It is sealed by the self-sealing elements;
- Design or mark the direction of the ball hole on the visible end of the
stem (two-way ball valve), or the way the fluid passes through the ball
(multi-way ball valve);
- The design of the connection between the stem and the ball shall ensure
that the position of the above-mentioned marks or identifications cannot
be changed when re-assembled after disassembly.
5.1.3 The minimum flow area shall be designed according to the requirements
of Table 3, Table 4, Table 5 ...