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GB/T 21385‑2025 New National Standard for Metal‑Seated Ball Valves | Gaote Holding as Standard‑Drafting Enterprise
2026-08-18
Introduction
1. Scope of the New Standard: Dual Compatibility for Metric and Imperial Systems
- Nominal Size: DN15‑DN800 / NPS½‑NPS32
- Pressure Class: PN16‑PN400 / Class150‑Class2500
- Operating Temperature: ‑29℃ ~ 550℃
- Applicable Media: gas, liquid, gas‑solid / gas‑liquid / solid‑liquid / gas‑solid‑liquid multi‑phase flow media
- End Connections: flanged, welded, threaded
2. Key Technical Upgrades in GB/T 21385‑2025
1.Enhanced design specifications for high‑temperature working conditions
Complete structural models for high‑temperature trunnion‑mounted ball valves are newly added. Clear requirements for extended bonnets, heat‑dissipation insulation structures and pre‑load spring selection are defined, solving common pain‑points such as packing‑seal failure and spring‑performance degradation under high‑temperature service.
2.Reinforced strength for body and connection structures
Stud bolts connecting valve body and bonnet shall withstand tensile and bending loads from pipelines. Clear constraints are given for fast‑ener material, thread tolerance and sealing structures to eliminate leakage risks at body joints caused by pipeline stress.
3.Optimized seat‑seal pairs for particle‑containing media
For services with solid‑particle media, disc springs (Belleville springs) are preferred as seat pre‑load components. Protective structures shall be implemented to prevent solid contaminants from entering spring chambers, avoiding spring jamming and seal failure.
4.Mandatory anti‑static safety requirements
Ball valves shall be equipped with anti‑static structures. The overall circuit resistance among valve body, ball and stem shall be less than 10 Ω. Static‑electricity discharge performance is guaranteed for flammable‑and‑explosive‑medium applications and improves operational safety for petrochemical facilities.
5.Body‑cavity overpressure‑relief considerations added
For ball valves with double‑seat sealing pairs, risks of medium overpressure inside the body cavity under full‑open or full‑closed positions shall be evaluated, and relief structures may be configured to eliminate hidden dangers caused by trapped‑medium overpressure.
6.Multi‑fold stem‑safety protection
Anti‑blow‑out stem structure is mandatory: the stem cannot be blown out by internal‑medium pressure even when the packing gland is disassembled. Potential stem‑fracture points shall be located outside the pressure‑containing cavity. The torsional strength of the stem section inside the pressure chamber shall exceed that of the outer section to lower risks of stem torsional fracture.
7.Standardized lifting and operation requirements
Lifting lugs are recommended for ball valves weighing ≥50 kg or DN≥150 (NPS6), facilitating on‑site hoisting. The maximum manual operating torque shall not exceed 360 N. Switching direction, position indicators and limit structures are fully standardized.
8.Improved fire‑safe, material and testing systems
Where fire‑safe performance is specified in purchase orders, fire‑type tests shall be performed in accordance with JB/T6899 and ISO10497. Solid balls are required. Complete test methods for body‑wall thickness, material physical‑chemical properties, anti‑static performance and sealing performance are specified, distinguishing factory‑acceptance‑test items from type‑test items.
3. Gaote’s Product Implementation Aligned with GB/T 21385‑2025
1.Pre‑compliant structural design
Our three major series — floating‑ball, trunnion‑mounted and high‑temperature trunnion‑mounted metal‑seated ball valves — are developed complying with the standard’s structural drawings. Design rules for minimum flow‑pass diameter, body‑wall thickness, drain‑port dimensions and extended high‑temperature bonnets are strictly followed. Lifting lugs are equipped for large‑size and heavy‑weight units for convenient field installation and hoisting.
2.Process control for core components
Solid balls are adopted. Sealing surfaces are treated by hard‑facing or supersonic spraying, with controlled hardness, thickness and surface finish. For particle‑laden‑media services, disc‑spring assemblies plus anti‑contamination‑intrusion structures are applied. Anti‑blow‑out stem construction is implemented, with enhanced torsional‑strength for the in‑cavity stem section. Fasteners are manufactured using standard‑grade alloy steel or stainless‑steel materials.
3.Complete safety‑function configuration
Anti‑static assemblies are standard on our full‑range metal‑seated ball valves. Fire‑safe structures and body‑cavity overpressure‑relief options are available on request for flammable‑explosive, high‑temperature‑high‑pressure, particle‑containing multi‑phase‑flow and other complex working‑condition services. Packing glands support on‑site sealing‑force adjustment without valve disassembly for easy packing maintenance.
4.Dual‑level inspection mechanism strictly executed
Every metal‑seated ball valve undergoes factory acceptance tests one‑by‑one: body‑strength test, high‑ / low‑pressure sealing test, loaded switching operation test, nameplate‑marking inspection.
Full type‑tests are performed for new‑product finalization or major changes to materials and processes, covering wall‑thickness measurement, material‑mechanical‑property analysis, anti‑static testing and other complete items, ensuring consistent mass‑product performance. Full inspection records can be supplied to customers for project acceptance.
4. Main Application Scenarios
- Petrochemical industry: high‑temperature‑high‑pressure process pipelines, flammable‑explosive‑media pipelines, particle‑laden‑medium process piping
- Power‑generation industry: power‑plant process pipelines and multi‑phase‑fluid transmission systems
- Metallurgical industry: conveying pipelines for dust‑ and particle‑containing media
- Overseas projects: supporting both metric PN and imperial Class pressure ratings to satisfy technical specifications of international projects
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Chenggong Development Zone, Ximei Street, Nan'an City, Quanzhou City, Fujian Province
Gaote Holding Group Co., Ltd.
Tel: +86-595-8896-8800
Email: gaotegroup@126.com
Address: Chenggong Development Zone, Ximei Street, Nan'an City, Quanzhou City, Fujian Province
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