Standard No.:	GB/T 12246-2025
English Name:	Pilot operated pressure reducing valves
Chinese Name:	先导式减压阀
Chinese Classification:	J16    Valve
Professional Classification:	GB    National Standard
ICS Classification:	23.060.99 23.060.99    Other valves 23.060.99
Source Content Issued by:	the State Administration for Market Regulation the Standardization Administration of the People’s Republic of China
Issued on:	2025-10-31
Implemented on:	2026-5-1
Status:	to be valid
Superseding:	GB/T 12246-2006 Pilot operated pressure reducing valves
Target Language:	English
File Format:	PDF
Word Count:	7000 words
Translation Price(USD):	210.0
Delivery:	via email in 1~3 business day

GB/T 12246-2025 Pilot operated pressure reducing valves English, Anglais, Englisch, Inglés, えいご This is a draft translation for reference among interesting stakeholders. The finalized translation (passing through draft translation, self-check, revision and verification) will be delivered upon being ordered. ICS 13.220.10 CCS H 57 National Standard of the People's Republic of China ‌GB/T 12246-2025 Replaces GB/T 12246-2006 Pilot operated pressure reducing valves 先导式减压阀 Issue date: 2025-10-31 Implementation date: 2026-05-01 Issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China the Standardization Administration of the People's Republic of China Contents Foreword 1 Scope 2 Normative References 3 Terms and Definitions 4 Structural Types 5 Technical Requirements 6 Test Methods 7 Inspection Rules 8 Marking and Painting 9 Packaging, Transportation, and Storage Figure 1 Integrated Pilot-Operated Pressure Reducing Valve / Pilot Piston-Type Pressure Reducing Valve Figure 2 Integrated Pilot-Operated Pressure Reducing Valve / Pilot Diaphragm-Type Pressure Reducing Valve Figure 3 Independent Pilot-Operated Pressure Reducing Valve / Pilot Diaphragm-Type Pressure Reducing Valve Table 1 Recommended Material for Parts Table 2 Inspection Items 1 Scope This document specifies the structural types, technical requirements, test methods, inspection rules, marking, painting, and packaging, transportation, and storage for pilot-operated pressure reducing valves. This document applies to the design, production, and inspection of pilot-operated pressure reducing valves with nominal sizes DN15~DN800 and nominal pressures PN10~PN100, or nominal sizes NPS½~NPS32 and nominal pressures Class150~Class600, for gases, liquids, and steam with temperatures not exceeding 300°C. 2 Normative references The contents of the following documents, through normative citations in the text, constitute essential provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies. GB/T 699 Carbon structural steel for quality GB/T 1220 Stainless steel bars GB/T 1222 Spring steel GB/T 1239.2-2009 Technical requirements for cold-coiled cylindrical helical springs-Part 2: Compression springs GB/T 2059 Copper and copper alloy strips GB/T 3077 Alloy structural steels GB/T 4622 (All parts) Spiral-wound gaskets for pipe flanges GB/T 9124 (All parts) Steel pipe flanges GB/T 12220 Industrial valves-Marking GB/T 12225 General-purpose valves-Technical requirements for copper alloy castings GB/T 12226 General-purpose valves-Specifications for gray iron castings GB/T 12227 General-purpose valves-Specifications for ductile iron castings GB/T 12228 General-purpose valves-Specifications for carbon steel forgings GB/T 12229 General-purpose valves-Specifications for carbon steel castings GB/T 12230 General-purpose valves-Technical requirements for stainless steel castings GB/T 12244 Pressure reducing valves-General requirements GB/T 12245 Pressure reducing valves-Performance test methods GB/T 17241 (All parts) Cast iron pipe flanges GB/T 21465 Valves-Terminology JB/T 106 Marking and painting for valves JB/T 2205 Pressure reducing valves-Face-to-face dimensions JB/T 7928 Industrial valves-Supply requirements 3 Terms and definitions The terms and definitions defined in GB/T 12244, GB/T 12245, and GB/T 21465, as well as the following terms and definitions, apply to this document. 3.1 Integrated pilot-operated pressure reducing valve A pilot-operated pressure reducing valve with the pilot valve integrated into the main valve structure. 3.2 Independent pilot-operated pressure reducing valve A pilot-operated pressure reducing valve with the pilot valve independent of the main valve structure and connected to the main valve only via pipelines. 4 Structural types The pilot-operated pressure reducing valve (hereinafter referred to as "pressure reducing valve") can be classified into integrated pilot-operated pressure reducing valves and independent pilot-operated pressure reducing valves based on the combination of the pilot valve and main valve, and into pilot-piston-type pressure reducing valves and pilot-diaphragm-type pressure reducing valves based on the main valve driving component, as shown in Figures 1 to 3. 5 Technical requirements 5.1 General requirements 5.1.1 The face-to-face dimensions of flange-connected pressure reducing valves shall comply with the provisions of JB/T 2205 or the requirements of the purchase order. 5.1.2 The flange dimensions and sealing surface forms of steel pressure reducing valves shall comply with the provisions of GB/T 9124 (All parts) or the requirements of the purchase order. 5.1.3 The flange dimensions and sealing surface forms of iron pressure reducing valves shall comply with the provisions of GB/T 17241 (All parts) or the requirements of the purchase order. 5.1.4 Unless otherwise specified in the purchase order, the nominal pressure and nominal size of the connection flanges at both ends of the valve body shall be consistent. 5.1.5 The pressure reducing valve shall be equipped with a pressure adjustment mechanism and anti-loosening device. The pressure shall be adjustable by rotating the handwheel or other components (adjustment screw) clockwise to increase the downstream pressure, with the valve disc in the open state. 5.2 Springs The design and manufacture of springs shall comply with the Class 2 accuracy requirements in GB/T 1239.2-2009. The spring pressure class shall be selected according to the appropriate range specified in the purchase order. The spring index (ratio of mean diameter to wire diameter) shall be selected within the range of 4 to 9. Both ends of the spring shall have support surfaces covering no less than three-quarters of a turn, with no less than one full turn as the support. The working deformation of the spring shall be controlled within the range of 30% to 70% of the deformation under test load. 5.3 Performance requirements 5.3.1 Shell strength During the shell test, the pressure reducing valve shall not exhibit structural damage, and no visible leakage shall be permitted. 5.3.2 Sealing performance For soft-sealed (elastic-sealed) structures, the seat sealing shall show no visible leakage. For metal hard-sealed structures, the seat sealing leakage shall not exceed 0.5% of the maximum flow rate, or the rate of pressure rise at the outlet shall not exceed 0.2 MPa/min. All connections of the pressure reducing valve shall show no visible leakage. 5.3.3 Pressure regulation performance Within the specified pressure regulation range, the outlet pressure shall be continuously adjustable between the maximum and minimum values without any sticking or abnormal vibration. 5.3.4 Flow coefficient The deviation of the flow coefficient (Kv or Cv) under the maximum opening condition of the pressure reducing valve shall not exceed 10% of the manufacturer's specified value. 5.3.5 Flow characteristics During the flow characteristic test, the pressure reducing valve shall not exhibit abnormal vibration, and the deviation of the outlet pressure from the flow characteristics shall not exceed 10% of the outlet pressure. 5.3.6 Pressure characteristics