GB/T 35842-2026Technical requirements for pre-insulated directly buried valves for urban heating (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part

1.Structure and Drafting Rules of Standardization Documents". Drafting. This document supersedes GB/T 35842-2018 "Technical Requirements for Prefabricated Direct-Buried Insulated Valves for Urban Heating" and is consistent with GB/T 35842-2018. Aside from structural adjustments and editorial changes, the main technical changes are as follows:

a) The scope of application for steel valves has been changed and the scope of application for PE-RT II valves has been expanded (see Chapter 1,.2018 edition). Chapter 1);

b) The terms and definitions for valve welded ports, switching torque, bending moment, and no-load conditions have been removed (see 3.3-

3.6 of the.2018 edition);

c) The valve performance standard has been changed (see 4.2,.2018 version of 4.2);

d) The connection methods between the insulated valves and the pipelines have been increased (see 4.3);

e) The corrosion protection requirements for steel valve stems have been changed (see 4.4,

4.8 in the.2018 edition);

f) Valve sleeve requirements have been changed (see 4.5,

4.12 in the.2018 edition);

g) The requirements for valve structure, on/off conditions, application requirements for separable connections, valve stem structure and length, and O-ring requirements have been removed. (See 4.3-

4.7 in the.2018 edition);

h) Requirements for gear mechanisms, keyway requirements for actuator connections, valve stop device requirements, and insulation for steel butterfly and ball valves have been removed. Gearbox disassembly and assembly requirements during valve manufacturing (see sections 4.9-

1 Scope

GB/T 35842-2026 is the Chinese national standard covering the valve buried in a district heating line - insulated and jacketed like the pipe around it, with an extended stem to the surface, and required to still operate after twenty years underground because digging it up is the alternative. It replaces GB/T 35842-2018. It was issued on 28 January 2026 and has been in force since 1 August 2026, replacing GB/T 35842-2018. The document is under the responsibility of the Ministry of Housing and Urban-Rural Development. This page is published from the official record of the 2026 edition; the clause text of a standard this recent is not yet in circulation, and the figures, limits and tables it contains are those of the document itself, delivered in full with the English translation.

This document specifies the general requirements, requirements, test methods, and inspection procedures for prefabricated direct-buried insulated valves for urban heating (hereinafter referred to as "insulated valves"). Inspection rules, as well as marking, transportation, and storage. This document applies to.

---The continuous operating temperature of the conveyed medium is not less than 4°C and not more than 120°C, the occasional peak temperature is not more than 130°C, and the nominal size is... Manufacturing and inspection of prefabricated steel insulated valves for direct burial and manhole applications with a diameter of DN1600 or less;

---Prefabricated Type II heat-resistant polyethylene insulated valves for direct burial and manhole applications with a continuous operating temperature of not exceeding 75°C (hereinafter referred to as...) Manufacturing and inspection of "PE-RTII thermal insulation valve".

2 Normative references

The contents of the following documents, through normative references within the text, constitute essential provisions of this document. Dated citations are not included. For references to documents, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies. This document.

GB/T 3091 Welded steel pipes for low-pressure fluid transportation

GB/T 8163 Seamless steel pipes for conveying fluids

GB/T 9711 Steel pipes for pipeline transportation systems in the oil and gas industry

GB/T 14976 Stainless steel seamless pipes for conveying fluids

GB/T 20674.1 Plastic pipes and fittings - Welding equipment for polyethylene systems - Part

3 Terms and Definitions

The terms and definitions defined in GB/T 29047 and the following terms and definitions apply to this document.

3.1 Insulated valve Pipeline accessories consisting of a high-density polyethylene outer protective pipe, a rigid polyurethane foam insulation layer, valves, valve sleeves, etc.

3.2 Valve extension pipes Straight pipe sections are welded to both ends of the valve body to facilitate valve insulation and installation.

4 Valves

GB/T 28799.5 Heat-resistant polyethylene (PE-RT) piping systems for hot and cold water - Part

5 System suitability

GB/T 29046 Test Methods for Technical Indicators of Prefabricated Insulated Pipelines for Urban Heating

GB/T 29047 High-density polyethylene outer sheath rigid polyurethane foam prefabricated direct-buried insulated pipes and fittings

GB/T 37827 Welded ball valves for urban heating

GB/T 37828 Two-way metal hard-seal butterfly valve for urban heating

GB 50236 Construction Specification for Welding Engineering of On-site Equipment and Industrial Pipelines