Standard No.:	GB/T 39246-2020
English Name:	Prefabricated directly buried insulating fittings with seamless high density polyethylene casing pipe
Chinese Name:	高密度聚乙烯无缝外护管预制直埋保温管件
Chinese Classification:	P46    Heat supply and heating engineering
Professional Classification:	GB    National Standard
ICS Classification:	91.140.10 91.140.10    Central heating systems 91.140.10
Source Content Issued by:	SAMR; SAC
Issued on:	2020-11-19
Implemented on:	2021-10-1
Status:	valid
Target Language:	English
File Format:	PDF
Word Count:	10500 words
Translation Price(USD):	315.0
Delivery:	via email in 1 business day

Prefabricated directly buried insulating fittings with seamless high density polyethylene casing pipe 1 Scope This standard specifies the terms and definitions, product construction, requirements, test methods, inspection rules, as well as marking, transportation and storage of prefabricated directly buried insulating fittings with seamless high density polyethylene casing pipe. This standard is applicable to the manufacturing and inspection of the prefabricated directly buried insulating fittings with seamless high density polyethylene casing pipe whose conveying medium temperature (long-term operating temperature) is not greater than 120°C and peak temperature is not greater than 130°C. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. GB/T 8923.1-2011 Preparation of steel substrates before application of paints and related products - Visual assessment of surface cleanliness - Part 1: Rust grades and preparation grades of uncoated steel substrates and of steel substrates after overall removal of previous GB/T 12459 Steel buttwelding pipe fittings - Types and parameter GB/T 13401 Steel buttwelding pipe fittings - Technical specification GB/T 18475-2001 Thermoplastics materials for pipes and fittings for pressure applications - Classification and designation - Overall service (design) coefficient GB/T 29046 Test methods of technical specification for pre-insulated directly buried district heating pipes GB/T 29047 Prefabricated directly buried insulating pipes and fittings with polyurethane foamed-plastics and high density polyethylene casing pipes GB 50236-2011 Code for construction of field equipment, industrial pipe welding engineering CJJ/T 254 Technical specification for leakage surveillance system of directly buried heating pipe NB/T 47013.2-2015 Nondestructive testing of pressure equipments - Part 2: Radiographic testing NB/T 47013.3-2015 Nondestructive testing of pressure equipment - Part 3: Ultrasonic testing NB/T 47014 Welding procedure qualification for pressure equipment SY/T 5257 Steel bends for oil and gas transmission 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 seamless high density polyethylene casing pipe generic term for seamless casing elbow, seamless casing bend, seamless casing T-shaped tee, seamless casing reducer, etc., which are formed by extrusion or pulling from high density polyethylene raw materials 3.2 reinforced weld butt weld of polyethylene casing branch pipe of T-shaped tee using an electric fusion welding tape sleeve 3.3 determination of environmental stress cracking capability of polyethylene specimens to withstand sustained static tensile loads when they are immersed in a surfactant solution at a specific temperature 4 Product structure 4.1 The prefabricated directly buried insulating fittings with seamless high density polyethylene casing pipe shall be of a bonded insulation structure in which steel fitting, insulating layer and seamless casing fitting are closely bonded, and guiding holder and signal line may be set in the insulating layer. 4.2 The schematic diagram of product structure is shown in Figure 1.

Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 Product structure 5 Requirements 5.1 Steel fitting 5.2 Casing fittings 5.3 Insulating layer 5.4 Insulating fittings 6 Test methods 7 Inspection rules 7.1 Inspection classification 7.2 End-of-manufacturing inspection 7.3 Type inspection 8 Marking, transportation and storage 8.1 Marking 8.2 Transportation 8.3 Storage Annex A (Normative) Dimensions of T-shaped insulating tee