Standard No.:	GB/T 29047-2012
English Name:	Prefabricated directly buried insulating pipes and fittings with polyurethane [PUR]foamed-plastics and high density polyethylene [PE]casing pipes
Chinese Name:	高密度聚乙烯外护管硬质聚氨酯泡沫塑料预制直埋保温管及管件
Chinese Classification:	P40    Water supply and draining engineering in general
Professional Classification:	GB    National Standard
ICS Classification:	91.140.60 91.140.60    Water supply systems 91.140.60
Issued by:	AQSIQ; SAC
Issued on:	2012-12-31
Implemented on:	2013-9-1
Status:	superseded
Superseded by:	GB/T 29047-2021 Prefabricated directly buried insulating pipes and fittings with polyurethane foamed-plastics and high density polyethylene casing pipes
Superseded on:	2022-3-1
Language:	English
File Format:	PDF
Word Count:	20000 words
Price(USD):	500.0
Delivery:	via email in 1 business day

1 Scope This standard specifies product structures, requirements, test methods, inspection rules as well as identification, transport and storage of prefabricated directly buried insulating pipe (hereinafter referred to as insulating pipe) composed of high density polyethylene external protecting pipe (hereinafter referred to as external protecting pipe), rigid polyurethane foam insulating layer (hereinafter referred to as insulating layer) and working steel pipes or steel fittings as well as its insulating fittings and insulating joints. This standard is applicable to the fabrication and inspection of prefabricated directly buried insulating pipes, insulating fittings and insulating joints with the conveyance medium temperature (long-term operating temperature) not higher than 120℃ and occasional peak temperature not higher than 140℃. 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 8163 Seamless Steel Tubes for Liquid Service GB/T 8923.1 Rust Grades and Preparation Grades of Uncoated Steel Substrates GB/T 9711 Petroleum and Natural Gas Industries - Steel Pipe for Pipeline Transportation Systems GB/T 12459 Steel Butt-welding Seamless Pipe Fittings GB/T 13401 Steel Plate Butt-welding Pipe Fittings GB/T 18475-2001 Thermoplastics Materials for Pipes and Fittings for Pressure Applications - Classification and Designation - Overall Service (Design) Coefficient GB/T 29046-2012 Test Methods of Technical Specification for Pre-insulated Directly Buried District Heating Pipes GB 50236-2011 Code for Construction of Field Equipment, Industrial Pipe Welding Engineering CJJ 28 Code for Construction and Acceptance of City Heating Pipelines CJJ/T 81 Technical Specification for Directly Buried Heating Pipeline Engineering in City JB 4708 Welding Procedure Qualification for Pressure Equipment JB/T 4730 Nondestructive Testing of Pressure Equipment SY/T 5257 Steel Bend for Oil and Gas Transmission TSG Z6002 Examination Rules for Welding Operators of Special Equipment API SPEC 5L Specification for Line Pipe 3 Terms and Definitions For the purposes of this document, the following terms and definitions apply. 3.1 bonded insulation structure structure of integrated insulating pipe (or insulating fitting) formed by bonding together the working steel pipe (or steel fitting) and the external protecting pipe via insulating layer 3.2 steel fitting pipeline components such as steel reducer, T-branch, elbow, bend and fixed knot. 3.3 bend angle central angle corresponding to the arc section of elbow or bend 3.4 heat-extruded elbow elbow made of seamless steel pipe segment through pushing it with mandrel after heating 3.5 forge-welded bend elbow fabricated through longitudinal welding after being formed by pressuring steel plate

Foreword i Introduction ii 1 Scope 2 Normative References 3 Terms and Definitions 4 Product Structure 5 Requirements 5.1 Working Steel Pipe 5.2 Steel Fitting 5.3 External Protecting Pipe 5.4 Insulating Layer 5.5 Insulating Pipe 5.6 Insulating Fittings 5.7 Insulating Joint 6 Test Methods 7 Inspection Rules 7.1 Inspection Classification 7.2 End-of-manufacturing Inspection 7.3 Type Inspection 8 Marking, Transport and Storage 8.1 Marking 8.2 Transport 8.3 Storage Annex A (Normative) Actual Continuous Operating Conditions and Accelerated Aging Test Conditions Annex B (Normative) Calculation of Shortest Expected Life of Polyurethane Foamed-plastic Under Different Operating Temperatures Annex C (Normative) Requirements and Tests for Insulating Pipe with Long-term Continuous Operating Temperature Between 120℃ and 140℃ Annex D (Informative) External Protecting Pipe Welding Guide Bibliography