Standard No.:	GB/T 34611-2017
English Name:	Rigid polyurethane spray polyethylene winding prefabricated directly buried insulating pipes
Chinese Name:	硬质聚氨酯喷涂聚乙烯缠绕预制直埋保温管
Chinese Classification:	P46    Heat supply and heating engineering
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:	2017-10-14
Implemented on:	2018-9-1
Status:	valid
Language:	English
File Format:	PDF
Word Count:	8500 words
Price(USD):	250.0
Delivery:	via email in 1 business day

Rigid polyurethane spray polyethylene winding prefabricated directly buried insulating pipes 1 Scope This standard specifies the terms and definitions, product structure, general requirements, requirements, test methods, inspection rules, markings, transportation and storage of rigid polyurethane spray polyethylene winding prefabricated directly buried insulating pipe produced by polyurethane spraying process and polyethylene winding process (referred to as spraying and winding insulating pipe). This standard is applicable to the manufacturing and inspection of rigid polyurethane spray polyethylene winding prefabricated directly buried insulating pipes with a medium temperature (long-term operating temperature) not exceeding 120°C and occasional peak temperature not exceeding 140°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 3091 Welded steel pipes for low pressure liquid delivery GB/T 6671 Thermoplastics pipes - Determination of longitudinal reversion GB/T 8163 Seamless steel tubes for liquid service 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 coatings GB/T 9711 Petroleum and natural gas industries - Steel pipe for pipeline transportation systems 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/T 29047 Prefabricated directly buried insulating pipes and fittings with polyurethane foamed-plastics and high density polyethylene casing pipes CJJ/T 254-2016 Technical specification for leakage surveillance system of directly buried heating pipe 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 polyurethane spraying process where polyurethane spraying equipment is used to continuously spray the uniformly mixed polyurethane raw materials onto the outer surface of steel pipe to form polyurethane insulating layer 3.2 polyethylene winding process where the extrusion equipment is used to continuously wind the molten polyethylene sheet onto the outer surface of polyurethane insulating layer to form a continuous and dense polyethylene out casing

Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 Product structure 5 General requirements 6 Requirements 7 Test methods 8 Inspection rules 9 Marking, transportation, and storage Annex A (Normative) Inspection method for circumferential thermal reversion of out casing Annex B (Normative) Inspection method for circumferential shrinkage of out casing