Detail of CJ/T 246-2018

Introduction of CJ/T 246-2018

Preformed directly buried steam insulating pipes and fittings for urban heating 1 Scope This standard specifies terms and definitions, general requirements, requirements, test methods, inspection rules, marking, transportation and storage for the preformed directly buried steam insulating pipes (hereinafter referred to as “insulating pipes”) and fittings for urban heating. This standard applies to manufacturing and inspection of directly buried steam insulating steel jacket pipes and fittings with the working pressure of the conveyed steam medium less than or equal to 2.5MPa and the temperature less than or equal to 350 °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 985.1 Recommended joint preparation for gas welding manual metal arc welding gas-shield arc welding and beam welding GB/T 985.2 Recommended joint preparation for submerged arc welding GB/T 3087 Seamless steel tubes and pipes for low and medium pressure boiler GB/T 3091 Welded steel pipes for low pressure liquid delivery GB/T 3198 Aluminium and aluminium alloy foils 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 12459 Steel buttwelding pipe fittings - Types and parameter GB/T 12777 General specification for metal bellows expansion joints GB/T 13401 Steel buttwelding pipe fittings - Technical specification GB/T 17393 Specification for thermal insulation for use in contact with austenitic stainless steel GB/T 17430 Estimating the maximum service temperature of thermal insulation GB/T 28638-2012 Heat loss test for thermal insulation structure and evaluation methods for thermal insulation efficiency of district heating pipes GB/T 29046 Test methods of technical specification for pre-insulated directly buried district heating pipes GB/T 29047-2012 Prefabricated directly buried insulating pipes and fittings with polyurethane foamed-plastics and high density polyethylene casing pipes CJJ 28 Code for construction and acceptance of city heating pipelines CJJ/T 104 Technical specification for directly buried steam heating pipeline in city JC/T 618 Methods of chemical analysis of thermal insulation materials for leachable chloride, fluoride, silicate, sodium ions 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 47013.4-2015 Nondestructive testing of pressure equipments - Part 4: Magnetic particle testing SY/T 5037 Submerged arc-welded steel pipe for common fluid service pipeline SY/T 5257 Steel bends for oil and gas transportation ASTM C1371-04a Standard test method for determination of emittance of materials near room temperature using portable emissometers 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 protective layer interlayer set between the working pipe and the rigid inorganic thermal insulation to dampen vibration and prevent damage to the inorganic thermal insulation 3.2 steel components metallic components directly connected with the working pipe, used for producing pipeline fittings, such as bends, tees, reducers, fixed supports, expansion joints, steam traps, watertight end seals, and isolation components 3.3 force transfer components device in a fixed support to transfer the thrust of working pipe to the jacket pipe 4 General requirements 4.1 Basic structure of product 4.1.1 The insulating pipe and fittings adopt the following basic structure: working pipe - thermal insulation - jacket pipe (including anti-corrosion). 4.1.1.1 Insulating pipes are classified into those with sliding inside and those with sliding outside and their basic structures are as shown in Figure 1.

Contents of CJ/T 246-2018

Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 General requirements 5 Requirements 6 Test methods 7 Inspection rules 8 Marking, transportation and storage