4 Materials
4.1 Materials of Insulation Layer
Ⅰ Main Item
4.1.1 Insulation materials and their products must be provided with certificates of quality，and shall comply with product standards and design documents.
Inspection method:check documents.
4.1.2 Coefficient of thermal conductivity，density and applicable temperature range of insulation materials and their products shall comply with the current national or industrial codes or standards，and satisfy requirements in design documents.
Inspection method:verify performance test reports for spot examination at site.
4.1.3 Coefficient of thermal conductivity of hot insulation materials and their products shall not be larger than 0.10W/（m·K）if the average temperature of process fluid is equal to or lower than 350℃，and the coefficient of thermal conductivity of cold insulation materials and their products shall not be larger than 0.064W/（m·K）if the average temperature of process fluid is equal to or lower than 27℃.
Inspection method:verify performance test reports for spot examination at site.
4.1.4 Categories and specifications of insulation materials and their products shall comply with design documents.
Inspection method:perform spot examination at site.
Ⅱ General Item
4.1.5 Allowable service temperature and measured data of incombustibility，non-inflammability and flammability shall be included in the certificates of quality for insulation layer materials.For cold insulation materials，the measured data of water absorbability，moisture absorbability and hydrophobic nature shall be included in their certificates of quality.For rigid insulation materials，linear expansion rate or shrinkage rate shall be provided.
Inspection method:check documents.
4.1.6 Insulation materials and their products shall be chemically stable，and shall not be corrosive to metal.If they are used for austenitic stainless steel equipment and piping，contents of chlorine ions，fluoride ions，silicate ions and sodium ions leached from insulation materials shall comply with the current national standard Specification for Thermal Insulation for Use in Contact with Austenitic Stainless Steel:GB/T 17393.
Inspection method:verify performance test reports for spot examination at site.
4.1.7 Bulk insulation materials shall not be mixed with any impurities.Shot content of fiber insulation material shall comply with product specification and design documents.
Inspection method:perform visual examination and check documents.
4.1.8 Preformed insulation materials and their products shall be free of defects such as crack，deterioration and fragment when they are visually examined.
Inspection method:perform visual examination.
4.1.9 Moisture content of hot insulation materials and their products shall not be larger than 7.5%，and moisture content of cold insulation materials and their products shall not be larger than 1%.
Inspection method:check documents or perform spot examination.