Pipeline components, including pipelines, fittings, flanges, valves, compensators, safety devices, etc. , pipe support must have the manufacturer's quality certificate and certificate of conformity, and its quality shall not be lower than the current national standard.
The materials, specifications, models and quality of pipeline components and pipeline supports shall comply with the provisions of design documents, and shall be visually inspected according to national standards. Unqualified persons shall not be used. The visual inspection of pipelines shall meet the following requirements:
(1) No crack, shrinkage cavity, slag inclusion, folding and other defects;
(2) The depth of corrosion, depression and mechanical damage shall not exceed the allowable negative deviation of wall thickness.
(3) Thread sealing surface, groove and machining accuracy should meet the requirements of design standards;
(4) product identification.
Materials with high temperature impact value requirements in design documents should have high temperature impact value in product quality certificate, otherwise supplementary tests should be carried out as required.
The pipeline quality certificate shall include the following contents:
(1) product standard number; (2) the brand of steel; (3) serial number, batch number, delivery status, weight and number of pieces: (4) variety name, specification and quality grade; (5) All inspection results specified in product standards (6) Manufacturer's inspection marks.
Valve inspection. (1) The appearance of the valve shall be free of cracks, scale, looseness, sand sticking and other defects. Factors affecting strength. (2) Before installation, the valves of flammable and toxic process pipelines shall be subjected to liquid pressure test one by one, and the test pressure shall be 15 times of the nominal pressure. If the pressure stops for 5 minutes, the shell and packing shall be considered acceptable. (3) Flammable and toxic process pipes and valves shall be sealed one by one. The test pressure shall be the nominal pressure. Stop the pressure for 5 minutes, and the sealing surface of the disc shall not leak. (4) Before installation, pressure test and sealing test shall be carried out in accordance with (2) and (3) for pipeline valves conveying nonflammable fluids and nontoxic fluids with design pressure of 1MPa or design temperature of 186℃.