What are the three key elements in the installation of pressure pipelines?

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To enhance the construction of pipelines for transporting flammable and explosive materials, it is required that the construction party provide on-site technical instructions regarding the following \"technical requirements\": 1. The pipeline materials brought into the site must meet the specified conditions during inspection and testing; the quality certificates for these pipelines should include the following information: a) Product standard number； b、 Steel grade ； c、 Furnace pot number, batch number, delivery status, weight, and quantity ； d. Variety name, specifications, and quantity grade ； e. Various test results specified in the product standards ； f. The stamp of the technical supervision department. If the pipe grade, furnace and tank numbers upon arrival do not match those on the quality certificate, or if there are discrepancies regarding the characteristic data, the supplier shall conduct verification tests in accordance with the relevant standards or trace back to the product manufacturer. The pipeline batch shall not be used until the objection is resolved. Pipeline markings at the construction site must be clear. 2. Before installing the valve, random inspections should be conducted on the sealing surface of the valve body, as well as on the materials of gaskets and packing that have special requirements; at least one sample from each batch should be inspected. The valve bodies of alloy steel valves should be subjected to rapid spectral analysis one by one. If the requirements are not met, these valves shall not be used. 3. Before installing the valves on pipelines that transport flammable and explosive media, each valve body must undergo a hydraulic pressure test; the test pressure should be 1.5 times the nominal pressure, and if there is no leakage after holding the pressure for 5 minutes, the valve is considered qualified. (It is not allowed to close the valve for performing pressure testing on the valve body.) 4. For connection bolts and nuts under conditions where the pipeline pressure is 10 MPa or higher, rapid spectral testing should be carried out on each individual piece; in addition, two pieces from each batch should be sampled for hardness testing. If the requirements are not met, action shall be taken in accordance with the relevant specifications. 5. For rapid spectral analysis of other alloy steel pipeline components, 5% of each batch shall be sampled, with a minimum of one sample per batch. In the event of non-compliance, appropriate actions will be taken in accordance with relevant regulations. 6. Before installing the pipes, sand, iron filings, slag, and other debris inside them should be removed one by one. And promptly seal the open pipes. 7. After grinding the cut openings in the pipes, any remaining iron shavings, slag, and other debris must be cleaned up promptly. 8. The flange surfaces and gaskets at the pipe connections must be free from any defects such as scratches or rust that could affect the sealing performance. For metal ring seals, the contact line when the metal ring seal rotates 45° must not have any interruptions. 9. For connection bolts made of 35CrMo, 30CrMo, and 35# materials, they must be tightened using a torque wrench, with the torque value being set in accordance with relevant specifications. (Since the bolts of this material lack a plastic deformation zone, brittle fracture can occur easily if force is applied improperly.) 10. When installing pipes for rotating equipment, pipe supports should be installed first; the weight of the pipe valves must not be borne by the rotating equipment. After the pipes are installed, the connecting bolts should be removed so that they can pass through the flange holes freely. The specific requirements for flange connections in rotating equipment are shown in the table below: Mechanical rotation speed, rpm/min; Parallel deviation of the connection flanges, mm; Radial deviation of the connection flanges, mm; Flange spacing, mm