Compressed Air Piping Installation Precautions

(1) Pipes, pipe fittings and valves shall be installed only after they have been inspected and calibrated according to the design requirements.

(2) All pipe supports and hangers are made of finished supports and hangers, the specific quantity of which is calculated by the contractor himself.

(3) Pipes used for flange connection can be installed twice, i.e. after welding the flanges to the pipes, then dismantle, calibrate and clean them for re-installation.

(4) Small pipelines not indicated in the pipeline layout plan, the direction of which is to be decided at the time of on-site construction, including instrumentation pipes, etc., shall be neatly laid out and have a reasonable direction, and shall be installed after other pipelines have been installed in accordance with the requirements of engineering regulations and design documents.

(5) Pipes shall be well protected as finished products during installation, and gloves, bolts, welding materials and other sundries are strictly prohibited from falling into them.

(6) All fittings which will be subjected to corrosion shall be rust-proofed and coupled with appropriate antirust coatings, while at the same time electrolytic action due to direct contact of different metals shall be prevented when the installation work is carried out.

(7) Pipes should be fixed with braces, especially those with flexible joints and those not allowed to bear weight, which should be fixed with additional braces.

(8) Maximum pipe support spacing should not exceed 5 meters. The actual arrangement and details will be provided by the design requirements and parameter list to be submitted to the project management and owner for approval.

(9) Curved pipe supports are generally used for uninsulated power piping supports, but in order to prevent accidental dislodgement of piping due to radial displacement in the horizontal direction, sliding supports should be provided every 24m or so.

(10) Pipe bracket, support and parts in the rust and dirt removal after brushing rust paint twice, gray top coat.

(11) The welding of the support bracket should be welded by qualified welders, and there should be no defects such as leakage, under-welding or welding cracks. When the pipe is welded with the bracket, the pipe shall not have the phenomenon of biting edge and burning through.

(12) The circumferential weld of the pipe shall not be placed on the bracket and shall leave the edge of the bracket not less than 200 millimeters, and the longitudinal weld of the welded steel pipe shall be oriented in a direction that is convenient for inspection.

(13) When the compressed air pipeline is threaded, each branch pipe shall be equipped with a live joint near the threaded valve and other maintenance parts to facilitate maintenance.

(14) design pressure greater than 1.0MPa compressed air piping after installation should be sampling radiographic inspection, sampling ratio of not less than 5%, the quality is not less than Ⅲ.

(15) power pipeline installation should be piping system strength test, when using air pressure test, low-pressure system test pressure of 1.15MPa, high-pressure system test pressure of 1.61MPa. test medium for dry and clean air, the test needs to be agreed by the construction unit, while the pressure test process should be effectively done to protect the safety and isolation measures.

Before the test, air must be used for pre-test. During the test, the pressure should be gradually and slowly increased, when the pressure rises to 50% of the test pressure, if no abnormalities or leakage is found, continue to increase the pressure step by step according to 10% of the test pressure, and stabilize the pressure for 3min each level until the test pressure. Then stabilize the pressure for 10min, and then reduce the pressure to the design pressure for checking to foamer test no leakage as qualified.

(16) The Contractor shall submit the pressure test program to the project management and the Owner for approval before the pressure test.