How is the pressure test and flushing of glass fiber reinforced plastic pipes operated?

① In order to reduce the temporary pipelines added during purging, save the time of pressure test and purging, and improve the qualified rate of pressure test and purging, the pressure test and purging of pipelines shall be carried out according to the system, area and pressure level. It is necessary to prepare a plan to guide the construction before pressure test and purging.

Clean water shall be selected for pipeline pressure test. When testing and flushing the stainless steel pipeline, the chloride ion content in the water shall not exceed 25 × 10(25ppm). The pipeline pressure test and flushing procedures shall comply with the rules of the general contractor.

③ During the pressure test, irrelevant personnel are not allowed to enter. At the end of the pressure test, no repair shall be made on the pipeline.

④ Before the pressure test, the following conditions shall be met:

a. The pipeline installation works within the scope of the experiment, except for painting and heat insulation, have been completed according to the planning drawings, and the installation quality conforms to the relevant rules.

B. Welds and other parts to be inspected have not been painted and insulated.

c. The expansion joint on the pipeline has been provided with a temporary restraint device.

D. experimental pressure gauge has been calibrated, and in the cycle, its accuracy shall not be less than 1.5, the full scale value of the table should be measured maximum pressure of 1.5-2 times, pressure gauge shall not be less than two.

E. the liquid or gas that meets the requirements of the pressure test has been prepared.

F. according to the experimental requirements, the pipeline has been reinforced.

g. The pipeline to be tested and irrelevant systems have been separated by blind plates or other methods.

h. The safety valve and external components on the test tube have been removed or blocked.

I. The experimental plan has now been approved and a technical disclosure has been conducted.

⑤ Hydraulic test should abide by the following rules:

A. before the experiment, the liquid should be drained of air.

The ambient temperature should not be lower than 5 ℃ during the experiment. When the ambient temperature is lower than 5 ℃, the antifreeze method should be adopted.

c. The pipeline test pressure is 1.5 times the planned pressure.

d. When the planned temperature of the pipeline is higher than the experimental temperature, the experimental pressure is calculated according to the following formula:

Ps=1.5P[s]1[s]2

Where Ps ---- experimental pressure (gauge pressure)(MPa);

P-planning pressure (gauge pressure)(MPa);

[σ]1 ---- Allowable stress of pipe at experimental temperature (MPa);

[σ]2-Allowable stress of pipe at planning temperature (MPa).

When [σ]1[σ]2 is greater than 6.5, 6.5 is taken.

E when the pipeline and equipment are tested as a system, and the experimental pressure of the pipeline is equal to or less than the experimental pressure of the equipment, the experiment shall be carried out according to the experimental pressure of the pipeline; When the experimental pressure of the pipeline is greater than the experimental pressure of the equipment and the experimental pressure of the equipment is not less than 1.15 times of the planned pressure of the pipeline, the experiment can be carried out according to the experimental pressure of the equipment with the approval of the construction unit.

f. For pipelines with large potential difference, the static pressure of the experimental medium shall be included in the experimental pressure. The test pressure of the liquid pipeline shall be subject to the highest point, but the pressure at the lowest point shall not exceed the bearing capacity of the pipeline components.

g. The hydraulic test pressure shall be slowly boosted. After reaching the test pressure, stabilize the pressure for 10min, and then reduce the test pressure to the planned pressure. Stop the pressure for 30min, with no pressure drop and no leakage as qualified.

h. After the experiment, the blind plate and expansion joint limiting facilities shall be removed in time to drain the liquid. Avoid negative pressure when discharging liquid, and do not discharge anywhere.

I. When leakage is found during the experiment, it shall not be treated with pressure. After eliminating the shortcomings, the experiment should be repeated.

⑥ For pipelines carrying toxic fluids, it is also necessary to carry out leakage tests, and the leakage test medium is air (I. e., airtight test). The airtightness test shall be conducted according to the following rules:

a. The airtight test pressure is the planned pressure.

B. air-tight test points to check the valve stuffing box, flange or thread connection, vent valve, exhaust valve, drain valve, etc.

C. airtight test with the method of brushing soapy water or other foaming agent for inspection, in order to not leak as qualified.

⑦ After the pipeline is qualified in the pressure test, the purging or cleaning operation plan of the pipeline shall be arranged according to the purging plan.