What are the requirements for the hydrostatic test of ductile iron pipes?
The pipe work pressure P is less than 0.5MPa, the test pressure is 2P, the pipe work pressure is greater than 0.5MPa, the test pressure is P+0.5. After the water pressure rises to the test pressure, the pressure is fixed for 10 minutes, and the pipe joint and the pipe body are not damaged and leaked.
The hydraulic pressure test shall be carried out in the backfill before trying to allow the pressure after passing the backfill, backfill, the graded gravel fill to 300mm above the top of pipe, and then the soil backfill, backfill process by 200~300 tamped pipeline above 500mm within more than 500 can be used in artificial ramming, mechanical compaction. The degree of compaction shall not be less than 0.93.
Hydraulic test of pipeline segment length should not be more than 1 kilometers, the test pipe should be in full of water, no pressure under the condition of full immersion, soaking time of ductile cast iron pipe without mortar lining not less than 24 hours, a mortar lining the immersion of not less than 48 hours.
