Services relating to Hydrostatic Pressure Testing
Hydrostatic pressure testing is a process that uses water to exert pressure on a pipeline at levels much greater than its usual operating pressure, to test the strength of the segment under test.
Prior to the new pipeline being commissioned it must be tested. The segment of pipeline is exposed at either end in excavations.
An initial air test is undertaken to prove the segment is suitable to be hydrostatically tested.
Next, the sealed test segment is filled with water using a pump. The water pressure is increased to a point higher than the pipeline will normally operate to see if it has any leaks. After holding the increased pressure for a pre-determined period, the test is complete.
The water is then drained from the pipeline test segment in accordance with applicable regulations and local requirements, and the test caps are removed from the ends. The pipeline segment is then thoroughly dried prior to a final air test before connecting and commissioning.
The segment of pipeline that is being tested is temporarily removed from service and excavations are dug at both ends of the segment to expose the pipeline. Then, the natural gas inside is safely vented.
On an existing pipeline short sections of pipeline are removed from both ends of the segment to be tested and the ends are sealed with test caps. Next, the sealed test segment is filled with water using a pump. The water pressure is increased to a point higher than the pipeline will normally operate to see if it has any leaks. After holding the increased pressure for eight hours or more, the test is complete.
The water is then drained from the pipeline test segment in accordance with applicable regulations and local requirements, and the test caps are removed from the ends. The pipeline segment is then thoroughly dried and new replacement pipe is installed at both ends to reconnect the pipeline segment into the system. Natural gas is safely reintroduced into the pipeline and it is brought back into service.
Failure of the pipeline, causing the pipeline to split under pressure causing high velocity jets with the potential of causing loss of life or serious injury, damage to vital equipment.
All new mains and services must be pressure tested before purging to gas, in accordance with the new main and service laying work procedures. Any part of the supply system which is diverted altered or renewed, must be pressure tested Joints which cannot be included in such a pressure test, must be tested at district operating pressure using an approved leak detection fluid. IP Mains are rated at 7 bar to be progressively tested as the pressure is increased.
AWL will ensure that all operatives undertaking hydrostatic pressure test activities have attended training in the use of all testing equipment used by the company. They will have carried out a supervised period of working until they have achieved and maintained the standards required of a Technician.
All works undertaken will comply with the following legislation:
- IGEM/TD/3 Ed 5 Steel and PE pipelines for gas distribution
- IGE/TD/4 Ed 4 PE and steel gas services and service pipework
- HSE GS/4 Safety requirements for pressure testing
- WWU T/PR/DIS 5.5.1
AWL Directors will carry out regular audits and reviews of processes to ensure compliance.
Please Contact us for any further information or details