PMC Ambergate offer pipeline recompression services allowing depressurisation of a section of pipeline between 2 proven isolation points. This gives the customer the opportunity to carry out remedial works on defects that require a percentage pressure reduction allowing works to be undertaken safely. We can also complete a total pipeline de-pressurisation and gas evacuation using a 200mm diameter, 12 metre high vent stack, and direct air purging equipment if full line intervention (cut outs and re-welds) are required.
The process involves transporting one (or two) Recompression Units, mounted on 12 metre trailers, to site along with associated pipework. Suction and Discharge points on the Units are connected to the pipeline system to fittings either side of a main isolation valve using a mobile crane. If Vent and Purge is required for full evacuation of the pipework system these are also piped in at this point. When all pipework is connected and flanged joints correctly torqued up a commissioning process is followed to gas up the system in preparation for running.
Once the system is pressurised and commissioned the Units are started and bought online to recompress the gas. The duration for recompressing gas is calculated on pipeline length, diameter, starting & finishing pressures and discharge pressure and will depending on how many Units are used and whether 24 hour running is possible.
PMC supply all documentation to support the operation including Method Statements, Risk Assessments, Hazardous area drawings and designs for the operation and will provide completion documentation to verify that any joints broken into to connect to the system will have be re-made to the correct torque settings and standards.