Hydrotesting and/or leak testing a recently installed pipeline is required before the line is put into service and the standard in Europe oft quoted is ‘DNV’, more correctly this should be DNVGL-ST-FS101_2021 (Standard) with reference to DNVGL-RP-F115, (Recommended Practice).
Online’s 6000SD Pressure & Temperature Subsea Data Logger monitors, displays and records pressure and temperature during the hydrotesting of a subsea pipeline. Following discussions with several clients regarding the need to confirm a successful hydrotest before recovery of the unit to surface, a modification to the existing programming was made to ensure that the time the DNV specified Pass or Fail occurred is clearly visible on the large OLED screen.
The advantage of this extra coding is that as well as the whole pressure test data being recorded for downloading after recovery, any drop in pressure below the DNV threshold criteria occurring after the specified time will not show as a ‘fail’. The end time of the test will still be displayed (and recorded) as a successful test. This can save valuable vessel time both from the avoidance of recovery of the 6000SD and having the worry that a full re-test might be needed.
6000SD Display showing that pressure test passed for both sensors.
The 6000SD was initially designed around ten years ago primarily to meet the DNV FS101 standard for sensor accuracy within the European market and so was offered with bar & °C on the display; however, for the North American market the option of psi & °F was needed and so this has been added. The current generation 6000 data logger is designed to operate in 3000m WD and in standard format for pressure measuring from 100 to 1000 bar capability. (Note lower pressure ranges are always preferred to ensure sufficient accuracy to measure and record that the maximum allowed drop of 0.2% has not been exceeded)
A further request was made to interface the 6000SD with customer supplied optical modems for fast data transfer/download whilst units were still subsea. This would also enhance the unit and provide added flexibility. This unit has a modified housing to provide the additional batteries that are required to power the optical modem. The standard data communications were augmented using Binary language to allow for much faster data transfer to the optical modems and then to the DSV via the umbilical, again saving valuable vessel time as the pressure / temperature graphs can be analysed prior to disconnection of the 6000SD from the pipe(s) being tested.
These product advancements highlight that Online Electronics has the capability and flexibility to quickly respond to our client’s needs and modify existing equipment to support them and the overall subsea and pipeline markets.