Different field and full-scale tests and monitoring installations have demonstrated the versatility of the Ferrx monitoring technology.

OG onshore-offshore

O&G onshore and offshore

FEMM technology is well suited for long term unattended monitoring of topside and subsea structures with sensors having a lifetime equal to that of the structure itself. The system for riser inspection has been qualified by DNV-GL in accordance with DNV-RP-A203 Technology Qualification. The FEMM technology is also well suited for harsh environments like high-temperature pipes in refineries.

 Other infrastructure

Wind turbine structures

FEMM′s high sensitivity is able to predict cracks in wind mill structures/components long before cracks happen. The FEMM has been developed for the O&G offshore market and for condition monitoring of subsea steel structures, however, it can be applied to any steel structure offshore and onshore where the sensors can be fit in.

It is regarded that there are several locations both in the nacelle, the tower and the substructure that are feasible for applying FEMM for fatigue monitoring. Focus has in first instance been the monitoring of substructures for offshore wind mills, e.g. jacket structures. The monitoring is proposed to be at the subsea part and close to the seabed. The potential cost savings by applying condition monitoring are regarded to be significant both related to Capex and Opex.

The construction cost savings are regarded to be significant as design fatigue factor can be reduced by a factor of 3 and thus allows for significant reduction of steel dimensions.

About 25% of the costs of offshore wind energy are related to the operations and maintenance and are important starting points in the reduction of costs. The availability of wind turbines can be increased further by effective maintenance that can reduce down time, which leads directly to an increased production and a lower cost of energy.

To obtain these goals it is regarded as most relevant to focus on measuring, monitoring and predicting degradation of the components in due time in order to perform planned maintenance, and avoiding unplanned maintenance as much as possible.

Most likely it is known which turbines are bearing the heaviest loads in a wind park and which the least, based on this the condition monitoring can be adjusted accordingly and it is regarded not needed to fit every turbine with instruments to produce accurate estimates of the loads and the consequences for the farm as a whole.

Highway infrastructure

Highway infrastructure (i.e bridges, ...)

Records the load variation and deterioration of welded joints at (inaccessible) locations for monitoring the condition of steel structures of bridges.

Monitoring railway neutral temperature

Monitoring railway neutral temperature

System installed on railway rail measuring stress for monitoring of the rail′s neutral temperature to prevent buckling related derailments. The system was powered by solar cell panels, took daily readings, and transferred data via GSM to an Internet server.

Monitoring corrosion in pipe

Monitoring corrosion in pipe

The picture to the left was taken during installation of electrodes on an 8-inch pipe spool for the customer. The whole area covered by the pin matrix is monitored for internal localized corrosion. Several spools were instrumented for monitoring general and localized corrosion. One autonomous system monitored 3 spools, each with 2 sensor interfaces.

Monitoring corrosion under insulation

Monitoring corrosion under insulation

One of the unique features of FEMM is the ability to see the difference between internal and external corrosion or cracks, which makes it feasible for monitoring corrosion on a pipe's outer surface under thermal insulation. As an example, a system can cover several meters of pipe if the monitoring purpose is just to detect if there is any corrosion attacks in the outer surface. Different system solutions can be applied. The simplest system installation comprises just sensors with a sensor interface and a connector located for easy access. Measurement is done by an operator with a portable instrument that is just plugged into the connector. The instrument automatically recognizes the tag and takes measurements as preset in its configuration. On the high system end, an online autonomous system is permanently installed and will regularly send data to the user′s PC.

Challenges related to inspection
  • Thermal insulation prevents visual inspection and early detection of corrosion / degradation

Advantages related to permanently installed sensors
  • Fast installation, approximately 3 minutes per measuring pin pair
  • Installation can be done at inspection time, when the area is temporarily uncovered
  • Based on custom pre-engineered solutions with arrays of pins

Prerequisite: dialog with customer
  • Determine best possible monitoring locations / pipe lengths
  • Choose the best location for the instrument connection point, max 20m from pin array excitation points
  • Integrate use of the monitoring system in the regular maintenance work

Monitoring fatigue in pipe butt weld

Monitoring fatigue in pipe butt weld

Monitoring fatigue development in a pipe′s butt weld and the HAZ

  • For a new riser pipe the first that changes will be residual stresses if the pipe is bent or loaded. These changes are regarded to have a significant effect on the operational life of the pipe. Furthermore, the external loads induce high stress in hot spots which can lead to crack nucleation.
  • FEMM monitors these changes of residual stresses and any permanent changes of the material caused by load variations
    • Detects changes of residual stresses, and variation in depth.
    • Has high sensitivity for detection of changes in the outer surface i.e. microcracks and macrocrack initiation.
    • Detects and locates defects internal in the pipewall e.g. creep.
    • Detects weld root corrosion and cracks and discriminates between cracks and corrosion at inside pipewall.
    • Detects, monitors, and quantifies the growth of internal and external cracks in pipes.

The picture shows a typical pin layout for monitoring a pipe′s buttweld and HAZ. The soldered connection points are protected with a robust epoxy