Understanding Fibre Optics and Its Applications in Pipeline Maintenance


Fibre optic cables are capable of sending information down plastic or glass pipes coded in a beam of light. Fibre optics technology is used extensively these days in computer networks, broadcasting, medicine, military applications, and pipeline maintenance.  

Fibre-optic cables comprise of incredibly thin strands of plastic or glass known as optical fibres. Each of these cables may contain just a few to several hundred strands. The thickness of these strands is less than a tenth of human hair. However, making use of optical technology, it is possible to carry loads of information between two places. 

Light signals are carried through optical fibres in the form of modes, which refers to the path followed by a light beam down the fibre. One of the modes is travelling straight down the middle. Another one follows a shallow angle while bouncing down the fibre. Modes may also involve bouncing down at somewhat steep angles. Fibre-optic cables may be single as well as multi mode.

Fibre Optic Monitoring of Pipes

Water authorities all over the world now utilise fibre optics technology to monitor vast stretches of underground pipeline networks from a remote location.  This helps them quickly pinpoint faults, assess how critical these faults are, and address them accordingly.  These monitoring systems can provide 24/7 monitoring and reduces unnecessary pipe maintenance by accurate and prompt fault and deterioration location.  This, in turn, ensures long service life of water conveying pipelines.  

Once a fault is identified, fibre optic systems can evaluate these faults remotely with the help of a data-acquisition system.  These systems can sense three variables, vibrations, stress and strain, and temperature.  When laser beams are sent to the optical fibre, the signals coming back are measured by it.  These signals are interpreted by analysing the spectrum, providing operators a clear indication about the type, location, and dimensions of the fault. Continuous remote monitoring using fibre optics means that onsite inspection is no longer a necessity. 

In addition to carrying water, pipelines are also used by different industries to carry oil and gas that are often dangerous for the environment as well as people.  Leakage of oil pipes can lead to serious contamination of the soil and groundwater. On the other hand, gas leaks may result in serious explosions. Often times, detection of leakage along these pipelines are extremely difficult. Moreover, visual inspections are not even possible, in case of buried pipelines. In these cases, a drop of the pressure indicates the presence of a leak. 

In the recent years, optical fibres have emerged as an effective aid to distributed temperature monitoring for leakages along pipelines. This monitoring and detection technique is based around the fact that local temperature anomalies are created in the vicinity of the pipeline by the formation of leakages. Depending on the substance transported, this may lead to a localised cooling or warming.  This is why pipeline temperature monitoring is an excellent way to detect leakages.

Optical fibres are excellent for pipeline monitoring over long distances because of their threadlike geometry and low propagation loss characteristics. Distributed temperature sensing techniques using fibre optics have now opened up new possibilities in pipeline rehabilitation and maintenance. 

At Austeck, we offer the most advanced range of fibre optics products for pipeline inspection and rehabilitation in Australia. Please contact us to find out more about our products.