The Challenge

Unlike liquid petroleum pipelines, the majority of gas pipelines cannot be checked for defects using inline inspection ( ILI) methods. Various direct assessment techniques are in use; however, the most effective – and the most onerous – is excavation followed by detailed ultrasonic or equivalent non-destructive examination (NDE). It is generally assumed that, once a pipeline has been examined in this way and then repaired, further degradation at the site does not occur. Although this may be true for the precise area that is repaired, the conditions that produced the degradation initially – soil pH, ground water, among others – continue to be present. Areas of the pipeline immediately adjacent to the repair are likely at the same risk of degradation as before the repair. Pipeline operators could have significantly higher confidence in the continued integrity of the pipeline if the region including the repaired area could be monitored following backfilling.

Is there a cost-effective sensor system that can operate in a remote environment and monitor the integrity of, for example, coating repairs? Is this system safe to use in a potentially flammable environment where leaks can occur? Is this system reliable and will the buried sensors function in the environment? Can the sensor system be accessed by periodic on-site measurements, or in a continuous mode at remote locations?

The Solution

FOX-TEK offers an engineered solution to improve direct assessment—FT fiber optic sensors. FT sensors are installed on degraded pipelines, on the repaired area and adjacent to the repair where problems are likely to occur. Since the pipeline is already exposed for detailed examination, the added cost of installing the sensors is minimal. Sensor configurations are available for monitoring areas 100 m or more in length, or for localized areas as small as 8 cm diameter. FOX-TEK software determines the wall thinning rate from sensor data collected with an FTI-series monitor. Real-time continuous monitoring or on-site periodic monitoring are options available to the user. The FOX-TEK software is configurable with pre-set wall thickness threshold values that, when reached, activate an e-mail alarm signal that is sent to various personnel. Information on the specifications for the FT sensors and monitors can be found in the “Systems and Services” section of this site.

Summary of Benefits

	Operations	Longer, safer operational lifetime of pipelines Continuous tracking of pipeline health Establish effectiveness of inhibitors
	Cost Savings	Maintenance schedules based on real-time operational status of pipe Reduced risk of pipe failure and clean-up costs
	Safety	Alarm signals when pipe wall thickness has reached threshold value Reduced risk of premature pipe failure Sensors are non-electrical and immune to EMI
	Environment	Reduced risk of contamination of environment by product spills

Configurations:

• Continuous Systems
• Field Inspection Systems
• Remote Systems

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