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Wrapsense: Hydrocarbon Leakage Detection Technology


TWI partnered with Canadian SME, Direct-C, to assess the performance of their WrapSense technology, which is based on a novel nano-composite coating material capable of detecting the slightest concentration of liquid hydrocarbons in direct contact with it.

The technology uses a sensor that continuously monitors the electrical resistance of a nano-composite, reporting significant changes via an Internet of Things wireless communication box that links to a cloud based management system to send automatic and customisable alerts via email, smartphone app or SMS text when a leak is detected.

The sensors are applied using a flexible yet resistant backing material that can adapt to a wide range of assets, such as pipelines, tanks, engines or aircraft fuel delivery systems.

The leak detection kit, which can cover up to 200 m. of an asset, is a highly sensitive technology for detecting leakages in oil and gas and aerospace applications.


TWI and Wrapsense

TWI provided small and large scale testing for the Wrapsense technology, including mimicking the typical operating temperatures for transportation pipelines in deserts in line with industry standards as well as a full-scale 6-month environmental test.

The testing was designed to validate the capabilities of Wrapsense for industry.


Environmental Testing and Results

Large-scale environmental tests were carried out over 6-months whereby the Wrapsense technology was installed on a ten-metre section of representative steel pipe and subjected to 6-months of winter weather. The pipe, a 300mm OD steel pipe, was fitted with ten 1-metre long sensors and connected to an IoT controller unit to transmit data from the sensors hourly. Meanwhile, a wireless weather station was installed alongside the pipe to correlate conditions including temperature, wind direction, wind speed, rainfall and humidity as well as any environmental damage to the sensors’ readings, to ultimately assess the sensors’ performance.

The objectives of this testing were to:

  • Validate sensor performance under environmental loading
  • Correlate slight sensor disturbances to the relevant weather information

The data from the exposure testing was assessed over a 3-month period from January to March and again in July, after 6 months of installation. No false alarms were registered during the test period and the system remained stable while the weather testing was also completed successfully, demonstrating correlations with temperature and humidity despite May 2021 being the wettest May on record in the UK.

The data received from the ten sensors (Figure 2) during the 6-month testing period was processed in order to normalise the signals and take account of short offline periods when the system was restarted and a 5-day period when the system was disconnected from the cloud service.

The weather station data showed that the maximum temperature recorded was 29°C on 14 June at 13:45 and the minimum was -5°C on 11 February at 2:00. Humidity, rainfall and wind speed were also measured, revealing that wind speed showed no measurable trends across the six-month period.

The signal data from each sensor was divided by month and then auto-correlated across a 15-day lag before being cross correlated with the final humidity and temperature data to demonstrate periodic weather variables. Data was also correlated with the non-periodic variables of rainfall and wind speed. Although this showed some disturbance in the sensor oscillation as a result of heavy rainfall, this soon returned to normal. The WrapSense performance assessment showed that there was no noticeable disruption to functionality for wind speeds of 42 kilometres per hour.


Aviation Hydraulics Testing

TWI also tested the Wrapsense technology to see if it was capable of detecting hydrocarbons in aviation hydraulics. Testing was undertaken on commercially-available hydraulics, including mineral oil-based fluids, synthetic hydrocarbon-based fluids, and phosphate ester-based fluids. A syringe was used for the controlled application of the fluids along with a multimeter, a camera to record values and a spill kit in case of any spillages.

The hydraulics were tested in 2ml and 10ml quantities and the multimeter readings were recorded for 5 minutes, with the electrical resistance for each test obtained from the video recordings every five seconds.

The results showed that the hydraulics tested made the sensor steadily increase in electrical resistance until reaching a saturation level, demonstrating that a full set of alarms could be developed by establishing thresholds of 1% increase in resistance.

Figure 1. (left) Pipe before installation (right) WrapSenseLD installed with Weather Station
Figure 1. (left) Pipe before installation (right) WrapSenseLD installed with Weather Station
Figure 2. Unprocessed WrapSenseLD 6-month readings
Figure 2. Unprocessed WrapSenseLD 6-month readings
Figure 3. Example of hydraulic test. The Wrapsense sensor (white) is laid over the spill blanket and connected to the multimeter using clamps. A reading of 95.74 kOhm is displayed
Figure 3. Example of hydraulic test. The Wrapsense sensor (white) is laid over the spill blanket and connected to the multimeter using clamps. A reading of 95.74 kOhm is displayed

Wrapsense Promotion

The results of the Wrapsense testing were presented at the online 16th Pipeline Technology Conference – PTC 2021 – in March 2021 as part of the ‘Monitoring, Remote Sensing and Leak Detection’ categories of the ‘Operation and Maintenance’ section of the conference. The presentation was made by TWI project leader Rodrigo Rueda and Direct-C’s chief science officer, Dr Stephen Edmondson, alongside the submission of a conference paper that summarised the results.

In addition, Direct-C presented findings and results of the Wrapsense project at an event in Houston in December 2021.



Following the completion of the testing it was possible to draw several conclusions about the Wrapsense technology:

  • WrapSense technology is highly sensitive to liquid hydrocarbons rendering it a low-cost, simple, flexible, reliable technology for oil and gas industry leakage detection
  • The WrapSense polymer nanocomposite coating’s sensitivity was not affected by the environmental variables over a 6-month exposure on a representative UK site
  • WrapSense voltage signal oscillations are periodic on a daily basis
  • WrapSense’s sensor performance appears to mirror relative humidity behaviour regarding phase, signal shape, amplitude and periodicity
  • None of the environmental variables triggered false alarms based on the 6 months of data collection
  • WrapSense sensors were sensitive and operational across temperatures ranging from -5°C to 29°C, humidity of between 25 and 100%, rainfall of up to 0.512mm and winds of up to 42kph


Further Developments

As a result of the findings so far, TWI and Direct-C, alongside Airbus, are now seeking additional public funding via InnovateUK’s Aerospace Technology Institute programme to develop Wrapsense further.


The Wrapsense Project is funded under InnovateUK Project Number 105611