Utilities company puts handheld gas detection to the test

29 January 2020

Launched in 2005, Wales and West Utilities (WWU) has a regulated gas distribution business which includes approximately 35,000 kilometres of gas pipes across Wales and the south west of England. Covering a sixth of the UK, WWU takes care of 2.5 million gas supply points in homes and businesses in a catchment area with a population of 7.5 million people.

(Click here to view article in digital edition)

WWU used three types of ‘traditional’ detection equipment; all of which involve pumping a sample from the potential leak source across a sensor commonly using catalytic or flame ionisation (FIM/FID) technology to detect flammable gases.

WWU operatives predominantly used these portable devices to scan an area for escaping gas by using a hand-held probe attached to the device. This method of leakage detection dominated the UK market for decades and although effective, had limitations as the operative was unable to visually observe the leak and so could not survey from a safe distance.

The readings are measured in three categories – Parts per Million (ppm), Percentage Gas in Air (% GIA) and Percentage Lower Explosive Limit (% LEL) which (for methane) can be converted to 50,000 PPM = 100% LEL = 5% GIA when in proximity of a leak.

Although this was an effective method of detection, the detection probe needed to be operated at arm’s length which meant an operative had to be close to the leak source. This presented problems when looking for leaks that were out of arms reach, such as those above rivers or train tracks or in locked/enclosed environments. There was also a delay in the device readings.

The challenge

In order to overcome these issues, WWU wanted to observe new technologies in action and understand how they could deliver the best results and support existing methods. The utilities company therefore conducted a trial of different technologies.

The purpose of the trial was for WWU to understand the technologies’ respective capabilities, how the new products performed alongside traditional gas measurement instruments and whether these products could improve efficiencies in surveying (including saving time and increasing safety).

The trial

In January 2017, WWU invited Crowcon Detection Instruments to take part in the trial which showcased three different technologies.

These included:

- Optical gas imaging (OGI) camera technology which gives a visual representation of the leakage point

- Laser detection which uses laser technology to detect methane concentration from a distance

- Infrared technology to detect leaks and potentially reduce bar holing

The seven scenarios

WWU carried out seven scenario surveys to detect leakage and monitor quality. The scope of the trial was to test the three products in different scenarios to gain an understanding of the products strengths, weaknesses and how each performed against the existing devices. This helped WWU identify individual capabilities and how they could achieve ‘increased timesaving and safety’.

The seven test scenarios included:

1. Leakage surveys on >7 Bar pipelines

Leaks on 7 Bar pipelines can be difficult to detect as much of the High-Pressure Network (HP) is buried = 1.1m deep as they are mainly situated in fields and must avoid farmers’ crops.

2. Offtake, Above Ground Installations, District Governors

Before gas becomes odorised, it can be more difficult to detect a leak as operatives cannot rely on their senses to alert themselves to leaks. In addition, there are many small fittings within the station, so surveys can take longer (depending on the size of the station).

3. Multi occupancy buildings

It can be difficult and costly to inspect a pipe that is located externally on multiple story risers due to lack of access. In this instance, scaffolding would have to be erected resulting in increased cost and the need for specialist resources

4. Undertaking surveys of gas storage facilities (pressure vessels)

Large pressure vessels can take a long time to survey with a handheld probe and operatives need to be at close range.

5. Location of gas leaks on made and unmade ground

The challenges in this scenario included minimising the time taken to find leakages, the use of bar holes (which can cause defects and incur costs) and potential damage to other underground utilities such as electric cables. Pipelines commonly run under roads and pavements, resulting in road closures and in this instance, there must be a safety consideration and again additional costs can be incurred. Additionally, the use of hand probes requires the operative to be near potential emissions.

6. Above ground crossings

River or railway line crossings can have pipelines crossing them. The challenge associated with this scenario is that these areas are difficult to access leading to the requirement for specialist equipment and resources.

7. Flight surveys

Flight surveys are currently conducted by helicopter. The operative will survey the local transmission system fortnightly. These flight surveillance activities confirm there is no construction or encroachment on high-pressure pipelines. Also, to utilise drone technologies for ‘difficult to survey’ assets such as those crossing estuaries.

The outcome

The trial results demonstrated there would be benefits to implementing Crowcon’s LaserMethane mini (LMm).

The LMm is a compact handheld detector which specialises in the detection of methane gas at a safe distance (0-100m). Utilising laser technology, methane leaks are located by pointing the laser beam towards the suspected leak, or along the survey line. LMm is aimed at industrial, commercial and research environments or anywhere that methane could be present and in need of locating or monitoring.

An automatic self-check during start-up ensures consistent performance and reliability every time units are turned on. The green laser guide light is highly visible, even under strong sunlight. A Bluetooth option is also available which allows the device to communicate gas levels, time and date to the GasViewer app, which combines these data points with position information from the android smart device.

WWU gained an excellent understanding of the LMm’s capabilities during both pre-trial workshops and in-field training sessions. This provided capability training as well as use-case insight to the team carrying out the trials. The trials themselves provided valuable insight into when and where the LMm’s strengths could be applied within the organisation.