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OIL & GAS QUICK AND ACCURATE LEAK DETECTION
Suspected gas leaks are among the biggest risks facing distribution network operators. For first responders, it’s imperative they have access to robust gas detection technology that can pinpoint the location accurately and safely. Here, Dean Kavanagh, Managing Director at QED Environmental Systems, explains more...
T
here are over 280,000km of local gas distribution pipework1
in the UK. This is an
enormous amount of pipework that needs monitoring, repairing and maintaining in order to deliver safe and efficient distribution. While major leaks are thankfully few and far between, even small leaks have the potential to spell disaster.
A large amount of the UK’s gas pipeline is made from cast iron, which is subject to corrosion, water infiltration and is in need of regular repair. This poses two major problems for Distribution Network Operators (DNOs). Firstly, the overall condition of the UK’s distribution network is resulting in the loss of enough gas to heat over 700,000 homes a year, with an assumed leak rate of 1.2%2
.
To date, there is no penalty for DNOs regarding methane leakage, with the primary motivation for maintenance being to keep disruption to a minimum. However, from an environmental perspective, reducing methane emissions remains a major focus on the global stage, with more than 40 countries unveiling methane reduction plans at COP 27. As such, DNOs should be doing all they can to curb this as much as possible. Moreover, given the domestic and commercial energy crisis which has dominated the news agenda over the past 12 months, minimising leakage could potentially offset some of the supply pressures that have been felt so keenly.
The second, and most important problem posed by aging infrastructure is the risk to life. Explosions and fires caused by gas leaks rose
40 APRIL 2023 | PROCESS & CONTROL
The Huberg METREX, which is certified to BS EN 60079-29, has a response time of less than eight seconds
by 46% between 2017 and 2020, causing at least 12 deaths in the past five years3
. While not all
instances can be attributable to the condition of pipe networks, the figures serve as a stark reminder of the importance of identifying and dealing with gas leaks.
Whether a suspected leak is reported, or detected as part of routine maintenance, the role of the first responder cannot be overstated. Taking accurate data is critical to effective pre- localisation, localisation and classification of leaks in natural gas distribution networks, and formulating a proportional response. Given how dangerous a potential gas leak can be, any mobile gas detection units should be certified to BS EN 60079-29 – the standard which sets out the requirements for the construction, testing and performance of flammable gas detection equipment intended for use in explosive atmospheres. Doing so will ensure that the product in question has been rigorously tested across a number of different operational parameters and subsequently guarantees the integrity of the data in hazardous (or potentially hazardous) locations. Traditionally, the predominant instrument for natural gas leak detection has often been portable hand-held flame ionisation detectors (FIDs). However, they pose a number of challenges for DNOs, namely slow response times and failure to always isolate methane from other gases.
For example, the average person can walk circa 26-27m in 20 seconds, which is the reaction time of the FID. This means that the first responder can be passed the area of the leak
when the FID alarms. They then have to double back and narrow down exactly where the leak is coming from. All of this takes time and has a cost. Likewise, in urban areas the current technology has a tendency to pick up other hydrocarbon gases often emitted from vehicles, adding time and cost to the job. Conversely, semi-conductor-based technology, such as the Huberg METREX – which is also certified to BS EN 60079-29 – has a response time of less than eight seconds. This is critical as, in partnership with secondary detection technology such as the Huberg Laser One, it can facilitate a much faster and more accurate identification of any gas leak. Not only will this ensure that the leak can be dealt with as soon as possible, including all necessary precautionary safety steps, but it can limit any subsequent excavation work to the immediate area to help keep overall remedial OpEx to a minimum. Moreover, portable gas analysers which use semi- conductor technology do not require the operator to carry heavy fuel calibration gas cylinders, unlike those using FIDs. Finally, modern gas detection units now often feature both integrated GPS and Bluetooth capability, which when coupled with extended data capture capabilities, provide a shift away from the manual recording process typically associated with FID systems. Not only does this streamline the detecting and recording process, but it removes the risk of human error and provides a clear and
obvious data trail for audit purposes. 1
https://environment-
analyst.com/uk/105638/hydrogen-heating-pilo
t-in-scotland-proposed 2
k-ahead-of-cop26 3
https://www.bloomberg.com/news/articles/20 21-10-22/giant-methane-leaks-detected-in-u-
https://www.theguardian.com/business/2022/j un/27/at-least-12-people-died-in-domestic- gas-explosions-in-britain-since-2017
QED Environmental Systems
www.qedenv.com/products/new-metrex
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