AVK Donkin has introduced new 25mm and 32mm (high capacity) sizes of its flow limitor (sometimes known as an emergency shut-off valve). It has also discontinued some sizes that are no longer ised and is actively considering adding others – all part of its on-going policy to keep the range in step with market requirements. The flow limitor ensures that service supplies to a property remain safe by preventing a gas leak when the pipe is fractured by, for example, accidental mechanical damage or excessive ground movement during second-comer excavations.

Using ingenious technology pioneered by AVK Donkin more than 30 years ago, the flow limitor depends for its operation solely on the pressure of the gas in the service pipe. If the flow exceeds normal limits, it instantly trips and shuts off the supply – and remains closed until repairs are completed and the pressures equalise, the flow limitor automatically resets allowing the gas to flow freely again. Different sizes are necessary because of the different service operating pressures used by different gas utilities.

The UK has a 75 millibar system, for example, whereas Ireland favours a pressure of 4 bar.