Much of the UK’s original 250,000 kilometre-long gas pipeline network consists of iron pipes and “ is over a hundred years old,” states Jonathan Callighan, Construction and Procurement Director of Cadent Gas, the largest regional gas distributor in the country. Pipeline age, risk and safety lie at the heart of the current gas mains replacement programme initiated by Britain’s national safety regulator, The Health and Safety Executive (HSE).
Under the HSE’s leadership, the Iron Mains Risk Reduction Programme (IMRRP) addresses the potential risk of failure of ‘at risk’ iron gas mains and potential consequences, such as injuries, fatalities and damage to buildings. A significant benefit of the decommissioning of all ‘at risk’ iron pipes, identified from a risk prioritisation model, is to reduce the possibility of gas explosions by a significant 60 percent on pre-2005 levels.
Britain has now reached the mid-point of its gas-mains replacement programme. Started in 2002, the replacement work is progressing at the rate of about 3,500 km a year and will be paid for by 23 million gas customers through their bills.
The gas mains stakeholders
Around 80 percent of British homes are connected to the UK’s gas pipeline network which has two components. The national transmission network, owned and operated by the National Grid (see Figure 1), transmits gas throughout the country to the eight regional Gas Distribution Networks (GDN) which supply customers directly. The regional distributors are natural monopolies and are regulated at national level by the Office of the Gas and Electricity Markets (Ofgem).
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