WET News

9 WET NEWS JULY 2017 Reliability engineering key to resilience • As a result of the 2014 Water Act and Ofwat, water companies are increasingly studying how resilient they might be to stresses and strains, both now and in the future. Reliability engineering is the answer, says Alec Erskine, of MWH. T he 2014 Water Act specifically added a fih clause to the water industry regulator Ofwat's purpose, namely to secure: • "(a) the long-term resilience of [water & sewerage] systems as regards environmental pressures, population growth and changes in consumer behaviour, and (b) that undertakers take steps… to meet, in the long term, the need for the supply of water and the provision of sewerage services to consumers," Following the 2014 Water Act, Ofwat spent time interpreting its implications and in its Towards Resilience document (December 2015), it provided a definition: "Resilience is the ability to cope with, and recover from, disruption, and anticipate trends and variability in order to maintain services for people and protect the natural environment, now and in the future." Given that avoiding "disruption" is pretty much the same as providing reliability, this signals that Ofwat wants to ensure reliability now and in the future. To do this we need the ability to firstly assess our reliability, and secondly predict the future. For the legislators of the Water Act, there was perhaps an assumption that we were on top of reliability now, and they wanted to make sure we were taking a long-term view of it. The truth is that there is still work to do to ensure we are top of our reliability now. In Towards Resilience, Ofwat also makes the point that measuring resilience (or reliability) would be a good idea, and recommends that the water companies consider how best to do this. But guidance on measuring resilience is scarce. There is a relevant British Standard (BS 65000:2014, Guidance on Organisational Resilience) which is mainly focused on the cycle of learning from your mistakes. However, estimating reliability is an area of engineering roughly a century old. Safety Reliability engineering was first used shortly aer the First World War in the context of aeroplane safety. Engineers working on the German V-1 missile programme worked out the basic theory during World War 2. Space research in the 1950s and '60s pushed the theory further forward and the first journal emerged in 1963 (Institute of Electrical and Electronics Engineers Transactions). In 1965 Richard Barlow and Frank Proschan wrote the seminal text entitled Mathematical Theory of Reliability. Oil and gas and the nuclear industry employ the techniques of reliability routinely but in our industry, it is rarely spotted, with the notable exceptions of its close relative the HAZOP Workshop, and the odd Safety Integrity Level (SIL) assessment for safety systems. So what is reliability engineering? Reliability engineering is a whole collection of techniques intended to help us determine whether an item or a system is going to function or not. It can split between two approaches: the physical and the actuarial. The physical approach is to do with variation in "load" – if we understand the variation in load and we understand the load at which the system fails, There is still work to do to ensure the industry is top of its reliability now. Courtesy: MWH, now part of Stantec ONSITE RESiLiEnCE Reliability engineering was first used after the First World War in the context of aeroplane safety

• Cover