African Fusion June 2018

Figure 2: The formation of biofilm and its effects on bacterial growth. Source: A review of current and emergent biofilm control strategies; Manuel Simoes, Lucia C Simoes, Maria J Vieira; LWT – Food Science and Technology 43 (2010) 573–583).

specification route. Having noted this principle, the EN standards for welding have become closer to method speci- fications. Based on (international) standards, administration has become the driver rather than the facilitator. Checklists su- persede appliedengineering skills, while inspectors have replaced supervisors. Consequently, quality tends not to be built in but inspected out. Resource limitations, particularly related to materials coupled to energy use and global warming have encour- aged manufacturers to use significant quantities of scrap as an input material. This has the advantage of reducing the energy (and hence water) requirement, so mitigating against global warming, while recognising the finite limits of materials. Whilst in principle this is not a problem, extensive scrap use requires different, higher, levels of control in terms of collection, grading andmelting. Operational changes Life extension responds to the second aspect cited, the operational circum- stance changes over the past 20 to 30 years. These include: • Globalisation. • The triple bottom line of planet, people, prosperity (e.g. Interna- tional SHE). • Global warming. • Internet/digital design aids/en- hanced communication tools. • Resource limits: The finite limits of engineering material availability; limits of energy sources; and water resource limitations. The strategy of sweating the assets: Life extension What does ‘sweating your assets’ actu-

ally mean? The term came out of the manufacturing industry. Usually it’s thought about in terms of machinery, fixed assets and physical equipment against their criteria of optimal use. Time is a measurement issue here. Consider these asset groups: build- ings/space, machinery and people: • If a fixed asset such as a building, plant, structure or large area of space is owned or rented, sweating this asset implies getting the most out of it. Leveraging fixed asset ca- pacity may be an important issue. Can the asset be usedmore or more effectively? • The next asset class is machinery. Large expensive machinery, equip- ment and plant really need to be used as much as possible to de- crease their unit cost. • The less obvious side of assets is people. Sweating people assets implies maximising the capacity of people. This could involve resizing or retraining. The use of time has been noted above. It also implies working existing assets either beyond design life or under dif- ferent operating conditions. To get themost value fromhigh-val- ue assets such as production facilities, there is a need to find the right balance between maintenance, modernisation and operational activity so as to extend service life, enhance performance and minimise ‘down-time’ over the asset lifecycle. In Johannesburg, one example of sweating the assets is the practice of increasing water pressure even beyond design pressure to facilitate service delivery to an increasing population. Clearly failures are to be expected – the weakest link will break first.

tempers, designations and standards. This makes steel selection more com- plex than one would prefer. The identification of performance equivalence is not always easy, even between manufacturers in the same country quite apart fromglobal imports. Globalisation has also encouraged inter- national standards, generally drawn up from developed countries’ lead. Some are input defined, others performance defined, a difference in philosophy. This challenges theNDTprofessional in terms of interfaces betweenproducts supplied to different standards. It is not always as simple as ‘use the most conservative approach’. Steel designations are important as they help choose correct material for the specific operating circumstances considered. They also help in choosing the correct electrode for the material and welding position. However, in seeking to take advan- tage of the commercial opportunities of globalisation, buyers are faced with the reality of a range of internationally recognised country standard designa- tions, locally recognised local grade/ alloy standard designations, and indi- vidually recognised manufacturer or stockist designations. The reality on site is that apparently similar materials may perform differently. In teaching, we recommend that if a different sup- plier to the one against whose product weld procedures are developed, test the new product against the existing procedures to ensure procedure and process relevance. From a systems control point of view, input (method) specifications are preferred to output (performance) specifications. But South Africa has chosen the EN route, the performance

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June 2018

AFRICAN FUSION