In the previous edition of EnergyNow, Kiriti Bhattacharya outlined the challenges of managing ageing plant in the energy and process sector. The following is a continuation of the article
Physical plants are subject to age-related degradation mechanisms. Examples of these would be classified as follows; corrosion, fatigue, wear, metallurgical transformations, non-metallic degradation, and subsistence.
However, not all failures due to degradation are age-related, for example stress corrosion cracking, underbead weld cracking, static stress overload, prolonged, runaway temperature excursions etc., can happen at any time due to poor design, low quality construction, inadequate maintenance procedures or operational errors.
The EC&I Failures in Aged Facilities
Many catastrophic failures are linked to failures in the Electrical, Controls and Instrumentation (EC&I) systems. This is more so with failures in safety instrumentation systems (SIS). In the last few decades, a large number of catastrophic incidents in the oil and gas industry have been due to failure of SIS. SIS is designed to provide: emergency shutdowns, trips and alarms, overfills, etc. which act individually or as part of a more complex control system.
The consequence of tank overfills alone, for example, due to malfunctioning or obsolete level Indicators and missing independent alarms over the last three decades amount to 29 fatalities and more than 43 injuries – not counting the complete demolition of the facility by explosion and fire. If one were to include other process equipment (such was the case in Texas City Refinery explosion and fire in 2005: 15 fatalities and more than 100 injured), the numbers would be much higher.
The key to preventing SIS-related incidents are generally identified as:
o Awareness among operators and maintenance staff about the critical significance of the SIS components.
o Regular inspection to ensure that the above mentioned degradation mechanisms, such as corrosion and wear, are not occurring.
o A planned programme of replacing malfunctioning and obsolete instrumentation i.e. EC&I equipment in the plant which may be operating but are no longer supported by spare parts, should be replaced in a phased manner – especially the SIS components.
o Reinforcement training on emergency response to alarms.
Organizational and Human Failures in Ageing Facilities
It may come as a surprise to many that we should concern ourselves with the human and organizational inadequacies when discussing age-related major incidents. The fact is that as one asks the so-called “Four Why’s” – we end up with a failure in human error or judgement – due to lack of frontline competency, procedural errors or organizational dysfunction. The thoroughly investigated Buncefield (UK) and Texas City (USA) massive accidents of 2005, Macondo Blowout (GOM) in 2006 and their reports deal with the hidden management and organizational flaws which resulted in breached safety culture with tragic consequences. The much earlier Piper Alpha explosion which killed 167 persons (1976) was also rooted in human error.
One must understand that with ageing and the increasing probability of failure (POF), the competency of frontline staff competency becomes all the more important as barriers to AI and PS incidents. Some authorities claim that beneath the apparent hardware failure – if one dug down:
“More than 85% incidents in the chemical process industry are due to human error”.
In ageing plants, even as POF increases, it is easy to lose not only competency (ageing plants often have ageing staff – many of whom have retired) but also documentation and knowledge about the history of the plant. More recent efforts to place all the reports, records and drawings from paper to electronic medium – are only effective if the transfer of the documents from paper to electronic databases are complete and through. This is not always the case.
Failure to learn from major accidents which are occurring across the global industry with unrelenting frequencies and repetition of the same handful of causes.
Documentation of maintenance records, inspection reports, updated drawings, etc. are one of the critical factors in managing assets – not knowing enough about the asset or its history can be dangerous and block meaningful risk assessments. The culture of documentation is an important organizational factor in preventing accidents.
Calling in the Consultants? Critical Success Factors for LEAP Reviews
To be blunt, the global industry is filled with expensive external consultancy reports gathering dust on shelves. There are many factors which work for and against such exercises being a successful contribution to the asset owner’s understanding and strategies – or a passive exercise. One senior executive of an energy company was quoted as saying “A consultant may be a pill for your headache, or just another headache” – that depends on how the selection process, engagement, scope definition, support from the facility workers, and implementation of the findings, are managed.
A review of Ageing Plant Management could be guided by the outline guidance in the HSE(UK) documents and similar documents from the Norwegian regulatory authorities. These cover both plants and offshore facilities.
Regulatory Practices
Trinidad is not a country of sub-continental dimensions. It is a small island. We cannot afford to have ecological damages beyond the ability of the island to heal itself. Furthermore, with dwindling hydrocarbon resources and the urgency of developing alternate means of economic survival (diversification) we need to preserve the environmental conditions – such that we do not jeopardize the blessings of our arable lands, our very small waterways, our forests and the very same geographical resources on which any future tourism, agro-industry or fisheries can be based. Some degree of regulations with respect to control of management practices and minimum AI-PS requirements should be enacted by law and enforced. The regulations have to monitor Leading indicators. The UK, Norway and ISO (19902) standards, already exist for managing new and ageing facilities. In the USA similar recommended practices and codes have been long in existence. There are fundamental differences in approach between Europe, Australia and USA. These are discussed by other authors and organizations. It is beyond the scope of this article to discuss these – but suffice it to say, if Trinidad & Tobago were to embark on such a legislative journey, there are many effective templates to follow – which can be adapted to our needs. There is no need to reinvent all of the wheels.
In conclusion, plants which operate beyond their design life are considered to be ageing. The degree of ageing however depends on their documented and actual conditions and not just their arithmetic age. Global data on major incidents suggest that aged assets are involved in a large number of these incidents and probability of failure increases with age because several age related degradation mechanisms are at work. This is often compounded by financial uncertainties of the last few decades leading to the budget squeeze and neglect. Knowledge, understanding, monitoring and control of age related degradation mechanism are critical to support AI-PS. But it also equally important to recognize that human and organizational factors can be critical to the safe operation of plants and ageing assets. To make it all work, Trinidad and Tobago needs to adopt regulatory requirements to preserve the fragile environment and also have specific and focused independent reviews to help chart the current state of facilities and identify immediate risks and deliver a road map for life extension.