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Major Accident Hazards and Identification of SCE

10 Jan

Major Accident Hazards are defined as any risk events, such as an explosion or emission of hazardous substance, which could lead to multiple fatalities of either death or serious injury or cause damage to connected installations and the stability of the operating system.

At AIE, we believe that properly engineered and specifically tailored assurance programs of work will deliver robust and cost-effective management of Major Accident Hazard risks.  AIE’s risk management process is composed of six discrete steps, which are as follows:

flexible hose integrity assessment

Figure 1: Strategy to manage risks of Major Accident Hazard Facilities

The strategy begins with the identification of Major Accident Hazards, Safety Critical Elements and the development of SCE Performance Standards.  The identification and analysis of Major Accident Hazards aid in the identification of Safety Critical Elements (SCEs) associated with those hazards.

Safety Critical Elements can be defined as such parts where the failure could cause or contribute substantially to a major accident or an item with a purpose of which is to prevent or limit the effect of, a major accident.

The functions that each of the Safety Critical Elements is required to perform are formally defined in Performance Standards, and there is one Performance Standard for each Safety Critical Element. This defines how the element will be required to perform in order to prevent a major accident or, in the event that a major accident occurs, how the element will mitigate the effect of a major accident.

Identification of Safety Critical Components

Safety Critical Components are the constituent parts of Safety Critical Elements; the identification of Safety Critical Components is absolutely vital, primarily because the inventory of components that make up each Safety Critical Element is usually relatively sizeable (e.g. ‘Hydrocarbon Containment’ is a Safety Critical Element, however the number of components that this encompasses is particularly vast, and will likely include the majority of the pressure systems equipment at each given Major Accident Hazard facility).

Safety Critical Components can then be individually tagged for the equipment which form part of each Safety Critical Element and for which contributes directly to the safety requirements of the associated Performance Standard.  Failure of Safety Critical Components may serve to prevent the associated Safety Critical Element from meeting its stated Performance Standard criteria.

Safety Critical Components must be maintained in a fit-for-purpose condition for safe production operations; it logically follows that Safety Critical Elements must therefore be cascaded down to component level in order to be meaningful and properly representative.

The Challenges

Process plants contain large inventories of equipment; Some examples of safety critical categorization include:

  1. Process equipment failures which result in the uncontrolled loss of process containment could lead to a major accident event; such equipment would logically be categorized as safety critical.
  2. An actuated valve that fails to open or close could initiate a series of events that eventually causes a major accident and could therefore also be categorized as safety critical.
  3. Pressure relief valves provide over-pressure protection and thereby would be deemed to be safety critical.
  4. Sensors designed to detect process upsets, the failure of which could lead to a major accident, may be considered safety critical.

The inventory of Safety Critical Components throughout operating plants can be significant if the assessment is not performed with the correct focus, skill and experience. The primary challenge is deciding whether a component item is truly critical to safety and thereafter how the relative importance of the identified Safety Critical Component is then prioritized for on-going maintenance.

The Solution

In AIE, we proactively work in support of our clients in the management of Major Accident Hazard risks; our processes and procedures serve to facilitate the accurate and robust identification of the process plant and equipment that is the most critical to safety.

We have shown repeatedly that some plant safeguards do not actually significantly reduce risk, and therefore are not critical to safe operations when compared with those that provide order-of-magnitude risk reductions.  Our processes serve to limit the inventory of Safety Critical Components to only those which are truly critical to safety.

We do not advocate an ‘include it all’ approach to the categorization process as this would lead to a substantially larger than necessary inventory of Safety Critical Components that would place unnecessary resource demands to inspect, test and maintain. We, however, advocate proper identification of the critical components to safety, this approach is efficient as only the necessary components are regularly inspected, tested and maintained.

AIE focusses its efforts on providing our clients with an enhanced understanding of safety criticality across their facilities; this allows the requisite focus on the proactive management of Safety Critical Components thereby optimizing the process and maximizing its effectiveness.

Maintenance is very clearly an integral part of the process by virtue that failure of Safety Critical Components may likely compromise the associated Safety Critical Element.  Safety Critical Components are therefore required to be captured within the Computerised Maintenance Management System with appropriately defined and scoped Planned Maintenance Routines (PMR).  This serves to provide the requisite level of assurance that the Safety Critical Components will meet their required functionalities, thereby ensuring that each associated Safety Critical Element will continue to meet its stated Performance Standard criteria.

AIE offers the full suite of services; we can provide the necessary support and assistance for all steps in the process (per Figure 1) from the identification of Major Accident Hazards, right through to defining the requisite Planned Maintenance Routines (including the population of these within the Computerized Maintenance Management System) and conducting Performance Assessments.  Within AIE, we tailor our services to suit our clients’ needs and requirements.


AIE possesses the requisite knowledge, experience and track record in this specialised area of operations; we believe that engagement of our services will add value and deliver the following benefits:

  • Robust identification of inventories of Safety Critical Components and the specification of the requisite measures to assure functional reliability whilst in-service.
  • Assurance of the functional reliability of Safety Critical Elements, thereby maximising safety performance and the effectiveness of the measures being deployed in the management of Major Accident Hazard risks.
  • Provision of robust services that are specifically tailored to the needs of our clients.
  • Execution of services by an organisation that is strongly focussed on quality, delivery and client satisfaction.
If you would like to know more about our consultancy services and how our team can support your requirements, please visit our contact us page and we will promptly respond to your inquiry.

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