Design and Safety Systems of processes Based on standards vs Based on risk

First of all, the Major Hazard Facilities or “Major Hazard Facilities” will be defined, which are facilities that store and/or process substances characterized as dangerous (flammable, toxic, harmful, etc.) with inventories that exceed a certain limit in the case of Europe defined by the Seveso Directive. Additionally, in this type of facilities, in addition to processing hazardous substances in large quantities, this is generally done with high pressures and temperatures, which makes greater their potential danger.

Historically, the design of process plants and industrial facilities has been based in compliance with a series of international reference standards such as ISO, API, ISA, etc. or others specific to each industrial sector, all complemented by the specifications of the large operators, which include their own experiences in the design and operation of industrial plants. All this design based on standards and specifications, over time, must also comply with increasingly demanding legal regulations in terms of Safety, Health and the Environment, in many cases derived from major accidents. For example, Seveso originated the regulations that frame the management of Major Risk facilities in Europe, it obligates Process and Industrial Plant Operators to demonstrate and justify compliance with the regulations and that the risk levels caused by the facility for its environmental and social environment are acceptable.

Therefore, compliance with globally recognized standards in the design of process and industrial plants, for some years has not been enough condition for both the operator itself and the competent administration to approve its installation. It must be demonstrated and justified through the identification of the hazards and risks associated with the installation, their quantification and their evaluation against risk criteria provided by the administration, compliance and evidence thereof through the description of all the facility’s protection barriers (from the process design itself, through control and safety systems to passive protection measures and emergency plans).

The concept of “Risk-Based Process Safety” has been developed by the Center for Chemical Process Safety (CCPS) and assumes that all hazards and risks are not equal and, since resources are always limited, the following activities must be carried out , to optimize resources and increase the efficiency of the plant’s process safety systems:

• Commit to Process Safety: implement a culture that has compliance standards, training and performance evaluation.
• Know in detail the dangers and risks of our installation through the proper development of all the necessary safety documentation, the generation of methodologies for the identification and evaluation of risks and their implementation throughout the life cycle of the installations. Among the methodologies to be applied, the HAZID, HAZOP, LOPA, QRA, BOWTIE or SIL Determination studies stand out. Each installation will apply the one or those that best adhere to its operation and moment of the life cycle in which it is located.
• Risk management through the development and application of operational procedures, maintenance, emergency, etc., and highlighting among them, the proper implementation of a Change Management system for both the process and procedural and personnel.
• Implement and maintain the training, a system of learning from experience that includes, among other things, accident investigation procedures, monitoring of “Lead” and “Lag” indicators of Process Safety, audits and process improvement.

Therefore, the focus of implementing a Process Safety System based on risk from the design of a facility is a much more complete system, with a life cycle vision and that optimizes the efficiency of investments in capital and in operations for the following:

• From the conceptual phase of a facility, the focus is placed on the most dangerous systems/operations that the facility will have.
• The design based on compliance with regulations, standards and safety specifications is complemented/validated through its evaluation in the engineering project phase through risk studies (HAZOP, LOPA, QRA, etc.) which allows, if necessary, to take the necessary actions at a time whose impact on the Project is still acceptable to correct them.
• Change management is enabled, which ensures that in the event of any change that occurs during the life cycle of an installation, its impact on safety has been evaluated, the change has been approved (or not) and the necessary measures have been taken.
• Knowledge of the safety risks of the installation is promoted from the beginning of its conception, which, involving future operators from that initial phase of the Project, allows the risks to be known and therefore the operation of a safer plant. In the same way, it allows lessons learned/experiences to be “captured” in risk studies by participating personnel both from the future operating team and from engineering and specialized consultants who enrich the studies with experiences of potential incidents and analysis of other facilities.
• Allows efforts to be focused on providing personal and technical resources to the most dangerous areas of the facilities without neglecting the rest, but without proceeding with designs and overloads of security systems in the area, which in addition to additional investment leads to then a significant maintenance cost during the life of the installation. There are studies to identify critical safety systems and provide them with performance standards to ensure that from their design and supply phase and throughout their operational life they meet the expected level of performance in the event of a serious accident.

Therefore, process safety systems have evolved from a focus on compliance with standards and regulations, through continuous improvement systems, to systems based on risk management, covering a vision of the installation’s life cycle. In the following graph it can be seen that risk identification and assessment is carried out in all phases of the cycle and must be part of the Process Safety policies and systems that support the Safety culture.

Security Life Cycle

Reference:

“Guidelines for Risk Based Process Safety” CCPS.

Author: Manuel S. Jadraque Marfil