SIL determines risk reduction needed to prevent industrial accidents

TEMA, pioneer consultancy in terms of safety and environment, master this basic tool which ensures optimum operation in industrial plants

silCompanies developing industrial activities that might lead to human, environmental or facility risks use safety systems to look after the correct operation of the plant and contribute to accident prevention. One of the most effective analyses is the Safety Integrity Level (SIL), which determines necessary measures that must be applied to avoid potential damage.

SIL analyses the functionality of each of the automatized protection mechanisms in the industrial facility. These mechanisms can be automatic valves, sensors, relays or other instruments with the ability to detect unusual operating conditions of the equipment and process, such as flow, temperature and pressure. SIL analysis is applied to each of the instruments used to avoid system failures. Safety Integrity Level establish the requirements and recommendations needed for proper operation. For instance, the periodicity of valves maintenance, software configuration… All of this is done in accordance with the IEC61511 international standard.

In addition, SIL classify the safety requirement level for each instrument or safety function in the facility. For this purpose, it assesses the potential harm to people, the environment and the assets of the company. SIL 1 indicate that only a low risk reduction is needed, whereas SIL 3 could take place in complex processes of large industrial facilities such as oil refineries, electrical generators or petrochemical plants which demand a rigorous and sophisticated safety system. According to María Almazán, from the commercial and technical department, “Along the way we have detected very few SIL 3s, the most common situation is working with SIL 1s or SIL 2s”.

Prior to SIL analysis, it is necessary to use another essential methodology to identify safety elements required in the facility. This is the HAZOP (Hazard and Operability technique which identifies the safety instruments required and those who need a SIL analysis. Safety and Environmental consultancy TEMA has extensive experience in the use of this basic safety methodologies risk assessment and accident prevention in industrial plants.