Functional safety

In the Process Industry (Oil & Gas, oil refining, petrochemicals, chemicals, non-nuclear power generation, but also deposits of combustibles, oil and gas pipelines, distilleries, paper mills, pharmaceutical industries, metals and mines and more generally all the RIR industries) the risk to Life, Health and the Environment of the production process mostly applies to industrial and semi-industrial installations.

The degree of risk of the production process is understood as a combination of the probability (low, moderate, high) of the potential incidental events that can be considered and the level of the potential consequences (minor, serious, extensive, catastrophic).

An incidental event may, in general, have an impact on:

  • consequences on the Life and Health of the staff of the production site; and/or
  • consequences on the Life and Health of the community outside the production site; and/or
  • consequences on the environment (air, soil, surface water, groundwater); and
  • direct material and consequential damage (equipment, machinery, facilities, buildings, reconstructions, loss of production, loss of market share, penalties, fines, legal fees, damages)
  • immaterial damage (loss of image due to the brand’s association with the incidental event, negative media over-exposure).
  • The increase in the level of safety of the production process is a problem that affects social, regulatory, cultural, managerial, relational, productive, operational and maintenance aspects. Also affected are the aspects of management and control of Safety, Quality and Security, and also in the implementing phase including the organisational, design, engineering, and integrative aspects.

The instrumented systems installed in most process industries include:

  • Process Control System;
  • Alarm System;
  • Safety Instrumented System (SIS);
  • F&G System (F&GS);
  • Expert Information System;
  • Emergency Alarm Alert System.

In addition to the essential safety requirements imposed by the European Directives Seveso III and PED in order to reduce the risk of relevant accidents, the SIS and F&GS systems must be in conformity with the requirements of the Standards CEI EN 61508 and CEI EN 61511.

To comply with the CEI EN 61508 Standard, and particularly for the process industry with Standard CEI EN 61511, for each Safety Instrumented System (SIS) and every Fire & Gas system (F&GS) deployed to reduce the risk to Safety and the Environment, there must be a Safety Life Cycle (supported by a functional safety management system) including the following activities :

  • Process Risk Analysis;
  • Allocation of safety functions and safety instrumented functions (SIF);
  • Determination of the objective SIL of the SIF;
  • Preparation of the Safety Requirements Specification (SRS);
  • Design, Engineering, Hardware and Software Integration;
  • System verification (including verification of the actual SIL of the SIFs);
  • FAT (Factory Acceptance Test);
  • Installation and Commissioning;
  • SAT (Site Acceptance Test);
  • Operation, Maintenance, Inspection and Tests;
  • Decommissioning.

The above activities will be planned and conducted according to a Functional Safety Management System (FMS) in compliance with the applicable CEI EN 61508 and CEI EN 61511 Standards.

Similarly, at least one Functional Safety Assessment (FSA), performed by an expert in functional safety, independent of the Design Team, must take place before starting or restarting the installation, i.e. before potential hazards to Safety and to the Environment occur.

A benefit in the actual risk reduction for Safety and Environment, as well as for material damage, performed through SIS and F&GS systems, implemented and conducted in compliance with CEI EN 61508 and CEI EN 61511, is also  an improvement assessment of the Operator Safety Index by the authorities, as well as a reduction in insurance premiums. Spurious failure rate reduction targets of the SIF sent by SRS are an important element in improving the operational reliability of the installation and in reducing the risk associated with spurious failures.

The services that TECSA S.r.l. can offer through its process safety specialists, risk analysts and functional safety experts in this field are:

  • the definition and implementation of a Functional Safety Management System Plan;
  • analysis of Process Risk Assessment (Hazid, HazOp, LOPA, possibly even a full Quantitative Risk Assessment);
  • allocation of safety functions (inclusive of alarms) and of safety instrumented functions (SIF);
  • determination of SIL objective of SIF;
  • processing of the Safety Requirements Specification (SRS);
  • verification of the SIL and Spurious Failure Rate (STR) of the SIFs;
  • Functional Safety Assessment (FSA);


  • assessment of the competence of staff in the field of functional safety;
  • staff training on functional safety;
  • auditing of the functional safety management system and of the functional safety plan.
  • The services that Tecsa S.r.l. can offer to lay the foundations for Alarm Management System design in accordance with the standard ANSI/ISA 18-2 ed EEMUA 191 integrate this framework.

Upon completion of the consultation in the field of functional safety and alarm systems management, Tecsa S.r.l. through its certified technicians can provide specialist assistance in the activities of:

  • basic and detail engineering of supervisory and control systems (DCS, PLC) and of the safety system (ESD);
  • basic and detail engineering of gas and fire detection systems (F&G);
  • the definition of F&G systems positioning criteria policy;
  • F&G systems positioning optimisation (including through 3D simulation: “Fire&Gas Mapping”);
  • preparation or verification of project chrono-programs for automation part;
  • verification of P&IDs through comparison with process specifications (Cause-Effect Matrix/Interlock Description) according to the ISA regulations;
  • preparation of cause-effect matrices;
  • verification of the specifications of safety interlocks;
  • definition of alarms and deadlocks for safety purposes;
  • preparation/verification of signals lists;
  • the study and realisation of architectures for the purchase of automation systems;
  • the preparation/verification of technical specifications for automation for basic engineering, FEED, detailed design;
  • preparation/verification of specifications for the purchase of systems;
  • verification and follow-up of supply specifications developed by vendor/contractors;
  • coordination and supervision of the FAT phases of automation systems;
  • coordination of commissioning, loop check, field tests for acceptance of systems (SAT).

It is useful to remember finally that Legislative Decree no. 105/2015, which is the Italian transposition of the Seveso III Directive provides that for safety interlock systems (typically  ESD type) Facilities Safety Reports should indicate the criteria to determine the construction-related, architectural and functional characteristics and periodic test modes; this also relates to risk analysis conducted and to the identification of critical elements for safety purposes.

TECSA S.r.l. also have n. 5 CFSP certified technicians (Certified Functional Safety Professional), the exida LCC skills certification program. TECSA S.r.l. technicians are the only ones in Italy to have had this certification in the Process Safety area.