We can lead your process hazard analysis assessments (HAZOP, HAZCOM, HAZID) to identify what systems may require SISs and we have extensive experience in a wide field of industry sectors in doing so. We can also lead your SIL determination studies using risk graph, layers of protection analysis (LOPA) or fault tree analysis (FTA) to determine the safety integrity gap that exists. The outcome of these assessments is the definition of the safety integrity level (SIL) of the SIS to be installed. Most of the safety-related systems defined for process industries will be SIL 1 or SIL 2. SIL 3 systems are possible but more difficult to implement and certify in practice. SIL4 systems are highly specialised and are most likely to occur only in nuclear or aircraft situations. We can also provide functional safety assessments for machinery systems (usually high-demand mode).
We can also assist in the design of SISs to determine the configuration required to achieve the specified SIL in terms of the number of I/O devices and how they are implemented in practice. We can assist in the development of functional safety integrity proof testing schedules and associated integrity proof testing procedures.
4 Square aims to provide clients with a range of options in terms of the most suitable type of assessment, SIS design and configuration to enable clients to make informed choices that provide for the most effective long terms solution.
Our engineers are TUV (Rheinland) certified Functional Safety Engineers, having required to prove long term functional safety system experience and passed the required competency assessments.