This post gives some brief information about HAZOP (Hazard and operability study), SAFOP (Electrical Safety and Operability Study) & SIL (Safety Integrity Level Assessment).
HAZOP (Hazard and operability study)
A hazard and operability study (HAZOP) is an organized and systematic examination of a complex planned or existing process or operation in order to identify and evaluate problems that may represent risks to personnel or equipment.
The purpose of performing a HAZOP is to assessment of the design to pick up design and engineering issues. The technique is based on breaking the overall complex design of the process into a number of simpler sections called ‘nodes’ which are then individually reviewed.
HAZOP is carried out by all multi-disciplinary experienced team with series of meetings based on nodes. Potential hazards as well as operability issues to be identified by participants based on each participants imagination, during HAZOP meeting and this technique is qualitative.
This is organized review process by using standard guide words for each nodes. Every discussion whether it is valid or not valid, is taken positively and with frank debate for perception of good judgement.
The main input for any HAZOP Study is approved for HAZOP PEFS or P&ID, in line with applicable international standards or company procedures. The HAZOP is carried out after the HAZID review and Design review when at least engineering design has sufficiently done with some more detail.
SAFOP (Electrical Safety and Operability Study)
Identification of potential hazards to personnel in the vicinity of electrical systems. Critical assessment of electrical network and plant design for limitation and their effects on both operability and security of the overall system. Analysis of operator actions to determine areas of potential operator error. Making recommendations to eliminate or reduce risks.
SIL (Safety Integrity Level Assessment)
Safety integrity level (SIL) is defined as a relative level of risk-reduction provided by a safety function, or to specify a target level of risk reduction. In simple terms, SIL is a measurement of performance required for a safety instrumented function (SIF).
The requirements for a given SIL are not consistent among all of the functional safety standards. In the functional safety standards based on the IEC 61508 standard, four SILs are defined, with SIL 4 the most dependable and SIL 1 the least. A SIL is determined based on a number of quantitative factors in combination with qualitative factors such as development process and safety life cycle management
The Safety Integrity Level (SIL) assessment is the Instrumented Protective Functions (IPF) classification process and incorporates a Layers of Protection Analysis (LOPA) to demonstrate that risk is reduced ALARP. The SIL determines the Safety Instrumented System (SIS) design and planned maintenance frequencies.