Process Safety - HAZOP, QRA, HAC, SIL, JHA, PHA

Hazardous Area Classification is a method of analyzing and classifying the environment where explosive Gas, Vapour atmosphere may occur so as to facilitate the proper selection and installation of apparatus to be used safely in that environment, taking into account gas, vapors, chemicals groups and temperature classes.

Quantitative Risk Assessment (QRA) is defined as ‘The quantitative evaluation of the likelihood of undesired events and the likelihood of harm or damage being caused, together with the value judgments made concerning the significance of the results’.

Hazard and Operability (“HAZOP”) study is a systematic evaluation of a planned and existing process or operation in order to identify and assess problems that may represent a risk to personnel or equipment.

HAZOP is a systematic team-based Process Hazard Analysis (PHA) technique. It is used to identify & analyze the consequences & risks arising from possible deviations from design and operational intent of a process. HAZOP can be used for continuous or batch processes. Also, it can be used during the design stages of a new process or project, for major process modifications and for periodic review of existing operations. can be adopted to evaluate written procedures.

Even though hazard identification is the key focus, operability problems should be identified to understand if they have the possibility to result in process hazards. HAZOP is applied to identify:

• Hazards – the ways in which a system can fail leading to injury or damage
• Operability – the ways in which a system can fail to perform its intended function

HAZOP identifies deviations from design intent by applying guide words, such as More, Less, No, As Well As, Part-Of to process parameter such as flow, temperature, pressure, quantity, addition, reaction, etc. within established sections of the process, called nodes. The HAZOP team then brainstorms causes of each deviation within each node and identify the possible consequences and available effective safeguards that protect against them. Risk Ranking is carried out in terms of severity and frequency for a scenario and the scope for further improvements to reduce risk are identified.  

HAZOP requires a review of all the available Process Safety Information (PSI) which should include:

• Process description and Operating Procedures
• Process flow diagram (PFD)
• Piping and instrumentation drawings (P&IDs)
• Cause & Effect Diagrams and Control Philosophy
• Hazardous materials and their properties including combustibility, flammability, explosivity, reactivity, self-heating, toxicity, electrostatic properties
• Equipment design details (including Pressure relief systems specifications)

At AmbiRisk, our experts provide objective facilitation of a HAZOP study, ensuring that brainstorming meetings are well structured and performed systematically, encouraging participation & creative solutions.