Process Hazards Analysis


PHA (Process Hazards Analysis) studies have the goal of identifying, evaluating and understanding the hazards associated with production processes on the basis of deviations of physicochemical parameters that characterize the process in question. They also have the goal of assessing the adequacy of the provided protection systems in order to detect, prevent and mitigate the accident scenarios resulting from the identified hazards and, if situations of unacceptable residual risk persist, it is intended to provide directions for additional technical and/or procedural protection measures. PHA studies are based on a qualitative risk assessment for Safety, Environment, Business/Asset and Reputation aspects, through the use of Risk Matrices.

PHA studies are developed through Workshops (held in person or by video-conference) featuring a facilitator (Chairman), a Scribe and a team of technical specialists competent for the process in question.


The services offered by RAMS&E within the PHA Analysis are the following:

  • HAZOP (HAZard & OPerability),
  • HAZard/ENVironmental IDentification (HAZID/ENVID),
  • HAZID with Check Lists,
  • What-if Analysis,
  • SIMultaneous OPerations (SIMOPS).

The services delivered include: conducting activities for the Workshops, preparatory activities prior to carrying out the analyzes and reporting and support activities for the follow-up of the aforementioned studies.


PHA (Process Hazard Analysis) analysis including semi-quantitative Risk Assessment and assessments related to the requirements of Functional safety for the Instrumented Safety Functions of petrochemical plants – Multinational company in the petrochemical sector, factory in the industrial area of Rotterdam harbor.



The goal of the project was to carry out a PHA study, using HAZOP technique, for production and storage plants of chemicals deriving from the processing of petroleum products, in order to identify potential dangers and assess and minimize the risks for plant personnel and the environment, and ensure correct operation of the plants during the entire life cycle. The periodic conduct of the PHA study for the plants in operation has the function of ensuring correct management of the plants for good production efficiency, safety of production processes and system reliability.



To support the customer’s needs mentioned above, a HAZOP study including a semi-quantitative Risk Assessment was developed for the assessment of the frequency of accident scenarios and for the definition of severity levels for the accident scenarios regarding Safety, Environment and Plant assets.

The peculiarities of the semi-quantitative HAZOP study were the following:

  • Determination of the frequency of the initiating event for the accident scenario according to the type of cause (operational error, malfunction of a control loop, failure of a compressor or pump)
  • Assessment of the accident scenario based on the hazardous characteristics of the substance (flammable and/or toxic) and on the quantity released in the event of a loss of containment from equipment and/or piping
  • Identification and reliability characterization of protection systems (Independent Protection Layer) with LOPA approach
  • Multiple Risk assessment for Safety, Environment and Asset/Business aspects:
    • Risk Not Mitigated: assessed without considering existing safeguards;
    • Current Risk: assessed considering the safeguards in place;
    • Mitigated/Future Risk: assessed considering the recommendations that emerged during HAZOP.

PHA study provided the analysis of the technical documentation of the production plants in question (P&IDs, plant plans, Material Safety Data Sheets, description of the control and safety logics, operating procedures), updated considering the system and procedural changes that occurred in the years following installation.

To complete the HAZOP study, a Register of Critical Elements for Safety and the Environment was drawn up, to support operational management and definition of testing and maintenance plans for these elements.

Ask for advice!

Phone: +39 011 2258621