PHA, HAZID and HAZOP Studies

FSES can provide Process Hazard Analysis (PHA) and HAZard and OPerability (HAZOP) study chairpersons. Our expert PHA facilitators hold certification in conducing HAZOP, HAZAN and CHAZOP.

Hazard and Operability (HAZOP) Studies & Process Hazard Assessments (PHA)


Process Hazard Assessment (PHA) is a set of organised and systematic assessments of the potential hazards associated with an industrial process. A PHA can provides information intended to assist in making decisions for improving safety and reducing the consequences of unwanted or unplanned releases of hazardous chemicals. A PHA is often directed toward analysing potential causes and consequences of undesirable events and it focuses on equipment, instrumentation, utilities, human actions, and external factors that might impact the process.

PHA methods are qualitative in nature. The selection of a methodology to use depends on a number of factors, including the complexity of the process, the length of time a process has been in operation and if a PHA has been conducted on the process before, and if the process is unique, or industrially common.


Methods of Process Hazard Assessment


There are a variety of methodologies that can be used to conduct a PHA, including but not limited to:

– Checklist;

– What if?;

– Hazard and Operability Study (HAZOP);

– Hazard Identification (HAZID);

– Failure Mode and Effects Analysis (FMEA).


FSES Typical HAZOP Workflow


The following workflow provides a typical guide on structuring the hazard assessment or quantitative risk assessment workshop.






What inputs are required by FSES in order to conduct the PHA Study?

As a minimum the following information would be required in order to conduct the workshop:

– Existing PHA / HAZOP report (if available)

– P&ID’s

– Cause and Effects Diagrams

– Facilities Design

– Operating Data and Procedures

– Maintenance Data and Procedures

– Interlock List

– Equipment Data Sheet

Based on the project requirements, additional information may be required, which will be highlighted within the Terms of Reference (ToR).

Who is required to attend the PHA Workshop?

As a minimum the following personnel would be required in order to conduct the workshop:

– Process Engineer

– Controls and Instrumentation Engineer

– Process Safety Engineer

– Maintenance representative

– Operations representative

Based on the project requirements, additional personnel may be required to attend the workshop, which will be highlighted within the ToR.

What is the expected output of the PHA Study?

On award of the study FSES will issue a project ToR, which will highlight the assumptions that shall be made in the study, along with the workshop details, methodology and data sources that will be utilised as well as any further information required from the client.

Upon acceptance of the ToR, FSES will facilitate the PHA study through a workshop providing the facilitator and scribe. Once the workshop has been conducted FSES will prepare a PHA report describing the facility, the scope of work, a detailed methodology, the PHA worksheets, a summary of the PHA actions and any recommendations based on the discussions during the workshop. FSES highly recommend that following on from the PHA study, a SIL Determination analysis is conducted in order to determine the SIL requirements for the SIF’s identified during the workshop.




FSES are a globally renowned facilitators of Process Hazard Assessment studies having facilitated 100’s of hours of PHA studies, with a team of TUV Rheinland certified Functional Safety Engineers available for facilitation. FSES can facilitate PHA studies using various methodologies such as HAZOP’s, HAZID’s, What If’s etc. For more information, or to discuss your needs for conducting a PHA study, please contact us using the form below or email [email protected] .

Our Services at FSES

Compliance to the international Standards such as IEC 61508 and IEC 61511 are imperative to meeting the Functional Safety requirements for many processes and have formed part of the quality management systems of many companies. Provision of Functional Safety Services in line with the Phases and Activities detailed in the Safety Life-cycle is an area in which our consultants are able to demonstrated experience and expertise.

Learn more about our services

PHA, HAZID and HAZOP Studies

FSES can provide Process Hazard Analysis (PHA) and HAZard and OPerability (HAZOP) study chairpersons. Our expert PHA facilitators hold certification in conducing HAZOP, HAZAN and CHAZOP.

Functional Safety Training

FSES provide various Functional Training services for all of specific parts of IEC 61508 and its sector derivatives

Consequence Modelling

Discharge and Dispersion is often required to evaluate the consequence of identified hazardous events.

Design Engineering

Functional safety activities are most effective by integration into a well-established and proven quality management system.

Building Risk Assessment

Building Risk Assessment (BRA) is a tool used to assess the risks to people in occupied buildings in the facility.

Escape, Evacuation and Rescue Analysis

Escape, Evacuation and Rescue Analysis ensures that the design of a facility is such that the risk to personnel is kept to within the ALARP region.

Functional Safety Assessment

Independent Management of Functional Safety Assessments, Audits & Support.

Functional Safety Lifecycle and Management

Functional Safety Lifecycle and Management is a key requirement demonstrating how Functional Safety is to be implemented and achieved.

Human Factors

Human factor assessment is a key area in identifying potential hazards which may be instigated by human errors.

Legacy Systems

Legacy Systems Review and Compliance.

Prior Use

Prior Use Assessment.

Proof Testing Procedures

Proof Testing is one of the main requirements to ensure that Functional Safety is maintained throughout the operational phase.

Operation and Maintenance

FSES can carry out review studies and provide consultancy to ensure Functional Safety requirements are maintained during Operation and Maintenance.

Quantitative Risk Assessment

Quantitative of Risk in terms of IRPA, PLL and graphical demonstrations such as FN Plots.

Reliability, Availability and Maintainability Study (RAMS)

Reliability, Availability and Maintainability Study (RAMS) is used as a decision making tool to increase the availability of the system, and thus increase the overall profit as well as reducing the life cycle costs.

Safety Requirements Specification

The Safety Requirements Specification (SRS) is a core document, which is used as the main reference to be followed by designers, installers, and operators of a Safety Instrumented Function (SIF).

SIL Determination

FSES are able to us various methods in identifying SIL targets; qualitatively by Risk Graphs, semi-quantitatively by Layers of Protection Analysis (LOPA) or fully quantitatively by Fault Tree Analysis (FTA).

SIL Verification

Calculation of Random Hardware Reliability and Architectural Assessments for Safety Instrumented Functions (SIFs)

SIS Conceptual Design

Safety Instrumented System (SIS) Conceptual Design