Building Risk Assessment (BRA)

Building Risk Assessment (BRA) is a tool used to assess the risks to people in occupied buildings within, or located around a facility. This is also sometimes identified as an Occupied Building Risk Assessment (OBRA).

Stages of a BRA

ES apply the three stages of the BRA as required. The three stages are as follows:

Stage 1: Building Screening

In this stage ES will screen the building based on the occupancy and function of the buildings in the scope of workBuildings found to be of low occupancy and low risk function will be eliminated from the assessment at this stage.

Stage 2: Building Hazard Assessment

The consequences identified from the Fire, Explosion and Toxic Gas Dispersion and Explosion analysis is used to determine the effects of the hazardous releases on the buildings in Stage 2. Mitigation and Risk reduction measures are typically identified in this stage if required.

Stage 3: Risk Management Assessment

In instances where further risk reduction measures are not appropriate, a risk management assessment will be conducted to evaluate the risks associated with the building.

Method of Conducting BRA

ES apply a software based approach using DNV PHAST. The consequence models are analysed and the risk is calculated to the various occupied buildings taking account of the average building occupancy.


As a minimum, the following information would be required to conduct the study:

– Existing PHA / HAZOP report

– Consequence Analysis Models

– List and Drawings of occupied buildings

– Building Occupancy figures

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

On award of the study ES will issue a project ToR. This will highlight the assumptions that will be made in the study. It will also include the methodology that will be utilised as well as any further information required from the client.
Upon acceptance of the ToR, ES will conduct the analysis and prepare a BRA report. The report will describe the facility, the scope of work, include a detailed methodology, the identified buildings, the occupancy of each building, the results of each stage of the assessment and any recommendations and identification of further mitigation measures based on the results.

ES have conducted several BRA’s for clients around the world. ES can also conduct them preceding the consequence analysis, as well as other risk analyses such as QRA’s, to quantify the total risk to the facility. For more information, or to discuss your needs for conducting a BRA, please contact us using the form below or email [email protected]