Building safety risk assessment: HAZID methodology

If you’re responsible for the risk assessment of an occupied, high-rise residential building, there are numerous methods to choose from. You do not have to use any particular method to assess building safety risks.

The method you use should be fit for purpose and match the risk profile of your building(s). The scale and depth of assessment needed will depend on the complexity of the building being assessed. The method below is just one option that may be helpful for some buildings.

What is a HAZID (also known as a “what if” study)?

A HAZID is a systematic process of hazard identification. It’s usually performed by a team of people with a range of skills, knowledge, and experience.

In the “what if” approach, team members are encouraged to explore all eventualities. They do this by asking questions such as “what if…” or “how could…” about the item or area under consideration.

In answering the questions, the hazards and how they may develop should be explored. The group can then consider who, and how many, could be affected, along with the control measures in place to prevent and mitigate the occurrence.

Structure of a HAZID team

The team is key to the success of a HAZID. A range of relevant expertise is essential.

For identifying building safety risks, the team should include people with the following expertise and knowledge:

• details of the building being assessed, including its construction and any subsequent refurbishments or modifications
• the resident profile of the building – visit Building information for more details
• fire safety
• structural safety
• the use of other parts of mixed-use buildings, such as retail or offices
• the maintenance regimes for the building
• the safety management system
• an overview of the maintenance regimes and safety management systems of other accountable persons (APs) where a building has more than one AP
• the session facilitator and recorder should have risk assessment and management expertise, with experience of HAZID

Stages of the process

Divide the building into areas for assessment

Do this before the HAZID study or as part of the first session to encourage full ownership of the process.

How the building is divided up will depend on its design and use. Potential options include:

• by control – in buildings with multiple APs
• by blocks or cores – where these have been designed as the building ‘system’
• into floors – grouping identical floors for consideration together
• by function – dwellings or utilities for example
• a combination – having regard to any unusual or unique features

No matter how the building is divided, the study team will need to consider any interactions between functions or areas.

Conducting the HAZID

HAZID sessions should be time-limited to maintain the focus of the team. It’s likely you’ll need several sessions to assess a whole building.

For each session:

• introduce the team and the parts of the building being assessed
• provide a description for the part of the building being assessed, including plans and resident profile. Record areas or limits of responsibility and interactions with other APs
• the facilitator should present a starting point to the team. Facilitators should encourage them to ask questions to identify how building safety risks might occur, how they could develop and what the consequences could be
• the recorder, with the support of the facilitator, should capture the key elements of the discussion, filling in a HAZID record sheet
• recommendations should be recorded for later consideration

The following table provides an example of how to record assessments, but there is no set format.

Questions that might help encourage discussion include: ‘What if...?’, ‘How could...?’ and ‘Is it possible...?’

Once identified, rank or prioritise risks to focus the team’s attention.

Example of how a HAZID could be recorded

Return to: Safety cases and reports: How to assess building safety risks