The LWF Blog

Fire Engineering for Healthcare Premises – Fire Engineering – Design Assessment – Part 6

October 26, 2020 12:57 pm

In LWF’s blog series for healthcare professionals, our aim is to give information on best practice of fire safety in hospitals and other healthcare premises. In part 5 of Fire Engineering for Healthcare Premises, LWF looked at the design process for fire engineering. In part 6, we look at how the presented fire safety engineered designs should be assessed.

A fire engineered design should follow the procedures given in BS 7974 – Application of fire safety engineering principles to the design of buildings. Code of practice. and will require the results of a quantified analysis to be compared with the original design criteria, which will have been determined during the qualitative design review.

BS 7974 outlines three methods of assessing a design, as follows:

Comparative criteria – a design can be shown to have a comparable level of fire safety to another method, e.g. Approved Document B of the Building Regulations.
Deterministic criteria – a design shows that a specific set of fire safety conditions have been achieved.
Probabilistic criteria – a design illustrates the probability of an event occurring is shown to be less than the given frequency.

The assessment method and criteria should be agreed with all parties (client, design team, etc.) before the quantitative design stage.

The failure of a design at this stage requires modification of the design and the qualitative design review and qualitative analysis cycle should be repeated until a successful design can be accepted.

In terms of reporting and presentation of a design, it should be presented in such a way that a third party can readily understand the procedures and assumptions outlined within the report.

BS 7974 gives the following elements as essential for inclusion:

• Objectives of the study
• Building Description
• Results of the qualitative design review
• Quantified analysis
• Comparison with acceptance criteria
• Fire safety strategy
• Management requirements
• Conclusions
• References
• Qualifications and experience of the fire safety engineers

Any assumptions used or engineering judgments included should be clearly identified.

It is important that sufficient detail is included so that the quantified analysis can be reviewed by a third party and outlined in sufficient detail to allow clear understanding of the analysis and judgements made. A sensitivity or uncertainty analysis should be performed to estimate the confidence limits for the key output variables which provide the comparison against the acceptance critieria.

In Part 7 of LWF’s blog series, LWF will consider some of the advantages and disadvantages of fire safety engineering before considering fire engineering in the context of healthcare premises. In the meantime, if you have any questions about this blog, or wish to discuss your own project with one of our fire engineers, please contact us.

Lawrence Webster Forrest has been working with their clients for over 25 years to produce innovative and exciting building projects. If you would like further information on how LWF and fire strategies could assist you, please contact LWF on freephone 0800 410 1130.

While care has been taken to ensure that information contained in LWF’s publications is true and correct at the time of publication, changes in circumstances after the time of publication may impact on the accuracy of this information.

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