The LWF Blog

Fire Safety Engineering for Design – Quantitative Risk Assessment – Part 65

January 31, 2022 11:32 am

LWF’s Fire Safety Engineering blog series is written for Architects, building designers and others in the construction industry to highlight and promote discussion on all topics around fire engineering. In part 64, LWF discussed quantitative risk assessment (QRA) and cost-benefit analysis (CBA). In part 65, we look at how the CBA process may be used.

When considering the implementation of measures to reduce risk from fire to business, property or assets, a cost-benefit analysis (CBA) may be used, however, it may be possible to simply quantify the negative benefit of the potential loss.

If a CBA is undertaken, the input data should be agreed with all stakeholders, along with criteria for residual tolerable risk prior to commencement.

A CBA in isolation cannot constitute an ALARP (as low as reasonably practicable), which is a case where the risk is weighed against the time, trouble and cost of controlling it.

Additionally, it cannot be used to try to argue against statutory duties, which must be followed, nor can it justify risks that are intolerable. A CBA cannot be used to support a poor engineering design.

When carrying out a CBA, it can be relatively simple to ascertain the estimated costs, but significantly more challenging to assess the level of risk. It is important, however, that both sides of the equation represent accurate indications of each.

Discipline should be used when estimating costs; only those costs which relate directly to safety can be included in the analysis. Any cost that does not relate to safety – such as those which relate to aesthetics or potential loss of revenue – cannot be included in a safety-related CBA. It is acceptable to include the cost of installation, training and any additional maintenance costs. It is also possible to include business losses that might result from assets taken out of service, only when they relate to the purpose of putting the measure into place.

Following on from this, any cost savings resulting from the implementation of the risk reduction measure should also be considered and should be offset against the cost of the risk reduction measures in the CBA.

When considering life safety issues, the cost demonstrated must be that for the minimum safe solution. Non-safety requirements are valid costs but must be subject to an alternative CBA, as the cost of these must not impact upon the decision as to whether a measure is ALARP. Equally, only costs payable by the duty holder can be taken into account. Any cost to a third party cannot be included.

In part 66 of LWF’s series on fire engineering, we will discuss some of the pitfalls of the QRA process. 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 the LWF office on 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.