The LWF Blog

Fire Safety Engineering for Design – Design Scenarios – Part 47

September 20, 2021 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 46, LWF began to discuss design scenarios, beginning with occupancy. In part 47, we will look at how multiple safeguards should be in place to avoid a single catastrophic failure in fire safety design.

It is important that a fire safety design for the purpose of protecting building occupants should not be reliant on one fire safety feature alone. In such a scenario, the failure of that one system could result in disaster and casualties.

Equally, if a failure of one element could result in the failure of multiple fire safety systems, it must be mitigated against. In addition, there are circumstances where, although the failure of one feature might not result in an outright failure of another system, it could impact negatively.

Such issues are known as common mode failures and they should be anticipated and avoided. The potential impact of a system failure should be assessed as part of a ‘what if’ assessment.

Foreseeable events and their outcomes are assessed in a ‘what if’ assessment as part of an efficient fire safety design. They work to identify system failures and any other foreseeable events that might have a significant impact on the outcome of the study.

Some common ‘what if’ scenarios are:

  • What if the fire-resisting shutters between compartments failed to operate?
  • What if the fire door were propped open?
  • What if combustible materials were introduced into sterile areas?
  • What if the compartment walls were penetrated and not fire-stopped after?
  • What if some materials used were greater than specified flammability?
  • What if the power fails and the smoke vents do not open?
  • What if the sprinkler system fails because of poor maintenance?
  • What if the ventilation system affects the fire detection system?
  • What if a fire started blocking an exit?
  • What if fire safety procedures were poorly managed?
  • What if fire safety training was inadequate and this increased fire risk?

The ‘what if’ scenarios should be followed through to their logical conclusion and then remedies/safeguards put in place to ensure that they will not happen.

Any uncertainty in the design data should err on the side of conservatism. Any uncertainties and the resulting solutions should be recorded in the fire safety strategy report. Such sources of uncertainty might be – input parameters; necessary simplifications in modelling techniques; limitations of empirical relationships; and human response.

In part 48 of LWF’s series on fire engineering, we will begin to look at the fire safety design 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.

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