The LWF Blog

Fire Safety Engineering for Design – Building Types & Fire Precautions – Part 18

March 1, 2021 12:55 pm

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 17, LWF began to look at the fire engineering implications of building height. In part 18, we will continue discussing building height before beginning to look at a building’s depth below ground.

In a tall building, the potential for interaction between firefighters accessing the building and building occupants who are evacuating must be considered. The building design in relation to firefighting shafts and the necessity for phased evacuation regimes or partial evacuation of the building must be taken into account.

Firefighting shafts can be used as a refuge location for building occupants with mobility issues, but other fire safety design features can be considered, such as evacuation using lifts, the creation of refuge floors within the building and also smoke management by pressure differential or smoke extraction systems.

Fire safety engineering in high-rise builds must address the potential for risks arising from fires with multiple seats or multiple floors, instead of a single accidental fire outbreak. The basis is that any increase in risk arises from the vertical stacking of usable space and therefore preventing the vertical movement of fire and smoke is of prime importance.

A fire-engineered analysis of a tall building commonly results in the provision of a phased evacuation system with protected stairs, voice alarms, sprinkler protection, firefighting access, compartment floors and increased fire resistance.

While a below-ground floor level in a building does not increase the risk of a fire occurring or the consequences if there were a fire, it does have certain risk-related implications that must be considered when producing a fire safety engineered design.

  • The potential for the products of combustion (smoke, hot gases etc.) to follow the same route upwards as evacuating occupants leaving the building and firefighters entering the building.
  • A fire hazard which is housed below ground level is often considered to be greater with an associated increase in risk.
  • An increased level of risk and difficulty to firefighters attempting to access the basement/below ground level floor.
  • The increase of physiological stress on the human body when escaping upwards.
  • The potential for fires to be under-ventilated which can lead to backdrafts and unpredictable fire behaviours.

In part 19 of LWF’s series on fire engineering, we will continue to discuss buildings with basement/below ground level floors and fire safety engineering. 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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