The LWF Blog

Fire Safety Engineering for Design – What is fire engineering – Part 2

November 11, 2020 10:49 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 1, we looked at what fire engineering is and how it is governed. In part 2, we discuss the main approaches to fire safety engineering before considering the authorities which have jurisdiction.

The three main approaches to fire engineering are Equivalency, Deterministic and Probabilistic.

Equivalency can also be known as a comparative approach and it is a fire engineered design which shows equivalent levels of fire safety to that which would have been applied through the prescriptive codes.

Deterministic designs aim to show that in the initial worst-case scenario assumptions, a set of circumstances and conditions will not occur. This method is dependent upon reliable input data and where there is any doubt, a cautious approach should be adopted. The use of explicit safety factors to compensate for uncertainties may be necessary.

With the Probabilistic approach, the objective is to show the level of risk for a given event is acceptably low. Expressions of this type of data are normally given in terms of the annual probability of an unwanted event occurring. While it is possible to reduce risks to a low, or acceptable, level, it is never possible to reduce risk to zero.

Whichever approach is most appropriate for the project, a fire safety engineered approach to building design can bring increased design flexibility, a reduction in construction or running costs and measures more suited to the building’s use.


Authoritarial Jurisdiction

The authority having jurisdiction (AHJ) is the governmental agency or sub-agency which regulates the construction process and is commonly local to the building location. While contact and co-operation with the AHJ is necessary in all construction projects, early and informative communications are essential when a fire engineered solution is sought.

The acceptance, or indeed non-acceptance in some cases, of a fire engineered approach by the AHJ will be dependent on the following:

– Building type
– AHJ’s perceived competence of the design team
– AHJ’s level of experience
– Individual personalities within the AHJ
– Client/Owner’s previous behaviour and history (reputation).

Part 3 of LWF’s series on fire engineering will begin to look at the legislation relevant to fire safety engineering in the UK and worldwide. 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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