Kristian Farr MEng, LCIBSE EngTech
Kristian joined the lift industry as a Vertical Transportation consultant in 2020 and now works as a Senior VT Engineer for AECOM. He has worked on hundreds of projects across many sectors and countries over the years designing VT systems.
Kristian won the “Dr Gina Barney Emerging Excellence” award for his paper titled “Theoretical Evaluation of Evacuation Lift Capacity Assessments” presented at the Lift and Escalator Symposium 2024 which proposed a methodology to undertake the first phase of an evacuation in an office building.
Alastair Bartlett MEng PhD CEng MIFireE
Alastair holds a PhD in fire safety engineering, focussing on timber construction, and now works as an Associate Director in AECOM’s fire engineering team, working on strategies for a wide range of buildings including high-rise hospitals, offices, and government buildings necessitating the inclusion of evacuation lifts.
This paper assesses the evacuation time for a 24-storey office building. The scenario modelled assumes that a fire has arbitrarily taken place at Level 11, and a whole building evacuation is required. The evacuation will be via a phased evacuation strategy utilising the stairs for those who are able to self-evacuate, and evacuation lifts for those who are unable to self-evacuate by stairs. The stair widths have been designed to be compliant with BS 9999 recommendations.
To determine the suitability of the evacuation strategy, a comparative analysis of stair evacuation times against the total lift evacuation times.
As a base design assumption, the building is provided with two escape stair cores and provided with one evacuation lift per escape stair core. The proportion of users who are likely to require the use of the lifts for evacuation has been taken as 15% in line with the Department for Workplace and Pensions family survey information.
Initial findings indicate that the estimated stair evacuation time, when calculated in line with PD 7974-6, is approximately 65 minutes, while the lift evacuation time extends to approximately 3.5 hours. The initial calculation results indicate a significant disparity in evacuation time which would likely raise concerns with the available evacuation lift capacity in line with the Fire Strategy requirements and other human factors.
This paper aims to explore strategies for providing lift evacuation times more in line with the stair evacuation times and enhancing overall evacuation efficiency.
THEORETICAL WHOLE BUILDING EVACUATION
Primary Authors: Kristian Farr, Alastair Bartlett
AECOM, UK