A 2020 Pathfinder simulation study of a representative 17-storey Malaysian public housing (PPR) block found that reducing staircase availability from three to two substantially prolongs evacuation, that the position of the closed staircase barely changes movement (clearance) time, and that closing a side staircase concentrates about two-thirds of the occupant flow onto the remaining centre staircase, producing severe localized stagnation — but it modelled movement time only, for a single building layout, with pedestrian parameters borrowed from other Asian studies and no empirical validation. The open problem is to establish a validated, behaviourally representative evacuation model for Malaysian public multi-storey housing that spans realistic layouts and occupant distributions, and to use it to determine whether escape-route redesign (staircase repositioning, additional stair provision, guided routing) can systematically minimize both total evacuation time and harmful stagnation; because drill or real-evacuation data for this housing class do not yet exist, this objective includes specifying the validation design by which the model's predictions would be tested against such data.

Background

Malaysia houses much of its low-income urban population in public multi-storey residential blocks built under the Program Perumahan Rakyat (PPR, Malay for 'People's Housing Project'). These are high-density blocks — a typical floor holds around twenty dwelling units — whose safe vertical evacuation depends almost entirely on staircases, and whose actual populations often exceed the occupant-density assumptions used when the number and width of egress routes were fixed by design rules. Understanding how staircase availability and layout govern evacuation in such buildings is therefore a fire-safety engineering question with direct regulatory and retrofit consequences.

The standard tool for this class of question is agent-based egress simulation. Pathfinder is a commercial evacuation simulator in which each occupant is an agent with individual parameters (walking speed, body or shoulder size, acceleration) navigating a building model; in its 'steering mode' agents steer around one another rather than moving as a uniform hydraulic flow. A key convention is that such simulations typically report only movement time — the interval from the start of walking until the last occupant reaches safety — whereas a real evacuation timeline also includes fire detection, alarm signalling, and pre-movement behaviour (the recognition and response delay before occupants begin to move), which can dominate total duration. In this statement, 'movement (clearance) time' denotes that movement-only interval, and 'total evacuation time' denotes the full timeline — movement time plus detection, alarm signalling and pre-movement behaviour. 'Stagnation' in this context means localized flow standstill and congestion at staircases, including repeated route switching and back-and-forth movement by agents seeking a less crowded route, as distinct from total clearance time.

The source study (Hanapi, Sh Ahmad, Ibrahim and Abd Razak, 2020) simulated a 17-storey, 340-unit PPR block in Pathfinder steering mode across nine scenarios: three occupant loads (1,428, 1,700 and 2,040 occupants, corresponding to 4.2, 5.0 and 6.0 persons per unit) crossed with three staircase-availability configurations (all three staircases — centre plus two sides — open; the centre staircase closed; one side staircase closed). Its findings: maximum evacuation duration rises from 347–449 s with three staircases to 447–634 s with two, so losing one of three stairs roughly halves the margin; at the highest load the closed staircase's position barely changes movement (clearance) time (634 s with the centre closed versus 628 s with a side closed); but closing a side staircase drives about two-thirds of the flow onto the remaining centre staircase, with route-searching behaviour from roughly 30 s to 460 s and repeated back-and-forth movement — severe stagnation — whereas closing the centre staircase produces a milder pattern. The study's declared limitations: a single representative layout; pedestrian parameters adopted from Thai and other Asian studies (walking speed 1.3–2.6 m/s, 40 cm by 40 cm body size); randomly placed occupants; movement time only (no ignition, alarm, or pre-movement phases); and no comparison with drill or real-evacuation data.

The surrounding literature brackets this study without filling its gaps. Staircase and exit layout effects have been studied numerically in other building classes — e.g. Lei and Tai (2019) compared four staircase-and-exit layouts of a four-storey dormitory using the coupled fire-and-evacuation simulator FDS+Evac — and staircase evacuation models have been validated against egress drills, notably Xu and Song's (2009) four-storey drill comparison, which is the validation paradigm the source calls for but for a different building type and region. Pre-movement time variability is well established in general terms (Forssberg et al., 2019, Fire Technology). For Malaysian high-rise housing specifically, later Pathfinder work exists but stays within movement-time, single- or few-layout designs: the same research group examined open-staircase position and width (Hanapi, Sheikh Ahmad and Abd Razak, 2020, Journal of Engineering & Technological Advances), escape-route elements for elderly occupants (Hanapi, Sh Ahmad and Abd Razak, 2020, Environment-Behaviour Proceedings Journal — staircases dominate escape time while door and corridor width have minimal effect), and staircase number, occupant distribution balance, and width in a linear residential layout (Hanapi and Abd Razak, 2023, AIP Conference Proceedings — balanced distribution across staircases improves efficiency, and wider stairs shorten time but lengthen travel distance). Independently, Gian et al. (2021) simulated three Selangor high-rise residential buildings and found emergency-staircase placement (left versus middle) changing evacuation time by about 21 percent — evidence that the source's 'position does not affect movement (clearance) time' finding is layout-dependent rather than general. Rismanian, Zarghami and Azadarmaki (2022) related whole-building geometric shape parameters (e.g. gyration radius) of double-staircase high-rises to travel time, citing the source, but at building-shape level rather than layout-specific housing scenarios.

What is not yet available for Malaysian public multi-storey housing is: cross-layout generalization of the availability, position, and stagnation findings under realistic (non-random) occupant distributions; models incorporating pre-movement delay, alarm and detection dynamics, and behavioural heterogeneity; a systematic assessment of whether escape-route redesign can jointly minimize total evacuation time and harmful stagnation; or validation against drill or real-evacuation data for this housing class. That intersection is the open problem.

Problem Statement

For representative Malaysian public multi-storey housing (PPR-type blocks), establish a validated quantitative basis for escape-route design by answering four linked questions:

(1) Generalization. Do the source study's findings — that losing one of three staircases substantially prolongs movement (clearance) time, that the position of the closed staircase (centre versus side) barely changes movement (clearance) time, and that side closure concentrates roughly two-thirds of the flow on the remaining centre staircase causing severe localized stagnation — hold across other realistic multi-storey housing layouts and under non-random, behaviourally plausible occupant distributions (including mixed-age populations)?

(2) Full evacuation timeline. How do detection and alarm dynamics, pre-movement delay, occupant behavioural heterogeneity, and (where modelled) fire and smoke spread alter the numerical evacuation durations and the onset, location, and duration of stagnation relative to the movement-only simulations?

(3) Escape-route redesign. Can staircase repositioning, additional stair provision, or guided-routing strategies systematically minimize both total evacuation time and harmful stagnation (localized flow standstill, route switching, disproportionate loading of single stairs) across a realistic range of occupancy scenarios — and where the two objectives (or travel distance) conflict, what are the quantitative trade-offs?

(4) Empirical validation. Given that drill or real-evacuation data for comparable Malaysian housing stock do not yet exist, what validation design is required — which data must be collected and by what procedure to test the simulation findings, and which pedestrian parameters (walking speed, body size) must be measured for the Malaysian population?

The four questions are linked: (1)–(3) are quantitative results obtained from a single model of the housing class, and (4) specifies the validation design that would test them.

These questions share one scientific objective: a behaviourally representative, empirically validated evacuation model of Malaysian public multi-storey housing, applied across representative layouts and occupancy scenarios, on which evidence-based decisions about staircase provision, egress redundancy, escape-route layout, and retrofit priorities can rest. They arise as linked open research questions from the source study's declared limitations — a single layout, movement-time-only simulation, randomly placed occupants, pedestrian parameters borrowed from Thai and other Asian studies, and no comparison with drill or real-evacuation data — and each remains open in its own right; empirical validation (4) is itself an open question precisely because the drill and real-evacuation data it would require do not yet exist for this housing class.

References

  1. Nurul Liyana Hanapi, Sabarinah Sh Ahmad, Norhati Ibrahim, Azli Abd Razak (2020), 'Staircase evacuation for public multi-storey housing in Malaysia', International Journal of Environment and Sustainable Development 19(3), 258–268. DOI: 10.1504/IJESD.2020.108156, https://doi.org/10.1504/IJESD.2020.108156 (source paper)
  2. Nurul Liyana Hanapi, Sabarinah Sh Ahmad, Azli Abd Razak (2020), 'Evaluation of Escape Route Design in Public Multi-Storey Housing in Malaysia for Elderly Occupants', Environment-Behaviour Proceedings Journal 5(SI2), 25–31. DOI: 10.21834/ebpj.v5iSI2.2521, https://doi.org/10.21834/ebpj.v5iSI2.2521
  3. Nurul Liyana Hanapi, Azli Bin Abd Razak (2023), 'Staircase efficiency during evacuation process in a high-rise building', AIP Conference Proceedings 2947, 070006. DOI: 10.1063/5.0168037, https://doi.org/10.1063/5.0168037
  4. Nurul Liyana Hanapi, Sabarinah Sheikh Ahmad, Azli Abd Razak (2020), 'Crowd Dispersal in Staircase Design for Multi-Storey Building', Journal of Engineering & Technological Advances 5(1), 22–33. DOI: 10.35934/segi.v5i1.22, https://doi.org/10.35934/segi.v5i1.22
  5. Caleb Michealangelo Gian, Mohd Zahirasri Mohd Tohir, Mohamad Syazarudin Md Said, Ahmad Faiz Tharima, Nur Aliah Fatin Mohd Nizam Ong, Mohd Rashid Ramali (2021), 'Effectiveness of travel time during evacuation in high-rise residential buildings: a case study in Selangor, Malaysia', International Journal of Emergency Services. DOI: 10.1108/IJES-09-2020-0053, https://doi.org/10.1108/IJES-09-2020-0053
  6. Mahdi Rismanian, Esmaeil Zarghami, Marzieh Azadarmaki (2022), 'Architectural design and emergencies in double staircase high-rise buildings: the effect of geometric shape parameters on travel time', Architectural Science Review 65(6), 449–478. DOI: 10.1080/00038628.2022.2101981, https://doi.org/10.1080/00038628.2022.2101981
  7. Wenjun Lei, Chuanmin Tai (2019), 'Effect of different staircase and exit layouts on occupant evacuation', Safety Science 118, 258–263. DOI: 10.1016/j.ssci.2019.05.030, https://doi.org/10.1016/j.ssci.2019.05.030
  8. Xuan Xu, Weiguo Song (2009), 'Staircase evacuation modeling and its comparison with an egress drill', Building and Environment 44(5), 1039–1046. DOI: 10.1016/j.buildenv.2008.07.009, https://doi.org/10.1016/j.buildenv.2008.07.009
  9. Martin Forssberg, Jesper Kjellström, Håkan Frantzich, Axel Mossberg, Daniel Nilsson (2019), 'The Variation of Pre-movement Time in Building Evacuation', Fire Technology 55(6), 2491–2513. DOI: 10.1007/s10694-019-00881-1, https://doi.org/10.1007/s10694-019-00881-1
  10. Nurul Liyana Hanapi, Sabarinah Sh Ahmad, Azli Abd Razak (2019), 'Emergency safety for multi-storey public housing in Kuala Lumpur', e-Academia Journal 8, 64–70. ISSN 2289-6589, https://ir.uitm.edu.my/id/eprint/86781/