articles by Peter J Lawrence
Fire Safety Journal, Jun 1, 2001
When evacuating through fire environments, the presence of smoke may not only have a physiologica... more When evacuating through fire environments, the presence of smoke may not only have a physiological impact on the evacuees but may also lead occupants to adapt their evacuation strategy through the adoption of another exit. This paper attempts to introduce this type of adaptive behaviour within the buildingEXODUS evacuation model through enabling occupants to make decisions concerning the selection of the most viable available exit during an evacuation involving fire. The development of this adaptive behaviour requires the introduction of several new capabilities namely, the representation of the occupants’ familiarity with the structure, the behaviour of an occupant that is engulfed in smoke and the behaviour of an occupant that is faced with a smoke barrier. The appropriateness of the redirection decision is dependent upon behavioural data gathered from real fire incidents (in the UK and USA) that is used to construct the redirection probabilities. The implementation is shown to provide a more complex and arguably more realistic representation of this behaviour than that provided previously.
Journal of Applied Fire Science, Jan 1, 2002
This article examines occupant behavior exhibited during evacuation conditions. This is based on ... more This article examines occupant behavior exhibited during evacuation conditions. This is based on a review of a wide range of published literature concerned with evacuation. Factors influencing evacuation performance can be categorized into four broad areas, namely, configurational, environmental, procedural, and, most importantly, behavioral. The contributory factors associated with each of the four influencing categories are examined in detail and it is suggested that these factors should be represented within evacuation models.
Safety Science, 2017
Forest fires are an annual occurrence in many parts of the world forcing large-scale evacuation. ... more Forest fires are an annual occurrence in many parts of the world forcing large-scale evacuation. The frequent and growing occurrence of these events makes it necessary to develop appropriate evacuation plans for areas that are susceptible to forest fires. The buildingEXODUS evacuation model has been extended to model large-scale urban evacuations by including the road network and open spaces (e.g. parks, green spaces and town squares) along with buildings. The evacuation simulation results have been coupled with the results of a forest fire spread model and applied to the Swinley forest fire which occurred in Berkshire, UK in May 2011. Four evacuation procedures differing in the routes taken by the pedestrians were evaluated providing key evacuation statistics such as time to reach the assembly location, the distance travelled, congestion experienced by the agents and the safety margins associated with using each evacuation route. A key finding of this work is the importance of formulating evacuation procedures that identifies the threatened population, provides timely evacuation notice, identifies appropriate routes that maintains a safe distance from the hazard front thereby maximising safety margins even at the cost of taking longer evacuation routes. Evacuation simulation offers a means of achieving these goals.
Fire and Materials , Aug 17, 2012
This paper presents a detailed description of an agent-based lift (elevator) model developed with... more This paper presents a detailed description of an agent-based lift (elevator) model developed within buildingEXODUS software intended to represent evacuation scenarios. The main components of the lift model are described including the lift: kinematics, attributes and dispatch control. The agent-lift interaction model is also described, including the lift bank selection, the lift waiting area behaviour (wait location selection and wait duration) and the lift car selection and entry. The lift model is used to investigate a series of full building evacuation scenarios based on a hypothetical 50 floor building with four staircases and a population of 7840 agents. The analysis explores the relative merits of using up to 32 lifts (arranged in four banks) and various egress lift dispatch strategies to evacuate the entire building population. Findings from the investigation suggest that the most efficient evacuation strategy utilizes a combination of lifts and stairs to empty the building and clear the upper half of the building in minimum time. Combined stair lift evacuation times have been shown to be as much as 50% faster than stair only evacuation times. The introduction of the agent milling behaviour resulted in reductions in evacuation times compared with the same scenarios without milling behaviour.
Fire Technology, Jul 21, 2018
The devastating effects of wildfires cannot be overlooked; these include massive resettlement of ... more The devastating effects of wildfires cannot be overlooked; these include massive resettlement of people, destruction of property and loss of lives. The considerable distances over which wild fires spread and the rates at which these fires can spread is a major concern as this places considerable challenges on the evacuation mechanisms that need to be put in place. It is therefore crucial for personnel, involved in evacuation planning, to obtain reliable estimates of evacuation times faster than real time, to assist their decision making in response to actual unfolding of events. In this work, we present a hybrid approach, which we refer to as the Hybrid Spatial Discretisation (HSD) for large scale evacuation simulation. The HSD integrates the three spatial representation techniques typically used for representing space usage in evacuation models; namely Coarse regions, Fine nodes and Continuous regions. In this work, we describe the core models constituting the HSD coupled with the approaches used for representing the transition of agents across the different spatial types. Using a large scale case, we demonstrate how the HSD can be used to obtain higher resolution of results where it is most required while optimising the use of available computational resources for the overall simulation. The HSD is seen to provide improvements in run times of more than 40% when compared to modelling the whole area using just the Fine node method.
Ocean Engineering , Dec 1, 2017
International guidelines (IMO MSC.Circ 1533) specify that evacuation models used to certify evacu... more International guidelines (IMO MSC.Circ 1533) specify that evacuation models used to certify evacuation performance of passenger ships must demonstrate that the calculated representative evacuation time, the sample 95th percentile time τ S , is lower than a prescribed Pass/Fail Criterion Time (PFCT). In this paper a Confidence Interval Convergence Test (CICT) method is presented that minimises the computational burden required to demonstrate that a model design has passed/failed by calculating a CI for the population 95th percentile time, τ P , rather than simply relying on τ S determined from an arbitrary sample of 500 simulations as specified in the current guidelines. The CICT has comparable pass/fail accuracy to using 500 simulations whilst significantly reducing the number of simulations required when the PFCT is far from the τ P. In addition, the proposed method has superior accuracy to the convergent method described in the IMO guidelines. Furthermore, the methodology described in the guidelines fails to identify situations where there may be uncertainty in the pass/fail status due to proximity of τ P to PFCT. The CICT identifies these situations and provides a means of resolving the uncertainty. The CICT can be applied to any stochastic evacuation model to determine parameter convergence. KEYWORDS: 95 th percentile, confidence intervals, evacuation modeling, convergence, maritime safety, IMO. Nomenclature CI Confidence Interval CI(x%) CI with an x% confidence level CICT Confidence Interval Convergence Test IMO International Maritime Organisation PFCT Pass/Fail Criterion Time TET Total Evacuation Time (s) n sample size of simulations R CI range of the CI (s) T b TET of simulation b (s) τ 95 th Percentile TET (s) τ P population 95 th Percentile TET (s) τ S(=n) sample (of size n) 95 th Percentile TET (s)
Fire Safety Journal, May 1, 2020
Evacuation of high-rise construction sites is one of the most challenging evacuation scenarios co... more Evacuation of high-rise construction sites is one of the most challenging evacuation scenarios conceivable. Over the past 50 years, very little evacuation research has focused on issues uniquely associated with high-rise construction sites. To address this, FSEG, in collaboration with IOSH and Multiplex, undertook a three-year project to develop an evidence base describing evacuation performance of high-rise construction site workers. This data was used to define a unique evacuation validation data-set for high-rise construction sites. The validation data-set, described in this paper, contains a complete description of the evacuation scenario, including geometry, population, procedures, response times and exit curves. A performance metric is defined which objectively describes the goodness of fit between model predictions and experimental data. Given the level of uncertainty in the validation data-set an objective measure of acceptable agreement between the model prediction and the experimental data is specified for the metric. The level of acceptability is based on the performance of a modified version of buildingEXODUS, which provides a benchmark defining an acceptable level of agreement with the experimental data. The analysis demonstrates that suitably adapted evacuation simulation software can predict the evacuation performance of high-rise construction sites with a reasonable level of accuracy.
Ocean Engineering, 2020
Naval platform survivability is a key enabler to ensure maritime warfighting capability. Therefor... more Naval platform survivability is a key enabler to ensure maritime warfighting capability. Therefore, assessment of naval platform recoverability, after a damage event, is critical to assure platform survivability in a warfighting environment. To support such an assessment, an innovative modelling and simulation capability, known as the Naval Damage Incident Recoverability Toolset (NavDIRecT) is being developed. NavDIRecT is being designed as a component-based, open architecture providing the necessary framework to allow analysts to integrate domain models of their choosing. NavDIRecT will facilitate analysis of warfighting and peacetime damage events using a variety of mathematical models, thereby avoiding the limitations of other survivability assessment techniques. Development of NavDIRecT is exemplified by integrating the human movement simulator, maritimeEXODUS, the fire simulation environment, SMARTFIRE, and a three-dimensional naval platform model. NavDIRecT will enable analysis of crew interaction with damage events, thereby allowing acquisition programs and mission planners to examine platform survivability with respect to mission capability requirements. The impetus for NavDIRecT development is for assessment of naval platform survivability and mission success; however, the tools and techniques are equally suitable for use in incident management, training, and analysis of merchant and commercial shipping in accordance with the Safety of Life at Sea (SOLAS).
Fire Technology, 2020
In hospitals, the evacuation of those with severe movement impairments can be highly problematic ... more In hospitals, the evacuation of those with severe movement impairments can be highly problematic for the patients, for the staff and for other evacuees. It is critical to understand the performance of horizontal and vertical evacuation procedures , including the means by which people with reduced mobility can be assisted during stair descent. Microsimulation modelling provides a useful tool to assess evacuation strategies, given the challenges of preparing and transporting patients in need of ongoing care and the unfeasibility of real evacuation drills. However, current simulation models typically focus on the movement of individual agents, not the staff-patient interactions and sizable equipment required to carry out assisted evacuation. To address this, the buildingEXODUS evacuation model has been enhanced to represent moving objects in addition to moving individual agents. This paper describes the modelling theory behind this development, where dedicated data has been applied to enable the explicit specification of evacuation devices, operated by agents (for instance, representing the vertical travel speeds achieved-with averages ranging between 0.6 m/s and 0.84 m/s-when employing different movement devices). Algorithms are presented that calculate the movement of devices along corridors, through doorways and in stairway descent, including a method of geometric decomposition of the available hospital evacuation routes. This new functionality addresses the key evacuation components of repeated patient collection and has numerous applications, both in simulating hospital evacuation and in representing evacuation of other premises that include people with reduced mobility. Examination of the performance of this functionality found it predicated performance within 6% of expectation. Once further testing is completed, the resultant tool can be used to significantly enhance planning and diagnostic capabilities related to the evacuation of hospital and other healthcare facilities.
Journal of Fire Protection Engineering, Feb 1, 2007
Signage systems are widely used in buildings to provide information for wayfinding, thereby assis... more Signage systems are widely used in buildings to provide information for wayfinding, thereby assisting in navigation during normal circulation of pedestrians and, more importantly, exiting information during emergencies. An important consideration in determining the effectiveness of signs is establishing the region from which the sign is visible to occupants, the so-called visibility catchment area (VCA). This study attempts to factor into the determination of the VCA of signs, the observation angle of the observer. In building regulations, it is implicitly assumed that the VCA is independent of the observation angle. A theoretical model is developed to explain the relationship between the VCA and observation angle and experimental trials are performed in order to assess the validity of this model. The experimental findings demonstrate a consistency with the theoretical model. Given this result, the functionality of a comprehensive evacuation model is extended in accordance with the assumptions on which the theoretical model is based and is then demonstrated using several examples.
Fire Safety Science, Jan 1, 2014
Signage systems are widely used in the built environment to aid occupant wayfinding during both c... more Signage systems are widely used in the built environment to aid occupant wayfinding during both circulation and evacuation. Recent research conducted by the authors shows that only 38% of people ‘see’ conventional static emergency signage in presumed emergency situations in an unfamiliar built environment, even if the sign is located directly in front of them and their vision is unobstructed. However, most people who see the sign follow the sign. These results suggest that current emergency guidance signs are less effective as an aid to wayfinding than they potentially can be and that signs are likely to become more effective if their detectability can be improved while upholding the comprehensibility of the guidance information they provide. A novel dynamic signage design is proposed to address this issue. The effectiveness of the new sign is tested under almost identical experimental settings and conditions as in the previous experiments examining conventional, static signs. The results show that 77% of people ‘see’ the dynamic sign and 100% of them go on to follow the sign. In addition, a dynamic method to identify that an exit route is no longer viable is tested using an international survey to gauge understanding of the new signage concept. Survey results suggest that the purpose of the new sign can be clearly understood by over 90% of the sample. Signage systems are widely used in the built environment to aid occupant wayfinding during both circulation and evacuation. Recent research conducted by the authors shows that only 38% of people ‘see’ conventional static emergency signage in presumed emergency situations in an unfamiliar built environment, even if the sign is located directly in front of them and their vision is unobstructed. However, most people who see the sign follow the sign. These results suggest that current emergency guidance signs are less effective as an aid to wayfinding than they potentially can be and that signs are likely to become more effective if their detectability can be improved while upholding the comprehensibility of the guidance information they provide. A novel dynamic signage design is proposed to address this issue. The effectiveness of the new sign is tested under almost identical experimental settings and conditions as in the previous experiments examining conventional, static signs. The results show that 77% of people ‘see’ the dynamic sign and 100% of them go on to follow the sign. In addition, a dynamic method to identify that an exit route is no longer viable is tested using an international survey to gauge understanding of the new signage concept. Survey results suggest that the purpose of the new sign can be clearly understood by over 90% of the sample.
Fire Prevention Fire Engineers Journal, Aug 1, 2003
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articles by Peter J Lawrence
The work on two dimensional triangular unstructured grid generation by Lewis and Robinson [LeR76] is first examined, in which a recursive bisection technique of computational order nlog(n) was implemented. This technique is then extended to incorporate new methods of geometry input and the automatic handling of multiconnected regions. The method of two dimensional recursive mesh bisection is then further modified to incorporate an improved strategy for the selection of bisections. This enables an automatic nodal placement technique to be implemented in conjunction with the grid generator. The dissertation then investigates methods of generating triangular grids over parametric surfaces. This includes a new definition of surface Delaunay triangulation with the extension of grid improvement techniques to surfaces.
Based on the assumption that all surface grids of objects form polyhedral domains, a three dimensional mesh generation technique is derived. This technique is a hybrid of recursive domain bisection coupled with a min-max heuristic triangulation algorithm. This is done to achieve a computationally efficient and reliable algorithm coupled with a fast nodal placement technique. The algorithm generates three dimensional unstructured tetrahedral grids over polyhedral domains with multi-connected regions in an average computational order of less than nlog(n).
University College London and the University of Greenwich are in the final year of a three year EPSRC funded research project to integrate the simulation of personnel movement into early stage ship design. This allows the assessment of onboard operations while the design is still amenable to change.
The project brings together the University of Greenwich developed maritimeEXODUS personnel movement simulation software and the SURFCON implementation of the Design Building Block approach to early stage ship design, which originated with the UCL Ship Design Research team. Central to the success of this project is the definition of a suitable series of Naval Combatant Human Performance Metrics which can be used to assess the performance of the design in different operational scenarios.
The paper outlines the progress made on deriving the human performance metric from human factors criteria measured in simulations and their incorporation into a Behavioural Matrix for analysis. It describes the production of a series of
SURFCON ship designs based on the RN Type 22 Batch 3 frigate, and their analysis using the PARAMARINE and maritimeEXODUS software. Conclusions to date will be presented on the integration of personnel movement simulation into the preliminary ship design process.