Investigating the impact of occupant response time on computer simulations of the WTC North Tower evacuation

This work explores the impact of response time distributions on high-rise building evacuation. The analysis utilises response times extracted from printed accounts and interviews of evacuees from the WTC North Tower evacuation of 11 September 2001. Evacuation simulations produced using these “real” response time distributions are compared with simulations produced using instant and engineering response time distributions. Results suggest that while typical engineering approximations to the response time distribution may produce reasonable evacuation times for up to 90% of the building population, using this approach may underestimate total evacuation times by as much as 61%. These observations are applicable to situations involving large high-rise buildings in which travel times are generally expected to be greater than response times

Approximating the evacuation of the World Trade Center North Tower using computer simulation

This article concerns an investigation of the full scale evacuation of a building with a configuration similar to that of the World Trade Center (WTC) North Tower using computer simulation. A range of evacuation scenarios is explored in order to better understand the evacuation of the WTC on 11 September 2001. The analysis makes use of response time data derived from a study of published WTC survivor accounts. Geometric details of the building are obtained from architects' plans while the total building population used in the scenarios is based on estimates produced by the National Institute of Standards and Technology formal investigation into the evacuation. This paper attempts to approximate the events of 11 September 2001 and pursue several `what if' questions concerning the evacuation. In particular, the study explores the likely outcome had a single staircase survived intact from top to bottom. More generally, this paper explores issues associated with the practical limits of building size that can be expected to be efficiently evacuated using stairs alone.

‘Nothing will prevent me from doing a good job’. The professionalisation of part-time teaching staff in further and adult education

Approximately 85,000 part-time teaching staff working in further education (FE) and adult and community learning (ACL) are often seen as ‘a problem’. The intrinsic ‘part-timeness’ of these staff tends to marginalise them: they remain under-recognised and largely unsupported. Yet this picture is over-simplified. This article examines how part-time staff make creative use of professional autonomy and agency to mitigate problematic ‘casual employment’ conditions, reporting on results from Learning and Skills Development Agency-sponsored research (2002–2006) with 700 part-time staff in the learning and skills sector. The question of agency was reported as a key factor in part-time employment. Change is necessary for the professional agency of part-timers to be harnessed as the sector responds to ambitious sectoral ‘improvement’ agendas following the Foster Report and FE White Paper. Enhanced professionalisation for part-time staff needs greater recognition and inclusion in change agendas.

The potential use of mapped extent and distribution of habitats as indicators of Good Environmental Status (GES)

The Healthy and Biologically Diverse Seas Evidence Group (HBDSEG) has been tasked with providing the technical advice for the implementation of the Marine Strategy Framework Directive (MSFD) with respect to descriptors linked to biodiversity. A workshop was held in London to address one of the Research and Development (R&D) proposals entitled: ‘Mapping the extent and distribution of habitats using acoustic and remote techniques, relevant to indicators for area/extent/habitat loss.’ The aim of the workshop was to identify, define and assess the feasibility of potential indicators of benthic habitat distribution and extent, and identify the R&D work which could be required to fully develop these indicators. The main points that came out of the workshop were: (i) There are many technical aspects of marine habitat mapping that still need to be resolved if cost-effective spatial indicators are to be developed. Many of the technical aspects that need addressing surround issues of consistency, confidence and repeatability. These areas should be tackled by the JNCC Habitat Mapping and Classification Working Group and the HBDSEG Seabed Mapping Working Group. (ii) There is a need for benthic ecologists (through the HBDSEG Benthic Habitats Subgroup and the JNCC Marine Indicators Group) to finalise the list of habitats for which extent and/or distribution indicators should be considered for development, building upon the recommendations from this report. When reviewing the list of indicators, benthic habitats could also be distinguished into those habitats that are defined/determined primarily by physical parameters (although including biological assemblages) (e.g. subtidal shallow sand) and those defined primarily by their biological assemblage (e.g. seagrass beds). This distinction is important as some anthropogenic pressures may influence the biological component of the ecosystem despite not having a quantifiable effect on the physical habitat distribution/extent. (iii) The scale and variety of UK benthic habitats makes any attempt to undertake comprehensive direct mapping exercises prohibitively expensive (especially where there is a need for repeat surveys for assessment). There is a clear need therefore to develop a risk-based approach that uses indirect indicators (e.g. modelling), such as habitats at risk from pressures caused by current human activities, to develop priorities for information gathering. The next steps that came out of the workshop were: (i) A combined approach should be developed by the JNCC Marine Indicators Group together with the HBDSEG Benthic Habitats Subgroup, which will compile and ultimately synthesise all the criteria used by the three different groups from the workshop. The agreed combined approach will be used to undertake a final review of the habitats considered during the workshop, and to evaluate any remaining habitats in order to produce a list of habitats for indicator development for which extent and/or distribution indicators could be appropriate. (ii) The points of advice raised at this workshop, alongside the combined approach aforementioned, and the final list of habitats for extent and/or distribution indicator development will be used to develop a prioritised list of actions to inform the next round of R&D proposals for benthic habitat indicator development in 2014. This will be done through technical discussions within JNCC and the relevant HBDSEG Subgroups. The preparation of recommendations by these groups should take into account existing work programmes, and consider the limited resources available to undertake any further R&D work.

Visions for the North Sea: The Societal Dilemma Behind Specifying Good Environmental Status.

We augment discussions about the Good Environmental Status of the North Sea by developing two extreme visions and assessing their societal benefits. One vision (‘Then’) assumes restoration of benthic functioning; we contend that trawling had already degraded the southern North Sea a century ago. Available information is used to speculate about benthic functioning in a relatively undisturbed southern North Sea. The second vision (‘Now’) draws on recent benthic functioning. The supply of five ecosystem services, supported by benthic functioning, is discussed. ‘Then’ offers confidence in the sustainable supply of diverse services but restoration of past function is uncertain and likely to be paired with costs, notably trawling restraints. ‘Now’ delivers known and valued services but sustained delivery is threatened by, for example, climate change. We do not advocate either vision. Our purpose is to stimulate debate about what society wants, and might receive, from the future southern North Sea.