Elaborating metrics for the accessibility of buildings

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Abstract

This paper presents a methodological approach for measuring building accessibility. Buildings are seen as service providers, and their accessibility is evaluated by defining a set of representative service paths, and measuring their quality. We will depart from existing methodologies, developed to measure location accessibility, and transpose them for use in the building domain, in an effort to propose a concrete way to audit building accessibility and lay down some analytical metrics for its measurement. Such methods may be instrumental in better and deeper understanding accessibility. They may enable tools to be developed, to help support decisions on embedding accessibility in new building design or in the course of a refurbishment process. We argue that it is not adequate to pursue a black or white approach to accessibility. In this sense, compliance to standards that, if observed, secure accessible paths in buildings is a very useful approach but does not fully unveil the essence of accessibility. Put simply, there can be large differences in accessibility even if standards are equally well or not well observed. We wish to elaborate on the subtle nature of these differences and to propose a framework to start measuring them.

Introduction

Accessibility has received considerable interest in the recent years, initially as an attempt to respond to the needs of special communities, such as disabled people, and to counteract discrimination and societal exclusion. Now, increasingly, accessible environments are considered to be to the interest of society at large, and not a “luxury” provision reserved for special communities. Two main reasons support this rationale. First, the realization that senior people, pregnant women, small children, injured or other temporarily disabled people will also largely benefit from an enhanced accessibility of the built environment. Second, the gradual understanding that there may also be important benefits accompanying accessible design, as buildings will become much more functional, to the benefit of all. At the cross-point of these considerations a wealth of, often overlapping, concepts have been introduced. Universal design, design for all, barrier-free design all claim some different perspectives of an otherwise common goal, i.e., to create high quality and non-discriminatory building environments.

Although such inclusive approaches appear to be gradually gaining momentum, they are far from being established as mainstream practices, as the building industry, often assumes, with regard to them, a conservative and skeptical attitude. Imrie et al., in the course of an interview-based research with property developers, attempt a classification of the reasons behind these industry reservations (Imrie & Hall, 2001a). It appears that developers are primarily concerned about the costs that are associated to accessibility. This position is supported in the literature also by other researchers (Guy, 1998). What seems to be the typical position of the industry is its attention primarily to the short-term building exchange value and the profit it generates, rather than to any broader, lifetime, value. Related, maybe, to this business perspective, the authors also provide evidence that tenants and potential clients of buildings, rarely ever raise the issue of accessibility in any emphatic way. This lack of demand is one more disincentive for developers to go beyond their legal obligations, and the compliance to the existing building regulations.

Interestingly however, Imrie et al. report in their findings that a substantial number of developers pinpoint the ethical aspect of accessibility as a justifying element of their eventual decisions. In another work of the same authors (Imrie & Hall, 2001b), such attitudes are shown to depend largely on the type of the development project. Developers that intend to sell immediately after the completion of the construction are less likely to be motivated by ethical concerns, compared to developers in the service of local authorities or utilities. Even more, in the case of shopping and leisure centres, a potential for commercial profit may be one further driver for increasing the accessibility of the premises.

The driving forces for an enhanced building accessibility are therefore multifold. Adherence to legislation and building regulations remain the primary driver for accessibility in the building development industry. Yet, there are cases where accessibility decisions are also positively influenced by commercial considerations. Ethical concerns may also be important, especially in the case of public sector projects. As far as the barriers are concerned, the most common argument raised is about the additional construction costs that are usually perceived as inherent to enhancing accessibility. This remains however a highly contested issue; there are many references in the literature (Jong, 1983, Imrie, 2000) according to which no significant additional costs are generated because of the provision of increased building access.

According to all indications, societies, maybe at different paces, eventually move towards an increased accessibility of the building domain and of the urban space. We do believe that the better we understand and control the economics of this transformation the more efficient and fast it will be. This is not to say that the social imperative is not self sufficient on its own. But we argue that the more we understand the economic repercussions of accessibility, be it cost or benefit, the more sound the arguments in favor of it will be. There is an analogy here with the sharp rise of the concern for the environment, which took place in the 1970s. Initially business reacted as if the quest for environmental protection was one more awesome, financial burden. Nowadays it is much less so, as companies have come to understand the mechanics of clean technology and eco-design and have tapped into significant benefits, not really visible from the very beginning. Along this line of thought, we would argue that voluntary schemes, such as building accessibility labels or accessibility management schemes, could provide for one more accessibility driver, next to laws, profits and social responsibility, which have been highlighted above. Such instruments typically presuppose adherence to the building regulations and in addition may offer a high visibility to the building owner or manager, which may be instrumental for additional commercial profits or for communicating and promoting a socially responsible image. In addition, they very often embed the requirement for “continuous improvement” and in this way they may help gradually visualize the lifetime benefits of accessibility, which may not be easy to realize from the very beginning, when considerations on productivity and exchange values prevail.

How has policy reacted and interfaced to such considerations? In recent years we have truly witnessed an increasing number of policy instruments that have been enacted in support of accessibility. There are however impressive obstacles towards their implementation. There are many reasons for this deficiency but the difficulty in measuring implementation success can be considered as among the most important. We simply lack a convincing way to measure accessibility beyond check-listing the compliance or not to any particular standard specification. How are we to measure implementation progresses if we cannot even adequately measure accessibility itself? This “go/no-go” approach, embedded in standard compliance approaches, is of course important, yet rather inadequate to help understand what is really at stake every time, or to suggest how things can be most cost efficiently managed, or which intervention directions would have the greatest potential. Gould has very well highlighted the underlying difficulties in saying that “accessibility is a slippery notion; everyone uses the term until faced with the problem to define and measure it” (Gould, 1969).

Further evidence as to the need to look into accessibility in a more refined and quantitative way is provided by the workings of TC 59/SC 16, the subcommittee that has been set up at ISO (the TC—technical committee—59 deals with building domain related standards) in order to elaborate an international standard for building accessibility. In the, so-called, business plan document of this subcommittee it is stressed that it is necessary that different levels of accessibility should be considered.

Church et al. have been very systematic in their approach to go beyond the absolute, standard based, mindset as to accessibility (Church & Marston, 2003). They have introduced measures of relative accessibility, which may capture important differences in terms of accessibility. For example, if an accessible path really exists but it takes 10 times more time or effort to reach the same destination, can this be considered acceptable enough?1 There are numerous such cases in modern buildings and laying down measures of relative accessibility is a good way to unveil these differences.

In the following, we will briefly report the work carried out by these researchers and seek to take it one step further, towards understanding the essence of building accessibility and shaping some metrics for its measurement. We will then introduce a methodology for carrying out systematic accessibility audits, for identifying architectural and functional barriers of the built environment and suggesting cost efficient solutions for their removal. Such audits can emerge into key instruments in drafting actions plan for interventions seeking to enhance the accessibility level of a building, be it in design process or already constructed, or even the accessibility of broader urban areas.

Section snippets

Accessibility measures

Church et al. summarize a number of measures that have been introduced in the literature, for measuring the accessibility of any given location (Church & Marston, 2003). We will repeat below these basic access metrics. In the following sections we will attempt to transpose this knowledge into the building domain and to propose an approach for measuring building accessibility.

Overall, in the literature, besides the absolute, standard compliance measures, which are of a “yes/no” nature there are

Building accessibility

The measures suggested in the previous section focus on the accessibility of a given person being at a location (i). How can we adapt this approach to a built environment? What will the location point (i) in such an environment really be? This is the core question that will be addressed in this section.

We would like to propose to view a building as a provider of services to citizens. So, it is rather the accessibility to the building services that is of interest. This links us conceptually much

From the accessibility of a given location to the accessibility of a building

The discussion in the previous section has in effect attempted some redefinition of the basic terms defined in Section 2, in a way that they may become meaningful to the building accessibility context, which is the topic of this work. We repeat here the definition of the basic indices defined in there, in order to define the accessibility of a given location:

  • (i), a given location whose accessibility is under evaluation;

  • (k), a particular activity that is to be accessed by location (i);

  • (j), the

A first approach to building accessibility metrics

Let us for a moment restrict the discussion to a particular citizen type (l = lb). How could his accessibility to building services be approximated? We will restrict this example to the multiple activity measures, applicable for distinct locations (Eqs. (9), (10)) and see how they develop in the case of a building. We will be consistent with the symbols used up to this moment and use (A) to represent building accessibility. In fact, we will use the symbol Alb, as we restrict ourselves to the

Applying the methodology. A real life example

In this section we will look into a simplified example in order to better understand the mechanics of the proposed methodology, especially the detailed requirements and background assumptions for its application. We will refer to a university building, serving educational purposes, the School of Applied Technology at the Technology Institute of Crete.

Our building has a ground and a first floor, plus a basement. In the basement as well as in the ground and first floor, the main services offered

A decision support system for building accessibility. Implementation issues

The above analysis provides a conceptual framework for dealing with and evaluating building accessibility in a structured and detailed way. As such, it has been used as a theoretical foundation for the design and implementation of a decision support system (DSS), capable to perform analyses of building accessibility and to provide suggestions as to specific interventions that could be undertaken in order to enhance it. This work is currently carried out in the framework of an EU funded project (

Results and conclusions

A methodological framework has been developed to assess, in a relative manner, the accessibility of various citizen categories to buildings. Though the effort has largely been built upon previous work, looking at location-oriented accessibility, in our case the approach is service (employment, entertainment, etc.) and not location centered; it also looks into both indoor as well as critical outdoor paths rather than just distinct elements (ramps, etc.).

This work is an attempt to complement the

Acknowledgments

The research on which this paper is based forms part of the POLIS (Decision Support Tools and Policy Initiatives in Support of an Universal Design of Buildings) project, which is funded by the EU Sixth Framework Program (Policy Oriented Research—Contract No. SP24-CT-2003-500862). The research partnership comprises Business and Project Management SA (Greece), ASM Market Research and Analysis Centre sp. z o. o (Poland), EMTTU (Greece), Belgian Building Research Institute (Belgium), Building

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