A project can be analysed in terms of the fundamental units of space, time and money. And every project has a solution that uses the first to minimise the second and maximise the third. Here's how to find it
The refurbishment of an occupied building can have a critical impact on a client and its business. When that building is a railway station, hundred of clients may be affected. The contractor must ensure that train operators can run their service efficiently, that concession holders, such as newsagents, can still attract customers and that the general public are still able to reach their places of work and repose with ease – and, above all, that nothing lands on them from a great height.

Balanced against the contractor's need to satisfy a client by minimising the site's intrusion on its business is the contractor's desire to maximise its working area. On most sites, hoardings are used to section-off areas where work is under way. "Much of the impact of a refurbishment on a client's business is down to where the hoardings are positioned," says John Kelsey, a lecturer at the Bartlett School of Construction and Project Management at University College London.

Kelsey is part of a team at UCL led by Alan Penn that has developed a software tool aimed at making refurbishment projects run smoothly for the client and the contractor. The team has established the critical factors that define a hoarding's location. They have then used this information to develop a simulation tool to plan the position of the hoardings and minimise a project's disruption. The tool gives the programme manager the ability to consider what is happening outside the hoarding as well as on the site itself.

The software – called RaCMIT (which stands for Refurbishment and Customer Movement Integration Tool) – has been developed from an existing suite of tools called Space Syntax, which is a way of modelling the way the urban environment affects people.

"When contractors put up hoardings, they are temporarily redesigning the remaining public space, whether they like it or not," says Kelsey. The problem for the contractor is to understand how this reconfiguration will affect the way pedestrians move around a space and hence impact on their client's business. The location of the hoardings may even influence a person's decision on whether or not to enter that space. "Since hoardings can remain in place for months – or even years – this is no small matter," he says.

The Space Syntax tools are based on studies of how the shape of an open space affects the way people move through it. Kelsey says: "People will not stand for long in the middle of an area of moving pedestrians. In a retail environment, people want the time and space to make a decision as to whether or not to enter a shop, in particular they need time to look in the shop window to see what is on offer. If they feel hassled by other pedestrians moving around them while standing outside, they tend to decide not to enter." Likewise, people do not like to stand in isolated areas; they like to stand in places where they can see what is happening around them.

Space Syntax software has been used to improve the circulation at the Tate Modern, to model the reconfiguration of Trafalgar Square, and more recently in determining the location of entrances to the Swiss Re tower. It has also been used inside Selfridges and Harrods to plan revisions to their layouts.

To calibrate the program for the temporary space created by hoardings and to estimate the cost impact to shops, UCL undertook a series of case studies at London's Victoria Station and Manchester's Piccadilly Station. The team studied people movements before, during and after a phased construction programme. The programme necessitated the closure of various entrances and exits to the station, which allowed the UCL team to assess the hoarding's impact on pedestrians.

To apply the modelling software to the temporary configuration of a construction site, a contractor must first input the building layout and the proposed phasing of the construction works to define which areas of the development will be closed during the works. The software will then illustrate the site's impact on pedestrian flow, which will allow the client to allow them to decide whether the proposal is feasible or not.

The studies at the two stations highlighted the unpredictability of refurbishment works and demonstrated the usefulness of the tool, not just at the planning stage but in accommodating changes in the programme.

Although the software will undoubtedly prove useful to contractors in phasing the construction works, it will probably be most useful in stimulating discussion between the client and the contractor about the best way of phasing the construction. A client will be able to appreciate the disruptive effects of an occupied refurbishment on their business and, more importantly, the software will allow a client and contractor to model different scenarios to decide whether to increase the area of the construction site to speed the works.

Kelsey sees the software's use extending to work on hospitals, schools and housing estates – it has already been used to reduce crime on some estates on London's South Bank. "Areas that have people moving through them attract less crime," says Kelsey. The program has been used to model the way the shape of open spaces affects the way people move through an estate, and so highlight which areas are prone to crime.

The software will initially be available through Space Syntax – a UCL company that already does special analysis of developments. However, the university is looking to extend its development: research is under way on modelling the impact of space on a construction site – inside the hoardings – using a program developed by UCL called VirCon. Armed with VirCon and RaCMIT a contractor will be able control both sides of a site hoarding – although unfortunately they won't be able to control the acronyms UCL uses for its software.

Divide and rule: How to arrange a site hoarding

Ensure that the construction planner and facilities manager work together to pool knowledge of the construction process and the facility in normal operation to minimise disruption. Understand how internal pedestrian movement relates to the operation of the facility and the immediate external environment and identify the following:
  • Entrances and exits, and their importance in terms of pedestrian movement
  • If there is a bias in the direction of pedestrian movement
  • The times/days when pedestrian movement peaks, and any changes in pedestrian flow, such as commuting patterns at railway stations
  • The spaces where people tend to congregate and remain static, such as customer information screens at railway stations or food outlets in shopping centres
Try to predict the effect of closing an entrance or blocking a major pedestrian route and identify the following:
  • The new primary and entrances and exits and new major pedestrian routes
  • New areas where pedestrians are likely to congregate
Beware of the factors that influence pedestrian movement. Remember, pedestrians prefer:
  • Straight, or gently curved, uncomplicated routes to maximise visibility
  • Moving in the direction where their view of the surrounding area is greatest
  • To remain static in an area where their visibility of their surroundings is greatest and they are outside the main pedestrian routes.
Plan the construction with reference to the above points to minimise the effects of the site hoardings on the client. Widen corridors at sharp turns using chamfered corners and ensure that the hoarding configuration complies with the fire and other emergency evacuation plans. Remember:
  • Maximising visibility will increase the area covered by CCTV cameras
  • Allow sufficient height in temporary ceilings to reduce the danger posed by smoke
  • Install supplementary signage where necessary, such as on escape routes.