We explain how the design process was optimised
A vital part of BAA's strategy for getting Terminal 5 delivered on time and to budget is sophisticated IT. The sheer scale of the project means that there are vast numbers of drawings coming from a battalion of 120 consultants and specialists. If the information in these drawings isn't consistent, work will either grind to a halt or go wrong, and costs will start to rise – and with a project the size of Terminal 5, even a small percentage increase is vast.

The airport operator has therefore created an optimal IT system: this means that the whole project team works within one common 3D computer model. This will be used to design, build and maintain T5 with the objective of cutting 10% from the project cost. "It's all about trying to get people to collaborate and communicate with each other rather than working in isolation then throwing the information over the wall," says Andrew Manington, BAA's production support manager. "This produces better quality information, reduces ambiguity and clashes and gives more certainty on time and cost earlier in the project."

BAA's post mortems on its previous projects have shown that they went over budget because of inconsistencies in drawings. Conventionally, the architect designs the building and passes the CAD drawings to the engineer. The engineer then draws the building again using a different program to do the engineering analysis – in itself a process that is guaranteed to introduce errors. This procedure cascades down the team to the specialists and their design departments, until hundreds of sets of drawings of the same structure have been created. The inevitable inconsistencies between these drawings have to be reconciled on site, leading to problems with delay, workmanship and cost. So, "the idea behind the single-project model is to derive an unambiguous set of data through the sharing of data", says Mervyn Richards, Laing O'Rourke's CAD technology manager. "With this, the engineer never redraws the information; it can reuse the architect's data and add to it. We are getting everyone to work on the same data set to drive out error and improve efficiency."

The massive roof nodes that connect the roof structure together are good example of how the single-model environment works. Richard Rogers Partnership designed the node and passed it over to Arup, which was acting as structural engineer. Arup used the architect's drawing to carry out the structural analysis before returning it RRP for design modifications. After that was done, the model was passed to steel fabricator Severfield-Rowen, which used it to fine-tune those parts of the node that had to be specially made. Finally, they used the model to control the computer-aided manufacturing machinery that shaped the roof parts.

Information contained in the model has been used during the construction phase. It has supplied information to plan the methodology for constructing the building, and for managing time efficiently. It has also contributed to better health and safety because it has eliminated the need to botch together impromptu solutions to the drawing errors. The model is constantly updated with as-built information in case of small variations on site. Now that the concrete and steel structural work is finished, the fit-out contractors can use this information to do the detail design on their part of the project, including the complex baggage-handling systems. "This gives us tremendous confidence that the baggage-handling systems will fit," says Manington.

The model will also help the airport operator make savings in maintaining its buildings, and will increase the team's knowledge base for future projects. "We need to tie the model into the facilities management systems – so if, for example, you find a series of valves that keep failing you can change the specification on the next project," says Manington. "You can forget that you need to keep replacing that valve because maintenance teams change so often." The FM teams and others without specialised CAD skills or software will be able to see the information in the model as it can be accessed on BAA servers using a 3D viewer called NavisWorks.

The single-model environment incorporates intelligent object technology to further improve efficiency. This means that objects in the drawing possess information about themselves and how they relate to other objects in the building. "The FM team will be able to go into the model, walk through the corridors, click on objects and retrieve data about that item," says Richards. That information will make it easier to service or replace the component. In the future, manufacturers could make their products available as intelligent objects on the web and designers could download them into the model so it will be easier to keep information accurate.

The drawback to the common data environment – if drawback it is – is that discipline is needed to make it work. Everyone who uses it has to follow the same rules. Richards says: "We have had to lay down a series of protocols that say how data is managed and moved around." This includes getting team members to ensure CAD data is dimensionally correct and produced at full size to the same co-ordinates. There are conventions for naming different parts of the drawing and data exchange is carefully managed. Clash detection software is used to check that everyone has stuck to the procedures. If a lapse is discovered, the reason is identified, and if necessary, further training given.

The aspirations for this rationalisation of the construction process are bearing fruit. "So far we have been on target with time and cost as the single-model concept is giving real visibility," says Manington. "What I hope is we will know about the time and cost issues all the way through the project to its completion even though the more complex stuff is yet to come." The rest of the industry will benefit from BAA's work, too. Lessons learned at T5 are being fed into a DTI-funded project called Avanti that aims to show how smaller projects can benefit from the single-model environment.

System Integration

According to Nick Gaines, BAA’s head of IT, systems integration could be crucial to the public’s first experience of T5. “It’s a high-risk activity that delays programmes; airport terminals usually don’t open on the right day because of failures,” he says. Systems integration is the linking of building services, security, fire and lighting systems, so, for example, if a fire alarm goes off in one part of the building, all the doors to the runway don’t open automatically. It also includes the flow of information between air-traffic control in Swanwick and the airport, the distribution and updating of flight information, the baggage-handling systems and the organisation of the aircraft stand. In other words, it’s complicated.

A low-risk strategy is being adopted at T5. The first part is to do the bare minimum to get the terminal building functional on the opening day. The idea is to provide the framework to add higher-level integration systems after the building opens. The other advantage of this approach is that new and better software can be easily added as it becomes available and the systems can be changed along with the way the building is used over time. Using tried and tested off-the-shelf systems is also part of the strategy. At T5, building services manufacturers’ own interfaces will be used, but BAA will create one super BMS interface to make it easier for operators to control the building, and easier for engineers to configure and commission so the terminal opens on time.

Wireless communication on site

BAA is trying out new technology to help site workers to work more efficiently. “The T5 site is enormous,” says Cedric Carr, Laing O’Rourke’s head of building services. “Our people have a plan for the day’s work, and if something goes wrong and they need information, they could lose two hours driving back to the office and finding it. That’s three tasks they don’t get done.”

BAA is therefore experimenting with wireless links between its site office and the B building – a satellite to the main terminal. This will enable managers to wirelessly access T5’s main IT system. They can look up drawings within the single-model environment and information within ProjectFlow, the tool used for planning the work schedule, using a wirelessly enabled laptop or PDA.

According to Nick Gaines, BAA’s head of IT, the solution has gone down well with the people using it – although it is too early to tell whether the cost of implementing wireless is worth it. “Right now there are some very strong feelings but no figures in front of me. Everyone loves new technology but we have to be cautious.”