The techniques and innovations being used at T5 have evolved over the last decade on other BAA projects, writes Jackie Whitelaw.
Enormous though it is, T5 is just part of BAA's development plans.
The £4bn being spent on the single T5 scheme will be more than matched over the next 10 years by a further £4.5bn of investment in the rest of Heathrow and the company's other airports.
All the work has to be carefully timed and planned so the business does not compete among itself for expensive, finite resources. And the knowledge from all the projects - both T5 and a raft of £70M to £100M schemes elsewhere - needs to be shared so everyone can make the best gains on time, cost, quality and safety.
Modularisation is one of the most obvious examples of this, says BAA group technical director Richard Petrie. Schemes at the operational terminals have been adopting the technique more and more as it allows disruptive construction work to be carried out off airport.
Modules are being fitted quickly and cleanly overnight with minimum annoyance to passengers.
'We are putting together whole 8m by 4m ceiling modules at our manufacturing centre at Crawley, Sussex - with all the wiring, lighting, air conditioning etc. As a result, we've shortened our pier construction programme from 22 to eight weeks, ' says Petrie.
There is a huge logistical benefit. Modules can arrive on site off the critical path; contractors can work on the travelators in parallel to ceiling installation rather than having to follow on; and what is being installed are high quality products manufactured under factory conditions.
'T5 will also be installing substantial numbers of preassembled mechanical and electrical modules, ' adds Petrie.
'The idea comes from a common root.'
There is an added benefit of modularisation, he points out. BAA was concerned that the resource demands of T5 would not overstretch suppliers and push up prices as a result. Fit-out is where BAA could have the biggest issue and everyone recognises that when T5 switches to its M&E phases, there could be a problem.
'But with modularisation, 40% of the work can be done away from the airport, which means we can spread the resource demand around the UK and Europe and lessen the impact, ' says Petrie.
Petrie and his team have also been experimenting with a preassembled baggage handling system at Terminal 1. 'It was fully built and tested before it came here, ' says strategist David Hall.
'Traditional baggage handling can be plagued by teething troubles but commissioning was a great success this time. We were able to check off site, not just that the system did what it was supposed to, but that the operators and airlines were happy that the system could handle the capacity of bags expected of it.'
Much of the work at Heathrow in the next decade will be the result of the space created at Terminals 1 and 4 by BA's move to T5.
T1 is likely to see the biggest changes. Rather than it being a domestic terminal, it can be reconfigured for long-haul flights.
This means new piers, lounges, check-in desks and baggage handling.
The arrival of the giant A380 planes will also require serious adjustment of piers, stands and taxiways.
The key issue though will be upgrading the facilities at the older terminals to meet the expectations of passengers and airline operators who will want the same standard as T5.
'Passenger delight will be an important issue for us. We have to engender a more exciting experience, ' says Petrie. 'T5 will be a platform for that. It will introduce a step change in the look and feel of airport terminals.'