These are just some of the challenges Bruce Jones has faced on this, and many other odd-shaped buildings. He heads facade access consultancy Reef, whose projects also include the entire Canary Wharf estate and London's City Hall. His input affects the architect's design so he needs to step in early. "We need to get involved with the architect on day one," he explains. "It's so much easier to develop a design at this stage rather than bolting kit on later." Richard Hyams, project architect at Foster and Partners, which worked with Jones on City Hall, says: "Reef, and companies like it, have a great impact on our detailing – it's an extra level on top of our design."
Jones has to juggle a multitude of constraints when working out a solution. Architects like to have clumsy access equipment tucked away when it's not being used so it doesn't mess up the sleek lines of their buildings. Compact equipment is vital to maximise lettable space in expensive locations. Heavy plant affects a building's structure, and there are also other factors to consider, such as putting frequently used equipment speedily into working position.
City Hall was a particularly challenging project for Reef. Its weird, lopsided shape and solar control system makes facade access very tricky. External brise-soleil would have made cleaning impossible, so glazed areas incorporate a blind sandwiched between two skins of glass. Because this cavity is ventilated, the glass and fiddly louvred blind also need periodic cleaning.
Jones and Hyams started off with several access options, and narrowed these down in tandem with the facade design. "The number of different facades we went through was unbelievable," says Jones. Rope access was ruled out because the only way to clean the glass and blind in the cavity is from below because the outer sheet of glass opens from the bottom.
The final solution was to use the world's biggest cherrypicker. It has a reach of nearly 46 m, enough to get to the top of the facade. This solution had a knock-on effect on the whole design as it required an uninterrupted run around the entire building; this area, and part of the floor slab on which the machine is kept below the building, had to be specially reinforced because of the machine's 21-tonne weight.
Cleaning considerations also had an effect on the detailing. Jones suggested seals for the outer pane of glass to stop rainwater penetrating the cavity and causing streaking. Within the cavity, the blinds slide down so the inner skin of glass can be easily washed. The blinds can also be removed once every five years for a more thorough clean. Hard-to-reach areas have fritted glass that needs less frequent cleaning, as it doesn't show the dirt. These include the top of the glazed area facing the debating chamber, and the rooflights.
More recently, Reef has been faced with a new challenge – Foster and Partners' Swiss Re tower in the City of London. After lengthy consultations with the architect and client, the firm came up with a bespoke solution. Their answer was to create a device that slides out of a hole in the side of the building on rails (see The Wrap, page 65) and can reach both above and below.
Jones says there is nothing particularly special about the equipment, despite this being the biggest access project in Europe. The machinery consists of three standard elements from different manufacturers: the garaging system, a standard access cradle on cables and a hydraulic boom – which is simply a cherrypicker with the wheels ripped off. "All we have done is merge three companies that are very strong in their respective fields to produce a one-off system that works incredibly well," he says.
Jones believes solving the access problems of even more complex buildings than Swiss Re isn't a problem. "There's enough out there already," he says. "Bringing the market sectors together to provide the solutions is the biggest challenge."
Clients approve of this partnering approach, as they do not want to be guinea pigs for untested systems. And although people might like the idea of robots because of the potential labour savings (see Techno Trouble, left), for the time being at least, it looks as if there is no substitute for the bucket and sponge.