A large sewerage pipe was responsible for determining the basic shape of RTE's new Television Programmes Building. Architect Ronnie Tallon, of Scott Tallon Walker, explains that part of the area available in Donnybrook is bisected by the sewerage mains from Tallaght and could not, therefore, be built upon.

As a result, the site was triangular in form and this is reflected in the building which has as many curves as straight lines.

Scott Tallon Walker has been responsible for every major RTE structure over the past 40 years. Ronnie Tallon remembers the first work he undertook for the State's public broadcasting agency was the original television studio building in Donnybrook in 1960. This won a gold medal from the RIAI.

Understanding that the company would probably grow in the years ahead, he specifically made the structure expandable and, indeed, it has been extended twice in the intervening decades, although where and how would be hard to detect.

Mr Tallon feels somewhat proprietorial towards RTE and was very happy to have the opportunity to design the Television Programmes Building, won by public competition. The main sight greeting arrivals is of a large curving screen of windows rising three storeys, although the entrance itself is carried around to a straight side. Much of the exterior is glass and granite, the lightness of one contrasting with the solidity of the other.

New planting around the building will soften the landscape over time because a large section of the ground on one side of the building is used for car-parking. This is despite the new structure's basement having a large number of car sites. On the grass in front is a substantial stone sculpture by Michael Warren; intact, this was a three-metre cube but it has been divided into five units arranged along an approximate north-south axis following the stone path leading to the building's principal doors.

The work was commissioned for the scheme, as were two large canvases called Orange and Red by painter Michael Coleman; they hang in the entrance foyer above a semi-circular desk by Drum Ltd of Co Limerick. Rising up two storeys, the foyer continues the building's twin themes of light and curve. The floor is of granite but within the offices, carpeting is extensively used. Walls throughout are painted white and some internal partitions are made of glass bricks to further enhance the sense of light. Ronnie Tallon says the internal geometry of his design is a circle intersecting with a square.

Undoubtedly, the most striking feature of the work is the central meeting hall. This rises the full three floors of the building and its glass roof is divided between a cone and a pyramid. Such technical details are unlikely to strike visitors, however, since they are more likely to be admiring the waterfall surrounded by banked trees and shrubs; more trees line the facing wall in a series of large tubs. Wooden benching flanks the fountain and this area will be furnished with chairs and tables (and a small coffee bar).

Ronnie Tallon says the space has been wired to act as a studio because, as anyone who has ever been out to Donnybrook can testify, interviews are frequently conducted in RTE's grounds.

However, the rest of the building will not be used for these purposes. Studios remain in their existing premises (linked to the new building by a glass walkway) and the occupants of the 10,000m space will be 460 people involved in programme making, many of whom until now have done their jobs in temporary structures. The departments due to move into these offices range from Programmes Acquisition to the Irish Language Unit. They will find themselves relocated in large, open-plan spaces dominated, once more, by curving lines. This leitmotif is carried everywhere - from the forms of the desks supplied by Castle T Furniture Ltd of Limerick to the ceiling covers for lighting. The latter is low-energy, while radiators throughout are fed by energy-saving condensing boilers; heat reclaim is achieved by means of heat transfer to the building structure itself and separate heat recovery coils.

But here, unlike other buildings in the RTE complex which have their heating controlled, both internal and external windows can be opened as suits daily requirements. A special flooring system has been installed to accommodate a flexible range of electrical, voice and data service outlets.

Although officially opened by RTE at the end of last month, the Television Programmes Building is not yet occupied. The first members of staff are due to move in over the next two weeks. Only when they are settled will it be possible to see just how well the place meets expectations.