Glass routes.

A new national museum of glass at Broadfield House, Kingswinford in the West Midlands, testifies to an enduring fascination with the substance, which has lasted from roughly 1500 BC, when the ancient Egyptians fused vitreous surfaces on to stone and clay.

The museum's situation is significant, for nearby Stourbridge has been associated with glass-making for 400 years - most particularly with the golden age of English glass that occurred during the nineteenth century. From 1800-1914, an extraordinary spirit of invention and artistry prevailed: 'Perhaps the only other period in which one could find cameo, rock crystal, engraving, cutting of every description, furnace-applied decoration and moulded glass was during the Roman Empire'.(1)

Today, in this part of the Black Country, there are few signs of what was a great and creative industry - only a few brick furnace cones remain in a landscape once dominated by these strange structures.

The museum, by Brent Richards of Design Antenna, retrieves the great glass makers from obscurity, and celebrates the exquisite works of art they created. In designing it, Richards and the project architect, Robert Dabell, had another purpose - to establish some kind of historical continuity, summoning modern invention to attend on the Victorian. They have done so by making innovatory use of glass to form a new structure that impinges upon the old, and by creating a procession through the museum that physically takes the visitor back in time.

The museum contains the largest collection of eighteenth and nineteenth-century English glass in Europe; set out in the refurbished galleries of Broadfield House, a fine, early nineteenth-century mansion with a Palladian facade. At the back of the house, on the south-west side, there is a new public entrance with amenities that include a glass-blowing studio arranged around a courtyard But it is the entrance - a glass pavilion - on which the architects have concentrated invention. An elaboration of Rick Mather's glass extension in Hampstead (AR February 93), it is said to be the largest all-glass structure to have been built so far, measuring 11m long, 3.5m high and 5.7m wide. Like Mather's building, it is an exact structure built on to an inexact one, but three times as large, and for public rather than private use. There was also the problem of a south-west, rather than northerly, orientation.

Structurally, the pavilion appears simple enough. It is built against the rear wall and a projecting side wall of Broadfield House, with a roof and facade of glass and a gable end of rendered blockwork. But its simplicity obscures the difficulties inherent in its resolution, and here the architects acknowledge the contribution made by Tim MacFarlane of Dewhurst MacFarlane (who was also the engineer on Mather's building).

Elements of the pavilion's glass skin have been laminated in various thicknesses for strength and safety. (The roof of Mather's extension was tough enough to support the weight of a running burglar, and this one would be too.) The glass panelled skin is supported on a triple-laminated glass structural frame which has beams that span at 1.1m centres from the rear brick wall to columns along the front. At back, the beams bear on to the wall through metal brackets concealed by lighting panels; at the front, glass to glass bonded mortice and tenon joints form the connections.

Roof and wall panels are designed to keep heat out. Those forming the roof consist of three glass panes. The outer one is made of St Gobain's Cool-Lite (K 169 Neutral) glass, spattered inside with a microscopic deposit of silver to reduce solar gain. It is separated by a 10mm air gap from two laminated panes of toughened glass. The inner one has a pattern of ceramic bars fritted on to it, their spacing finely calculated so that the whole plane acts as an effective solar screen reducing the amount of solar energy entering the building to less than 37 per cent. The same Cool-Lite glass has been used for the outer pane of wall panels, and once again is separated from a toughened inner pane by an (10mm) air gap, the arrangement also substantially reducing solar gain. For the hottest weather, there is an air extract system, while heating is concealed under a handsome limestone floor.

If the design of this building had, to be exact, (if only not to roast or freeze its occupants), then so did construction. Each roof panel, for example, had to rest on half the 32mm width of the beams that the fritted bars matched up precisely. In addition, beams and columns could not be mass produced and had to be specially made (by the firm of F.A. Firman of Romford which has worked for Mather and Eva Jiricna).

This finely contrived pavilion is an architect's conceit. Apart from the glass connection, there is no sensible reason, given a tiny budget ([pounds]60 000) and the difficulties of manufacture, for making it the biggest all-glass building yet. But Richards' passion for the poetry of light and space that can be produced by glass has plainly sustained him in trying to make a fitting setting for the nineteenth-century triumphs of the industry.

1 British Glass: 1800-1914. Charles R. Hajdamach, Senior Museums Keeper for Dudley Metropolitan Borough