Hoare Lea’s angle poise
With an angular, raked ceiling and further constraints imposed by the requirements of disabled access and energy efficiency, Hoare Lea has read a tricky situation well at Canada Water Library. Jill Entwistle reports
Southwark council leaders have called the new Canada Water Library the ‘shape of libraries to come’. It is reassuring to know that libraries are in any kind of shape at all, given that they are currently more associated with closures than openings.
In literal terms, it is an inverted pyramid shape, a crafty strategem by architect CZWG, given the small footprint, to squeeze as much space as possible out of the first floor for the part of the building given over to books.
Lighting a space with a lot of angles is tricky, of course. It was one of the factors that drove the decision to integrate the lighting into the bookshelves. A further constraint was the need to meet a Disability Discrimination Act requirement for the shelving to be low enough (1.3m) for someone in a wheelchair to reach the top shelf.
And then there was the LG5 stipulation for 200 lux to fall on the books from top to bottom. “Our first thought was to use the general lighting to light the books, but that was where the shape of the building caused problems,” says Dominic Meyrick, lighting principal and partner of Hoare Lea Lighting.
“The issue there was the ceiling, which has got every angle in it apart from a 90-degree one. You can see the number of pendants we’ve got in just for general lighting, let alone to try and provide 200 lux on the spine of a book
A further consideration for the lighting designers was that the client wanted total flexibility to move the bookshelves around. “Logic dictated that we had to look at the idea of some sort of lighting integral to the shelving,” says Meyrick.
Fluorescent versus LED
Then it became a matter of fluorescent versus LED. Here the DDA restriction on the height of the bookshelves was an issue. “With shelving of conventional height, most of the systems kicking around would have a linear fluorescent coming away from the shelf, providing asymmetric washing,” says Meyrick.
“You’re just outside the shadow of the asymmetric light going on to the shelving, so you can reach for a book without your hand being in the way of the lighting. But, with lower heights, achieving even lux levels from top to bottom and avoiding shadowing was a problem. It meant having some sort of structure on top of the shelves to house the lamp.
“Given that the peak distribution of an asymmetric fluorescent is somewhere in the centre, maybe 20-30 per cent of the light would be lost in the gap between where the structure would have to be so you didn’t bang your head and where the book shelf is. And then you would be looking to push the peak of that onto the bottom shelf. The product was getting bigger and uglier.”
Small, neat and with the right optic to deliver the 200 lux on book spines on the bottom shelf, LEDs it was. This also pleased architects CZWG, who were looking to retain the clean eyeline across the space, and Southwark Council, which was keen to have an efficient, low-maintenance solution after the halogen nightmare of another library in its portfolio.
The shelving was customised to house ACDC Lucina LED profiles, 150 in all, each 1m long. Their colour temperature is 3,000K and the extra-bright 66W version was used, rather than the standard 33W.
Piers Gough of CZWG chose the ambient lighting for the library space: iGuzzini’s globe-shaped Gem pendant, originally designed for Charles de Gaulle airport in Paris. The Gem’s shell, which houses 125W TC-T fluorescent lamps, is made of moulded polycarbonate, photoengraved for optimal light diffusion. The ceiling, needless to say, was again an issue.
“The pendant was difficult to detail because of all the different angles in it,” says Meyrick. “Finally, the plasterboard was pierced to attach pendants directly to the concrete slab with a hook and chain arrangement.
“It was crucial to agree the arrangement carefully, as the fittings also illuminate the staircase – they are positioned at library level to ensure they can be maintained on that floor, rather than having to build scaffold in the stair core.”
Things were rather simpler on the ground floor entrance and café areas, especially when more elaborate suggestions were pared back for budgetary reasons. The lighting here is based on Optelma’s linear fluorescent system, an apparently random arrangement that suits the edgier ambience.
“Lighting on the ground floor is pretty basic,” says Meyrick. “It’s not about regular arrays, straight lines, fitting in with grids. It’s a ‘pick up sticks’-type arrangement of linear fluorescents, which goes with the whole feel of the space.”