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Theme: lighting

As lighting is increasingly integrated within architecture, there are technical developments to help it play a more sophisticated role

As materials and technology develop and architecture continues to challenge the boundaries of craft and construction, lighting becomes increasingly important and appreciated in revealing and enhancing design and material relationships.

While there is something to be said for the honesty of a surface-mounted fluorescent batten in the right location, lighting design is progressively about a more directly interwoven relationship with the architecture, creating a 'look, no hands' environment. The desire is to support and augment the design through the integration of the lighting equipment in the fabric of the building. This can be done, for example, by using a cove detail in contrast to an exposed fluorescent batten, so that the built form becomes the focus rather than the celebration of the luminaire itself. Using discreet luminaires helps to reveal and indeed enhance the physical intent, and this type of effect is best achieved by detailing the lighting as an integral part of the architecture.

This integration is twofold, allowing expression of the physical space and providing the appropriate and most receptive material for the desired environmental effect.

Certain luminaires lend themselves to this type of assimilation. Size and efficiency are both important characteristics for this type of considered design. Compact sources, such as LEDs and the smaller, more efficient T5 fluorescent batten, suit tight conditions. Highly considered and developed optics ensure the required light distribution (as illustrated by the Elliptipar range of exterior linear luminaries). Remote sources such as fibre-optic and light-pipes allow for the mundane but necessary considerations of installation and maintenance in difficult situations.

Natural materials Natural materials can bring with them innate beauty in texture, depth, colour, etc.

Considered lighting design can not only complement but also enhance such characteristics - the uplit face of a rough stone wall, the stippled reflection on patinated metal and the varying shades of warmth of a timber screen. As the boundaries of material qualities are tested by use in architecture, previously considered limitations are lifted and perceptions are expanded. The simple process of deconstructing the solidity of timber to a thin veneer or the reduction of a mass of stone to a thin cladding allows lighting to expose what it was once unable to penetrate.

Reflections on glass Throughout history, glass has had a strong relationship with both natural and artificial lighting. Recently, this has been enhanced by the rich and varied colours and textures available. Developments in colour, dichroic coatings, solar insulation, frosting techniques, optical inserts, forming and moulding all give rise to the possibilities of a new exposure through lighting.

Dichroic glass, which exhibits different colours when viewed from different directions by separating visible light into usable spectral regions, is already being put to good use in the lighting industry as an external light filter and as an internal colour-mixing device for luminaires. Its colour-mixing properties have great potential to be integrated directly into the very fabric of a building.

One exciting development in the world of glass is Priva-lite, produced by Saint Gobain Glass, which allows one surface to provide a view and create a partition at the flick of a switch. Available since the late 1980s, this material has only recently become more viable in the general architectural market. Application of an electric voltage to a liquid-crystal film sandwiched between two glass panes changes the opacity of the glazing from non-transparent to transparent. Creating more than just a window, there is a playful game to be had between views and defined partitions. This material is greatly enhanced by its coordination with lighting in front of the glass, emphasising the opacity of the partition when closed off, behind it, reinforcing the clear views through the glazing, and blurring images between the two. This is used with great humour in the changing rooms of the Prada store in New York City.

Film stars Optical films also allow the manipulation of architectural environments. 3M produces a variety of film products specific to the lighting industry. Its dichroic, spectral film produces the same effect as dichroic glass, but with more flexibility. 3M also produces a series of products based on the principle of total internal reflection in the form of optical-light film and high-luminance light fibre. The optical-light film is a prismatic film that is used in light guides and thin sign boxes to provide bright and uniform light over a given distance. High-luminance fibre is a solid-core optical fibre that is solid and flexible, and a potential replacement for cold cathode with less energy usage.

Some lighting manufacturers have already embraced these technologies and incorporated these materials directly into their products. Both ETC and Space Cannon use dichroic glass in their colour-change luminaires. Encapsulite UK has for a number of years provided a dichroic film sleeve as an accessory for its T5 and T8 range of batten luminaires. TIR Systems of Canada has developed film products with 3M and incorporated the optical-light film into its Light Pipe exterior remote-source systems.

The wonder of LEDs No discussion of material technology and lighting integration can ignore light-emitting diodes (LEDs. ) Since the early 1990s, LED technology has been developing following the initial scientific accomplishment of producing blue and white LEDs. It is now a varied medium, used both as an independent light source and as a potential material for assimilation into architecture.

LEDs are sold as an amazingly low-consumption, high-output source, but there are still issues to address, including those associated with heat, colour stability and life.

Controlling heat within the LED luminaires is a problem. The circuit boards create just enough heat to alter their own composition and, over a period of time, degrade the light source itself. There are also problems with colour stability under heat, with varying voltages and during the course of the LEDs intended life. Which brings us to the great 'leave and let' myth. LEDs have been revered as a 100,000-hour source, which would equate to more than 20 years of useful life.

Manufacturers are catching on quickly, but word is not spreading fast enough that this is simply not true. Red and amber LEDs have a life rated to 100,000 hours, but the most recently developed and most useful LEDs in terms of rendering and colour mixing, blue and white LEDs, have an average life of only about 25,000 hours, equating to approximately five years' use. At present, LEDs are generally not designed like lamps, to be replaced after an acknowledged period of life, as they have circuit boards that are often integral to the luminaire. Nevertheless, LEDs as a developing technology are a marvel, with their size and power consumption making them a noteworthy material for incorporation into architecture.

The most direct assimilation of LEDs into a useful architectural product so far has been made by Glas Platz of Germany, which has embedded LEDs in its Power Glass.

Using double-sided LEDs on an electrically conductive transparent coating inside a laminated glass unit, the customisable product allows a variety of aesthetic solutions and patterns of LEDs to be considered. The product is light and fluid, interweaving the two technologies with apparent ease.

Working with solar power The low power consumption of LEDs makes them a perfect candidate to marry with the use of solar power, in the lighting industry generally as well as in the architectural marketplace.

The options for solar lighting products are, at present, few and far between with the majority of what is available on the market still verging on gimmickry. However, companies such as Urbis Lighting, in connection with SolarGen Solutions, have been making strides in developing and testing integrated solar street-lighting systems with local authorities in the UK. MoonCell Incorporated, based in the US, has taken the idea one step further, integrating wind and solar power to supply LumiLeds light sources in a street 'lantern'. As aesthetics are clearly not a priority, the result is an ungainly street column head not easily adaptable for a considered environment, but since the principle is right this bodes well for the future of sustainable lighting.

The most effective marriage so far is the LED/solar-powered luminaire designed and BATH SPA CASE STUDY The exterior lighting of the new spa complex for Bath has been designed as a single composition. It provides a coherent night-time identity for the four historic buildings and Nicholas Grimshaw and Partner's contemporary insertion.

This contextual approach reveals the juxtaposition between the historic and contemporary architecture. It aims to attract people to use the impressive new facilities during the evening as well as in the day.

Consideration has been given not only to the image of the site and to improving the perception of safety and security, but also to minimising light spill and light pollution. This is particularly important given the transparent nature of the new elements and the presence of a rooftop pool. The lighting addresses these issues through:

lconsideration of the external impact of the internal lighting;

lcareful selection of luminaires to suit the required tasks;

luse of fixed light sources to minimise accidental de-focusing creating glare or light spill;

luse of a lighting-control system to manage the ambience, lighting levels and the brightness of surfaces.

The lighting to the existing historic buildings has been designed to be soft, subtle and discrete, highlighting a limited number of details. The exteriors of the Cross Bath and the Hot Bath are united by backlighting to the porticoes, creating a focus at the entrances. Uplighting to other original details adds interest. The exterior lighting was carried out using in-ground luminaires (Louis Poulsen) and small surface-mounted spotlights (Light Projects) employing tungsten-halogen sources.

The interior lighting of Cross Bath was designed to be seen from the street and therefore forms part of the external lighting scheme. The most visible element is the softly washed curved wall to the back of the reception area, which is lit by compact fluorescent downlights (Wila). The pool is illuminated through underwater lighting (Bega) and discreet uplighting to the external curved walls using fibre optics (Group C). The source of the spring is picked out with a narrow-beam tungstenhalogen spotlight (Concord Marlin).

The public areas of the Hot Bath are visible from the roof of the main pool. The circular rooflights are picked out with blue cold cathode (Oldham). The tungstenhalogen underwater pool lighting throws ripples onto the original stone walls. This soft effect is visible through the structural glass rooflight.

The external appearance of the main entrance and new pool building is largely reliant on the internal lighting. The facades to the stone cube, circular stair tower and supporting columns glow softly as a result of the reflected light and the lighting to the areas behind them.

The external terraces are lit from continuous concealed fluorescents (Encapsulite) integrated within the handrail at the top of the glass balustrade. The fittings are fully louvred to prevent glare when seen from the street. The rooftop pool is illuminated using underwater tungsten-halogen lights (Bega). Levels are kept to a minimum while allowing the routes around the pool to be clearly visible by using a series of LED floor-recessed marker lights (WE-EF).

The project is controlled from a preset dimming system (iLight), fitted with a time-clock and photocell, which allows different lighting scenes to be selected automatically or manually and for the lighting to be set to the appropriate brightness and intensity for each scene.

TEAM CREDITS ARCHITECTS Nicholas Grimshaw and Partners Donald Insall Architects LIGHTING ARCHITECT Speirs and Major Associates (Mark Major, Claudia Clements, Steve Power, Henrietta Lynch) M&E ENGINEER Arup MAIN CONTRACTOR Mowlem ELECTRICAL CONTRACTOR Skanska manufactured by Astucia Lighting. The range includes complete luminaires incorporating integral LEDs, photovoltaic panels and battery, therefore requiring no wiring.

At present, the range is specifically pitched to the road-lighting industry, but it has a distinct future in the architectural marketplace.

The luminaires have an adaptable housing and, despite all the development of LEDs that is still required, the price of these units is so reasonable that it allows for complete replacement in five years' time with the added benefit of no electrical wiring cost.

Photovoltaic panels themselves are also becoming increasingly suitable for architectural use. The solar cells are beautiful as a material, rich in texture as well as having the obvious benefits of clean power generation.

Within the UK there are significant grants available for the development and support of clean power sources. The Department of Trade and Industry has introduced the first phase of its demonstration programme in which it gives grants for up to 60 per cent of the total installation costs in order to stimulate the demand and use of solar electricity.

Solar Century has developed direct material replacements for standard architectural products, for example shingles and slates, as well as a range of solar-cell products that provide aesthetic colour and textural variety.

The solar cells can be integrated into tiles, glass and even fabrics.

MANCHESTER WALL CASE STUDY The Manchester Sportcity Screen Wall was designed to create an attractive edge to a busy road on the edge of Sportcity, as part of the new development and regeneration of the Bradford area to the east of Manchester city centre.

Planning conditions required the developer of the adjacent commercial property to screen the loading bay with something that could be regarded as an 'art piece'. The intention was that this should be linked to the regeneration of the surrounding area to create a positive visual statement without being a distraction to passing motorists.

The design team, comprising Trevor Horne Architects and Speirs and Major Associates, wished to create a 'Light-Art' installation that touched on themes of the past, present and future of the area.

A strong influence on the final design was the work of mathematician Alan Turing, whose wartime work at Bletchley Park and post-war work at the National Physical Laboratory and the University of Manchester led to the theoretical foundation for the modern computer. Turing's concept of a 'Universal Turing Machine' (a machine that could be programmed to organise information) was an integral part of the installation. Using Turing as a starting point, the intention was to create subtle sweeps of colour along the length of the wall and contra moving rows of light, suggesting the movement and activity of the city and the sport activity adjacent to the site.

The primary design priorities were sustainability in terms of long life sources, avoidance of light pollution into the sky, discreet integration of lighting equipment and ease of maintenance.

Colour-change linear luminaires were mounted on the vertical surface of the wall so that they could be seen from the roadway side of the wall. The luminaires were distributed evenly in three horizontal rows along the length of the wall, and mounted behind a perforated mesh screen to both protect and diffuse the light sources.

The wall incorporates 702m of cold cathode (Oldham) within 156 IP 55-rated light boxes. Each light box contains three 1,500mm long cold-cathode tubes, with the colours carefully chosen to allow for full RGB colour mixing. Each of the cold-cathode tubes is individually DMX controlled by the Martin Lightcorder programmed with the Martin Matrix software. The Lightcorder replays a series of sequences that vary from one to 10 minutes in length, and the whole sequence totals approximately 1 hour and 45 minutes before repeating. The system is controlled by a photocell and runs from sunset to sunrise every day.

The luminaires were programmed to go through a series of sequences of colour and intensity changes to create constantly changing looks for the wall at night. Final programming was designed carefully in terms of colours used and speed of change, to avoid any conflict with adjacent traffic signals and safety signage.

TEAM CREDITS ARCHITECT Trevor Horne Architects (Trevor Horne, Darren Hall) LIGHTING ARCHITECT Speirs and Major Associates (Jonathan Speirs, Malcolm Innes, Carrie Donahue Bremner) ENGINEER Arup Engineering GENERAL CONTRACTOR HBG Construction Northwest LIGHTING CONTRACTORS Lee Engineering Oldham Lighting Going organic And the next step? That will be completely integral and fluid lighting fused with materials that are both natural and man-made.

Perhaps it sounds like science fiction, but the technology is getting there. Organic light-emitting devices (OLEDs), derived from organic phosphor compounds, are making leaps and bounds in the media and communication industry. Standard for use in cell phones and alarm clocks, OLEDs are now challenging computer display technology and the television industry.

Transparent organic light-emitting devices (TOLEDs) are available for integration into glass, windows and walls, offering 70 per cent transmission. Flexible organic lightemitting devices (FOLEDs) have also been designed to break the constraints of flat displays. They can be built on flexible substrates such as clear plastic films and metal foils, so it is hard to identify restrictions on their use.

Following years of study alongside the scientific development of OLEDs, LEDs and electroluminescent technology, there is one architect who is embracing such advances and integrating these developments in building design. Sheila Kennedy of Kennedy & Violich Architecture, Boston, has used a design research studio at Harvard University Graduate School to investigate the potential of these types of materials in the architectural field. Her interests lie in the future of cool light sources. These provide a higher percentage of their energy as light than do standard light sources, which give off 90 per cent of their energy as heat and only 10 per cent as light. The studio has developed a chameleon cloth, made up of a mesh of metal and fabric infused with photoluminescent phosphors, which, when stimulated by incidental light or electricity, glow. The colour of the light can be controlled by the specific combinations of phosphor fused with the base material.

Kennedy believes that it will be possible to dissolve light into all building materials, completely dispersing the distinction of materials and what we perceive are their base characteristics. These advances would provide opportunities to bring a second life to materials that would otherwise be hidden and secret, and to give a new meaning to the lit environment.

Whilst presently out of reach of the reality of integrated lighting design, due to restrictive cost and the scientific development still required, these are exciting and thought-provoking technologies, which it will soon be possible to integrate in everyday design.

Carrie Donahue Bremner works with Speirs and Major Associates READER ENQUIRIES 3M 1400 Astucia Lighting 1401 Bega 1402 Concord Marlin 1403 EncapSulite UK 1404 ETC 1405 Glas Platz 1406 Group C 1407 iLight 1408 JCC 1409 Light Project Group 1410 Louis Poulsen 1411 Martin 1412 MoonCell Incorporated 1413 Oldham 1414 Phillips 1415 Saint Gobain 1416 Solar Century 1417 SolarGen Solutions 1418 Space Cannon 1419 Thorn 1420 TIR Systems 1421 Urbis Lighting 1422 WE-EF 1423 Wila 1424 Zumtobel 1425

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