Movilidad internacional del alumnado de educación terciaria

The Grand Mosque in Abu Dhabi is a project that overflows with incredible statistics. The building consists of a series of single-level public spaces that cover over 72,000 square feet. It has capacity for 40,000 worshippers. But for all the complexity and vast scale of the project, the design approach taken for the interior lighting was deliberately restrained and respectful. However, the simple palette of lighting approaches that was used required some complex and accurately crafted installations to create the perfect results.

The main prayer hall is the principal space in the complex and is the most ornately decorated of the public spaces. The hall is large enough to accommodate over 7,000 worshippers and is topped by three domes, including the largest dome of its kind, which stands at 280 feet. All the surfaces of this vast space are intricately decorated, from the world’s largest handwoven carpet (18,460 square feet) on the floor to the inlaid marble walls and carved plasterwork of the ceiling. The hall is a visual feast of decoration.

With this in mind, Speirs and Major

creating another pattern of holes in the ornate plaster ceiling by installing the lighting there. Despite the vast proportions of the space, the decision was taken to use the vertical surfaces as the principal “light givers.” The whole hall was envisioned as being a luminous object with light seeming to emanate from the walls. For the designers it was important that the light was as even as possible over the full height of the outer walls so that the whole surface became luminous. In more modest spaces this can easily be achieved with good-quality wall-wash luminaires that are specifically designed for such a purpose. However, this is not a typical architectural space, and the 44-feet height of the walls precluded the effective use of such luminaires, which might have managed to light only the top 15 feet of the wall effectively.

The other self-imposed restriction was that the designers were determined to position the luminaires in such a way that they would not be seen from any normal viewing position at ground level. The solution involved the use of a 31_⁄-feet-

Left

There are two open prayer halls behind the main prayer hall that open directly on to the courtyard beyond. The designers wanted to create a unifying feel in these spaces, with luminous walls washed from a perimeter slot at high level. The ceilings in the open prayer halls are 37 feet above floor level, so the wall-wash solution uses different luminaires and a different slot detail to create the same effect as in the prayer hall. The luminous vertical walls approach was repeated in external lobbies and colonnades; each type of space required a different, carefully crafted lighting treatment to create a continuity of lit effect. The open prayer halls have wind catchers on the roof; these are capped with decorative open fretwork grilles at ceiling level. These grilles, and some smaller decorative ones, are backlit to provide additional lighting for the space. The backlighting to the fretwork changes color over the course of the day to represent external daylight conditions. The color gradually shifts from the crisp white daylight feel of this image to a subtle midnight blue in the evening.

When higher light levels are required, a small number of recessed downlights are switched on (as seen here) to provide direct light at ground level.

Opposite

Although the ambient light levels at ground level are not high, the use of strong wall washing to create luminous vertical surfaces gives the perception of a space that is much brighter than would be measured by a lux meter. The lighting is dynamic and changes depending on activities inside the building and the time of day.

Above

The only way to ensure the best visual results for the wall wash was to build a full-size mock-up. The vertical wall was modeled on the ground plane to allow foot- candle level measurements to be taken and so that the luminaires were easy to reach for adjustments. Earlier computer modeling suggested that the idea of creating a wall wash from two different sets of luminaires could work in principle, but the physical tests were required to determine the details. Different tilt angles were tested, measured, and photographed before the best option was chosen. For the final installation, both the wall-wash luminaires for the upper wall and the spotlight luminaires for the lower wall were specified with a tilt angle of 2.5º. This angle was preset in the factory so that every luminaire would be exactly the same. The cornice-level gold and silver reflectors seen in these images were replaced with white marble to produce a softer, untinted reflection.

Below left

The mock-up was created on a theater stage. The installation was turned on its side to make the testing easier, with the stage floor representing the vertical wall. The test setup allowed for the adjustment of the spacing between luminaires, the distance between luminaires and the lit surface, and the tilt angle of the luminaires. This image shows the testing of four very narrow-beam spotlights fitted with linear spread lenses. These luminaires were used to illuminate the lower part of the wall.

Each narrow spotlight was partnered with a luminaire with wall-wash reflector that was used to illuminate the upper part of the wall. One of the wall-wash luminaires, switched off for the test, is in the center of the image. The luminaires were to be concealed in a slot above the ceiling; the scaffold bars on the ground represented the ceiling plane in the test.

Below right

This photograph, taken during construction, shows how well the wall wash illuminates the floral-patterned inlaid- marble walls.

0º tilt (parallel to wall) 5º tilt (parallel to wall) 10º tilt (parallel to wall) 20º tilt (parallel to wall)

Reflector options for cornice 16 meters

Lighting for architecture 117

Above

Despite the scale of the mosque, the construction of the lighting slot had to be millimeter-perfect. The lighting is maintained from above and a maintenance walkway runs above the ceiling level. The luminaire to the right in this partial section drawing is a special-use spotlight, which is directed into the hall and is only used to provide additional light at ground level for television broadcasts. The pairs of wall-wash luminaires are on the left of the drawing and face toward the vertical wall. As it is possible for people to see into the slot when they are standing close to the wall, the detailing was carefully considered. The materials used for the decorative wall are run into the slot and a gentle curve wraps the vertical surface round to create a soffit without introducing a visible line. The wall-wash luminaires are actually centered over the

edge of the ceiling, which makes it possible to look into the slot from ground level without being blinded by the luminaires. This means some light from the luminaires is cut off by the soffit line. This light was put to use by creating a carefully angled reflector panel that reflects light back into the slot to ensure there are no visible scallops of light from the various luminaires.

POTENTIAL LOCATIONS OF CABLE ROUTING ONLY. REFER TO ELECTRICAL ENGINEER'S DRAWINGS FOR CABLE ROUTING DETAILS. DRAWING PACKAGES: RAP-PN-ELI... RAP-PN-EPW... RAP-PS-ELI... RAP-PS-EPW... Power supply Mechanical fixing and electrical supply to luminaire for gear housing Unistrut support for luminaire mechanical fixing

Luminaires HAB & HAC to be mounted in row. See plan for distances

Ref. HAB

Ref. HAC Ref. HAH

12 in from the underside of the finished slot ceiling to the structural support

32 in from finished ceiling level to the underside of the

slot ceiling Fixed reflector panel Fretwork ceiling 380 245 20º 245 280 Plasterboard finish equal to marble design texture, color, and reflectivity

R 300

+751_⁄2 in to

spatium specification

c.123_⁄4 in for marble and structure

to spatium specification

431_{⁄4 in from finish of marble wall to}

centerline of luminaire stirrup 51 in from finish of marble wall to

edge of upper ceiling plane 55 in clear opening from finish of marble wall to centerline of

luminaire stirrup 60 in from finish of marble wall to

edge of ceiling 69 in from finish of marble wall to

edge of upper ceiling plane Marble tile finish

and a careful layering of light sources to create the desired effect. Extensive testing proved that the full 771_{⁄2 feet of the side walls (including the}

slot) could be evenly illuminated from a series of luminaires mounted only 5 feet from the wall surface.

The lighting designers’ instinct was that it might be just about feasible to make this solution work, but not with proprietary wall-wash lighting systems. A solution was found by testing different luminaire combinations and positions using a virtual model built in DIALux lighting design software. However, computer modeling was only one part of the testing, because the results could not effectively describe what the lighting would really look like. Given the scale of the task and the very small space available to work with, it was essential to produce a full-size mock-up so that the lit effect could be properly assessed visually, and precise measurements of the aiming angles and spacing of the luminaires could be made. The task of setting up the mock-up was not easy. There are not many suitable spaces with a large enough area of flat surface and complete

tests. In the end, the tests were carried out on the stage of a large theater that was empty between productions.

The full-scale mock-up allowed the designers to check how closely the results from the computer modeling matched the measured results from the real luminaires. Minor changes were made as a result, and the designers were confident they could detail a solution that would work for the final installation.

Above

Although it is possible to see into the perimeter slot from the edges of the room, the wall-wash luminaires are positioned in such a way that they cannot be seen from any normal viewing position at ground level. The dark dots in the image are special luminaires used only for television broadcasts.

Opposite

The lighting design includes direct lighting in areas where higher light levels are required, such as providing light for worshippers who wish to study the copies of the Qur’an located between the column clusters. The wall-wash treatment is the principal lighting for the floral walls, but they also contain inlaid glass patterns that are backlit at certain times of day to suggest daylight filtering through the colored glass. As this decorative wall is actually several yards from the outer skin of the building, the backlighting is provided by fluorescent strips mounted behind the glass.