Thunder Art Lasers clean the Tower of Pisa

Pisa, June 29th 2009

Quanta is proud to announce that its Thunder Art laser series is successfully cleaning the famous Tower of Pisa. The laser has been put on field by Dr. Alessandro Zanini of El.En., on behalf of Quanta System.

Professor of Archeology, Dr. Zanini belongs to the El.En. Group, and has been working closely with company CBC, subcontractor for the restoration works of the Tower. After a phase (1990-2008) of structural strengthening, the tower is currently undergoing gradual surface restoration, in order to repair visual damage, mostly corrosion and blackening.

These are particularly strong due to the tower's age and to its particular conditions with respect to wind, pollution and rain.

The work is done under the supervision of the Ministery of the Cultural Heritage of Italy. The project and the direction of works belong to the “Committee for the Interventions and the Restoration of the Pisa Tower " & the Central Institute for Restoration – ICR The last phase of the works foresee the conservative restoration of the surfaces.

The laser is used for cleaning the capitals of the Tower.

The History of the Tower of Pisa

The Leaning Tower of Pisa or simply The Tower of Pisa is the freestanding bell tower of the cathedral of the Italian city of Pisa. It is situated behind the cathedral and is the third oldest structure in Pisa's Cathedral Square (Piazza dei Miracoli) after the cathedral and the baptistry.

Although intended to stand vertically, the tower began leaning to the southeast soon after the onset of construction in 1173 due to a poorly laid foundation and loose substrate that has allowed the foundation to shift direction. The tower presently leans to the southwest.

The height of the tower is 55.86 m (183.27 ft) from the ground on the lowest side and 56.70 m (186.02 ft) on the highest side. The width of the walls at the base is 4.09 m (13.42 ft) and at the top 2.48 m (8.14 ft). Its weight is estimated at 14,500 metric tons (16,000 short tones). The tower has 296 steps; the seventh floor has two fewer steps on the north-facing staircase. The tower leaned at an angle of 5.5 degrees, but after the restoration works between 1990 and 2001 the tower leans at an angle of 3.99 degrees. This means that the top of the tower is 3.9 metres (12 ft 10 in) from where it would stand if the tower were perfectly vertical.

The Tower of Pisa was a work of art, performed in three stages over a period of about 177 years. Construction of the first floor of the white marble campanile began on August 9, 1173, a period of military success and prosperity. This first floor is surrounded by pillars with classical capitals, leaning against blind arches.

The tower began to sink after construction progressed to the third floor in 1178. This was due to a mere three-meter foundation, set in weak, unstable subsoil. This means the design was flawed from the beginning. Construction was subsequently halted for almost a century, because the Pisans were almost continually engaged in battles with Genoa, Lucca and Florence. This allowed time for the underlying soil to settle. Otherwise, the tower would almost certainly have toppled. In 1198, clocks were temporarily installed on the third floor of the unfinished construction. In 1272, construction resumed under Giovanni di Simone, architect of the Camposanto. In an effort to compensate for the tilt, the engineers built higher floors with one side taller than the other. This made the tower begin to lean in the other direction. Because of this, the tower is actually curved. Construction was halted again in 1284, when the Pisans were defeated by the Genoans in the Battle of Meloria.

The seventh floor was completed in 1319. The bell-chamber was not finally added until 1372. It was built by Tommaso di Andrea Pisano, who succeeded in harmonizing the Gothic elements of the bell-chamber with the Romanesque style of the tower. There are seven bells, one for each note of the musical major scale. The largest one was installed in 1655.

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Quanta System SpA was founded in 1985 and has been part of El.En group (listed on the Milan Star Stock Exchange) since January 2004. As Italian company, strongly oriented to internationalization, Quanta System has strengthened with years its presence on the markets throughout the world; it is currently organized into three business units: industrial, medical and scientific divisions.

Quanta System designs and manufactures sophisticated laser and opto-electronics devices For more information please contact: Dr. Alessandro Zanini

El.En. S.p.A.Via Baldanzese,
17 50041 Calenzano Firenze - Italy
Tel. (+39) 055.88.26.807 Fax (+39) 055.88.32.884 conservazione@elen.it