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I N F O
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A D D I T I O N A L   I N F O
P A R T   I I I


CONSTRUCTION AND EQUIPMENT
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In-building equipment development
Construction logistics
Structural notes (September 11th)
The facade materials
The glass walls
Rooftop water tanks and water supply
Elevators - the lifeline
NYC skyscrapers with public observatories
Advertisement signs



* IN-BUILDING EQUIPMENT DEVELOPMENT
AIR-CONDITIONING AND HEATING

Although building heating systems, such as steam and hot water radiators, as well as warmed air blown into the spaces with fans, were all developed by the end of the 19th Century, the effective cooling of interiors was still a problem.

The cooling problem itself had been solved already in 1851 with the introduction of refrigerating machinery in France by Ferdinand Carré and the ice-making device by John Gorrie in the USA, but in order to gain the wanted atmosphere, also humidity had to be removed from the incoming cooling air.

The solution came in 1902 with an idea by Willis H. Carrier of "fogging" the incoming hot and humid air, thus condensing off the humidity and cooling the air at the same time. His "Apparatus for Treating Air" was patented in 1906 and the first notable installation of a Carrier refrigerating unit was to the Rivoli Theater in New York City in 1925. During the next five years, his company equipped over 300 theaters with the cooling equipment.

Expanding to office building air-conditioning, as an inconspicuous enough installation and coupled with equipment for restoring the lost humidity into air, also followed shortly.

Two methods of air-conditioning equipment placement evolved in the 1920s and 1930s: the local and central systems. In the "local" method, the cold water for cooling was distributed to each floor, where local air-handling units supplied -- and retrieved -- the air, with the heated water returned for re-cooling. In the "central" system, a single (or a limited number) refrigerating unit provides the cooling air for all floors, with the air circulating in ductwork to and from the recipient spaces.

The advent of glass-walled skyscrapers necessitated more effective means of air-conditioning -- and during the cold months, warming. As a solution, Carrier developed his "Weathermaster" system in the late 1930s, equipping such buildings as the glass-walled United Nations Secretariat. In addition to the ceiling-mounted vents, also water convector units, supplied with either warm or cold water, were installed just inside the curtain wall to deal with the heat loss or gain through the vast window area.

Refinements to the "Weathermaster" system were forthcoming; the dual-duct system of the 1960s supplied both warm and cold air which were mixed in proportion according to the needs, and, as a more energy-conserving alternative of the 1970s, the variable air volume system, in which only air in single temperature was supplied, the amount being dictated by the heating and cooling needs. The latter system largely replaced its more energy-consuming predecessors. The brief flirt with solar panel heating in the late-1970s affected skyscraper equipping little -- examples like the Citicorp Center were pioneering but unsuccessful.

Info mainly by the Encyclopedia Britannica's building construction history.

LIGHTING

The available methods of lighting the office interiors have notably affected contemporary building design. Before the adaptation of the fluorescent illumination in the late-1930s (as compared to the much weaker and inefficient incandescent bulbs used earlier), the working spaces had to be relatively close (10 m or less) to the outer walls, and the individual windows as large as possible, thus also increasing the floor height to even 4 meters. (One would think though that the adaptation of a McGraw-Hill-like glass wall would have helped the situation more than the, after all, rather modest size of the Art Deco era openings -- although, before the introduction of effective air-conditioning, that would have also increased the heat load on the sides with direct sunlight pouring in.)

After the introduction of effective illumination, also the working spaces could be extended towards the building interiors, thus increasing the rentable office floor area dramatically. And although the amount of light isn't always the key, the windowless interior rooms still being less attractive in many cases for human workers, the interiors have been used to house machinery, such as telephone equipment in the NY Telephone Co's Barclay-Vesey Building or computer equipment in the World Financial Center towers.

The recommendations for office space lighting have increased rather drastically since the beginning of the century: from the 8 to 9 foot-candles in 1916 to over 20 in the 1930s and to 100 in the 1960s. (As a comparison, typical natural daylight levels inside an office with large floors average to about 50 to 100 foot-candles at the outer wall, although will fall drastically in the interior parts of the floor.) Just like with the air-conditioning, the ever-decreasing price of energy led to consuming higher light intensities within buildings, until the energy crisis curtailed the development.

Expanded from info from the NYC Skyscraper Museum site.
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CONSTRUCTION LOGISTICS
Due to the usually inherent lack of space -- especially in case of the small building sites along busy city streets -- adhering to strict timetables is essential.

During the work on the foundations and basement it is still possible to store equipment and materials within the building site itself, but once the tower rises higher -- and the interior and facade surface work on the street level floor start, thus ruling this floor out as temporary storage space -- especially all larger construction materials, like the structural members and exterior cladding, have to be assembled almost straight from the material transports. As there is no extra space to keep the trucks waiting in, they have to be able to unload their cargo as quickly as possible, the cargo being often fastened straight into the bulk of the rising building.

If the transports are delayed, the whole construction work is delayed until the next load arrives, if the work of unloading and fastening runs behind the schedule, several transports may stand at the site at the same time, severely disrupting the street routes (the one-way street patterns don't make it any easier to channel the trucks to possible waiting areas). In both instances the delays will cost money for the developers.

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* STRUCTURAL NOTES
FOUNDATIONS

The construction of skyscrapers often requires more careful planning than the low-rise buildings because of the differing conditions and stresses. The foundations, for example, have to carry enormous loads in a relatively small area, and choosing the right type of foundation is very important.

The foundations can consist of a concrete slab if the soil is tight enough, or of concrete or steel piles if the soil is too weak to support a slab. One possibility is to take the foundations all way down to the level of ground-rock or to a tight sand-gravel layer. With the use of caissons, pressurized wells, and later piles or concrete pillars, foundations could be extended into considerable depths to reach the supporting layer, in case of Manhattan, the subsoil bedrock.

The size of the foundations for the World Trade Center, extending six floors underground, below the surface level of Hudson River, required massive earthworks as well as construction of a concrete "dam" to keep water from seeping to the building site. The removal of 900,000 m³ of land from the Center foundations enabled the landfill for the Battery Park City in Hudson River.

In New York City the presence of Grand Central Terminal's underground railway platforms and tracks has led to special arrangements in founding the buildings directly above. All buildings between Madison and Lexington Avenues from 42nd to 46th Streets and the buildings along Park Avenue from 46th to 51st Street are founded on steel structure platforms supported by rows of columns situated between the railway tracks. Because of this, some buildings built above Grand Central's platforms have elevators starting from the second floor instead of street level because of the requirement of a pit at the bottom of an elevator shaft, an empty space extending below the elevator car. To provide space for this, elevators are thus moved up one floor. Also the structral colonnade of buildings like the ex-Union Carbide Building are based directly on the spacing of the underground supports.

Forum thread

FRAMEWORK

Another problem encountered with skyscrapers is the wind stress which can cause substantial strains within the structure. The wind stress can be usually estimated and calculated but in the case of very large or unconventional-formed masses wind tunnel tests are required. A typical method of countering horizontal wind loads is a series of shear walls or a shear core of concrete or of heavily braced steel frames. These make the framework more rigid to minimize the effects of wind, such as the uncomfortable swaying in windy conditions. The center cores are also ideal for placing the elevators and vertical services, and for the placement of rescue stairs. In very tall buildings, the swaying effects of wind can also be reduced by the use of counterweights ("dampers") on the top floors of buildings -- like in the case of the Citicorp Center.

A system nowadays used for the tallest of steel-framed skyscrapers is the tubular structure system, pioneered by the Bangladesh-born engineer Fazlur Khan while working for the architectural firm of Skidmore, Owings & Merrill. In this, the majority of columns are grouped on the outer wall, together with the stiffening horizontal plate spandrels, to form a rigid tube along the wall line, carrying both horizontal and vertical loads. These tubes can be also grouped together as was done in Chicago's Sears Tower. Also the World Trade Center towers used the tube system to deal with wind stresses, the interior steel columns within the core transmitting vertical loads only. At the WTC the floors spanned the 20 meters between the outer wall and the internal core, as well as stiffened the outer wall against wind pressures. An example of the economy of tube-type bracing as compared to standard in-frame bracing is the fact that the frame of the Chase Manhattan Bank (1960) in Downtown Manhattan took 275 kg of steel per m², whereas the tube frame of the John Hancock Building (1970) in Chicago took only 145 kg of steel per m², despite its much greater height.

The steel frame of a skyscraper has involved three methods of construction: riveting and, later, bolting and welding. The first method used was riveting, in which five-man teams worked with red-hot rivets, driving them with compressed-air hammers to form bonds between steel beams. A team could attach 800 rivets during a work-day; up to 38 teams worked at the same time on the frame of the Empire State Building. Today's steel erectors move the beams into place with large tongs and then either drive the nut to the bolt to attach the elements, or use gas or electric welding. The main advantage of a steel frame is the large span between vertical support members that can be gained; also the footprint of individual steel columns is relatively small, further freeing floorspace.

Another major material used for the supporting members is concrete. In the concrete construction method, the columns are cast into wooden moulds, around a steel reinforcement, and the slabs are cast around a mesh of steel, used to strengthen the slab against bending under loads. The frame is stiffened by the use of shear walls, a concrete tube frame with stiffening beams, or a combination of both (as in the CBS Building). A newer method is another Khan innovation, as used on the 780 Third Avenue, in which the bracing is in-built as a series of diagonal braces on the perimeter wall. The use of lightweight concrete on the floor slabs can reduce the loads on other frame members by 25 per cent. With the types of new higher-strength concrete, concrete is a potential alternative to steel in high-rise frames. The majority of new residential high-rises have, in fact, concrete frames due to the less strict grid alignment, better soundproofing and lower structural height of the flat concrete slabs, as well as its better resistance to swaying motion than steel. Also the need for less strict construction tolerances and thus less experienced workforce makes concrete a potential choice over steel. Use of concrete allows the dazzling two-day cycle in structural construction, as used recently in the just-topped out [Aug. 2000] Trump World Tower, the tallest residential building in the world. Utilizing fast-hardening concrete, a flat slab poured in one go and a sliding formwork (image) for core and columns, the frame of a floor can be constructed very quickly before moving to the floor above. Interestingly, the 100 years old method of timber supports (in lieu of steel rods or other more modern support alternatives) for the slab form plates was chosen as the fastest alternative...

In some cases, a mixed structural frame is used, with one part of the frame built with steel or composite members and another with concrete. Examples of this method are the Sheraton Centre and Olympic Tower.

The framework in a skyscraper is of course especially vulnerable to fire due to the loss of integrity that high temperatures cause in steel (and even dangerously more did so with cast-iron, which could brittle in lower temperatures), making some sort of fire protection necessary. The same problem is present also with conrete frames, which rely on internal steel rods inside the columns (and slabs) to counter the massive tensions that concrete can't alone handle. As one common solution, just like concrete protects the steel rods in concrete structures, the "H"-profiled steel columns are encased in concrete to form a square-section column with structural steel "core". Here the concrete absorbs the heat for at least long enough to evacuate the building and control the fire -- which is also helped by the installation of sprinker systems. Other means of shielding steel structural members against fire are to encase them in protective panels or to cover them with sprayed, mortar-like protection material.


The experiences from the September 2001 terrorist attacks have given new insights into fire protection in skyscrapers. The intense heat that led to the collapse of the World Trace Center towers was rather indefensible against in itself but there has been suspicion that the impacts -- from the striking aircraft in 1 and 2 WTC and from hitting debris in the case of the 7 WTC -- shook off much of that protection, baring the framework to the fire. There are still differing theories about the details of the causes that led to the collapse of all the three skyscrapers that were lost on 9/11 -- the 1, 2 and 7 World Trade Centers -- but at the time (early Dec. 2001) the following has been deducted:

In the 1 and 2 WTC, the trusses that were welded to bolted support consoles on the inside of the facade elements -- consisting of sections of columns and the interconnecting spandrel plates -- and which supported the floor plates are considered to be the cause of the collapse. As the aircraft hit the towers, to the Floors 94 to 99 in the 1 WTC (North Tower) and the Floors 78 to 84 in the 2 WTC (South Tower), the planes themselves were largely destroyed even as they burst through the outer colonnade, with limited damage to the inner core, but not before having caused an impact of approx. 11,000 (metric) tons on the buildings, with the stiffened box structure successfully countering the force and preventing them from tipping over. The outer wall of close-spaced columns also helped to shift the load around the destroyed portions of the facade. The jet fuel, however, spread throughout the floors and caused a horrific fire that was never even contemplated in laboratory tests for structural fire resistance. Steel starts to lose its strength at 600 to 800 degrees Celsius and the burning jet fuel reached in some parts temperatures almost double that figure within seconds. The intense heat led to the weakening of the trusses on the outer walls and to a subsequent failure of the bolted consoles. As the stiffening floor plates gave way, the columns on the outer walls, further weakened by fire, lost their bracing and buckled, leading to all the upper floors crashing down and a collapse of the whole building. Another "school" of opinion claims that the greatest heat around the center core would have caused the inner bracing of the floors to collapse, but in both cases the loss of the rigidity in the tube frame eventually led to the disaster. The reason for the second-hit 2 WTC collapsing first is seen to be caused by the fact that the building's center core was hit off-centerline, weakening more support columns than at the 1 WTC, where the middle of the core was hit head on, hum, so to say.
(14 Dec 2001: Although probably not decisive in itself, the towers apparently had notable portions of frame fire protection missing as the planes hit, making the structures more susceptible to fire damage.)
(12 Feb 2002: Assessments by experts have cast doubts on the steel melting being the cause of the collapse of the building frames. Although temperatures of 1,200 degrees Celsius cause steel to lose half its strength, even that isn't seen as enough to cause the collapse on a calm day. On the other hand, the theory of the loss of strength of the colonnades must have been discounted by now anyway. The uneven heating of the steel in the floor plates may have caused tensions and buckling that, in turn, stressed the consoles, which then failed. Also most of the fire load on the structure is believed to be from the burning of the huge amounts of paper, as well as other combustible materials within the tower, with the jet fuel acting mainly as an igniter.)
(26 Feb 2002: The effect of the speeds of the aircraft hitting the towers has been brought into the equation as one of the decisive factors leading to the towers' fall. The planes' speeds when they hit the towers have been estimated at 860 to 940 km/h in case of the 2 WTC and 690 to 790 km/h for the 1 WTC. (Speeds well over the 767's regulation limit of 460 km/h at that altitude and for the United plane even over the emergency dive limit.) The difference in speeds means that the 1 WTC suffered impact energy 50 percent higher than the other tower, an estimated equivalent of 0.75 tons of TNT. Only about 6 percent of such a force was needed to destroy the outer wall columns, with 25 and 56 percent to plunge through the floor plates and the inner core columns, respectively. About half of the inner core columns may have been damaged with such an impact. The hitting point on the 2 WTC was also lower, with more weight on top of the damage point. The way the 2 WTC was hit asymmetrically seems also likely to have contributed to the faster collapse as the loads on one side couldn't be supported properly. All this is estimated to have contributed to the difference of the times the buildings stood, 2 WTC's 56 minutes as compared to 1 WTC's 102 minutes. The forces of the impacts and the subsequent building collapses were such that also the flight data recorders, the "black boxes", of the planes have almost certainly been destroyed.)
(19 Apr 2002: Another factor added to the spectrum of speculations about the destruction goes back to the upgrading of the fireproofing on structural members after the 1993 terrorist attack. The mortar-like fiber protection in the floor-supporting trusses was doubled to 1.5 inches on 18 floors on 1 WTC and 13 floors on 2 WTC -- the plane hitting the north tower happened to hit the section that was already refitted, whereas on the south tower the impact area was mostly in its old form. Whether the better fireproofing was a factor in the fact that the north tower lasted almost twice as long as its twin isn't easy to determine. The floor trusses (perhaps along with the previously mentioned perimeter wall trusses that held the floors up) are also now seen as a possible cause for the collapses.)
21 June 2003: The construction of the building under the supervision and regulations of the Port Authority -- as opposed to the city's building code, had the complex been built on city-owned land -- could also have played a role in the disaster. Despite the PA as early as in 1963 asking the structural engineers to stick to the city code and the subsequent decision to demonstrate the fire resistance of the structure as a whole, as the construction began five years later, the agency had already shifted to the more lenient regulations that the Authority-owned land allowed. The sprayed-on fireproofing, for example, was to be applied in a thin, one-half inch coating, without any fire tests taken to determine the effectiveness of a protection of that thickness on the truss structures. Even in 1975, five years after the tower opened, when a fire on the 9th to 19th floors of the 1 WTC led to sagging of parts of the floor trusses, there was no study on the effects of a major fire on the floor structures.

31 May 2005: As a late addition, an official study on the causes of the collapse (released in Oct. 2004) stated that the original assumption about the main role of the floor trusses may have been incorrect (although there are also differing voices). (Forum entry)

The conditions within the 7 WTC were somewhat more vague as the floor plates were connected to the outer columns with sturdy beams in lieu of the more light-weight trusses used in the Twin Towers. However, one explanation to the fact that the 7 WTC was the only other skyscraper to collapse around the WTC was the fact that large amounts, 160,000 liters in all (the planes had 38,000 liters of jet fuel each), of diesel fuel for emergency generators was stored within the building. Although the fuel tanks were fire-protected, the availability of fuel is a possible cause for an out-of-control fire that, possibly with some other factors, eventually led to the collapse.
26 November 2002: The Con Edison, along with its insurers, has entered a court battle with the Port Authority to get $314 million in damages for negligence in fuel tank care and the burning fuel's role in the destruction of the substation beneath the building.

Ever since the 1968 NYC fire code change that allowed the shifting from the old masonry or tile protection to a sprayed coating, there has been some concern about the latter's overall effectiveness. The belief in the effectiveness of sprinkler systems has further decreased the requirements for actual structural fireproofing, leading to higher reliance on sprinklers. This despite the uncertainty of a reliable water supply to the whole sprinkler system or its actual performance in a catastrophe. Although an extensive tile fire-protection such as the one that was built within the 90 West Street -- with its steel columns encased in 10 cm of clay tiles and a 30 cm thick floor protection of the same material as fire-proofing -- is not feasible nowadays due to its weight and expense, the apparent success of such a protection will lead to a reconsideration of fire protection means, with improvements to the formula of the sprayed mineral fiber protection to better keep it attached in case of strong impacts.

As well as giving new thoughts about fire protection, the attacks also helped to reassess the life-saving qualities of framework, with the ability to shift the loads in case that some of the columns collapse. With the beams and floor bracing calculated and appropriately sized to carry the weights even if an intermediate column is removed, an actual occurrence is much less likely to cause grief to the framework as a whole. The cases of lost outer wall columns in the 1 Bankers Trust Plaza and 3 World Financial Center are such examples from the 9/11. In fact, the command center of the Department of Design and Construction -- that leads the removal of debris from the WTC site -- in the 3 WFC is located directly above one such missing column on the outer wall...


An important part of the history of New York's skyscraper construction have been the Mohawk Indians, who are known for their extraordinary ability to work at great heights without fear. Originating from the Kahnawake reservation in present-day Canada, they first became known for their abilities during the construction of the nearby Canadian Pacific railroad bridge in 1886, starting originally as hired hands on the ground, but eventually used as ironworkers on the high bridge. They've also had their share of tragedy: 35 Mohawk lost their lives in the collapse of the then-under construction Quebec Bridge in 1907. The Mohawk also had their own small enclave in Boerum Hill in Brooklyn during the heyday of New York construction, but little by little the neighbourhood shrunk as the residents moved at least their families back to Canada while the men went after construction work where-ever needed. At the start of the new Millennium, approx. 250 Mohawks from Kahnawake work again on several New York construction sites, ranging from Brooklyn Courthouse to the imposing new (AOL) Time Warner Center, as the construction boom continues.

An NY Times article
Forum thread

Along with the other precarious occupations aloft, like the ironworkers and window washers, the hod hoist carpenters are specialized in a dangerous, yet essential work: extending the steel mast along which the construction elevator, the hoist, travels. The extension work ("jumping the hoist") itself is dangerous as the workers cling to the mast structure and attach the extension sections to the top of the elevator tower and also secure the stabilizing ties to the bulding itself. The work requires seamless co-operation between the team members who often work together for years. (In August 2002, two hoist carpenters died at the construction site of the CIBC Headquarters as the clamps that temporarily secured the elevator car to the top of the tower broke off and the hoist fell 19 floors to the ground.)

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* THE FACADE MATERIALS
GENERAL

The most visible choice, along with the general form of the building, made by the designers/developers is about the facade treatment. The one hundred years have seen a myriad of NYC high-rise facade claddings that partly also reflect the technological advances of the day. The primary materials are presented below, divided by their origin.

1 - STONE FACINGS

Limestone is a sedimentary rock that consists of hardened sediments of calcium carbonate created in prehistoric seabeds from remnants of shells, corals etc.. It is usually white or light-coloured and relatively soft and porous, making it easy to cut. Limestone is probably the most common natural stone facing in the city's skyscrapers, but it has also other important uses for building industry: in smelting of iron and lead and making of Portland cement, used in concrete.
Travertine is a porous white limestone that is filled with cavities and visible remnants of fossils. Found especially in Italy. See the Grace Plaza and its, well, plaza.

Marble is a stone metamorphosed from limestone or its "cousin", dolomite, by mechanical forces and water into a crystallized form. Quarried in a variety of colours and vein patterns, marble is usually used as a polished finish. As a commercial term, marble can mean any polishable rock consisting of calcium carbonate. Marbles from Vermont in the USA and from Italy are widely used as claddings.

Granite is an igneous rock that was solidified from the molten magma below the Earth's crust. It includes quartz and is thus very durable and suitable also for demanding surroundings. Quarried in differing colours, granite is usually used in skyscrapers as a polished finish. An exception: the "Black Rock", the CBS Building is clad in unpolished black granite.

Schist is metamorphosed from shale and is characterized by distinct layers which have been used to full effect on the facade of the 100 William Street.

As porous materials, marble and limestone absorb water easily and thus expand. This may cause bending of facade plates after continuous rains or other causes of dampness, of course degrading tne look of facade. These stones are also susceptible to impurities in air, which can considerably darken the colour of the stone. Damp acidic surroundings, like rain in industrial areas, can also cause deterioration in these stones -- due to the usually polished marble finishes, the effects are more readily apparent in it than in limestone.

Marble and granite facings are usually polished to a shiny finish that not only shows better their colours and patterns, but also makes them easier to maintain, whereas limestone has been generally used as a coarser facing.

Stones can be also cut to thin, diamond-cut stone-slices of down to 6-8 millimeter thickness, as opposed to the normal 30-40 mm stone plates. These cuttings can be reinforced with, for example, layers of glass-fibre to enable the manufacture of larger plates without a loss of rigidity.

The facade stone plates are anchored to the frame with pins made of stainless steel, although in older buildings the steel pins can be of rusting type, causing the cladding blocks to fall down, something that has occured to several buildings in Chicago in recent years.

Stones are used also as durable floor finishes and pavings, as well as in interiors, indicated by the amount of marble lobbies in NYC...

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2 - BRICKS AND CERAMICS

Terra-cotta, meaning "cooked earth", is made of molded red clay that is hardened in high temperature to a red-coloured entity. It can be used as natural-coloured, painted or glazed (in the baking oven). Although considerably older as a material, its architectural use derived from the Greek in the 7th Century B.C. and had its hey-day in the Renaissance period. Easily manufacturable, cheap and enabling the molding of long series of delicately decorated facade pieces, it was a material that finally gave the skyscraper, literally, its face in the late 19-Century USA. Moreover, it was fire-resistant and light in weight, not loading the frame with its own weight to a great degree, like stone did. There are still at least 200 terra-cotta buildings in the city. Terra-cotta enabled the intensive through-building facade decoration of the Flatiron Building.

The modern-day rarity of the material made the replacement of 7,000 damaged or missing stones on the facade of the 90 West Street difficult because there are only two factories in the US that can make the variety of custom-made pieces required.

Burned brick has been around already since 3000 BC. It consists of clay that is cut or compressed into blocks that are then burned. The resulting block is usually red, but with additives or selected type of clay, manufacture of bricks of other colours is also possible. Bricks absorb water, but their mechanical and chemical durability is good -- thousands of years old structures have lasted to our day. In many NYC buildings, the facing is done by large, so called "jumbo" bricks that cover a larger area on each layer. The AT&T Building is an example of a brick-faced high-rise and the Downtown Athletic Club makes good use of glazed brick. Red brick is also found around the city in the different housing projects' usually monotonic facades.

Sandlime brick has been manufactured widely only since the turn of the century. The raw materials are sand with high quartz content, lime and water. The mass is compressed, cut to blocks and hardened. Sandlime bricks absorb water easily and deteriorate in acidic surroundings. Another facing found in city's post-war apartment buildings.

Ceramic tiles are another material dating back to antiquity. The raw material consists of clay and a variety of powdered minerals. The material is formed into thin tiles that are burned and usually glazed. Ceramic facade tiles are durable and easy to maintain, they also have a good resistance to water or chemicals.

3 - METAL FACINGS

Although cast-iron wasn't used as a facade material in considerably tall buildings, its use as a bolted-on exterior to a masonry or timber frame in the 19th Century loft buildings was followed in a similar principal by the other metal (and glass) facings. The SoHo Cast-iron District has several of these fake-masonry buildings.

Steel has been around in its present form from the mid-1800s. Steel is made from nature's iron ore which is melted and turned into raw iron in a blast furnace. That material can be then turned into either cast-iron or steel, depending on the amount of coal particles in the finished product. Cast-iron, with its higher coal content, is more brittle in high temperatures and was less suitable for tall structures, drawbacks that the Bessemer process of removing (most of) the coal removed and opened the way structurally to the really tall high-rises. As for steel's facade use, the usual material is stainess steel, with a high chrome content to prevent corrosion. Steel is rolled into plates of 0.5-1.2 mm thickness and used in skyscrapers mostly as a part of the glass facades. Nirosta ("non-rusting") steel was a type of stainless steel used in the Chrysler Building, perhaps the most famous use of facade steel cladding. Another finish type for resisting corrosion is the pre-rusted steel (Cor-Ten being one product name) in which the material is deliberately rusted to form a brown, "rusty" look, but to also form a layer on it that protects it from corrosion. A (non-high-rise) example is the Ford Foundation. Of course also protection by different coatings and finishes is possible.

Aluminium is the third most common element on the Earth, after oxygen and silicon. Aluminium is found and quarried mostly as a part of bauxite. Although the process of extracting aluminium from bauxite requires a lot of electricity, it pays much of that "investment" back with being much more recyclable and maintenance-free than steel. Although aluminium creates an oxide layer in open air as a protection against corrosion, it deteriorates if in contact with impurities and water. Corrosion can be prevented with chemical or electro-chemical surface treatments as well as finishes such as plastic layers or painting. The embossed facade of the Socony-Mobil Building is of aluminium.

The only example of the use of bronze in an NYC skyscraper facade is the Seagram Building, but the fact that it became the most expensive skyscraper ever per square foot should give one explanation (of course along with the intensively uncompromising degree of precision and the custom-made interiors)...

Copper has been used in buildings for thousands of years. It has very good resistance against corrosion in all conditions. A prominent characteristic of copper is the fact that it slowly weathers into a green surface, a sure way to tell apart an old copper surface. As copper, like alumium, oxidizes to create a protective surface (which in copper's case darkens the surface) there is really no need for specific protective treatments -- it can be, however, treated to weather into green faster than naturally. Although generally used also as a facade material, in NYC high-rises its use has been as a roof material. The Hotel Pierre is an example.

4 - CONCRETE

Concrete is a material of Roman origin, which, however, practically disappeared between the 5th and 19th Centuries. The development of Portland cement in 1824 started the widespread modern concrete industry. Concrete's raw materials are cement (different types), appropriate stone aggregate, water and additives. The mass is poured into forms, either in factory or cast in-situ, and allowed to dry.

As a "man-made" stone, the type of raw materials and method of mass mixing and drying all affect the properties of resultant finish, but in general exposed concrete absorbs water and suffers in acidic surroundings as well as under heavy mechanical wear. Also the impurities together with rainwater can cause problems, albeit usually only aesthetic (like with all light-coloured, coarse-surfaced materials).

Usual, "unflaired" concrete is gray, but different-coloured concrete can be made by choices of cement and colour pigmentation. A variety of form surfaces can be used to produce different finishes, but in facade use the work is aimed at the best possible result, especially if an exposed concrete facade is used. The surface can be also covered with ceramic or brick tiles or painted.

The exposed, pre-cast concrete elements of the ex-Pan Am Building tower are an example of skyscraper concrete facing.

5 - GLASS

The history of glass dates back to 7000 B.C., and the first modern manufacturing method is from the 17th Century. The raw materials of glass are diverse, but the most common combination is silicate oxide as the main material, natrium oxide to lower the melting temperature of the main glass material and calcium oxide as a stabilator.

Glass plates can be treated in specific ways to improve their mechanical resistance. Hardened glass will resist 5 to 7 times better the imposed mechanical loads. Laminated glass consists of two or more layers of glass that are joined with a plastic membrane to give a strong, yet transparent material. As facade members, there are also sound-muffling glasses as well as different types of sunlight protective glasses, such as selective, heat absorbing or reflective glasses.

The chemical resistance of glass is very good, there are few compounds that are harmful to glass. As glass also gets regularly cleaned (at least in the corporate skyscrapers, but don't look through your home window!), the impurities and dirt don't affect the looks of the glass-walled buildings like ones of, say, limestone. Look at any (not even so) old photo of the Chrysler or RCA/GE Building with a layer of dirt on the surface -- even in Chrysler's spire... Moreover, through the innovation of self-cleaning glass -- glass that has a coating that by absorbing sun's ultra-violet rays detaches dirt from its surface, to be washed away by rain -- the cleaning problem seems diminished too.

See also The glass walls below.

Info expanded mainly from Siikanen: Rakennusaineoppi and
the Rock pages from Compton's Encyclopedia Online.
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THE GLASS WALLS
The development of glass-making process with the introduction of sheet glass method in the 1900s, as opposed to the earlier manufacturing of plate glass, made the material much more affordable for large scale use. In the 1950s, the float glass method further eased the manufacturing process by eliminating the need for polishing and grinding.

The first multi-storey all-glass wall building was the A.O. Smith Research Building in Milwaukee (Holabird and Root, 1928), which also used aluminium for framing the glass plates. However, not until the introduction of effective air conditioning and sealants of cold-setting synthetic rubber in building industry after the WWII, was a glass-walled building feasible.

A notable factor making curtain wall so common from the 1950s on was the lack of skilled stoneworkers needed for the limestone claddings of the pre-war period. The use of glass walls also cut construction costs as opposed to limestone and brick facings. The increased amount of light and "spaciousness" also improved with the all-glass walls, superficial illumination or not.

The "new" material used for framing the glass plates of a curtain-wall skyscraper was aluminium, and its use became common after the WWII, as the costs for its energy-intensive manufacturing and anodizing decreased. In addition to its lightness and ease of forming into different shapes, a factor favouring aluminium is its resistance to corrosion.

To counter the excessive heating by sunlight, tinted and reflective glass plates were introduced in the 1950s and 1960s, respectively. In the latter, a thin layer of metallic coating was applied to a glass plate, to act as a reflector of sunlight. The green glass of the Lever Building is an example of the use of tinted glass, the 1 and 2 U.N. Plaza of the reflective glass wall. The heat-mirror glass of the 1980s has a coating on one surface of the glass plate to reflect the heat radiation from the outside, but to also bounce back the radiation that is emitted from the building (ie. loss of heat).

Info by the Encyclopedia Britannica's building construction history.

GLASS WALLS IN RESIDENTIAL BUILDINGS

The new breed of 2000s all-glass-walled residential buildings in the city brings with it not only a new residential aesthetic but also issues that extend to the technical, practical and economical. (As for the "newness", although there have been curtain-walled residential high-rise buildings (860-870 U.N. Plaza) or portions (Olympic Tower), the almost touching consensus of glass as the new "in" thing has now really made the style commonplace.)

As is so often the case, the large amount of glass has its pros and cons; ample light and views are never a bad thing for a luxury condominium, but the amount of glass walls in an apartment may add to interior design woes in arranging the furniture and the usage of the space. The abundance of floor-to-ceiling curtain wall requires that the visible interior is kept in a relatively uncluttered condition, especially if there are any other occupied buildings nearby -- something that usually is no problem for the people who opt for these apartments in the first place. The glass-walled buildings are, after all, often sought after by people who don't mind showing off a bit of the accumulated wealth and design items. (In fact, obtaining an apartment in a building designed by a "name" architect is in itself a design acquisition that is reflected in the price.) And peeping is a popular pastime (1 2) in NYC.

The heating economy of glass-walled buildings is generally worse than of those with a more traditional insulated wall with openings, although the heating and cooling demands can be reduced by the use of thermal windows and coatings (even silk-screened). Structural means, such as exterior louvers and separate, cantilevered glass walls outside the main curtain wall -- creating a buffer zone of semi-heated/cooled air in the intermediate space -- aren't particularly improving the view from an apartment or the aesthetics of the building and thus are mostly confined to other occupational uses. From an architectural point of view, the variety of shade and curtain designs within a facade can severely alter the appearance of a building (an example from the Taino Towers) from the serene sales brochure renderings. (That issue was something that Mies van der Rohe "pre-empted" by designing the Seagram Building with similar shades allover. Trying to force one vision into an apartment building is of course a failure waiting to happen.)

From an economic point-of-view, the prospect of higher costs from heating or now-competitive amenities, combined with other factors such as a possible future downturn in the Manhattan luxury market, interest rate hikes and the inevitable tax increases after the phasing out-period of the property tax abatements for new condominiums. All these factors may lead to a gradual rise of cost of living in a new building while simultaneously leading to a relative depreciation in resale value.

Whereas the so-called post-war residential buildings (ranging from the 1950s all the way to the 1980s) are generally less sought after than the pre-war or 2000s luxury units, the latter also continue to have their pecking order. The prewar co-ops, with their famously fastidious co-op boards, continue to trail the new residential condo developments in value: the average sq.ft prices in Manhattan are $972 and $1,212, respectively (Miller Samuel). The raised appraisal of the new buildings will, however, also tend to affect the value of the pre-war apartments. The limited supply and they-don't-make-them-like-this-anymore appeal of the pre-wars -- as well as the prime location of many -- are factors that also work in their favour.

For the time being, however, the sleek and modern, fully equipped, first-owner luxury condo drives the Manhattan residential market. The risen value of (also) the pre-war has led many of their owners to cash in and switch to the new design with curtain walls, modern fixtures and amenities. For example, with the Metropolitan at 181 E. 90th Street, 30 percent of the buyers moved in from the nearby pre-war buildings.

Expanded from info by the New York Times.
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* ROOFTOP WATER TANKS AND WATER SUPPLY
With all its simplicity, the water tank is a natural solution to water distribution in a high-rise city like NYC. The maintaining of water pressure required for normal day-to-day water usage can be effectively obtained only by placing water reservoir tanks on roof tops, where the water flows into plumbing with its own gravity. The tank naturally also stores a short-term water supply.

So, instead of maintaining a high water level with the high-placed communal water tanks (in a closed pipe system, the water level sets naturally to a uniform level throughout, a water tank, or tower, can serve any buildings below its water level without the need of any additional pumping equipment), high-rise buildings must rely on their own tanks which are replenished from communal reservoirs.

A typical water tank is a circular cylinder with a diameter of up to 4 meters and with a similar height, which gives a capacity of about 50,000 liters. In commercial buildings there are also separate sprinkler tanks for firefighting water supply.

Now that the water tanks made out of steel (only about 1 per cent of all) are nearing the end of their use and are being replaced by wooden tanks, nearly all the tanks in residential buildings in NYC will be of the traditional wooden construction. Tree used in these tanks has been either cedar or California redwood. Not only are the wood tanks cheaper, but they don't corrode or give water a metallic taste and they can better even out the temperature fluctuations. A water tank can be expected to last operational for 20 to 25 years, which can be considerably extended by proper maintanance.

The water for residential uses, drinking, washing and bathing, is siphoned off the top of the tank -- the water at the bottom, with the inevitable impurities, will be used for firefighting purposes. It is not uncommon that a muddy sediment of up to two-three centimeters from the natural reservoirs gets accumulated to the bottom of the tank.

The city regulations state that water tanks for consumption use must be cleaned and disinfected at least once a year. This is basically an operation where the interior of an emptied tank is scrubbed with a chlorine solution and then refilled with water, along with a mixed chlorine solution. The soaked tank is then emptied. Maintenance also caulks any holes and "fine-tunes" the hoops that hold the wood shell in place. Also the supporting structure of a tank needs to be maintained to prevent costly and inconvenient replacement operations.

The sprinkler tanks, that do not get replenished like the consumption tanks, are therefore especially vulnerable to water leaks, which can lead to loss of sprinkler efficiency and even the loss of tank due to disintegration of dry wood.

Expanded from info mainly by Cityrealty.

The first water reservoir in NYC was the Croton Reservoir, located in the place of the modern-day New York Public Library in Midtown and completed in 1842. The high-walled reservoir pool was supplied by an aqueduct from Westchester County. The completion of the reservoir enabled, along with improved firefighting capability and sanitary conditions, the first installations of running water in the city in the 1860s.

Today's water supply to the city comes from a number of connected reservoirs from the Catskills area and from the east of Hudson River.

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ELEVATORS - THE LIFELINE
One of the decisive factors in making high-rise buildings possible -- or rather, economically viable -- was the introduction of the passenger elevator with a safety device.

Working as an engineer for Elisha Otis's company, Swedish-born and schooled David Lindquist developed the gearless-traction elevator that made the building of very tall buildings possible (and profitable). Lindquist made inventions that led to all in all 64 different patents. Not for nothing is Lindquist called the "father of the New York skyline".

In 1857 Otis's first passenger elevator was installed to the Haughwout Building at 488-492 Broadway; powered by steam, the elevator climbed four storeys per minute. That commission started the triumphant expansion of the Otis Elevator Company. After that, the previously less wanted upper floor offices became the most wanted and, consequently, the most expensive ones. The "vertical railroad" of the Fifth Avenue Hotel (1859, Fifth Ave. / W 23rd St.) introduced the same trend in accommodation as the first hotel elevator in the U.S.

In the 1870s the hydraulic elevator was introduced as the next step in technical development. It used water pressure to power the elevator cars' movement and offered better efficiency than the steam engine as well as an ability to carry loads higher. The first hydraulic passenger elevator was installed, again, in New York City, at 155 Broadway in 1878.

The elevators of the early propulsion types were, however, slow and unreliable -- the hydraulic ones used water pipes for the propulsion and these could leak water inside the elevator -- a better choice was needed. The turn of the century saw the birth of the electric-powered passenger elevator. Otis installed his direct-connected geared electric elevator in NYC in 1889 and the first Gearless Traction Electric Elevator in the Beaver Building in NYC in 1903. This innovation made the elevator an integral part of the new skyscrapers that were rising all over the country. (The escalator was another innovation of the era, one that has been since used extensively to cover relatively short vertical distances in public spaces like malls, airports or lobbies.)

The increasing height of skyscrapers, as well as the technological advances, led to revisions in the New York City elevator speed limit. The Woolworth Building (1913) and the Empire State Building (1931) increased the limit to 700 ft (213 m) and 1,200 ft (365 m) per minute, respectively.

The Rockefeller Center skyscrapers were the first ones designed from the outset for the full-scale use of express elevators (for rapid transportation) and air-conditioning (for pleasant working environment, together with the maximized use of natural light) to attract tenants. The RCA Building had the office tower built around the elevator shafts, as can be seen from the jagged form of the facade. The elevators are grouped according to the vertical "areas" they serve, passing the non-served floors altogether. There are also diagrams on steel plates on the elevator bank walls, with the current positions of each elevator marked by lights.

The World Trade Center towers were the first buildings that had the interior divided into several horizontal "zones" with two "sky lobbies" at 41st and 72nd floors serving as terminals for the 23 express elevators, and from where local elevators can be taken to the destination floor within the zone. The idea was derived from a somewhat similar method used by the NYC subway, with faster express trains stopping only at certain stations, enabling faster travel to a faraway station served by a slower local train. As the "feeding" express elevators all move rapidly to the sky lobbies, much of the vertical distance can be covered in a short time -- and most importantly, also the rest of the journey to the destination floor can be made fast, because almost all of the elevator shafts on that zone are then entirely for the local elevator use, reducing the amount of congestion and waiting time for the local elevators.

The need to find an optimum solution between building core size, number of elevators and their floor-area, elevator type, elevator speed vs. rate of acceleration etc. has led to a science of its own that studies these different factors and combines them with computer simulations into an elevator system that best suits the occupants' needs. For example, a suitable amount of elevators for a building is important as too large a system (from the general operations point-of-view) usually takes too much space and costs too much, whereas too few elevators cause a bottleneck especially in peak traffic times. In the commercial centers in the North America and Europe, an undersized system is generally the preferred one of the situations above, as the trend of flexible working hours, delayed transportation (big surprise for the MTA or London Underground users!) etc. makes peak traffic somewhat less than in the past. As for hotels and residential buildings, a somewhat oversized system is preferred.

The Petronas Towers in Malaysia have taken this development to its heights (indeed) with not only using the zone system with computer-controlled express and local elevators, but also using double-decked elevator cars (ie. ones serving two floors at the same time). The combination enables carrying of more passengers without enlarging the shafts or increasing their amount, with the zone system providing the needed speed (as well as respite from the air pressure change during a long travel at high speed). At the Sears Tower in Chicago the express elevators are double-decked, but the locals are single-decked.

The so-called super-speed elevators with speeds exceeding 2000 feet per minute, or 10 meters per second, provide designers a truly swift means to reach the upper floors or upper skylobbies, but speed is however not the whole truth about a system's effectiveness. In fact, slower elevators with swifter acceleration and deceleration can give the same overall performance in buildings of up to approx. 70 floors without the adverse effects of changes in air pressure that can be felt unpleasantly in ears. Fast acceleration also helps in gaining travel speed between stops to collect or drop off passengers.

In fact, in an example with eight double-decked, "normal" high-speed elevators rising to 400 meters, it would require 14 super-speed single-decker elevators to handle the same volume of passengers. Should the acceleration rate for the single-deckers be lowered to a more common value, a 15th elevator would be required to compensate for the increased travel time. Increasing single-deck elevator size also has its drawbacks as in large elevators people don't voluntarily fill the space as effectively as in smaller ones -- with observation deck etc. "ushered" elevators that can be overcome by elevator operators filling the whole elevator floor with people from the queue.

In addition to the air pressure problem, the super-speed elevator cars also have to be built to counter air resistance with streamlining, buffeting and noise with structural means, as well as improved safety control measures, increasing costs.

A decrease in the amount of elevators with double-decked or faster designs will usually lead to diminished core area within the internal plan, at the same time reducing the one portion of the building that helps supporting it against lateral loads with its concrete walls and trusswork. In these cases additional stiffening of the frame has to be performed to gain adequate support.

The Otis Elevator Company continues to introduce new schemes and technologies to elevator systems. The 1996 Odyssey Integrated Building Transit System featured elevators that could travel also in horizontal plane and transfer hoistways as a way to reduce elevator core area and speed up circulation. The 2000 Gen2 system replaced the steel cables with belts and featured a development of the gearless motor that doesn't require a separate machine room.

Although also cableless or non-counterweighted elevator systems are available, from the economic point of view they are less than optimum, using three to eight times more electricity than a counterweighted system. The elevators in a typical office tower use about four to eight percent of the total energy consumption -- multiplying that amount well and truly removes the effect of all the energy-conservation methods employed and adds even more strain on peak times. The possibility to use the potential energy of the counterweight takes off much of the strain and energy consumption that has to be otherwise compensated with lighter or smaller elevators, thus decreasing carrying capacity.

Rockefeller Center (as did the World Trade Center) uses the computerized SWIFT (Shorter Waiting Interval Faster Trips) Futura control system, which allows remote elevator control and troubleshooting via modem connection. (I only wait who will make the first movie about a hacker nerd "hijacking" an WTC elevator... And not to deter anyone using these elevators, but the system is using Windows 95 as the control OS -- don't know if that contributed to the August 2000 elevator clitch at the WTC, injuring people -- as the same OS is responsible for making of this site too, you can see its harmfulness...)
In general, the replacement of the old-day relay switch units with computer-controlled ones allows prioritizing of elevator calls (button presses) as well as better elevator car control in terms of acceleration, speed and positioning exactly on the floor level.

Also the regulations considering elevators are a facet that can affect elevator system performance: the US guideline for delayed door closing to accommodate possible disabled persons is one such. Also limits to elevator speeds in some countries can make the elevator system ineffective from traffic flow point-of-view.

The strongly tapering Transamerica Pyramid in San Francisco (1972) is an example of the conflicts between environmental/legal aims and, on the other hand, economic needs. The graceful, 260 m tall pyramidal form was chosen to fulfil the regulations given on a skyscraper's floor-area ratio at various heights and also to let more light to the street level. On the other hand, as the building of skyscrapers gets notably more expensive the higher it rises, the amount of the expensively built office space served by each of the elevators lessens sharply on the upper floors. As one engineer noted that the building would make more sense functionally if it were turned upside down...

A vital and essential type of elevator in a skyscraper is of course the service elevator which provides freight and upkeeping to the whole building. In office buildings there is generally one service elevator for approx. every 4,000 m² of office space, whereas, due to their differing use, in hotels their amount is as much as half of that of passenger elevators. A (sometimes) separate access, large size and stops on every floor of the building make these elevators also more suitable for the use of firefighters.

Today, no less than two-thirds of all elevators in the USA are installed in Manhattan high-rises, with an appropriately vast amount of "car" rides per year. Here the innovation and improvement of elevator technology has been embraced with special fervour because effective "car" traffic in this hectic atmosphere is considered especially important -- although one wouldn't believe it judging by the car "traffic" (of gridlocks) on the streets of Manhattan...

The History Channel: History of the Elevator and Elevator World.
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PUBLIC OBSERVATORIES
Of the buildings presented in this study, some have observation facilities open to the public:
- Empire State Building, has two observation decks, the open-air main deck on 86th floor and the enclosed smaller 102nd floor deck, although the latter is currently off-limits to the public.
- GE Building, has the 65th floor Rainbow Room restaurant, offering views of cityscape -- the building's open air deck, closed in 1986, will be reopened during 2005.
- Marriott Marquis Hotel, has an enclosed revolving rooftop lounge.
- Beekman Tower, also a hotel tower, has a top floor restaurant.
(- 2 World Trade Center, had the 107th floor enclosed deck and the 110th floor open-air rooftop deck. 1 WTC also had the 107th floor restaurant Windows on the World.)
- Although not strictly a skyscraper, Riverside Church also has a viewing facility at the top of the belfry.
In the earlier decades there have been many more more or less public observatories in the NYC high-rises, but particularly the opening of the Empire State Building observatory in 1931 meant the end for many of these. (Although Empire was itself challenged by the completion of the World Trade Center fourty years later, it still managed to attract a steady flow of tourists, not least due to its central location.) In the heyday of the observation tops, there had been no fewer than 11 public observatories, but now the likes of the Metropolitan Life Insurance Tower, Chanin Building and the Chrysler Building were forced to close their observatories soon after due to lack of public interest.

In the early days of the skyscraper, Downtown (then meaning indeed the "downtown", or center, of the city) towers like the Park Row Building and Woolworth Building offered vistas rather unsurpassed in their day, at least when it came to the height of the observation place -- maybe excepting structures like the Eiffel Tower and the Washington Monument. These, along with several other Downtown viewing platforms are now closed from mere mortals. Except for board members (Chase Manhattan Bank) and other executive crust (American International Building) (and an occasional member of cleaning staff!), the Downtown views are "restricted" to the WTC towers.

Failures of the later periods include the Gulf + Western Building's and 666 Fifth Avenue's rooftop restaurants.

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ADVERTISEMENT SIGNS
SPREADING THE SIGN...

Originally, in the mid-19th Century, the advertisement signs in NYC were painted works on building walls but differed from the brand and corporate signs of today by being mainly of small-scale or local products. By the end of the century, large signs were being posted on building walls as well as empty plots. A 1905 law restricting the placement of rooftop signs was overturned in court four years later and these, as well as signs lining Central Park or billboards inside the stations of the new subway continued to be used.

In 1912, there were 37,000 signs in the city -- hundreds of thousands of square meters -- and the next year the Billboard Advertising Commission could already state the nationwide brand products and their advertising as the reason for the overpowering presence of signage in the streetscape. Although the commission recommended removal of signs from specific, important public spaces and occupying whole widths of building facades, as well as banning ads of "improper" content or style, their efforts went largely unheeded, despite some enforced restrictions on sign construction.

The first successful means for major reduction and control of sign construction and placement was the 1916 zoning resolution. The differing zones of usage within the city led to banning of signage within residential neighbourhoods -- for example, 18 billboards were removed from areas bordering Central Park and Riverside Drive in 1918.

"But there were still giant signs in nonresidential districts, like one at the northeast corner of 42nd and Fifth, facing the elegant New York Public Library: Above a four-story high sign for Fatima cigarettes ("Nothing else will do") ran a 30-foot-long sign for Venus pencils covering the cornice; on top of that rose a double-decker for Brill Brothers Kuppenheimer, a clothes dealer, and Boyshform Brassiere." (1) Hum, seems properly diverse to me, from undergarments to pencils and "Fatties"...

Moreover, as the zoning in areas like SoHo and the immediate Village dates back to 1961, as a manufacturing district, it is still legal to place advertisement signs on the buildings here, evident by the concentration of large billboards at the intersection of Broadway and Houston Street.

In Feb. 2000 the city issued new sign placement regulations that unified the guidelines of application review and increased penalties for violations (some signs can boost city finances with up to almost a million a year). Despite the tightened regulations, local civic groups continue to battle against existing or planned advertisement signs that are seen as detrimental to the immediate surroundings. The outdoor advertising companies try to counter the restrictions; the three largest companies own 80 percent of the city's outdoor sign space, with a value of hundreds of million of dollars. The selling of advertising space is also a means of income for the real estate owners, a billboard space can yield thousands of dollars additional income per month.

As an indication of the permanent impact that the signage has had on the area through decades, new developments in Times Square are today required to have compulsory signage on their facades, in order to retain the area's character as an entertainment district. And boy, have they succeeded...

GREAT WHITE WAY & TECHNOLOGY

The first large advertisements were painted straight onto the facades of buildings by sign painters, "wall dogs". A typical painting could take two months to complete and, of course, be laborous to remove or replace. Compare that to today's printed vinyl panels for still images that can be installed in a matter of hours.

The first electric sign in NYC appeared at Times Square as early as in 1905, coining the term "Great White Way" for the immediate section of Broadway. The combination of large theaters, success shows and lit-up crossroads created a phenomenon that gave Times Square world-wide fame and a pattern to follow in the future. Today, with 20 million tourists with their cameras swarming the crossroads every year, a sign at Times Square is also a guaranteed way to get visibility.

The large electrical signs were called modestly "spectaculars", a term that has survived to this day. The first spectaculars were made with incandescent bulbs, with a heyday in the inter-war era, followed by the large neon-tube signs from the late-1920s onward, the workhorses of the great expansion of Times Square signage until the 1960s. The largest of them all was the eight-storey-high, two-panelled Kleenex spectacular that stood at Broadway and 43rd St. in 1952-1965 and featured the comics character Little Lulu in an animated spectacular. Another famous (as well as bizarre) Times Square advertisement was Douglas Leigh's 1940s cigarette-advertising Camel billboard ("I'd walk a mile for a Camel") that blew smoke rings from the mouth of its painted figure. The "smoke" was steam blown at intervals as rings.

Although neon signs are still built, they were largely replaced by less arduous and more efficient choices, fluorescent lighting in the 1960s and later, in the late-1990s, computer-controlled fiber optic and panel designs. An extreme example of three-dimensional signage was the British Airways sign featuring a 34-meter fiberglass and steel Concorde model (link), replaced by the new Times Square Tower. The costs of modern electric Times Square signs can range from $1 to $20 million and take six to nine months to complete.

In the seedier days of Times Square from the 1970s to the mid-1990s, the lights on the Great White Way were largely kept shining by Japanese capital. Such companies as Canon, Panasonic, Aiwa etc. showed off their large neon signs to a perhaps less affluent or middle-class clientele as today, but as the finances of these electronic giants began to falter, the US companies made a return in force and now dominate as part of an international electronic display case.

Coca-Cola has been present at Times Square since 1920 and will be present also in the future as the lease for the neon sign on the 2 Times Square (occupied since 1932) was renewed until 2011. Having undergone several designs, in its current form the sign is a 20 m high and 12,5 m wide fiber optic spectacular and weighs 55 tons, featuring an animated 14-meter fiberglass Coke bottle. The neon signs above this, for Suntory Whisky and Samsung, also face near-future changes, with the former being removed and the latter upgraded into an electric sign. An indication of the steep sign space prices at Times Square is the annual $2.5 million for Suntory's space at the 2 Times Square.
29 October 2002: The Coca-Cola spectacular will be removed and replaced by a newer design on the same location after 11 years in operation.
11 September 2004: The new Coke sign was unveiled in July, a 12.5 by 20 meter spectacular on a 3D-shaped base, incorporating 2,646,336 leds for a pixel density of 16.5 millimeters. The sign weighs 27 metric tons and cost $6.5 million to design and build.

The building bordering the crossroads to the south, the 1 Times Square, the old Times Tower -- which, along with the theater companies brought the character to the old Longacre Square -- also sports an array of signs that are, along with the ones on 2 TSQ, perhaps the best-known in the world. The building now makes its revenue almost totally through renting space for signs ranging from the bottom "zipper" (the first electronic "running" text sign was installed here as early as in 1928) to a 12 x 9 m Panasonic-NBC screen (the successor of the 1970s incandescent bulb Spectacolor Board) and a steaming Cup O'Noodles, something that the original architects hardly could have foreseen.

Next to the 1 Times Square, the eight storeys high, curving Nasdaq screen on the corner of the Condé Nast Building, facing the crossroads, is the largest, most advanced -- and expensive -- spectacular brought to Times Square so far. The total cost of the screen and the Nasdaq Marketsite facility inside the building was $37 million, providing a rounded 1,000 m², 16.7 million-colour video screen. The 8,200 video panels that consist of 18 million light-emitting diodes (LED) can be used to work as up to eight different screens. A LED screen gives unprecedented resolution and can last 100,000 hours of operation. The lease for the screen space is $2 million a year. The ABC News' Sony Jumbotron to the north also uses LED technology in its multi-zipper display.

LED signage of the new Millennium has been incorporated to the facades in unprecendented ways. The ex-Paramount Building opened its WWF marquee with its complex LED signage right after 9/11 and the Reuters Building at 3 Times Square not only exceeded the amount of signage required by the state regulation (1,300 m², with no less than 3,150 m² actually installed) but also featured new techniques. The three-level Reuters/Instinet LED sign on the north-eastern corner comprises of 11 screens with integrated data input. Four of the screens are located inside the lobby and seven outside, and the complete matrix reaches the height of 92.5 m. The 9,107,500 LEDs can create different advertisement patterns as well as display transparent panels to create a clear glass wall. The computerized sign is used, similarly to the Nasdaq sign across Broadway, to display a wealth of different moving imagery as well as news bulletins.

With the crossroads itself saturated, also the nearby 42nd Street is gaining its share in the form of new signage, the "cacophony of signage", as the co-ordinating 42d Street Development Project has put it. In the future, with new high-rise projects along Eighth Ave., Times Square-type signage will be more evident also here, with the signage on the catty-corner "Ewalk" and Port Authority Terminal as a starting point.

Another way forward are the skyscraper top signs as exemplified by the Condé Nast and the W hotel at 47th that allow the signs to be seen from farther away than with a traditional placement. The W hotel also features a free-standing sign tower, the 90-meter Times Square Spire that will feature a fake building facade in the form of panels that can be replaced one by one by advertisement panels.

The future of the massive light displays like experienced in and around Times Square may be in jeopardy if the proposed new "light pollution" legislation gets implemented. It would regulate the amount of light-intensive signage and its effect across plot lines as "light trespassing" as well as facade lighting of buildings and street lights, leading to more directed fixtures to reduce omnidirectional spill of light. The bill's advocates hope to curb the use of electricity as well as reduce the amount of light spilling to the sky, for example blanketing the night sky. As of January 2002, the bill hasn't been yet signed by the NY Governor, with worries about its effect on the signage (and economy) of New York City causing concern, not least due to the amount of street fixtures that would have to be replaced with new ones compliant with the regulations.

The new applicants to the profession of installing (and removing) the signs go through a five-year course given by the Sheet Metal Work Sign Hangers union. They have to be able to work fastening sheets or elements of animated signs while being suspended high above the street.

Times Square Signs | Spectacolor

Info by The New York Times (also quote (1)), Nyc24.com
SignWeb, Metropolis Magazine
and Gotham Gazette.

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ENTRANCE    CONTENTS    INTRODUCTION    ALPHABETICAL LIST

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