Smokestacks

Pillars of Western Civilization

Everyone blames smokestacks for pollution these days, though they are one of the most effective antipollution devices ever invented When the smokestack- makers of the world held a convention in Venice not long ago, at times it seemed like the huddling of an endangered species. "The Swedes are after us," said Professor F. Johnsen of Denmark. "They say we are destroying their forests." "Everyone is after us," said Mr. Max Beaumont of England. "Every time a tree or a fish dies in Europe, we get the blame."

Venice was an appropriate venue for this meeting. In the brief periods when they could see anything at all through the circumambient smog, the participants could see across the lagoon the smoking chimneys of Mestre and Marghera, where the Italian government a generation ago installed oil refineries and chemical plants to provide an industrial base for the region's economy and keep Venice from becoming merely a museum city. Now the Venetians angrily watch their monuments being eaten away by sulfuric acid in the air, and they are loudly putting all of the blame on Mestre and Marghera.


It does the smokestack makers little good to point out that if all the refinery chimneys were pulled down, some sulfur dioxide would still be coming out of the houses in Venice itself. Though like London, where thousands of people used to die yearly as a result of the noxious effusions from millions of home heating units burning soft coal, Venice has spectacularly cleaned up its air by requiring all householders to convert to oil heat, the complaints are as loud as ever. The people may be healthier, but their buildings and their landmarks are still sick. And Venice still lives or dies by the number of tourists who can be counted on to visit those landmarks.
It is easier to direct indignation at giant chimneys lording it over miles of countryside than at millions of inoffensive citizens heating their homes and driving automobiles. So in Venice, as in Pittsburgh, the Ruhr valley and most other industrialized parts of the world, it is the smokestack that has become the symbol of a dirty, decaying culture, an eyesore and an embarrassment in this squeaky-clean era of microchips and solar energy.


But sometimes people who condemn smokestacks as purveyors of pollution overlook their reasons for being in the first place. If you insist upon using electricity, you still need utility plants, and they require smokestacks. It you want to fly in planes, you must have aluminum mills, and they need smokestacks. If you want to read magazines, you need pulp mills, and they have smokestacks, too. Take away smokestacks and you take away most of the comforts and conveniences, and many of the necessities, of civilized life. A smokestack, after all, is only a chimney grown tall – more than 100 feet tall, according to the definition of the Comité International des Cheminées Industrielles (CICIND), the people who met in Venice. And the chimney is both the oldest and one of the most important antipollution devices in human history. When Homo erectus, or whoever, discovered the use of fire some half-million years ago, he also discovered that where there is fire there is smoke. And when, in the course of time, he took fire indoors for cooking meals and keeping the family warm in winter, he took the smoke in with him, to sear his lungs and eyes and expose his body to carcinogens. He did the best he could to get rid of the smoke by making holes in the roof or slits in the walls, which remained the standard human practice for tens of thousands of years and still is in many parts of the world today.
It took mankind a long time to develop the chimney. In the warm climates of Egypt and Mesopotamia, where civilization began, the heating of houses was not an urgent problem. Such at least was the general scholarly opinion until a French expedition recently published its findings after the excavation of the great lost city of Mari on the upper Euphrates revealed a place studded with chimneys nearly 4,000 years old. A current theory is that the idea of the chimney was brought to western Europe from the East more than 1,300 years ago by Syrian and Jewish traders, before trade with the East was cut off by the Arab invasions.
Whenever it happened, it was a turning point in history. For the West would take the chimney and turn it into the smokestack and use it to impose the patterns and structures of its civilization on every nook and cranny of the inhabited world.
Not all at once, of course. For its first few centuries, western chimneys would go on being merely imitations of, or gradual improvements on, eastern chimneys, providing welcome comfort to the rich and powerful, the people for whom comfort was invented in the first place.


. In the 11th-century reign of Norway's King Olaf III, one of the kingly acts deemed worthy of record was the installation of corner fireplaces with chimneys in the royal residence. Perhaps the oldest chimneys still standing are in the kitchen building of the 12th-century abbey of Fontevrault, where Henry II of England, his wife, Eleanor of Aquitame, and their son Richard the Lion Heart are buried. The abbey's five huge wood-burning fireplaces, used for cooking and smoking meat and fish for a monastic community of several hundred persons, are ingeniously connected to 20 pencil-shaped stone chimneys that blend harmoniously with the structure's Romanesque architecture.
Other early chimney makers were less skillful, or had fewer resources, than the monks of Fontevrault. They used rude methods like sticking a barrel with both ends removed through a hole in the roof, or building a framework of notched branches covered with clay, as was later to be done on the American frontier. If they were rich enough to afford stone or brick, they generally made the chimneys so large that almost all the heat would go straight up, and anyone roasting his front at the fire would be sure of freezing his rear. Design improved gradually. As people learned they could heat individual rooms and not have to huddle together in a great hall or kitchen, they began to build more and more chimneys. In the economic boom of the 15th century, Europe went wild for them, as you can see documented in two of the era's great works of art.


In the calendar that forms part of the book called Les Très Riches Hcures du Due de Berry, made for the Duke by the Limbourg brothers in the early 1400s, the page illustrating October shows the Louvre Palace in Paris as it was in the time of king Charles VI – a gleaming, sprawling, Gothic structure with a chaos of chimneys popping up here and there all over its acres of roof, wherever the King and his attendant lords wanted a warm place to eat or sleep or dance or dally with the ladies. The page for February presents a peasant hut, modest enough, but it, too, has a chimney, made of braided wicker, presumably daubed inside with mud to make it airtight and keep it from catching fire.
At the end of the century, Carpaccio's Miracle of the True Cross, one of the most famous or Renaissance paintings, reveals how the fad had spread to middle-class households. The "miracle" of the title takes place on the left side of the painting, on a balcony overlooking the Grand Canal where the Patriarch of Venice is healing a lunatic. The event is almost lost in the vast panorama of bright bustling city life, capped by a forest of tulip-shaped chimneys jutting sharply into the sky, tangible evidence of the newfangled comfort that the merchants of Venice could afford.
Such chimneys were journey work, stuck more or less at random through the roof wherever they were needed. But as time went on, architects began discovering the decorative possibilities of chimneys, and the country houses of Tudor England and Valois France were soon crowned with fantastic shapes and patterns. The Chateau of Chambord, which Francis I started in 1519, has 365 chimneys, each different, each decked out with sculpted shields, wreaths, columns, animals or nymphs.


Historically, chimney building had been an empirical art, the builders of one generation passing on their closely guarded secrets to the next. It was not until the end of the 18th century that a colorful inventor named Count von Rumford dispelled some of the mystery. Formerly known as plain Benjamin Thompson living in Rumford (now Concord), New Hampshire, he had been forced to leave the United States in 1776 because of his loyalist sympathies. A physicist, he spent some time in the British Civil Service before becoming the war and police minister of Bavaria and acquiring the title by which he is known to history. His scientific investigations led to the basic design of the fireplace and chimney as we know it today: a combustion chamber with slanted back to radiate heat into the room; a narrowed opening above the chamber, outfitted with a damper to regulate the draft; a flue to convey smoke and gases up the chimney; and a "shelf" at the bottom of the flue to prevent downdrafts from blowing smoke into the room.
Eventually the chimney became a universal symbol of warmth, protection and human solidarity. The traveler, in days when travel was slow and painful, could espy the smoke rising from far off and know that human fellowship was waiting for him, ready to refresh and revive. As he approached a town he could count the smoking chimneys and know how many households were active.
Chimney counting could have its sinister side as well. Once Spain's grand inquisitor took a colleague up to the top of a tower in Seville on a Saturday and said, in effect, "You see how cold it is. Yet how many chimneys do you see smoking?" He was referring to the houses of Jews who had converted to Christianity in fear for their lives, but could not bring themselves to light a fire on the Jewish Sabbath and were thus unknowingly marking themselves out for the stake.


In 17th-century England, a distinctly unpopular tax was the one that charged ten shillings for every chimney in the land. The revenue officials loved it because it is very difficult to conceal a chimney. But the people thought it grossly unfair – understandably, since a rich man was unlikely to have all that many more chimneys than a poor one. It was considered one of the finest accomplishments of the Glorious Revolution of 1688 that it got rid of this hated levy.
Count Rumford's 18th century may be considered the golden age of chimneys. It was a time when, all across the green peaceful lands of England, Holland and America, neat brick chimneys smoked comfortably over neat brick houses, when city dwellers no longer had to shiver in bed from fall to spring but learned how to heat their apartments, resulting in all those chimney pots sprouting up on the roofs—still a picturesque sight in the older quarters of cities like London and Paris.
The chimneys inevitably filled up with soot, however, and had to be cleaned out. It might have been done reasonably well with long brushes, but it was considered more efficient and economical to use "climbing boys." They had to be small, for the flues were sometimes no wider than the length of two bricks, and though by law in England the boys had to be at least 8 years old, they were often no more than 4. Up they went, crying and complaining, sometimes prodded from below by pins stuck into their bare feet. They spent their lives caked in black dirt and they generally died young from inflammation of the lungs or from "chimney-sweeps' disease," which was cancer of the scrotum. But it was not until 1875 that climbing boys were banned by Parliament.



By 1875, chimneys were wellnigh universal in the western world. And their very nature had changed. Western civilization has always been marked off from others by its restlessness, its obsessive desire for change and improvement, for what it is pleased to call progress. Just as it borrowed gunpowder from the Chinese, who had been using it for centuries to make fireworks, and turned it into an instrument for the conquest of all rivals. so it turned the chimney into a device for imposing the patterns and structures of its civilization on every nook and cranny of the inhabited world.
What brought all the other civilizations to heel, however venerable they might be, was the Industrial Revolution which began to pick up steam in the eighteenth century. The heart of the Industrial Revolution was the factory, and it is a rare factory which does not need a chimney.
Not any old chimney, a tall chimney, a smokestack.
Height was a matter of sheer necessity. Factory owners might have little or no regard for the safety or the comfort of their workers, but it was readily apparent that work could not be done well if men and women were surrounded by thick clouds of smoke or the factory was in continual danger of catching fire. At first they tried to blow the smoke away with fans, but that only blew it into neighboring houses and factories. So they were driven to constructing freestanding chimneys, and these stretched higher and higher.


Factory owners learned that there was a correlation between the height of a chimney and the intensity of the draft it created. They learned that the volume of the gases to be exhausted, the temperature of those gases and the temperature of the outside air were variables that also contributed to that intensity. And they discovered what had escaped home builders through the centuries, that downdrafts are not caused by mysterious forces. They are caused simply by the fact that winds meeting an obstacle, like hills or tall trees or buildings, go up them on one side and down on the other. So smoke- stacks had to be built higher than the adjacent trees, buildings or hills.


A smokestack is almost always round – a cylinder or, more often, a truncated cone – because that is the best aerodynamic shape to handle winds buffeting it from without and hot gases that may be swirling upward at a rate of 60 mph within. About what it should look like, there have always been two schools of thought. Some have preferred to put up their smokestacks plain and bare, naked expressions of power rising from the earth, a thrill to the owner's heart and, of course, the least expensive way of doing things. But others have wanted their stacks more or less elaborately disguised, decorated, beautified. Even today there are smokestacks covered with colorful patterns or sculpted to look like medieval bell towers or columns from the portico of a Greek temple. In Houston, the three stacks of the Anheuser-Busch brewery are designed to look like a tall, skinny, windowless building. Whatever they looked like, smokestacks had to be built to last. If a factory's stack stopped working, so did the factory. Consequently, industrial towers were constructed to withstand hurricanes, earthquakes, explosions, the steady pounding of rain, and the corrosive effects of hot gases shooting up their insides. In the 19th century they were made of solid masonry, brick and sometimes stone; the masonry might be several meters thick. One can appreciate their staying power by driving almost anywhere on the back roads of America or Europe and coming across the remains of long-abandoned factories. Nothing may be left of the main building but an outcropping of foundation stones and some rusted fragments of machinery. But the smokestack still stands.
Smokestacks proved their mettle in World War II. American airmen boasted at the start of the war that with the Norden bombsight they could hit a pickle barrel from a height of ten thousand feet. Whatever happened to pickle barrels there is no recorded instance of a bomb from any height going straight down a smokestack and destroying it. There are for that matter few if any recorded instances of giant smokestack being permanently put out of commission by enemy bombs and shells. The machinery and the workers at their base might often be destroyed, but machinery and workers could usually be fairly quickly replaced. A recurring image in the accounts of people who traveled in Germany during the war is of a town of city reduced to acres of smoking ruins, with no traffic in what once were streets and the smell of death everywhere, while in a ring around it in its suburbs the giant chimneys go on belching flame and smoke into the sky day and night,



Today, smokestacks are made of reinforced concrete, steel, fiberglass. The fundamental design is very simple: an outer shell to protect against the elements and a lining impervious to the smoke going up through it. In many big modern stacks, the shell and lining are separate structures; the air in between helps insulate against abrupt changes in temperature and provides space for inspection and repair crews to operate. Some giant stacks have, four, five or even more flues inside. The choice of materials, dimensions and safety devices poses formidable technical problems. They involve complicated laws of dynamics affecting an upright cylinder subject to the creeping and stretching caused by radial, axial and circumferential stresses. "When in doubt," says Mike Pritchard, an Exxon engineer and former president of CICIND, "the rule is, go for safety." The biggest threat is wind. Not what they call the "long-wind," the ordinary blasts we feel anytime we are outdoors; well-anchored well-built stacks will not be pushed over even by tornadoes. It is rather the crosswinds that are set up when the onrushing air, blocked by the stack, has to divide its flow to jostle its way around it. This movement sets up a succession of little vortices on each side, and the vacuums at the heart of these vortices pull the stack now one way, now the other. Every freestanding cylinder has its own harmonic, a frequency at which it will start to vibrate like a tuning fork. When a 250-foot-high chimney starts to "shudder" twice its own diameter in alternate directions, it is a terrifying sight for anyone who happens to be standing nearby. Max Beaumont, a chimney manufacturer in Mere Wiltshire, England, remembers climbing a 300-foot smokestack ladder in a roaring wind one night to attach guy-ropes that could control such shaking. Most big chimneys these days have some kind of antivibration device, such as fiber-glass bands that spiral around the shell.


For a long time, the thing smokestack makers worried most about was finding an economical way to make chimneys that were solid enough on the ground and high enough in the air to establish a draft that would keep the fires roaring. But as industries expanded and populations grew and the demand for electricity mushroomed, those fires began to spew into the atmosphere unprecedented amounts of pollution.
Responding to criticism from environmentalists, smokestack makers first thought that the simple answer to pollution was to make the chimneys higher, carrying the noxious material to upper layers of the atmosphere where it could be harmlessly dispersed in infinitesimal fragments and drift away. This did wonders for the local communities; fishing villages could welcome giant oil refineries into their midst and stay clean as well as prosperous. But unsettling reports soon began to come in from more distant places. CICIND members speak of the tallest smokestack in the world, the 1,250-foot one built for a nickel and copper smelter in Sudbury, Ontario Nickel and copper smelters are notorious for the amount of sulfur dioxide they put into the atmosphere, and three smaller stacks at Sudbury had been blamed for damaging vegetation and wildlife for miles around. The new stack, hailed by its builders in 1972 as a landmark in pollution control as well as a marvel of structural efficiency, has been blamed for threatening vegetation and waterways hundreds of miles downwind.
For years, factories and utilities in the United States have also been pouring pollution into the atmosphere.


When Congress passed the Clean Air Act of 1970, it required the Environmental Protection Agency to stipulate standards for levels of sulfur oxides and other damaging emissions. It also established clean-up deadlines, required new plants to adopt modern abatement technologies and, in a 1977 amendment, forbade the use of tall stacks as an alternative to emission controls.
Pollution varies from stack to stack, depending on what is being burned, processed or refined. Clean-up technologies vary, too. An important device for limiting sulfur oxide emissions is the flue gas scrubber, which transforms the offending matter into sludge or dry particles that can then be disposed of. Particulates are removed from smoke with filters or precipitators; hydrocarbons are burned off.


Scrubbers can have an unexpected esthetic effect. They may produce smoke that looks creamy white, leading an unwary observer to the conclusion that it is quite clean. Not so. Though scrubbers can be very efficient, getting rid of all but a few percentage points of the pollutant matter, the remaining pollution can do damage. In the form of acid rain, it destroys life and sometimes even upsets international relations. Acid rain is not a new phenomenon, however. The name was coined in 1872 by English engineer Robert Angus Smith in a work called Air and Rain: The Beginnings of a Chemical Climatology. He applied the term to the "acidifiers and organic substances of combustion processes existing in precipitation." Acid rain contains heavy concentrations of sulfuric and nitric acids, formed when emissions of sulfur and nitrogen oxides produced in the combustion process combine with water vapor in the atmosphere. It has been blamed for everything from troutless streams in Maine to the high mortality rate from senile dementia in southern Norway. Acid rain now occurs all over the world and, closer to home, has become a serious bone of contention between the United States and Canada. Waterways and structures, forests and wildlife are potential victims. Even smokestacks may be endangered, for there are reports of steel reinforcing rods corroding inside the concrete shells of chimneys. A likely cause is a loss of alkalinity in the concrete that makes it less resistant to moisture, causing it to deteriorate and expose reinforcing rods near the surface to corrosion.
Smokestack makers are paying close attention to the new techniques that are being proposed for suppressing the emissions that cause acid rain. There is a Swiss process for grinding coal so fine that sulfur particles can be removed mechanically before burning. There are methods of combustion that fix the sulfur in the form of sodium sulfide, which does not burn and therefore cannot go up in smoke. There is a way of spraying in chemicals to combine with sulfur during combustion, converting it to forms that can be re- moved before they reach the chimney.
The trouble with all of these processes is the tremendous expense of converting to any of them, and the fact that some have not been tested long enough to determine their effectiveness. Enthusiasm for clean air has its pocketbook dimension. People in the Mid-west will weep freely for maple trees dying in Vermont, but when they hear that cleaning up the smoke at local power plants may threaten their jobs or increase their utility bills, Vermont suddenly seems far away. Most public opinion polls, however, show overwhelming support for antipollution measures.


The smokestack makers have little doubt that under the pressure of necessity both technical and monetary problems can be solved. They expect to be in business for a long time to come. Ray Warren, who makes smokestacks in Atlanta, is typical. "As long as you are burning a fuel," he says, "you are going to have waste, for no combustion process is perfect. And the only places to put that waste are land, sea and air. Land and sea pose their own problems, as the chemical and nuclear industries have been learning over recent years. Only the air is left, and the only way to get to the air is through some form of smokestack—hopefully a nonpolluting one."
Everybody needs smokestacks. High-rise apartment buildings need them, chastely tucked away in their middles, for their furnaces and incinerators. Nuclear plants, which do not dare let their own wastes escape into the air, need start-up boilers and these need smokestacks. Some day, perhaps, new miracle processes, long foretold, will come into the world of reality, and we will get most of our energy from the sun's rays or the hydrogen atom or some other immaculate source. When that day arrives, perhaps CICIND will disband. But its handiwork will linger on. Solidly anchored, too bulky and too costly to tear down, fortified against wind and weather, smokestacks will no doubt be sticking up into the clear skies of the 22nd century, reminders of the time when they did the dirty work for a great industrial age.

©1987 Robert Wernick
Smithsonian Magazine September 1987

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