Royal Canberra Hospital implosion
The Royal Canberra Hospital implosion was a failed building implosion that killed one person and injured nine others. The implosion occurred on 13 July 1997, when the city's superseded hospital buildings at Acton Peninsula on Lake Burley Griffin were demolished to make way for the National Museum of Australia; the Royal Canberra Hospital closed on 27 November 1991 amid much controversy. Consultant physician Marcus de Laune Faunce wrote: "Towards the end of 1990 many Canberra citizens were either bewildered, angered or saddened as they realised that the Royal Canberra Hospital on Acton Peninsula was soon to be closed, its staffing structure and organisation were thought to have been planned in step with population needs and the hospital was and warmly placed in the memories and affections of many people. Its beautiful, central position on the lake had been marked by Walter Burley Griffin on his original plan. After its formative years, it served Canberra for more than three decades as a first-class hospital staffed by hard-working and caring health workers.
With its magnificent site and proximity to the Australian National University it had enormous potential as a future teaching hospital reflecting the best of Australian medical services." In April 1995 the Keating Government agreed in principle with the Australian Capital Territory Government to exchange certain sites of land within the ACT to facilitate the building of the National Museum. In July 1995 a feasibility study was undertaken for the demolition and clearance of the buildings on Acton Peninsula. On 4 August 1995 the ACT Cabinet approved a submission recommending the implosion method of demolition. On Friday 13 December 1996 the Prime Minister, John Howard, announced the design work on Acton Peninsula for the National Museum would begin immediately; the next day, a fence was erected around the site. The demolition had been planned for some time, the ACT Government decided to turn the building implosion into a spectator event. Over 100,000 people, one of the largest crowds in Canberra's history, came out to bid farewell to the birthplace of many Canberra residents.
However, the implosion of the Royal Canberra Hospital was a failure. The main building did not disintegrate and had to be manually demolished, but far worse, the explosion was not contained on the site and large pieces of debris were projected towards spectators situated 500 metres away on the opposite side of the Lake, in a location that nobody considered unsafe or inappropriate. A twelve-year-old girl, Katie Bender, was killed and nine other people were injured. Large fragments of masonry and metal were found 650 metres from the demolition site; the ACT Government led by Kate Carnell came in for sustained criticism, a number of official inquiries were held. Many people complained the event should never have been made a public spectacle, as this was inviting disaster. Other people felt that this was unfair, as implosions around the world excited local interest and had had an enviable safety record; the Chief Minister did give her full approval to promote the implosion as a public event, drawing a near-record Canberra crowd.
ACT Work Cover is the authority responsible for administering and enforcing legislation in the Australian Capital Territory covering occupational health and safety, workers' compensation, dangerous substances and labour regulation. The coroner found, it failed to ensure that the explosive workplan required by the ACT Demolition Code of Practice was met. It failed to scrutinise departures from the original demolition workplans and to issue appropriate prohibition notices in accordance with the OH&S Act to ensure the methodology was safe, not only to the workplace employees but to the public. Since the hospital demolition, the ACT Government has carried out 2 bridge implosions in secret, as part of the Gungahlin Drive Extension project; the first one was carried out with a surprise disruption to traffic in the middle of a weekday, the second one was carried at an early hour of a Saturday morning with a 1 km exclusion zone, with no prior notice given to the public. The implosions were featured in news reel footage in the film Joe Cinque's Consolation.
Photographic collection – Royal Canberra Hospital Implosion – James Nomarhas 1951
World War II
World War II known as the Second World War, was a global war that lasted from 1939 to 1945. The vast majority of the world's countries—including all the great powers—eventually formed two opposing military alliances: the Allies and the Axis. A state of total war emerged, directly involving more than 100 million people from over 30 countries; the major participants threw their entire economic and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. World War II was the deadliest conflict in human history, marked by 50 to 85 million fatalities, most of whom were civilians in the Soviet Union and China, it included massacres, the genocide of the Holocaust, strategic bombing, premeditated death from starvation and disease, the only use of nuclear weapons in war. Japan, which aimed to dominate Asia and the Pacific, was at war with China by 1937, though neither side had declared war on the other. World War II is said to have begun on 1 September 1939, with the invasion of Poland by Germany and subsequent declarations of war on Germany by France and the United Kingdom.
From late 1939 to early 1941, in a series of campaigns and treaties, Germany conquered or controlled much of continental Europe, formed the Axis alliance with Italy and Japan. Under the Molotov–Ribbentrop Pact of August 1939, Germany and the Soviet Union partitioned and annexed territories of their European neighbours, Finland and the Baltic states. Following the onset of campaigns in North Africa and East Africa, the fall of France in mid 1940, the war continued between the European Axis powers and the British Empire. War in the Balkans, the aerial Battle of Britain, the Blitz, the long Battle of the Atlantic followed. On 22 June 1941, the European Axis powers launched an invasion of the Soviet Union, opening the largest land theatre of war in history; this Eastern Front trapped most crucially the German Wehrmacht, into a war of attrition. In December 1941, Japan launched a surprise attack on the United States as well as European colonies in the Pacific. Following an immediate U. S. declaration of war against Japan, supported by one from Great Britain, the European Axis powers declared war on the U.
S. in solidarity with their Japanese ally. Rapid Japanese conquests over much of the Western Pacific ensued, perceived by many in Asia as liberation from Western dominance and resulting in the support of several armies from defeated territories; the Axis advance in the Pacific halted in 1942. Key setbacks in 1943, which included a series of German defeats on the Eastern Front, the Allied invasions of Sicily and Italy, Allied victories in the Pacific, cost the Axis its initiative and forced it into strategic retreat on all fronts. In 1944, the Western Allies invaded German-occupied France, while the Soviet Union regained its territorial losses and turned toward Germany and its allies. During 1944 and 1945 the Japanese suffered major reverses in mainland Asia in Central China, South China and Burma, while the Allies crippled the Japanese Navy and captured key Western Pacific islands; the war in Europe concluded with an invasion of Germany by the Western Allies and the Soviet Union, culminating in the capture of Berlin by Soviet troops, the suicide of Adolf Hitler and the German unconditional surrender on 8 May 1945.
Following the Potsdam Declaration by the Allies on 26 July 1945 and the refusal of Japan to surrender under its terms, the United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki on 6 and 9 August respectively. With an invasion of the Japanese archipelago imminent, the possibility of additional atomic bombings, the Soviet entry into the war against Japan and its invasion of Manchuria, Japan announced its intention to surrender on 15 August 1945, cementing total victory in Asia for the Allies. Tribunals were set up by fiat by the Allies and war crimes trials were conducted in the wake of the war both against the Germans and the Japanese. World War II changed the political social structure of the globe; the United Nations was established to foster international co-operation and prevent future conflicts. The Soviet Union and United States emerged as rival superpowers, setting the stage for the nearly half-century long Cold War. In the wake of European devastation, the influence of its great powers waned, triggering the decolonisation of Africa and Asia.
Most countries whose industries had been damaged moved towards economic expansion. Political integration in Europe, emerged as an effort to end pre-war enmities and create a common identity; the start of the war in Europe is held to be 1 September 1939, beginning with the German invasion of Poland. The dates for the beginning of war in the Pacific include the start of the Second Sino-Japanese War on 7 July 1937, or the Japanese invasion of Manchuria on 19 September 1931. Others follow the British historian A. J. P. Taylor, who held that the Sino-Japanese War and war in Europe and its colonies occurred and the two wars merged in 1941; this article uses the conventional dating. Other starting dates sometimes used for World War II include the Italian invasion of Abyssinia on 3 October 1935; the British historian Antony Beevor views the beginning of World War II as the Battles of Khalkhin Gol fought between Japan and the fo
The Kingdome was a multi-purpose stadium in Seattle's SoDo neighborhood. Owned and operated by King County, the Kingdome opened in 1976 and was best known as the home stadium of the Seattle Seahawks of the National Football League, the Seattle Mariners of Major League Baseball, the Seattle SuperSonics of the National Basketball Association; the stadium served as both the home outdoor and indoor venue for the Seattle Sounders of the North American Soccer League and hosted numerous amateur sporting events and other events. The Kingdome measured 660 feet wide from its inside walls; the idea of constructing a covered stadium for a major league football and/or baseball team was first proposed to Seattle officials in 1959. Voters rejected separate measures to approve public funding for such a stadium in 1960 and 1966, but the outcome was different in 1968. Construction began in 1972 and the stadium opened in 1976 as the home stadium of the Sounders and Seahawks; the Mariners moved in the following year, the SuperSonics moved in the next year, only to move back to the Seattle Center Coliseum in 1985.
The stadium hosted several major sports events, including the Soccer Bowl in August 1976, the Pro Bowl in January 1977, the Major League Baseball All-Star Game in July 1979, the NBA All-Star Game in 1987, the NCAA Final Four in 1984, 1989, 1995. During the 1990s, the Seahawks' and Mariners' respective ownership groups began to question the suitability of the Kingdome as a venue for each team, threatening to relocate unless new, publicly funded stadiums were built. At issue was the fact that neither team saw their shared tenancy as profitable, as well as the integrity of the stadium's roof as highlighted by the collapse of ceiling tiles onto the seating area before a scheduled Mariners game; as a result, public funding packages for new, purpose-built stadiums for the Mariners and Seahawks were approved in 1995 and 1997, respectively. The Mariners moved to Safeco Field, now known as T-Mobile Park, midway through the 1999 season, the Seahawks temporarily moved to Husky Stadium after the 1999 season.
The Kingdome was demolished by implosion on March 26, 2000. King County paid off the bonds used to build and repair the Kingdome in 2015, 15 years after its demolition. In 1959, Seattle restaurateur David L. Cohn wrote a letter to the Seattle City Council suggesting the city needed a covered stadium for a major professional sports franchise. A domed stadium was thought to be a must due to Seattle's frequent rain. At the time, the city had Husky Stadium and Sick's Stadium for collegiate football and minor league baseball but both were deemed inadequate for a major league team. In 1960, the city council placed a $15 million bond issue measure on the ballot to fund construction of a stadium, but voters rejected it due to doubt the stadium could be built within that budget, lack of a guarantee the city would have a team to play in the stadium. By 1966, the National Football League and the American League were both considering granting the city an expansion franchise, as a result the King County Council placed another bond issue measure on the ballot, rejected by voters.
In 1967, the American League granted Seattle an expansion franchise that would be known as the Seattle Pilots. The league stated Sick's Stadium was not adequate as a major-league stadium, stipulated that as a condition of being awarded the franchise, bonds had to be issued to fund construction of a domed stadium that had to be completed by 1970; the Pilots were supposed to begin play in 1971 along with the Kansas City Royals. However, when Senator Stuart Symington of Missouri got wind of those plans, he demanded both teams begin play in 1969; the American League had birthed the Royals and Pilots as a result of the Kansas City Athletics moving to Oakland, Symington would not accept the prospect of Kansas City waiting three years for baseball's return. In February 1968, as part of the Forward Thrust group of bond propositions, King County voters approved the issue of $40 million in bonds to fund construction of the "King County Multipurpose Domed Stadium." That year a committee considered over 100 sites throughout Seattle and King County for the stadium, unanimously decided the best site would be on the grounds of Seattle Center, site of the 1962 World's Fair.
Community members decried the idea, claiming the committee was influenced by special interest groups. The Pilots began play as planned in 1969, but Sick's Stadium proved to be a problematic venue for fans and visiting players alike, it soon became apparent that it was inadequate for temporary use; the Pilots only drew 677,000 fans that season, not nearly enough to break and a petition by stadium opponents brought the Sick's Stadium project to a halt. The Pilots' ownership group ran out of money by the end of the season, with the stadium plans in limbo, the team was forced to declare bankruptcy. Despite efforts by Seattle-area businessmen to buy the team as well as an attempt to keep the team in Seattle through the court system, the Pilots were sold to Milwaukee businessman Bud Selig, who relocated the team to Wisconsin and renamed it the Milwaukee Brewers a week before the start of the 1970 season; the push to build the domed stadium continued despite the lack of a major league sports team to occupy it.
In May 1970 voters rejected t
AfE-Turm was a 32-story, 116 m skyscraper in the Westend district of Frankfurt, Germany. The building was part of the Bockenheim campus of the Johann Wolfgang Goethe University and until 2013 housed the offices and seminar rooms of the departments of Social Sciences and Education. AfE is an acronym for Abteilung für Erziehungswissenschaft; the tower was demolished on February 2, 2014. Planning and construction of AfE-Turm began in the early 1960s; the building became necessary in 1961, when the College of Pedagogy was incorporated into the University, the old Bettinaschule in the Westend turned out to be inadequate as a provisional arrangement. The building inherently lacked the required functionality; the tower was the tallest building in Frankfurt until the construction of the City-Haus. The north side of the tower housed the library of the social sciences, as well as seminar rooms with 1.5 times the floor height. The south side consisted of offices only a single floor high, which required an intricate system of staircases and split-levels between the two halves complicating orientation.
After the construction, a cafeteria was established in the top floor, but was closed for lack of popularity. This floor was not accessible with all lifts, was considered a hard-to-find secret due to the good view in all directions; the student-managed TuCa on the ground floor was cleared by the police at the behest of the university administration, in order to open a café managed by the Studentenwerk, named the C'AfE. Since the beginning of 2007, the TuCa sat "in exile" on the fifth floor; the tower was designed for 2,500 students. However, the building was occupied since its opening with a multiple of that, so that at the seven elevators have waiting periods of up to fifteen minutes. In August 2005, a University employee was killed in an accident when her lift got stuck between two floors, she attempted to exit, it is still controversial whether this accident was a result of human error or a series of daily failures of the building's technology. Since the tower was to be demolished within the next few years, the university administration had to avoid all non-essential renovation work.
At intervals, facade repairs had to be carried out. The tower was a popular destination for student protests, as it could be sealed off with few helpers, in contrast to most other buildings of the university; the worsened study conditions within the tower in recent years were another motive. The resulting tower blockades were an integral part of periodic protests at the Goethe University for many years; the departments of Social Sciences and Education moved to the University's Westend Campus in Spring 2013. The building had been empty since the end of April 2013; the gradual demolition of the tower commenced in July 2013 and was finalized at the end of January 2014, when authorities gave the green light for its implosion. The implosion occurred on 2 February 2014, at 10:04 CET. List of tallest buildings in Frankfurt List of tallest buildings in Germany Media related to AfE-Tower at Wikimedia Commons AfE-Turm at A View On Cities
Ireland is an island in the North Atlantic. It is separated from Great Britain to its east by the North Channel, the Irish Sea, St George's Channel. Ireland is the second-largest island of the British Isles, the third-largest in Europe, the twentieth-largest on Earth. Politically, Ireland is divided between the Republic of Ireland, which covers five-sixths of the island, Northern Ireland, part of the United Kingdom. In 2011, the population of Ireland was about 6.6 million, ranking it the second-most populous island in Europe after Great Britain. Just under 4.8 million live in the Republic of Ireland and just over 1.8 million live in Northern Ireland. The island's geography comprises low-lying mountains surrounding a central plain, with several navigable rivers extending inland, its lush vegetation is a product of its mild but changeable climate, free of extremes in temperature. Much of Ireland was woodland until the end of the Middle Ages. Today, woodland makes up about 10% of the island, compared with a European average of over 33%, most of it is non-native conifer plantations.
There are twenty-six extant mammal species native to Ireland. The Irish climate is influenced by the Atlantic Ocean and thus moderate, winters are milder than expected for such a northerly area, although summers are cooler than those in continental Europe. Rainfall and cloud cover are abundant; the earliest evidence of human presence in Ireland is dated at 10,500 BC. Gaelic Ireland had emerged by the 1st century AD; the island was Christianised from the 5th century onward. Following the 12th century Norman invasion, England claimed sovereignty. However, English rule did not extend over the whole island until the 16th–17th century Tudor conquest, which led to colonisation by settlers from Britain. In the 1690s, a system of Protestant English rule was designed to materially disadvantage the Catholic majority and Protestant dissenters, was extended during the 18th century. With the Acts of Union in 1801, Ireland became a part of the United Kingdom. A war of independence in the early 20th century was followed by the partition of the island, creating the Irish Free State, which became sovereign over the following decades, Northern Ireland, which remained a part of the United Kingdom.
Northern Ireland saw much civil unrest from the late 1960s until the 1990s. This subsided following a political agreement in 1998. In 1973 the Republic of Ireland joined the European Economic Community while the United Kingdom, Northern Ireland, as part of it, did the same. Irish culture has had a significant influence on other cultures in the field of literature. Alongside mainstream Western culture, a strong indigenous culture exists, as expressed through Gaelic games, Irish music and the Irish language; the island's culture shares many features with that of Great Britain, including the English language, sports such as association football, horse racing, golf. The names Éire derive from Old Irish Eriu; this in turn comes from the Proto-Celtic *Iveriu, the source of Latin Hibernia. Iveriu derives from a root meaning'fat, prosperous'. During the last glacial period, up until about 10,000 BC, most of Ireland was periodically covered in ice. Sea levels were lower and Ireland, like Great Britain, formed part of continental Europe.
By 16,000 BC, rising sea levels due to ice melting caused Ireland to become separated from Great Britain. Around 6000 BC, Great Britain itself became separated from continental Europe; the earliest evidence of human presence in Ireland is dated at 10,500 BC, demonstrated by a butchered bear bone found in a cave in County Clare. It is not until about 8000 BC, that more sustained occupation of the island has been shown, with evidence for Mesolithic communities around the island; these Mesolithic communities lived as hunter-gatherers across the island until about 4000 BC. Some time before 4000 BC, Neolithic settlers arrived introducing cereal cultivars, domesticated animals such as cattle and sheep, large timber building, stone monuments; the earliest evidence for farming in Ireland or Great Britain is from Co.. Kerry, where a flint knife, cattle bones and a sheep's tooth were carbon-dated to c. 4350 BC. Field systems were developed in different parts of Ireland, including at the Céide Fields, preserved beneath a blanket of peat in present-day Tyrawley.
An extensive field system, arguably the oldest in the world, consisted of small divisions separated by dry-stone walls. The fields were farmed for several centuries between 3500 BC and 3000 BC. Wheat and barley were the principal crops; the Bronze Age – defined by the use of metal – began around 2500 BC, with technology changing people's everyday lives during this period through innovations such as the wheel. According to John T. Koch and others, Ireland in the Late Bronze Age was part of a maritime trading-network culture called the Atlantic Bronze Age that included Britain, western France and Iberia, that this is where Celtic languages developed; this contrasts with the traditional view that their origin lies in mainland Europe with the Hallstatt culture. During the Iron Age, a Celtic language and culture emerged in Ireland. How and when the island became Celtic has been debated for close to a century, with the migrations of the Celts being one of the more enduring themes of archaeological and linguistic studies.
The most recent genetic research s
Buffalo, New York
Buffalo is the second largest city in the U. S. state of New York and the largest city in Western New York. As of 2017, the population was 258,612; the city is the county seat of Erie County and a major gateway for commerce and travel across the Canada–United States border, forming part of the bi-national Buffalo Niagara Region. The Buffalo area was inhabited before the 17th century by the Native American Iroquois tribe and by French settlers; the city grew in the 19th and 20th centuries as a result of immigration, the construction of the Erie Canal and rail transportation, its close proximity to Lake Erie. This growth provided an abundance of fresh water and an ample trade route to the Midwestern United States while grooming its economy for the grain and automobile industries that dominated the city's economy in the 20th century. Since the city's economy relied on manufacturing, deindustrialization in the latter half of the 20th century led to a steady decline in population. While some manufacturing activity remains, Buffalo's economy has transitioned to service industries with a greater emphasis on healthcare and higher education, which emerged following the Great Recession.
Buffalo is on the eastern shore of Lake Erie, at the head of the Niagara River, 16 miles south of Niagara Falls. Its early embrace of electric power led to the nickname "The City of Light"; the city is famous for its urban planning and layout by Joseph Ellicott, an extensive system of parks designed by Frederick Law Olmsted, as well as significant architectural works. Its culture blends Northeastern and Midwestern traditions, with annual festivals including Taste of Buffalo and Allentown Art Festival, two professional sports teams, a music and arts scene; the city of Buffalo received its name from a nearby creek called Buffalo Creek. British military engineer Captain John Montresor made reference to "Buffalo Creek" in his 1764 journal, which may be the earliest recorded appearance of the name. There are several theories regarding. While it is possible its name originated from French fur traders and Native Americans calling the creek Beau Fleuve, it is possible Buffalo Creek was named after the American buffalo, whose historical range may have extended into western New York.
The first inhabitants of the State of New York are believed to have been nomadic Paleo-Indians, who migrated after the disappearance of Pleistocene glaciers during or before 7000 BCE. Around 1000 CE, 1,000 years ago, the Woodland period began, marked by the rise of the Iroquois Confederacy and its tribes throughout the state. During French exploration of the region in 1620, the region was occupied by the agrarian Erie people, a tribe outside of the Five Nations of the Iroquois southwest of Buffalo Creek, the Wenro people or Wenrohronon, an Iroquoian-speaking tribal offshoot of the large Neutral Nation who lived along the inland south shore of Lake Ontario and at the east end of Lake Erie and a bit of its northern shore. For trading, the Neutral people made a living by growing tobacco and hemp to trade with the Iroquois, utilizing animal paths or warpaths to travel and move goods across the state; these paths were paved, now function as major roads. During the Beaver Wars of the 1640s-1650s, the combined warriors of the Five Nations of the Iroquois Confederacy conquered the populous Neutrals and their peninsular territory, while the Senecas alone took out the Wenro and their territory, c.
1651–1653. Soon after, the Erie nation and territory was destroyed by the Iroquois over their assistance to Huron people during the Beaver Wars, it was Louis Hennepin and Sieur de La Salle who made the earliest European discoveries of the upper Niagara and Ontario regions in the late 1600s. On August 7, 1679, La Salle launched a vessel, Le Griffon, that became the first full-sized ship to sail across the Great Lakes disappearing in Green Bay, Wisconsin. After the American Revolution, the colony of New York—now a state—began westward expansion, looking for habitable land by following trends of the Iroquois. Land near fresh water was of considerable importance. New York and Massachusetts were fighting for the territory Buffalo lies on, Massachusetts had the right to purchase all but a one-mile wide portion of land; the rights to the Massachusetts' territories were sold to Robert Morris in 1791, two years to the Holland Land Company. As a result of the war, in which the Iroquois tribe sided with the British Army, Iroquois territory was whittled away in the mid-to-late-1700s by white settlers through successive treaties statewide, such as the Treaty of Fort Stanwix, the First Treaty of Buffalo Creek, the Treaty of Geneseo.
The Iroquois were corralled onto reservations, including Buffalo Creek. By the end of the 18th century, only 338 square miles of reservation territory remained. Early settlers along the mouth of Buffalo Creek were former slave Joseph "Black Joe" Hodges, Cornelius Winney, a Dutch trader from Albany who arrived in 1789; the first white settlers along the creek were prisoners captured during the Revolutionary War. The first resident and landowner of Buffalo with a permanent presence was Captain William Johnston, a white Iroquois interpreter, present in the area since the days after the Revolutionary War and was granted creekside land by the Senecas as a gift of appreciation, his house was built at present-day Seneca streets. On July 20, 1793, the Holland Land Purchase was completed, containing the land of present-day Buffalo, brokered by Dutch investors from Holland; the Treaty of Big Tree removed Iroquois title to lan
A chimney is an architectural ventilation structure made of masonry, clay or metal that isolates hot toxic exhaust gases or smoke produced by a boiler, furnace, incinerator or fireplace from human living areas. Chimneys are vertical, or as near as possible to vertical, to ensure that the gases flow smoothly, drawing air into the combustion in what is known as the stack, or chimney effect; the space inside a chimney is called the flue. Chimneys are adjacent to large industrial refineries, fossil fuel combustion facilities or part of buildings, steam locomotives and ships. In the United States, the term'Smokestack industry' refers to the environmental impacts of burning fossil fuels by industrial society including the electric industry during its earliest history; the term smokestack is used when referring to locomotive chimneys or ship chimneys, the term funnel can be used. The height of a chimney influences its ability to transfer flue gases to the external environment via stack effect. Additionally, the dispersion of pollutants at higher altitudes can reduce their impact on the immediate surroundings.
The dispersion of pollutants over a greater area can reduce their concentrations and facilitate compliance with regulatory limits. Romans used tubes inside the walls to draw smoke out of bakeries but chimneys only appeared in large dwellings in northern Europe in the 12th century; the earliest extant example of an English chimney is at the keep of Conisbrough Castle in Yorkshire, which dates from 1185 AD. However, they did not become common in houses until the 17th centuries. Smoke hoods were an early method of collecting the smoke into a chimney. Another step in the development of chimneys was the use of built in ovens which allowed the household to bake at home. Industrial chimneys became common in the late 18th century. Chimneys in ordinary dwellings were first built of plaster or mud. Since chimneys have traditionally been built of brick or stone, both in small and large buildings. Early chimneys were of a simple brick construction. Chimneys were constructed by placing the bricks around tile liners.
To control downdrafts, venting caps with a variety of designs are sometimes placed on the top of chimneys. In the 18th and 19th centuries, the methods used to extract lead from its ore produced large amounts of toxic fumes. In the north of England, long near-horizontal chimneys were built more than 3 km long, which terminated in a short vertical chimney in a remote location where the fumes would cause less harm. Lead and silver deposits formed on the inside of these long chimneys, periodically workers would be sent along the chimneys to scrape off these valuable deposits; as a result of the limited ability to handle transverse loads with brick, chimneys in houses were built in a "stack", with a fireplace on each floor of the house sharing a single chimney with such a stack at the front and back of the house. Today's central heating systems have made chimney placement less critical, the use of non-structural gas vent pipe allows a flue gas conduit to be installed around obstructions and through walls.
In fact, most modern high-efficiency heating appliances do not require a chimney. Such appliances are installed near an external wall, a noncombustible wall thimble allows a vent pipe to run directly through the external wall. On a pitched roof where a chimney penetrates a roof, flashing is used to seal up the joints; the down-slope piece is called an apron, the sides receive step flashing and a cricket is used to divert water around the upper side of the chimney underneath the flashing. Industrial chimneys are referred to as flue gas stacks and are external structures, as opposed to those built into the wall of a building, they are located adjacent to a steam-generating boiler or industrial furnace and the gases are carried to them with ductwork. Today the use of reinforced concrete has entirely replaced brick as a structural component in the construction of industrial chimneys. Refractory bricks are used as a lining if the type of fuel being burned generates flue gases containing acids. Modern industrial chimneys sometimes consist of a concrete windshield with a number of flues on the inside.
The 300 m chimney at Sasol Three consists of a 26 m diameter windshield with four 4.6 metre diameter concrete flues which are lined with refractory bricks built on rings of corbels spaced at 10 metre intervals. The reinforced concrete can be sliding formwork; the height is to ensure the pollutants are dispersed over a wider area to meet legal or other safety requirements. A flue liner is a secondary barrier in a chimney that protects the masonry from the acidic products of combustion, helps prevent flue gas from entering the house, reduces the size of an oversized flue. Since the 1950s, building codes in many locations require newly built chimneys to have a flue liner. Chimneys built without a liner can have a liner added, but the type of liner needs to match the type of appliance it services. Flue liners may be concrete tile, metal, or poured in place concrete. Clay tile flue liners are common in the United States, although it is the only liner that does not meet Underwriters Laboratories 1777 approval and they have problems such as cracked tiles and improper installation.
Clay tiles are about 2 feet long, available in various sizes and shapes, are installed in new construction as the chimney is built. A refractory cement is used between each tile. Metal liners may be stainless steel, aluminum, or galvanized iron and may be flexible or rigid pipes. Stainless stee