Chimneys: Powering World History And Industrialization:

The Tallest Chimney in the world is the GRES-2 Power Station in the country of Kazakhstan, a country made infamous in the 2006 comedy film “Borat: Cultural Learnings of America for Make Benefit Glorious Nations of Kazakhstan.” This chimney, built in 1987, measures a towering height of 1,378 feet and can be seen for miles. On May 30th, 2006, the chimney actually caught fire. Click here for the official website

The tallest chimney in the United States is located in Homer City, Pennsylvania, which also coincidentally is the Christmas Tree Capital of the World. The Homer City Generating Station (coal burning) is the third tallest chimney in the world. The second largest is actually also in North America, but is located in Ontario, Canada. The Inco Superstack is the tallest chimney in the Western Hemisphere.

In many countries, including England, Poland and Croatia, chimney sweeps are considered a “lucky” sign or good omen. In fact, in the UK it’s considered lucky for a bride to spot a chimney sweep on her wedding day. This belief persists even in modern times, so many enterprising British sweeps rent themselves out for weddings. Who can blame them? Chimney sweeping is dirty, tough and at times, dangerous work, so a attending a wedding is a heck of a lot easier.

The oldest modern chimneys were built and used in Northern Europe in the 12th Century. Before ancient Europeans built and used what we’d recognize as modern chimneys, the Romans used tubes (precursors of the modern chimney and flues) inside the walls of their buildings to vent smoke from cooking areas. Industrial chimneys became very common in the 18th century and were most prominent in London and Paris.

Pollution in London from burning coal to power factories was so bad in the 1800’s that during a week of high smog levels in 1873, smog killed over 700 people. The population of London during the 1800’s topped 1 million inhabitants and many toiled in these factories under extremely dangerous conditions, including inhalation of CO2, tar, lead arsenic and other contaminants that were deadly byproducts of burning coal in poorly ventilated, dirty, unregulated chimneys.

Here’s the formula for calculating the natural draught/draft rate of a chimney:

Q = chimney draught/draft flow rate, m³/s
A = cross-sectional area of chimney, m² (assuming it has a constant cross-section)
C = discharge coefficient (usually taken to be from 0.65 to 0.70)
g = gravitational acceleration, 9.807 m/s²

H = height of chimney, m
Ti = average temperature inside the chimney, K

Te = external air temperature, K.
Combining two flows into chimney: At+Af