Duct Installation and Sealing

Connecting New Ductwork to Existing System Components

Connecting new ductwork to existing systems is a critical step in any HVAC installation or renovation. Its not just about slapping some metal together; its about creating a seamless, airtight, and efficient system that will perform well for years to come. A poorly executed connection can lead to air leaks, reduced airflow, energy waste, and even comfort issues. So, how do we get it right?


First, you need to identify the best connection points. Ideally, you want to tie into the main trunk lines where airflow is strongest and most consistent. Avoid connecting to smaller branches or near registers, as this can disrupt the existing airflow balance. Once you've chosen your connection points, its time to prepare the existing ductwork. This might involve cleaning the surfaces with a wire brush to remove any debris or rust, and ensuring a smooth surface for a good seal.


The connection method itself depends on the type of ductwork youre using. For flexible duct, youll likely use a combination of draw bands and mastic sealant. The draw band creates a tight connection, while the mastic seals any gaps and prevents air leakage. For rigid metal ductwork, s-cleats and drive cleats are common, again sealed with mastic. Dont skimp on the mastic! A generous application is essential for a proper seal. Its messy, but its worth it.


When connecting different types of ductwork, say flex duct to rigid, youll need the appropriate connectors and adapters. These ensure a secure fit and prevent airflow restrictions. Again, mastic is your friend here. Seal all joints and connections thoroughly.


Finally, after the connections are made, its crucial to test for leaks. A simple test involves sealing off one end of the newly connected ductwork and pressurizing the system. You can use a duct blaster or even a smoke pencil to pinpoint any leaks. Any leaks found should be sealed immediately.


Connecting new ductwork to an existing system isnt rocket science, but it does require attention to detail and a commitment to doing the job right. By following these guidelines and taking the time to create airtight connections, you can ensure the new ductwork integrates seamlessly with the existing system, providing optimal airflow and energy efficiency for years to come.

Connecting New Ductwork to Existing System Components

Sealing and Insulating Ductwork: Best Practices and Materials

Sealing and insulating ductwork isnt glamorous, but its one of the most important aspects of a properly functioning HVAC system. Think of your ducts as the arteries and veins of your homes heating and cooling. Leaking ducts are like bleeding arteries, wasting energy and money. Proper sealing and insulation ensure that the conditioned air gets where it needs to go efficiently, keeping you comfortable and your energy bills in check.


So, what are the best practices? First, you need to identify leaks. While some are obvious, like gaping holes or disconnected sections, others are more insidious. A professional can perform a duct leakage test to pinpoint all the problem areas. Common leak locations include joints, seams, and connections to registers and grilles.


Once youve found the leaks, you need the right materials to seal them. Mastics, specifically mastic sealant designed for ductwork, are the gold standard. They adhere well to various materials and remain flexible over time, accommodating temperature changes and preventing future cracks. Avoid duct tape – its a temporary fix at best and degrades quickly. For larger gaps or damaged sections, metal tape or foil-backed tape combined with mastic can provide a robust seal.


Insulation is equally crucial, especially for ducts running through unconditioned spaces like attics and crawlspaces. It prevents heat transfer, keeping cool air cool in the summer and warm air warm in the winter. Rigid fiberglass duct board is a popular choice, offering excellent insulation and structural integrity. Flexible fiberglass insulation wrapped around the ductwork is another option, though it requires careful installation to ensure complete coverage and avoid compression, which reduces its effectiveness.


Finally, proper installation techniques are essential. Seams should be carefully sealed with mastic, ensuring complete coverage and avoiding gaps. Insulation should be snugly fitted and secured, with all joints and seams taped to prevent air leakage. Dont forget to insulate and seal registers and grilles as well, as these are common sources of leaks.


By following these best practices and using the right materials, you can significantly improve the efficiency of your HVAC system, saving energy, reducing your environmental impact, and enjoying a more comfortable home. Its an investment that pays off in the long run.

Testing and Commissioning the New Duct System

Testing and commissioning a new duct system isnt just a final step in duct installation-its the crucial moment where you ensure all that hard work pays off in efficient and effective climate control. Think of it like the test drive before you buy a new car; you wouldnt hand over the cash without making sure everything runs smoothly. Similarly, you shouldnt consider your duct installation complete until its passed a thorough testing and commissioning process.


This process primarily focuses on verifying two key aspects: airtightness and proper airflow. Leaks in the ductwork are the silent killers of energy efficiency, bleeding conditioned air into unconditioned spaces like attics or crawlspaces. This forces your HVAC system to work harder, wasting energy and increasing your utility bills. Testing for leaks, typically using a duct pressurization test, pinpoints these weaknesses so they can be sealed effectively. Imagine trying to inflate a balloon with holes in it – you'd be working hard with little to show for it. A leaky duct system is much the same.


Beyond airtightness, ensuring balanced airflow is critical. Each room or zone in your home requires a specific amount of conditioned air to maintain a comfortable temperature. Testing and balancing (TAB) involves measuring airflow at each register and adjusting dampers within the ductwork to achieve the desired distribution. This prevents scenarios where one room is an icebox while another feels like a sauna. Proper airflow also maximizes the lifespan of your HVAC equipment by preventing strain from uneven workloads.


The testing and commissioning process also involves checking the integrity of the installed components, such as dampers, registers, and diffusers, to ensure they function correctly. Think of it as a quality control check – making sure everything is installed correctly and operates as intended. This meticulous approach not only optimizes system performance but also identifies potential problems early on, preventing costly repairs down the line.


In conclusion, testing and commissioning your new duct system is an essential investment that ensures long-term comfort, energy efficiency, and system longevity. It's the final, crucial step that transforms a series of ducts and fittings into a high-performing system that delivers on its promise of comfortable and efficient climate control. Dont skip this vital step – its the key to getting the most out of your new HVAC system.

Post-Installation Inspection and Maintenance

After youve wrestled with all that ductwork and finally got it nestled into place, the job isnt quite done. A critical, often overlooked, step is the post-installation inspection and maintenance process. Think of it like getting a new car – you wouldnt just drive it off the lot without checking the oil, right? Your duct system deserves the same attention. A proper inspection ensures your hard work pays off with efficient and effective heating and cooling for years to come.


So, what does a good post-installation inspection entail? First, a visual check. Are all the connections secure? Are there any obvious gaps or kinks that could restrict airflow? Flex duct can be particularly prone to sagging or being crushed, so pay extra attention there. Next, test the sealing. Duct mastic and sealant are your best friends here. A simple test, like pressurizing the system with a duct blaster, can pinpoint leaks you might have missed. Remember, even small leaks can add up to significant energy loss over time.


Once everything checks out, its time to think about maintenance. This isnt a one-and-done deal. Regularly checking your filter is crucial. A dirty filter restricts airflow and forces your system to work harder, wasting energy and shortening its lifespan. Depending on your environment and usage, you might need to change it every few months, or even more frequently. Also, make it a habit to periodically inspect your ductwork, especially in accessible areas like the attic or crawlspace. Look for signs of damage, loose connections, or pest infestations.


Taking these simple post-installation steps can save you money on your energy bills, improve your indoor air quality, and prolong the life of your HVAC system. Its a small investment of time that yields big returns in comfort and peace of mind. So, dont skip this important final step - your future self will thank you.

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, stove, furnace, incinerator, or fireplace from human living areas. Chimneys are typically 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 (colloquially, stack) is also used when referring to locomotive chimneys or ship chimneys, and the term funnel can also be used.[1][2]

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.

History

[edit]

Industrial chimney use dates to the Romans, who drew smoke from their bakeries with tubes embedded in the walls. However, domestic chimneys first appeared in large dwellings in northern Europe in the 12th century. The earliest surviving example of an English chimney is at the keep of Conisbrough Castle in Yorkshire, which dates from 1185 AD,[3] but they did not become common in houses until the 16th and 17th centuries.[4] Smoke hoods were an early method of collecting the smoke into a chimney. These were typically much wider than modern chimneys and started relatively high above the fire, meaning more heat could escape into the room. Because the air going up the shaft was cooler, these could be made of less fireproof materials. 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 wood and plaster or mud. Since then chimneys have traditionally been built of brick or stone, both in small and large buildings. Early chimneys were of simple brick construction. Later chimneys were constructed by placing the bricks around tile liners. To control downdrafts, venting caps (often called chimney pots) 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, often more than 3 km (2 mi) long, which typically 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, and periodically workers would be sent along the chimneys to scrape off these valuable deposits.[5]

Construction

[edit]
Chimney in NED University

As a result of the limited ability to handle transverse loads with brick, chimneys in houses were often built in a "stack", with a fireplace on each floor of the house sharing a single chimney, often with such a stack at the front and back of the house. Today's central heating systems have made chimney placement less critical, and the use of non-structural gas vent pipe allows a flue gas conduit to be installed around obstructions and through walls.

Chimney in North London
Flue

Most modern high-efficiency heating appliances do not require a chimney. Such appliances are generally installed near an external wall, and a noncombustible wall thimble[clarification needed] 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.[6]

Industrial chimneys are commonly referred to as flue-gas stacks and are generally external structures, as opposed to those built into the wall of a building. They are generally 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 almost entirely replaced brick as a structural element in the construction of industrial chimneys. Refractory bricks are often used as a lining, particularly 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 (980 ft) high steam plant chimney at the Secunda CTL's synthetic fuel plant in Secunda, South Africa consists of a 26 m (85 ft) 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 cast by conventional formwork or sliding formwork. The height is to ensure the pollutants are dispersed over a wider area to meet legal or other safety requirements.

Residential flue liners

[edit]

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, and 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 usually have a liner added, but the type of liner needs to match the type of appliance it services. Flue liners may be clay or concrete tile, metal, or poured in place concrete.

Clay tile flue liners are very common in the United States, although it is the only liner that does not meet Underwriters Laboratories 1777 approval and frequently they have problems such as cracked tiles and improper installation.[7] Clay tiles are usually about 2 feet (0.61 m) long, available in various sizes and shapes, and 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 steel is made in several types and thicknesses. Type 304 is used with firewood, wood pellet fuel, and non-condensing oil appliances, types 316 and 321 with coal, and type AL 29-4C is used with high efficiency condensing gas appliances. Stainless steel liners must have a cap and be insulated if they service solid fuel appliances, but following the manufacturer's instructions carefully.[7] Aluminum and galvanized steel chimneys are known as class A and class B chimneys. Class A are either an insulated, double wall stainless steel pipe or triple wall, air-insulated pipe often known by its genericized trade name Metalbestos. Class B are uninsulated double wall pipes often called B-vent, and are only used to vent non-condensing gas appliances. These may have an aluminum inside layer and galvanized steel outside layer.

Concrete flue liners are like clay liners but are made of a refractory cement and are more durable than the clay liners.

Poured in place concrete liners are made by pouring special concrete into the existing chimney with a form. These liners are highly durable, work with any heating appliance, and can reinforce a weak chimney, but they are irreversible.

Chimney pots, caps, and tops

[edit]

A chimney pot is placed on top of the chimney to expand the length of the chimney inexpensively, and to improve the chimney's draft. A chimney with more than one pot on it indicates that multiple fireplaces on different floors share the chimney.

A cowl is placed on top of the chimney to prevent birds and other animals from nesting in the chimney. They often feature a rain guard to prevent rain or snow from going down the chimney. A metal wire mesh is often used as a spark arrestor to minimize burning debris from rising out of the chimney and making it onto the roof. Although the masonry inside the chimney can absorb a large amount of moisture which later evaporates, rainwater can collect at the base of the chimney. Sometimes weep holes are placed at the bottom of the chimney to drain out collected water.

A chimney cowl or wind directional cap is a helmet-shaped chimney cap that rotates to align with the wind and prevent a downdraft of smoke and wind down the chimney.

An H-style cap is a chimney top constructed from chimney pipes shaped like the letter H. It is an age-old method of regulating draft in situations where prevailing winds or turbulences cause downdraft and back-puffing. Although the H cap has a distinct advantage over most other downdraft caps, it fell out of favor because of its bulky design. It is found mostly in marine use but has been regaining popularity due to its energy-saving functionality. The H-cap stabilizes the draft rather than increasing it. Other downdraft caps are based on the Venturi effect, solving downdraft problems by increasing the updraft constantly resulting in much higher fuel consumption.

A chimney damper is a metal plate that can be positioned to close off the chimney when not in use and prevent outside air from entering the interior space, and can be opened to permit hot gases to exhaust when a fire is burning. A top damper or cap damper is a metal spring door placed at the top of the chimney with a long metal chain that allows one to open and close the damper from the fireplace. A throat damper is a metal plate at the base of the chimney, just above the firebox, that can be opened and closed by a lever, gear, or chain to seal off the fireplace from the chimney. The advantage of a top damper is the tight weatherproof seal that it provides when closed, which prevents cold outside air from flowing down the chimney and into the living space—a feature that can rarely be matched by the metal-on-metal seal afforded by a throat damper. Additionally, because the throat damper is subjected to intense heat from the fire directly below, it is common for the metal to become warped over time, thus further degrading the ability of the throat damper to seal. However, the advantage of a throat damper is that it seals off the living space from the air mass in the chimney, which, especially for chimneys positioned on an outside of wall of the home, is generally very cold. It is possible in practice to use both a top damper and a throat damper to obtain the benefits of both. The two top damper designs currently on the market are the Lyemance (pivoting door) and the Lock Top (translating door).

In the late Middle Ages in Western Europe the design of stepped gables arose to allow maintenance access to the chimney top, especially for tall structures such as castles and great manor houses.

Chimney draught or draft

[edit]

When coal, oil, natural gas, wood, or any other fuel is combusted in a stove, oven, fireplace, hot water boiler, or industrial furnace, the hot combustion product gases that are formed are called flue gases. Those gases are generally exhausted to the ambient outside air through chimneys or industrial flue-gas stacks (sometimes referred to as smokestacks).

The combustion flue gases inside the chimneys or stacks are much hotter than the ambient outside air and therefore less dense than the ambient air. That causes the bottom of the vertical column of hot flue gas to have a lower pressure than the pressure at the bottom of a corresponding column of outside air. That higher pressure outside the chimney is the driving force that moves the required combustion air into the combustion zone and also moves the flue gas up and out of the chimney. That movement or flow of combustion air and flue gas is called "natural draught/draft", "natural ventilation", "chimney effect", or "stack effect". The taller the stack, the more draught or draft is created. There can be cases of diminishing returns: if a stack is overly tall in relation to the heat being sent out of the stack, the flue gases may cool before reaching the top of the chimney. This condition can result in poor drafting, and in the case of wood burning appliances, the cooling of the gases before emission can cause creosote to condense near the top of the chimney. The creosote can restrict the exit of flue gases and may pose a fire hazard.

Designing chimneys and stacks to provide the correct amount of natural draft involves a number of design factors, many of which require iterative trial-and-error methods.

As a "first guess" approximation, the following equation can be used to estimate the natural draught/draft flow rate by assuming that the molecular mass (i.e., molecular weight) of the flue gas and the external air are equal and that the frictional pressure and heat losses are negligible: where:

  • 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<A, where At=7.1 inch2 is the minimum required flow area from water heater tank and Af=19.6 inch2 is the minimum flow area from a furnace of a central heating system.

Draft hood

[edit]

Gas fired appliances must have a draft hood to cool combustion products entering the chimney and prevent updrafts or downdrafts.[8][9][10]

Maintenance and problems

[edit]

A characteristic problem of chimneys is they develop deposits of creosote on the walls of the structure when used with wood as a fuel. Deposits of this substance can interfere with the airflow and more importantly, they are combustible and can cause dangerous chimney fires if the deposits ignite in the chimney.

Heaters that burn natural gas drastically reduce the amount of creosote buildup due to natural gas burning much cleaner and more efficiently than traditional solid fuels. While in most cases there is no need to clean a gas chimney on an annual basis that does not mean that other parts of the chimney cannot fall into disrepair. Disconnected or loose chimney fittings caused by corrosion over time can pose serious dangers for residents due to leakage of carbon monoxide into the home.[11] Thus, it is recommended—and in some countries even mandatory—that chimneys be inspected annually and cleaned on a regular basis to prevent these problems. The workers who perform this task are called chimney sweeps or steeplejacks. This work used to be done largely by child labour and, as such, features in Victorian literature. In the Middle Ages in some parts of Europe, a stepped gable design was developed, partly to provide access to chimneys without use of ladders.

Masonry (brick) chimneys have also proven to be particularly prone to crumbling during earthquakes. Government housing authorities in cities prone to earthquakes such as San Francisco, Los Angeles, and San Diego now recommend building new homes with stud-framed chimneys around a metal flue. Bracing or strapping old masonry chimneys has not proven to be very effective in preventing damage or injury from earthquakes. It is now possible to buy "faux-brick" facades to cover these modern chimney structures.

Other potential problems include:

  • "spalling" brick, in which moisture seeps into the brick and then freezes, cracking and flaking the brick and loosening mortar seals.
  • shifting foundations, which may degrade integrity of chimney masonry
  • nesting or infestation by unwanted animals such as squirrels, racoons, or chimney swifts
  • chimney leaks
  • drafting issues, which may allow smoke inside building[12]
  • issues with fireplace or heating appliance may cause unwanted degradation or hazards to chimney

Chimneys of special interest

[edit]

Chimneys with observation decks

[edit]

Several chimneys with observation decks were built. The following possibly incomplete list shows them.

Name Country Town Coordinates Year of completion Total height Height of observation deck Remarks
Chimney of Beitou Refuse Incineration Plant Taiwan Teipei 25°06′29″N 121°29′58″E / 25.108043°N 121.499384°E / 25.108043; 121.499384 (Chimney of Beitou Refuse Incineration Plant) 2000 150 m (492 ft) 116 m (381 ft) revolving restaurant in a height of 120 metres (394 ft)
Radio City Tower United Kingdom Liverpool   53°24′23″N 2°58′55″W / 53.406332°N 2.982002°W / 53.406332; -2.982002 (Radio City Tower) 1971 148 m (486 ft) 124.7 m (409 ft) chimney for the heating system of a nearby mall
Large Chimney of Warsaw Refuse Incineration Plant Poland Warsaw   52°15′41″N 21°06′18″E / 52.261448°N 21.105072°E / 52.261448; 21.105072 (Large Chimney of Warsaw Refuse Incineration Plant) 2024 72 m (236 ft)   observation deck only accessible at guided tours through the facility
Bernard Brewery Chimney Czech Humpolec   49°32′23″N 15°21′36″E / 49.539786°N 15.360043°E / 49.539786; 15.360043 (Bernard Brewery Chimney)   40.7 m (134 ft) 33 m (108 ft) observation deck added in 2020/21
Dům DÄ›tí a Mládeže v ModÃ…â„¢anech Czech Prague   50°00′44″N 14°24′49″E / 50.012154°N 14.413657°E / 50.012154; 14.413657 (Dům DÄ›tí a Mládeže v ModÃ…â„¢anech) 2004 15 m (49 ft) 12 m (39 ft) observation platform on chimney of the roof of a youth centre
Chimney of Zenner Heating Building Germany Berlin   52°29′17″N 13°28′38″E / 52.488097°N 13.477282°E / 52.488097; 13.477282 (Chimney of Zenner Heating Building) 1955 15 m (49 ft) 12 m (39 ft) perhaps never in use as observation tower

Chimneys used as electricity pylon

[edit]

At several thermal power stations at least one smokestack is used as electricity pylon. The following possibly incomplete list shows them.

Country City Coordinates Name Height Year of construction Voltage Remarks
Germany Gelsenkirchen   51°36′02″N 7°00′16″E / 51.600623°N 7.004573°E / 51.600623; 7.004573 (Scholven Power Station, Chimney for Units B, C, D and E) Scholven Power Station, Chimney for Units B, C, D and E 300 m   220 kV  
Belarus Novolukoml   54°40′45″N 29°08′09″E / 54.679048°N 29.135925°E / 54.679048; 29.135925 (Lukoml Power Station, Chimney 1) Lukoml Power Station, Chimney 1 250 m 1969 330 kV  
Belarus Novolukoml   54°40′48″N 29°08′07″E / 54.679941°N 29.135259°E / 54.679941; 29.135259 (Lukoml Power Station, Chimney 2) Lukoml Power Station, Chimney 2 250 m 1971 330 kV  
Belarus Novolukoml   54°40′53″N 29°08′04″E / 54.681290°N 29.134428°E / 54.681290; 29.134428 (Lukoml Power Station, Chimney 3) Lukoml Power Station, Chimney 3 250 m 1973 330 kV  
Lithuania Elektrenai   54°46′17″N 24°38′50″E / 54.771463°N 24.647291°E / 54.771463; 24.647291 (ElektrÄ—nai Power Plant, Chimney 1) ElektrÄ—nai Power Plant, Chimney 1 150 m   330 kV dismantled
Lithuania Elektrenai   54°46′12″N 24°38′48″E / 54.770110°N 24.646765°E / 54.770110; 24.646765 (ElektrÄ—nai Power Plant, Chimney 2) ElektrÄ—nai Power Plant, Chimney 2 250 m   330 kV dismantled
Moldova Dnestrovsc   46°37′40″N 29°56′23″E / 46.627864°N 29.939691°E / 46.627864; 29.939691 (Cuciurgan power station, Chimney 1) Cuciurgan power station, Chimney 1 180 m 1964 110 kV  
Moldova Dnestrovsc   46°37′44″N 29°56′23″E / 46.628880°N 29.939622°E / 46.628880; 29.939622 (Cuciurgan power station, Chimney 2) Cuciurgan power station, Chimney 2 180 m 1966 330 kV  
Moldova Dnestrovsc   46°37′49″N 29°56′23″E / 46.630199°N 29.939622°E / 46.630199; 29.939622 (Cuciurgan power station, Chimney 3) Cuciurgan power station, Chimney 3 180 m 1971 330 kV  
Russia Archangelsk   64°34′29″N 40°34′24″E / 64.574788°N 40.573261°E / 64.574788; 40.573261 (Archangelsk Cogeneration Plant, Chimney 1) Archangelsk Cogeneration Plant, Chimney 1 170 m   220 kV  
Russia Saint Petersburg   59°58′14″N 30°22′35″E / 59.970595°N 30.376425°E / 59.970595; 30.376425 (Vyborgskaya Cogenaration Plant, Chimney 1) Vyborgskaya Cogenaration Plant, Chimney 1 120 m   110 kV  
Russia Tobolsk   58°14′44″N 68°26′43″E / 58.245439°N 68.445224°E / 58.245439; 68.445224 (Tobolsk Cogeneration Plant, Chimney 1) TEC Tobolsk, Chimney 1 240 m 1980 110 kV  
Russia Tobolsk   58°14′45″N 68°26′55″E / 58.245781°N 68.448590°E / 58.245781; 68.448590 (Tobolsk Cogeneration Plant, Chimney 2) TEC Tobolsk, Chimney 2 270 m 1986 220 kV  
Russia Kashira   54°51′24″N 38°15′23″E / 54.856639°N 38.256428°E / 54.856639; 38.256428 (Kashira Power Plant, Chimney 1) Kashira Power Plant, Chimney 1 250 m 1966 220 kV  
Russia Energetik   51°45′12″N 58°48′09″E / 51.753324°N 58.802583°E / 51.753324; 58.802583 (Iriklinskaya Power Station, Chimney 1) Iriklinskaya Power Station, Chimney 1 180 m   220 kV  
Russia Energetik   51°45′12″N 58°48′14″E / 51.753453°N 58.803983°E / 51.753453; 58.803983 (Iriklinskaya Power Station, Chimney 2) Iriklinskaya Power Station, Chimney 2 180 m   220 kV  
Russia Energetik   51°45′13″N 58°48′22″E / 51.753483°N 58.806183°E / 51.753483; 58.806183 (Iriklinskaya Power Station, Chimney 3) Iriklinskaya Power Station, Chimney 3 250 m   500 kV  
Russia Konakovo   56°44′23″N 36°46′22″E / 56.739703°N 36.772833°E / 56.739703; 36.772833 (Konakovo Power Station, Chimney 1) Konakovo Power Station, Chimney 1 180 m 1964 220 kV  
Russia Konakovo   56°44′26″N 36°46′20″E / 56.740627°N 36.772308°E / 56.740627; 36.772308 (Konakovo Power Station, Chimney 2) Konakovo Power Station, Chimney 2 180 m 1966 220 kV  
Russia Koryazhma   61°18′09″N 47°07′13″E / 61.302456°N 47.120396°E / 61.302456; 47.120396 (Chimney 1 of Cogenaration Plant 1 of Kotlas Pulp and Paper Mill) Chimney 1 of Cogenaration Plant 1 of Kotlas Pulp and Paper Mill 105 m 1961 220 kV  
Ukraine Burshtyn   49°12′27″N 24°40′03″E / 49.207578°N 24.667450°E / 49.207578; 24.667450 (Burshtyn Power Station, Chimney 1) Burshtyn Power Station, Chimney 1 180 m 1965 330 kV  
Ukraine Burshtyn   49°12′31″N 24°39′57″E / 49.208595°N 24.665921°E / 49.208595; 24.665921 (Burshtyn Power Station, Chimney 2) Burshtyn Power Station, Chimney 2 250 m 1966 330 kV  
Ukraine Burshtyn   49°12′34″N 24°39′54″E / 49.209334°N 24.664918°E / 49.209334; 24.664918 (Burshtyn Power Station, Chimney 3) Burshtyn Power Station, Chimney 3 250 m 1966 330 kV  
Ukraine Trypillia   50°08′01″N 30°44′52″E / 50.133591°N 30.747659°E / 50.133591; 30.747659 (Trypillia Power Station, Chimney 1) Trypillia Power Station, Chimney 1 180 m 1968 330 kV  
Ukraine Trypillia   50°08′00″N 30°44′44″E / 50.133239°N 30.745553°E / 50.133239; 30.745553 (Trypillia Power Station, Chimney 2) Trypillia Power Station, Chimney 2 180 m 1972 330 kV  

Nearly all this structures exist in an area, which was once part of the Soviet Union. Although this use has the disadvantage that conductor ropes may corrode faster due to the exhaust gases, one can find such structures also sometimes in countries not influenced by the former Soviet Union. An example herefore is one chimney of Scholven Power Plant in Gelsenkirchen, which carries one circuit of an outgoing 220 kV-line.

Chimneys used as water tower

[edit]

Chimneys can also carry a water tank on their structure. This combination has the advantage that the warm smoke running through the chimney prevents the water in the tank from freezing. Before World War II such structures were not uncommon, especially in countries influenced by Germany.

Chimneys used as radio tower

[edit]

Chimneys can carry antennas for radio relay services, cell phone transmissions, FM-radio and TV on their structure. Also long wire antennas for mediumwave transmissions can be fixed at chimneys. In all cases it had to be considered that these objects can easily corrode especially when placed near the exhaust. Sometimes chimneys were converted into radio towers and are not useable as ventilation structure any more.

Chimneys used for advertising

[edit]

As chimneys are often the tallest part of a factory, they offer the possibility as advertising billboard either by writing the name of the company to which they belong on the shaft or by installing advertisement boards on their structure.

Cooling tower used as an industrial chimney

[edit]

At some power stations, which are equipped with plants for the removal of sulfur dioxide and nitrogen oxides, it is possible to use the cooling tower as a chimney. Such cooling towers can be seen in Germany at the Großkrotzenburg Power Station and at the Rostock Power Station. At power stations that are not equipped for removing sulfur dioxide, such usage of cooling towers could result in serious corrosion problems which are not easy to prevent.

See also

[edit]

References

[edit]
  1. ^ C.F. Saunders (1923), The Southern Sierras of California
  2. ^ "Jules Verne (1872), Around the World in Eighty Days". Retrieved 2006-07-30.
  3. ^ James Burke, Connections (Little, Brown and Co.) 1978/1995, ISBN 0-316-11672-6, p. 159
  4. ^ Sparrow, Walter Shaw. The English house: how to judge its periods and styles. London: Eveleigh Nash, 1908. 85–86.
  5. ^ "Lead Mining". The Northern Echo. Newsquest Media Group. Retrieved 10 April 2012.
  6. ^ Roofing, flashing & waterproofing. Newtown, CT: Taunton Press, 2005. 43–50.
  7. ^ a b Bliss, Stephen, ed.. Troubleshooting guide to residential construction: the diagnosis and prevention of common building problems. Richmond, VT: Builderburg Group, 1997. 197. Print.
  8. ^ "Field Installation of Draft Hoods" (PDF). A.O. Smith Water Products Company. 2009. Retrieved January 6, 2016.
  9. ^ "Guide to Draft Hoods on Gas Fired Heating Equipment". InspectApedia.com. 2017. Retrieved January 6, 2016.
  10. ^ Reuben Saltzman (September 24, 2013). "Water Heater Backdrafting, Part 1 of 2: Why it Matters and What to Look For". Structure Tech. Retrieved January 6, 2016.
  11. ^ Chimney Problems and Warnings Signs
  12. ^ "Chimney Airflow Problems". 8 June 2022.
[edit]

 

Industrial exhaust ducts are pipe systems that connect hoods to industrial chimneys through other components of exhaust systems like fans, collectors, etc. Ducts are low-pressure pneumatic conveyors to convey dust, particles, shavings, fumes, or chemical hazardous components from air in the vicinity to a shop floor or any other specific locations like tanks, sanding machines, or laboratory hoods. Ducts can be fabricated from a variety of materials including carbon steel, stainless steel, PVC, and fiberglass. [1] They can be fabricated through rolling (preferable for ducts of 12" or more in diameter) or extruded (for ducts up to 18").[2]

HVAC systems do not include this category of industrial application, namely exhaust systems. A distinction from HVAC system ducts is that the fluid (air) conveyed through the duct system may not be homogeneous. An industrial exhaust duct system is primarily a pneumatic conveying system and is basically governed by laws of flow of fluids.[3]

Fluid flow

[edit]

The conveying fluid that flows through the duct system is air. Air transports materials from the hood to a destination. It is also instrumental in capturing the material into the flow system. Air is a compressible fluid, but for engineering calculations, air is considered as incompressible as a simplification, without any significant errors.

Design

[edit]

Process design of exhaust system will include

  • Identification of contaminants, their density and size
  • Deciding of air flow
  • Sizing of the ductwork
  • Calculation of resistance
  • Finalizing the capacity of blower, etc.[4]

The goal is to keep contaminants out using minimum airflow. It is estimated that increase in an inch wg[clarification needed] of static pressure can add a few thousands of dollars to the operation cost per annum.

See also

[edit]

References

[edit]
  1. ^ Duct Work Assembly Archived 2020-02-24 at the Wayback Machine U.S. Bellows, (retrieved May 2012)
  2. ^ KCH Engineered Systems
  3. ^ [1] Archived 2015-09-19 at the Wayback Machine ASHRAE Technical Committee 5.2 - Duct Design
  4. ^ [2] Archived 2017-02-20 at the Wayback Machine Industrial Duct System Design Fundamentals

The word duct is derived from the Latin word for led/leading. It may refer to:

  • Duct (anatomy), various ducts in anatomy and physiology
  • Duct (HVAC), for transfer of air between spaces in a structure
  • Duct tape, a kind of adhesive tape
  • Ducted fan, motor for aircraft
  • Electrical bus duct, a metal enclosure for busbars
  • Duct (industrial exhaust), industrial exhaust duct system designed for low pressure-pneumatic convey of gas, fumes, dusts, shavings, and other pollutants from works space to atmosphere after cleaning and removal of contaminants
  • Atmospheric duct, a horizontal layer in the lower atmosphere in which the vertical refractive index gradients are such that radio signals (a) are guided or ducted, (b) tend to follow the curvature of the Earth, and (c) experience less attenuation in the ducts than they would if the ducts were not present
  • Surface duct, a sound propagation phenomenon at sea
  • Duct Publishing, an imprint of the German group VDM Publishing devoted to the reproduction of Wikipedia content
  • Dispatchable Unit Control Table (DUCT) in z/Architecture
  • Flexible Ducting

See also

[edit]

Driving Directions in


Driving Directions From Digital Audio Devices to
Driving Directions From Dream Maker Bath & Kitchen to
Driving Directions From SodKat to
Driving Directions From The George Home Team at LPT Realty to
Driving Directions From Hot Off the Press Promotions to
Driving Directions From Light of Life Ministries to
Driving Directions From essintawings to
Driving Directions From Platinum Builders to
Driving Directions From World's Most Famous Beach to
Driving Directions From Winterhaven Park to
Driving Directions From Old Fort Park to
View GBP

Driving Directions in Volusia County


Driving Directions From 29.061706404676, -81.0326684 to
Driving Directions From 29.088816727424, -80.984617022747 to
Driving Directions From 29.028157958573, -81.060352726571 to
Driving Directions From 29.033014057381, -81.024829630788 to
Driving Directions From 29.028151084356, -81.004962489051 to
Driving Directions From 29.049136304765, -81.084644568707 to
Driving Directions From 28.999209222387, -81.059645266341 to
Driving Directions From 29.056986724021, -81.064189694206 to
Driving Directions From 29.001405461926, -81.00524172939 to
Driving Directions From 28.996644563231, -81.045888938859 to
Proper sealing prevents energy loss, improves air quality, and enhances system efficiency, leading to lower utility bills and better comfort.
A: The best sealant depends on the duct material and location. Common options include mastic, foil tape (specifically UL 181A-P listed for ducts), and aerosol sealants, but a qualified installer will know the best option for your situation.
A: A qualified installer should perform a duct leakage test after installation to identify and seal any remaining leaks. This ensures optimal system performance and energy efficiency.