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Selects: How Fireplaces Work | STUFF YOU SHOULD KNOW

By iHeartPodcasts

Discover the warmth and wisdom of Josh Clark and Chuck Bryant in the "Stuff You Should Know" podcast as they ignite a discussion on the intricacies of fireplaces. Encircle yourself with the comfort of their voices as they contrast wood-burning hearths with their gas counterparts, unraveling the tapestry of tradition, efficiency, and modern convenience. With particular emphasis on the ideal types of firewood and the allure of realistic fake logs, they provide listeners with the fuel to make informed decisions about their own homes' centers of warmth.

Venture deeper into the structure and principles of fireplace design, where safety and physics intertwine. Clark and Bryant lay bare the critical components of fireplaces, from the hearth to the flue, and the necessity of each in maintaining a safe and inviting blaze. Engage with their enlightening conversation as they examine the fine balance between warmth production and heat loss and underscore the paramount importance of regular maintenance to avert the dangers of neglect. Their examination of the dark history of child chimney sweeps adds a solemn note to the narrative, ensuring this episode is a comprehensive treatise on the past, present, and future of this elemental household feature.

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Selects: How Fireplaces Work | STUFF YOU SHOULD KNOW

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Selects: How Fireplaces Work | STUFF YOU SHOULD KNOW

1-Page Summary

Types of fireplaces

Josh Clark and Chuck Bryant discuss wood-burning and gas fireplaces, contrasting their efficiency, installation, and fuel needs. Wood-burning fireplaces possess traditional charm but are criticized for their inefficiency; they require seasoned hardwood to operate effectively and are notorious for losing more heat than they produce. Conversely, gas fireplaces offer better efficiency and ease of installation; they draw combustion air from outside and feature realistic-looking fake logs. Gas models are preferable for their ability to maintain a warmer indoor environment without the significant heat loss associated with wood-burning options.

Fireplace components

Fireplace components are crucial for safety and efficiency, as Clark and Bryant explain. Key elements include the hearth, surround, firebox, smoke chamber, throat, flue, chimney, smoke shelf, and damper. Fireproof materials like rock, brick, tile, and stone feature prominently in construction to prevent fire spread. The firebox hosts the fire, the smoke chamber and throat channel smoke away, and the flue within the chimney directs smoke upward. The smoke shelf helps shield the fire from external elements, while the damper controls airflow. The fireplace may also have a spark arrestor, ash dump, fire grate, and andirons, all serving distinct functions to enhance the experience and safety of the fireplace.

Physics of fireplaces

Clark and Bryant delve into the physics underlying fireplace operation, highlighting the importance of radiation and convection in heat transfer. Fireplaces produce warmth through the circulation of hot air (convection) and direct heat emission (radiation), but the design necessity to expel smoke results in heat loss through the chimney. Consequently, traditional fireplaces can paradoxically cool rooms by drawing in cold outside air to replace the hot air being lost up the flue. Meanwhile, gas fireplaces, which don't use indoor air for combustion, are more efficient in heating a space.

Maintaining fireplaces

Fireplace maintenance is vital to safety and performance. Clark stresses regular chimney inspections for damage or blockages and emphasizes the role of professional chimney sweeps in preventing dangerous creosote buildup. Despite products claiming to help maintain chimneys, such as chimney sweep logs, they are subject to skepticism, and professional cleaning remains the recommended approach. Proper care and cleaning by qualified experts are essential to avoid significant hazards like chimney fires.

Child chimney sweeps

The use of child chimney sweeps in the UK is a bleak part of history. Young boys, as little as four years old, were exploited to clean narrow chimneys, facing ghastly conditions that led to debilitating illnesses, deformities, and sometimes even death from becoming trapped. Although laws like the Chimney Sweeps Act of 1788 and later amendments were enacted to combat the practice, it was not until a manslaughter conviction following the death of George Brewster that the use of children as chimney sweeps was effectively outlawed, ending this terrible chapter of British history.

1-Page Summary

Additional Materials

Clarifications

  • Gas fireplaces draw combustion air from outside, unlike wood-burning fireplaces that rely on indoor air. This external air intake helps improve efficiency and indoor air quality by not depleting oxygen or releasing combustion byproducts into the living space. By utilizing outside air, gas fireplaces can maintain a consistent and comfortable indoor environment without the heat loss associated with traditional wood-burning options. This design feature is a key factor in why gas fireplaces are often preferred for their convenience and performance.
  • Gas fireplaces often come equipped with ceramic logs that are designed to resemble real wood logs. These artificial logs are crafted to mimic the appearance of burning wood, providing a realistic and aesthetic appeal to the fireplace. They are a popular feature in gas fireplaces as they enhance the visual experience without the maintenance and cleanup associated with real wood-burning fires. The fake logs are positioned strategically within the fireplace to create a natural and authentic look, adding to the overall ambiance of the gas fireplace.
  • In fireplaces, heat transfer occurs through convection (circulation of hot air) and radiation (direct heat emission). Traditional fireplaces lose heat through the chimney due to the need to expel smoke, potentially cooling the room. Gas fireplaces, which do not use indoor air for combustion, are more efficient in heating a space.
  • Creosote buildup in chimneys is a flammable substance that forms when wood is burned incompletely. It can accumulate on the walls of the chimney and poses a significant fire hazard if not regularly cleaned. Creosote buildup is a byproduct of burning wood and can vary in consistency from a sticky residue to a hardened glaze, depending on factors like burning practices and chimney temperature. Regular chimney inspections and cleanings by professionals are crucial to prevent creosote buildup and reduce the risk of chimney fires.
  • Chimney sweep logs are products marketed to help maintain chimneys by reducing creosote buildup. They are designed to be burned in the fireplace, with the idea that they will help break down and loosen the creosote inside the chimney. Professional chimney sweeps are still recommended for thorough cleaning and inspection.
  • Child chimney sweeps in the UK were young boys, sometimes as young as four years old, who were employed to clean narrow chimneys in the 18th and 19th centuries. These children faced dangerous and deplorable working conditions, leading to severe health issues, deformities, and even death. Legislation like the Chimney Sweeps Act of 1788 aimed to address this exploitation, but it wasn't until a manslaughter case in the early 19th century that significant steps were taken to end the practice of using children as chimney sweeps in the UK.
  • The Chimney Sweepers Act of 1788 was a British law aimed at addressing the exploitation of young boys as chimney sweeps. It set regulations on the age at which boys could be apprenticed, required parental consent, and mandated certain living conditions and opportunities for education. The Act was a response to the harsh working conditions and dangers faced by child chimney sweeps during that time. Despite its intentions, the Act did not completely eradicate the practice of using children as chimney sweeps until later legal actions were taken.

Counterarguments

  • While wood-burning fireplaces are criticized for inefficiency, they can be made more efficient with the use of fireplace inserts or advanced combustion wood stoves.
  • Gas fireplaces, though efficient, lack the multisensory experience and the unique ambiance that wood-burning fireplaces provide.
  • The installation of gas fireplaces, while easier than traditional wood-burning ones, still requires access to natural gas lines, which may not be available or practical in all locations.
  • Some modern wood-burning fireplace designs have improved combustion technology that significantly reduces heat loss and increases heat output.
  • The use of fireproof materials is essential, but the choice of material can also affect the thermal mass and heat retention of the fireplace, which is not discussed in the text.
  • The physics of fireplaces also involves the concept of the stack effect, which can be managed to minimize heat loss, a point not covered in the text.
  • Gas fireplaces, while more efficient in some respects, may not be as environmentally friendly due to the use of fossil fuels and the associated carbon emissions.
  • Professional chimney cleaning is important, but the frequency of cleaning can vary based on the type of fireplace and how often it is used, which is not mentioned in the text.
  • While chimney sweep logs are subject to skepticism, some users may find them a useful supplement to professional cleaning, though not a replacement.
  • The history of child chimney sweeps is tragic, but it also led to significant social reform and the development of modern professional chimney sweep practices, which is a positive outcome not highlighted in the text.

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Selects: How Fireplaces Work | STUFF YOU SHOULD KNOW

Types of fireplaces

Josh Clark and Chuck Bryant explore the range of fireplace options, focusing on the differences between wood-burning and gas fireplaces in terms of efficiency, installation, and fuel requirements.

Wood-burning

Wood-burning fireplaces hold a traditional appeal, yet they face criticism for their inefficiency.

Clark and Bryant acknowledge the popularity of wood-burning fireplaces but point out their inefficiency. They explain that wood-burning fireplaces often lose more heat than they produce, which can be counterproductive in warming a space.

Require seasoned wood

The hosts emphasize the necessity of using the right kind of wood to ensure proper burning and heat production. Seasoned hardwoods such as hickory, ash, or oak are the best choice for a wood-burning fireplace, as freshly cut wood is less efficient, producing excess smoke and minimal heat due to its high water content.

Gas

Gas fireplaces are an alternative that provides improved efficiency and ease of use.

More efficient

Clark and Bryant discuss the ...

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Types of fireplaces

Additional Materials

Clarifications

  • Wood-burning fireplaces are often criticized for being less efficient than gas fireplaces. This inefficiency is due to wood-burning fireplaces losing more heat than they produce, which can result in a net loss of warmth in the room. Gas fireplaces, on the other hand, are considered more efficient because they do not rely on indoor air for combustion, drawing air from outside instead. This difference in air source contributes to gas fireplaces being more effective in maintaining a warm indoor environment compared to wood-burning fireplaces.
  • Using seasoned hardwoods in wood-burning fireplaces is crucial because freshly cut wood contains high moisture content, leading to inefficient burning, excess smoke, and minimal heat production. Seasoned hardwoods like hickory, ash, or oak have lower moisture levels, ensuring cleaner combustion and better heat output. Properly dried wood also helps prevent creosote buildup in the chimney, reducing the risk of chimney fires. Overall, the use of seasoned hardwoods enhances the performance and safety of wood-burning fireplaces.
  • In gas fireplaces, the mechanism of dra ...

Counterarguments

  • Wood-burning fireplaces can be efficient with the right design, such as EPA-certified models that reduce emissions and increase heat output.
  • The ambiance and sensory experience of wood-burning fireplaces are often preferred over gas fireplaces, which can be a significant factor for some homeowners.
  • Seasoned wood is not the only option for efficient burning; other sustainable firewood alternatives, such as pellets, can also be used in specially designed stoves.
  • Gas fireplaces, while more efficient in some respects, rely on fossil fuels, which can be a concern for those looking to reduce their carbon footprint.
  • The installation ease of gas fireplaces can vary depending on the existing infrastructure and whether there is ...

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Fireplace components

Understanding the various elements of a traditional fireplace can help in both appreciating its engineering and maintaining its safe operation, as Chuck Bryant and Josh Clark, the hosts, discuss.

Hearth, firebox, damper, flue, and more

Hearth

Materials used to construct the hearth go back half a million years, with clay, silt, and limestone being used historically. In modern times, the hearth is built from something fireproof like rock or brick, serving as a warming area and acting as an apron on the floor that extends from the fireplace, designed to help prevent fires from spreading.

Surround

The surround constitutes the area that goes up the walls along either side of the fireplace opening and above it. It is also made of fireproof materials like the hearth, including tile, brick, or stone. Its purpose is the same: to prevent fires from spreading.

Firebox

This is the square space that houses the fire. Smoke begins to collect here before advancing to the other components of the fireplace designed to safely channel it out of the home.

Smoke Chamber and Throat

The throat is the opening that connects the firebox to the smoke chamber. The smoke chamber then channels the smoke into the flue. This area has seen key improvements in fireplace design to enhance safety and efficiency.

Flue and Chimney

The flue is the passageway for smoke enclosed by the chimney, which is generally constructed of brick. The smoke travels in a zigzag path through these interior components on its way upwards.

Smoke Shelf

Located in the back rear of the smoke chamber, the smoke shelf features a concave and angled forward design to shield the fire from rain and prevent soot and particulates from descending into the firebox.

Damper

The damper is a movable cover that sits between the firebox and the space above it. When a fire is not burning, the damper should be closed to prevent drafts. Some fireplaces also have a chimney damper at the top of the flue, which can provide additional protection and airflow control, though its necessity is debated.

Spark Arrestor

This is typically a mesh grate positioned at the chimney's top to pre ...

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Fireplace components

Additional Materials

Clarifications

  • The throat in a fireplace is the passageway that connects the firebox, where the fire burns, to the smoke chamber. It serves as a transition point for smoke and gases to move from the firebox into the smoke chamber. This design feature helps control the flow of smoke and directs it towards the flue for safe ventilation. The throat plays a crucial role in the efficient operation of a fireplace by ensuring that smoke is properly channeled out of the home.
  • The zigzag path of smoke through the flue and chimney helps to slow down the smoke's ascent, allowing more heat to be transferred to the surrounding masonry. This design also aids in improving the draft efficiency by creating turbulence that helps carry the smoke up and out of the chimney. The smoke's journey through this path helps to cool it down gradually, reducing the risk of creosote buildup and enhancing safety. The zigzag pattern also contributes to increasing the surface area within the chimney, promoting better heat transfer and ultimately improving the fireplace's overall efficiency.
  • The smoke shelf in a fireplace is designed with a concave shape that slopes forward. This design helps prevent rainwater from entering the firebox and directs it towards the back of the fireplace. By angling forward, the smoke shelf shields the fire from moisture and helps prevent soot and debris from falling back into the firebox.
  • A chimney damper is a movable cover that helps control airflow in a fireplace. It should be closed when a fire is not burning to prevent drafts and heat loss. Some fireplaces also have a chimney damper at the top of the flue for additional airflow control. The debate around its necessity stems from varying opinions on its impact on efficiency and safety.
  • A spark arrestor is a mesh grate placed at the top of a chimney to prevent embers from escaping and potentially causing a fire on the roof. It acts as a safety feature by trapping any sparks or embers that may be carried up the chimney by the rising smoke. The spark arrestor helps protect the surrounding area from the risk of fire by containing any hot debris within the chimney system. Its primary function is to reduce the likelihood of external fires caused by stray embers from the fireplace.
  • The ash dump in a fireplace is an optional feature that provides a convenient way to remove ashes from the firebox. It typically consists of a hatch in the floor of the firebox where ashes can be swept into a collection area for easy cleanup. By using the ash dump, homeowners can efficiently dispose of ashes without creating a mess in the living space. This helps maintain a clean and functional fireplace for safe and ...

Counterarguments

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Physics of fireplaces

Understanding the physics of how a fireplace works is vital in maximizing its efficiency and ensuring it serves its intended purpose without causing problems such as house fires or smoke entering the room.

Heat transfer through radiation and convection

Chuck Bryant and Josh Clark explore the different kinds of heat: conduction, convection, and radiation. They note that conduction is not involved in a fireplace's heat transfer. Instead, fireplaces primarily use convection and radiation to warm an area. Convection is the process of circulating hot air to cooler areas, whereas radiation lets you feel the warmth directly from the flame. A fireplace produces infrared and visible light radiation, including some radio waves and microwaves, with most of the heat being transferred through convection.

However, because of the need to keep smoke out of the house, the convection currents that carry the heat are also directed out through the flue and chimney. Bryant points out the design of certain stoves allows heating on all sides and directs the stovepipe up and then out of the room so that the hot gas warms the surrounding air through radiation and convection. He also mentions the use of a tubular grate to improve efficiency. This grate draws in cool air from the bottom, which rises and potentially shoots out warmed air into the room.

In gas fireplaces with fake logs covering the gas vent, the fire gives off radiant and convected heat without requiring air from within the room, making them more efficient compared to traditional wood-burning fireplaces.

Tend to make rooms colder by removing warm air

Clark and Bryant delve into the inefficiency of traditional fireplaces and discuss how they ...

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Physics of fireplaces

Additional Materials

Clarifications

  • Conduction is the transfer of heat through direct contact between materials. Convection involves the movement of heat through the circulation of fluids like air or water. Radiation is the transfer of heat through electromagnetic waves, such as infrared and visible light. Each type of heat transfer plays a role in how fireplaces warm spaces.
  • In a fireplace, infrared and visible light radiation are forms of electromagnetic radiation emitted by the flames. Infrared radiation is felt as heat and warms objects directly, while visible light radiation is the light that you can see. These types of radiation contribute to the warmth and ambiance created by a fireplace.
  • Convection currents directed out through the flue and chimney: In a fireplace, convection currents are the flow of hot air rising and carrying heat away from the fire. These currents are directed out through the flue and chimney to remove smoke and gases from the combustion process, ensuring they exit the house safely. This process helps maintain air quality indoors by expelling harmful byproducts of the fire while allowing the heat to be efficiently distributed throughout the room.
  • Tubular grates in fireplaces are designed to improve efficiency by drawing in cool air from the bottom. This cool air is then heated by the fire and rises, potentially shooting out warmed air into the room. The design of tubular grates helps enhance the circulation of heated air, contributing to a more efficient heating process.
  • In traditional fireplaces, the negative pressurization effect occurs when the fire draws in air from inside the room to fuel combustion, creating a pressure imbalance. This process leads to ...

Counterarguments

  • Conduction may play a minor role in a fireplace's heat transfer, especially in the materials surrounding the fireplace that are in direct contact with the heat source.
  • While most heat is transferred through convection, the proportion of heat transferred through radiation can be significant, especially for those sitting close to the fire.
  • The efficiency of convection currents can be improved with the use of a properly designed fireback, which reflects heat back into the room rather than allowing all of it to escape through the chimney.
  • Some traditional fireplaces can be retrofitted with inserts or glass doors to improve their efficiency and reduce the amount of warm air being pulled from the room.
  • The statement that traditional fireplaces can make rooms colder might not account for the psychological comfort and localized warmth that a fireplace can provide, which can make occupants feel warmer even if the overall room temperature is lower.
  • The inefficiency of traditional fireplaces can be mitigated by using them in conjunction with other heating methods or by employing strategies to redu ...

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Maintaining fireplaces

Josh Clark discusses the importance of maintaining fireplaces, particularly cleaning them and hiring professionals like chimney sweeps to prevent issues like creosote buildup, which can be a significant fire hazard.

Cleaning, chimney sweeps, creosote buildup

While talking about the maintenance of fireplaces, it is mentioned that, from time to time, homeowners should inspect their chimneys for obvious signs of trouble such as a missing flue cap or noticeable cracks. These problems could not only reduce the efficiency of the fireplace but also pose safety risks.

Professional chimney sweeps are essential for the periodic inspection and cleaning of chimneys. They possess the knowledge and equipment needed to properly maintain a fireplace and chimney, thereby reducing the risks associated with improper care.

As for creosote buildup, it's a dangerous condition within the chimney described as resembling black lava. Creosote can easily catch fire within the chimney, potentially resulting in a chimne ...

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Maintaining fireplaces

Additional Materials

Clarifications

  • Creosote buildup in chimneys is a dark, tar-like substance that forms from the byproducts of burning wood in a fireplace. Over time, this substance can accumulate on the walls of the chimney, creating a flammable and hazardous situation. The buildup of creosote is a common issue in chimneys and requires regular cleaning to prevent chimney fires. Creosote buildup is a serious concern as it can ignite easily and lead to dangerous chimney fires if not addressed promptly.
  • Creosote is a highly flammable substance that can build up inside chimneys from burning wood. When creosote accumulates, it can ignite due to high temperatures, leading to a chimney fire. These fires can be dangerous as they can spread rapidly and pose a significant risk to the home and its occupants. Regular chimney maintenance, including cleaning by professionals, is crucial to prevent creosote buildup ...

Counterarguments

  • While professional chimney sweeps are recommended, some homeowners may have the skills and tools to perform basic inspections and cleaning themselves, potentially saving money.
  • The necessity of professional chimney sweeps could be less frequent if the homeowner uses the fireplace minimally and takes preventive measures to reduce creosote buildup.
  • Creosote buildup is a risk, but it can be mitigated by burning dry, seasoned wood and maintaining a hot fire, which reduces the amount of creosote that condenses in the chimney.
  • Chimney sweep logs may not be as effective as professional cleaning, but they could serve as a supplementary measure for reducing creosote between professional inspections.
  • The text does not address the potential environmental impact of fireplaces and whether alternative heating solutions might be more sustainable or safer in the ...

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Child chimney sweeps

The dark history of child exploitation in the United Kingdom's past arises specifically from the use of child chimney sweeps, a terrible chapter of history that was eventually addressed by law.

Terrible history of exploitation in the UK

Josh Clark alludes to the widespread historical issue of child chimney sweeps in England, particularly after the Great Fire of London in 1666. Following stricter regulations on chimney cleanliness and the prevalence of narrow chimneys, young boys were often exploited for this hazardous work.

Children as young as four were used as chimney sweeps, purchased and treated more like property than young apprentices. They were sent up narrow chimneys to chip away at creosote and soot, which would fall on them as they worked in these dangerous conditions. Rarely bathing and continuously inhaling harmful substances, many suffered from skeletal deformation due to hours spent in cramped positions. The children also faced a horrifying risk of cancer known as scrotal carcinoma, the first industrial cancer ever identified, which proved to be exceedingly painful and often fatal.

These young sweeps worked nearly every day, with May Day being their only day off, and even slept in rooms where soot was stored, constantly exposing them to treacherous conditions. Tragically, some children became stuck in chimneys and died, often due to positional asphyxia—a fact highlighted by modern references to people stuck in chimneys, such as an illustrative mention of the Grinch.

Laws eventually passed to stop the practice

Parliament first addressed child chimney sweeping with the Chimney Sweeps Act of 178 ...

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Child chimney sweeps

Additional Materials

Clarifications

  • Creosote is a type of chemical compound derived from the distillation of tars and plant materials like wood. It was historically used as a preservative for wood and had various industrial and medical applications. Creosote is known for its distinct scent and flavor, often associated with smoked meat. There are different types of creosote, such as coal-tar and wood-tar creosote, each with specific properties and uses.
  • Scrotal carcinoma is a type of cancer that affects the skin of the scrotum, the pouch of skin that holds the testicles. It was historically linked to the exposure of child chimney sweeps to soot and other harmful substances. The condition was notably associated with the hazardous working conditions and constant exposure to carcinogens experienced by young chimney sweeps in the past. Scrotal carcinoma was one of the first industrial cancers identified and was a significant health risk for those subject ...

Counterarguments

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