Engineering

"Air-intake control is the key to efficient fireplace combustion. The ignition of a correctly proportioned gas-air mixture will promote... complete combustion... and emit "clean" gases... carbon dioxide, water vapor, oxygen, and nitrogen."

"Fireplace installation in... efficiently weather-stripped houses creates a problem of... sufficient air for chimney draft. A partial vacuum... is the result, tending to pull smoke and combustion gases... into the room."

"When smoke and soot are... coming out of a chimney... combustion is incomplete."

"The air that enters the room through the air-box is fresh, though warm; and, computing the swiftness of its motion with the areas of the holes, it is found that near ten barrels of fresh air are hourly introduced by the air-box; and by this means the air in the room is continually changed, and kept at the same time sweet and warm."

"[T]he flame and smoke will ascend and strike the top... which will thereby receive a considerable heat. The smoke, finding no passage upwards, turns over the top of the air-box, and descends between it and the back plate to the holes in the bottom plate, heating, as it passes, both plates of the air-box, and the said back plate; the front plate, bottom and side plates are also all heated at the same time. The smoke proceeds in the passage that leads it under and behind the false back, and so rises into the chimney."

"[T]he operation of a standard fireplace will effect the displacement of over twice the amount room air required for optimum ventalation. Half the amount... should therefore, be drawn from outside... pass only indirectly through the building, and be prevented from immediate escape through the fireplace."

"[F]oot-chilling floor draft was... solved by Savot through... a subfloor inlet return for previously heated air. ...[T]his ...would eliminate ...trouble frequently encountered in modern homes ..."

"Unfortunately, most of the technical improvements in fireplace design have not yet emerged into common usage... in spite of the fact that improvements occurred as far back as 1624, when Louis Savot invented the first heat-circulating fireplace. His unit... became the prototype for Ben Franklin's 1742 Pennsylvania stove. The 1624 French fireplace achieved 30 to 45 percent more efficiency than... most American tract-home fireplaces today!"

"5. The German stove is like a box, one side wanting. It is composed of five iron plates, screwed together, and fixed so as that you may put the fuel into it from another room, or from the outside of the house. It is a kind of oven reversed, its mouth being without, and body within, the room that is to be warmed by it. This invention certainly warms a room very speedily and thoroughly with little fuel; no quantity of cold air comes in at any crevice, because there is no discharge of air which it might supply, there being no passage into the stove from the room. ...Its inconveniences are, that people have not even so much sight or use of the fire as in the Holland stoves, and are, moreover, obliged to breathe the same unchanged air continually, mixed with the breath and perspiration from one another's bodies, which is very disagreeable to those who have not been accustomed to it."

"Few people are aware that practically all of the technical features of Franklin's... stove were copied from earlier inventors. [Louis] Savot's concept of a preheated draft was employed by Franklin... Prince Rupert's descending flue, invented in 1687, was also applied... The smoke rose in front of a hollow metal back, passing over the top and down the opposite side. ...Ducts similar to those invented by Nicholas Gauger, in 1716, were also incorporated in the Franklin stove."

"The design of a house around its massive, central fireplace has... always felt right to this writer-builder."

"6. Charcoal fires in pots are used chiefly in the shops of handicraftsmen. They warm a room (that is kept close, and has no chimney to carry off the warmed air,) very speedily and uniformly; but, there being no draft to change the air, the sulphurous fumes from the coals (be they ever so well kindled before they are brought in, there will be some,) mix with it, render it disagreeable, hurtful to some constitutions, and some times, when the door is long kept shut, produce fatal consequences."

"The fireplace designed and built by the author... is unobstructed, free-standing, and insistent, at the same time that it is supportive of the roof. It is central to the room... as it stands sunken, in its fire pit. ...[W]here the massive stone chimney rises to pierce the roof, a translucent band cascades filtered, mellow illumination [from integrated skylights] down the stone face."

"The most noteworthy development of the open fireplace took place in 1796, when... Count Rumford published... "Chimney Fireplaces." His main contribution was the alleviation of the smoking chimney. One fault... he... asserted, was due to the large chimney throat. Rumford also introduced the inclined fireback, which increased fireplace effeciency by providing... greater . For the purpose of breaking up the current of smoke in the... downdraft, the back smoke shelf of Rumford's improved fireplace ended abruptly—a practice strictly adhered to... to this day."

"Vitruvius... thus describes the construction of the or stove for heating the or sweating room of a bath. The floor is made inclining, so that a ball placed on any part of it would roll towards the fireplace, by which means the heat is more equally diffused in the sweating-chamber. The floor is paved with tiles... and on these are built brick pillars... two feet high, and cemented with clay and hair mixed together. The pillars are placed at such a distance, as will allow tiles to be laid on them to form the ceiling of the hypocaust, and support the pavement of the caldarium. The air to the caldarium, or room over the hypocaust, is admitted through an aperture in the centre of its roof, from which a brazen shield is suspended by chains. By raising and lowering this shield, which opens or shuts the aperture, the heat of the caldarium is regulated. For heating the water to supply the baths, there are to be three caldrons... the arched cavities in which they stand are to be heated by one fire. After such minute instructions how to form the stove in which large quantities of wood were to be consumed, it is singular that he should omit to notice in what way the smoke produced was to be conveyed into the atmosphere. From this silence, it has been inferred that he was ignorant of what Anderson calls "the elegant and commodious tube now known by the name of a chimney.""

"It is to be observed, that the entering air will not be warm at first lighting the fire, but heats gradually as the fire increases."

"Fireplaces have... come a long way from their crude "open fire" origins to... safe, efficient units... The heavy masonry materials... are no longer necessary. The amount of space required has been dramatically reduced, and the amount of labor... as well. ...Current fireplaces provide the inherent "charm"... while serving as an efficient and usable source of heat."

"[O]f the [15 1/2] millions of tons of coals raised yearly from the mines, not more than [3 1/2] millions are consumed by steam-engines and in manufacturing operations, leaving [11] or [12] millions of tons of fuel to be mismanaged in kitchens and sitting-rooms throughout the country."

"To avoid the several inconveniences, and at the same time retain all the advantages of other fire-places, was contrived the PENNSYLVANIAN FIRE-PLACE, now to be described."

"The register-plate was described at the close of the fifteenth century by Alberti... and by others who wrote afterwards. Were this simple and cheap smoke-valve introduced into every cottage chimney, it would save the heat of [5] or [6] millions of tons of coals that is now annually wasted and thrown away."

"Cooling by evaporation of water or by fans and warming by heaters and fireplaces are artificial aids... From a practical, economic, or aesthetic point of view it makes much more sense to develop, where possible, constructional features for warming or cooling the owner-built home."

"It is more important for the owner-builder to understand the aerodynamics of combustion and ventilation than... detailed specifications for one particular fireplace..."

"A consists of a fire-place, in which the fuel is consumed, and a flue to carry off the smoke and vapour arising from the combustion; thus affording the benefit of the heat of a fire without the inconvenience of its smoke. But these objects were, and still are, very imperfectly attained; a large portion of the fuel being wasted without increasing the warmth of the apartment."

"In the mean time, very little is done by these chimneys towards warming the room; for the air round the fire-place, which is warmed by the direct rays from the fire, does not continue in the room, but is continually crowded and gathered into the chimney by the current of cold air coming behind it, and so is presently carried off."

"Dr. Franklin, in 1785, published "Observations on the Cause and Cure of Smoky Chimneys." He has very satisfactorily explained all the usual causes of this defect, and shown their remedies. To this pamphlet succeeded the "Essay" of Count Rumford, in 1796, whose improvements in the construction of fire-places have been very generally adopted. These two works together, form a valuable body of information. They are well known to the public, but it is not so generally known, that exactly a hundred years ago, viz. in the year 1715, Dr. Desagulier published his book, entitled "Fires Improved, being a new method of Building Chimneys, so as to prevent their smoking, &c." which is a translation of a still older work from the French of M. Gauger, which shows that the most, if not all, the principles pointed out by Count Rumford were understood, and are explained by M. Gauger. He also proposed seven different constructions of chimneys, in which there are hollow cavities made by iron plates in the back[,] jambs and hearth, through which plates the heat passing warms the air in those cavities, which is continually coming into the room fresh and warm. This construction had many obvious advantages; but the expense and difficulty attending it, at that early period, discouraged the propagation of the invention. In our own times, however, similar constructions have been brought forward as new, probably without the knowledge of what had been done so long before, and therefore with all the merit of invention."

"In both these sorts of fire-places, the greatest part of the heat from the fire is lost; for, as fire naturally darts heat every way, the back, the two jambs, and the hearth drink up almost all that is given them, very little being reflected from bodies so dark, porous, and unpolished; and the upright heat, which is by far the greatest, flies directly up the chimney. Thus five sixths at least of the heat (and consequently of the fuel) is wasted, and contributes nothing towards warming the room."

"[I]n the countries of modern Europe, the use of stoves prevail throughout the north; while in France and Great Britain, open fires are used. In the warm countries of Italy and Spain, there are very few chimneys, and the only method usually practised of tempering the cold, which is sometimes severely felt, is to burn charcoal in portable brasiers."

"[H]aving, in 1742, invented an open stove for the better warming of rooms, and at the same time saving fuel, as the fresh air admitted was warmed in entering, I made a present of the model to Mr. , one of my early friends, who having an iron furnace, found the casting of the plates for these stoves a profitable thing, as they were growing in demand. To promote that demand, I wrote and published a pamphlet, entitled, "An Account of the new-invented Pennsylvania Fire Places; wherein their construction and manner of operation is particularly explained, their advantages above every method of warming rooms demonstrated; and all objections that have been raised against the use of them, answered and obviated, &c." This pamphlet had a good effect; governor Thomas was so pleased with the construction of this stove as described in it, that he offered to give me a patent for the sole vending of them for a term of years; but I declined it, from a principle which has ever weighed with me on such occasions, viz: That as we enjoy great advantages from the inventions of others, we should be glad of an opportunity to serve others by any invention of ours; and this we should do freely and generously."

"Many homeowners abandoned the fireplace as a means of cooking with the emergence of the eighteenth century manufactured stoves. Led by the development of... the ', other types of cast iron stoves became available, including the potbelly stove and the massive kitchen range. The advantages offered by the stoves included radiation from the heated cast iron surfaces, better draft for more efficient burning, and successful operable dampers to regulate the fire."

"That there were no chimneys in the 10th, 12th, and 13th centuries, has been presumed from the terms "ignitegium" [curfew] or "inpritegium" the curfew-bell of the English, and couvrefeu of the French; which seem to intimate, that the people made fires in their houses in a hole or pit in the centre of the floor, under an opening formed in the roof; and when the fire was burned out, or the family went to bed at night, the hole was shut by a cover of wood."

"3. To remedy this, the Sieur Gauger gives, in his book, entitled La Méchanique de Feu, published in 1709, seven different constructions of the third sort of chimneys mentioned above, in which there are hollow cavities made by iron plates in the back, jambs, and hearths, through which plates the heat passing warms the air in those cavities, which is continually coming into the room fresh and warm. The invention was very ingenious, and had many conveniences; the room was warmed in all parts, by the air flowing into it through the heated cavities; cold air was prevented rushing through the crevices, the funnel being sufficiently supplied by those cavities; much less fuel would serve, &c. But the first expense, which was very great, the intricacy of the design, and the difficulty of the execution, especially in old chimneys, discouraged the propagation of the invention; so that there are, I suppose, very few such chimneys now in use. The upright heat, too, was almost all lost in these, as in the common chimneys."

"The oldest certain account of chimneys, is in the year 1347. An inscription at Venice, records... a great many chimneys (molti comini) were thrown down by an earthquake."

"The first chimney-sweepers in Germany came from , , and the neighbouring territories; and these for a long time were the only countries where the cleaning of chimneys was followed as a trade. Hence it is conjectured, that chimneys were invented in Italy."

"[M]any of the diseases proceeding from colds, as fevers, pleurisies, &c., fatal to very great numbers of people, may be ascribed to strong-drawing chimneys, whereby, in severe weather, a man is scorched before, while he is froze behind."

"An ironmonger in London, however, assuming a good deal of my pamphlet, and working it up into his own, making some small changes in the machine, which rather hurt its operation, got a patent for it there, and made, as I was told, a little fortune by it. And this is not the only instance of patents taken out of my inventions by others, though not always with the same success; which I never contested, as having no desire of profiting by patents myself, and hating disputes."

"Experiments by, and the design work of... led to the type of fireplace closest to the present day configuration. ...The designs Thompson perfected were known as Count Rumford Fireplaces."

"Our present century has seen the development, manufacture, and widespread use of double-walled steel heat-circulating fireplace unit."

"It has frequently been a subject of inquiry, whether the ancients were acquainted with chimneys, or open fire-places. In the houses discovered at and , there are no chimneys; they all appear to have been warmed by furnaces and flues."

"2. Most of these old-fashioned chimneys in towns and cities have been, of late years, reduced to the second sort mentioned, by building jambs within them, narrowing the hearth, and making a low arch or breast. It is strange, methinks, that though chimneys have been so long in use, their construction should be so little understood till lately, that no workman pretended to make one which should always carry off all smoke, but a chimney-cloth was looked upon as essential to a chimney. This improvement, however, by small openings and low breasts, has been made in our days; and success in the first experiments has brought it into general use in cities, so that almost all new chimneys are now made of that sort, and much fewer bricks will make a stack of chimneys now than formerly. An improvement so lately made may give us room to believe, that still farther improvements may be found to remedy the inconveniences yet remaining. For these new chimneys, though they keep rooms generally free from smoke, and, the opening being contracted, will allow the [house] door to be shut, yet, the funnel still requiring a considerable quantity of air, it rushes in at every crevice so strongly, as to make a continual whistling or howling; and it is very uncomfortable, as well as dangerous, to sit against any such crevice. Many colds are caught from this cause only, it being safer to sit in the open street; for then the pores do all close together, and the air does not strike so sharply against any particular part of the body."

"The first wall fireplaces were constructed without chimneys. They used an extended masonry or metal hood over the fire. Smoke exited through a simple hole through the wall... Early fireplaces... had no sides or other devices to form a firebox. ...Many fireplaces of the wall type were located in a corner of a room."

"[T]hough one or more expressions of ancient authors may appear to allude to a chimney, if the ancients were acquainted with the art of constructing, in mason-work, elevated funnels for conveying away the smoke, it must be allowed, when we consider the many proofs... to the contrary, that they were... extremely rare."

"4. The Holland iron stove, which has a flue proceeding from the top, and a small iron door opening into the room, comes next to be considered. Its conveniences are, that it makes a room all over warm; for, the chimney being wholly closed except the flue of the stove, very little air is required to supply that, and therefore not much rushes in at crevices, or at the door when it is opened. Little fuel serves, the heat being almost all saved; for it rays out almost equally from the four sides, the bottom, and the top, into the room , and presently warms the air around it, which, being rarefied, rises to the ceiling, and its place is supplied by the lower air of the room, which flows gradually towards the stove, and is there warmed, and rises in its turn, so that there is a continual circulation till all the air in the room is warmed. The air, too, is gradually changed, by the stove-door's being in the room, through which part of it is continually passing, and that makes these stoves wholesomer, or at least pleasanter than the German stoves... But... There is no sight of the fire... When the room is warm, people, not seeing the fire, are apt to forget supplying it with fuel... The change of air is not carried on quite quick enough; so that, if any smoke or ill smell happens in the room, it is a long time before it is discharged. For these reasons the Holland stove has not obtained much among the English (who love the sight of the fire) unless in some workshops..."

"The years of the central- fireplace brought the development of the first s. ...Metal andirons in their functional form consisted of two vertical bars on flat or arched leg bases, with an elevated horizonal cross-brace to space them apart and keep them upright. ...The upper part of the vertical members featured extended prongs or notches. This gave support for a horizontal rod, or spit, for cooking meat, and... hanging cooking pots directly over the fire."

"[C]rude efforts were eventually adopted to create s of s to channel the unwanted smoke... The masonry surface behind the fire aided... radiating heat, and the heavy mass... in the wall and the chimney stored heat... increasing its efficiency."

"The use of these fire places in very many houses, both here in Pennsylvania, and the neighbouring states, has been, and is, a great saving of wood to the inhabitants."

"Its advantages above the common fire-places are, 1. That your whole room is equally warmed, so that people need not crowd so close round the fire, but may sit near the window, and have the benefit of the light for reading, writing, needlework, &c. They may sit with comfort in any part of the room... 2. If you sit near the fire, you have not that cold draft of uncomfortable air nipping your back and heels, as when before common fires, by which many catch cold, being scorched before, and... froze behind. 3. If you sit against a crevice, there is not that sharp draft of cold air playing on you, as in rooms where there are fires in the common way; by which many catch cold, whence proceed coughs, catarrhs, tooth-aches, fevers, pleurisies, and many other diseases. 4. In case of sickness, they make most excellent nursing-rooms; as they constantly supply a sufficiency of fresh air, so warmed at the same time as to be no way inconvenient or dangerous. A small one does well in a chamber; and, the chimneys being fitted for it, it may be removed from one room to another, as occasion requires, and fixed in half an hour. The equal temper, too, and warmth of the air of the room, is thought to be particularly advantageous in some distempers... 5. In common chimneys, the strongest heat from the fire, which is upwards, goes directly up the chimney, and is lost; and there is such a strong draft into the chimney, that not only the upright heat, but also the back, sides, and downward heats are carried up the chimney by that draft of air; and the warmth given before the fire, by the rays that strike out towards the room, is continually driven back, crowded into the chimney, and carried up by the same draft of air. But here the upright heat strikes and heats the top plate, which warms the air above it, and that comes into the room. The heat likewise, which the fire communicates to the sides, back, bottom, and air-box, is all brought into the room; for you will find a constant current of warm air coming out of the chimney corner into the room. Hold a candle just under the mantel-piece, or breast of your chimney, and you will see the flame bent outwards; by laying a piece of smoking paper on the hearth, on either side, you may see how the current of air moves, and where it tends, for it will turn and carry the smoke with it. 6. Thus, as very little of the heat is lost, when this fire-place is used, much less wood will serve you, which is a considerable advantage where wood is dear. 7. When you burn candles near this fire-place, you will find that the flame burns quite upright, and does not blare and run the tallow down, by drawing towards the chimney, as against common fires. 8. This fire-place cures most smoky chimneys, and thereby preserves both the eyes and furniture. 9. It prevents the fouling of chimneys; much of the lint and dust that contributes to foul a chimney being, by the low arch, obliged to pass through the flame, where it is consumed. Then, less wood being burnt, there is less smoke made. Again, the shutter, or trap-bellows, soon blowing the wood into a flame, the same wood does not yield so much smoke as if burnt in a common chimney; for, as soon as flame begins, smoke in proportion ceases. 10. And, if a chimney should be foul, it is much less likely to take fire. If it should take fire, it is easily stifled and extinguished. 11. A fire may be very speedily made in this fire-place by the help of the shutter, or trap-bellows... 12. A fire may be soon extinguished by closing it with the shutter before, and turning the register behind, which will stifle it, and the brands will remain ready to rekindle. 13. The room being once warm, the warmth may be retained in it all night. 14. And lastly, the fire is so secured at night, that not one spark can fly out into the room to do damage."

"Longlande, in Pierce the Plowman'sVision, feelingly alludes to the change as prompted by a mean and selfish wish to abridge the ancient hospitality observed towards the poor. "Elynge is that halle eche day in the wyke, Ther the lorde ne the lady liketh nat to sitte. Nowe hath eche ryche a reule to eten by hym silve In a privey parlour for pore mennys sake; Or in a chaumbre wyth a chymney, and leve the cheef halle That was mad for melis men to eten inne." The chimneyed chamber was spacious and lofty, and usually formed with a large bay window, looking into the court of the castle."

"When this is the case the most effectual method... is, to bring the grate forward till the forepart of it is immediately under the inner edge of the mantle; then build up the vacancy at the back of it, the whole width of the fire-place from side to side, raising it perpendicularly till it is as high as the back of the grate, and then bending it forward towards the mantle, as... fig 4. When it is as high as the workman can reach, let it be suddenly turned backward again, sloping a little upward... then fit a sheet of milled iron to the inside of the mantle, making it slant a little upward toward the back... a small distance above the new... masonry, and extending within a few inches of the back wall... By this construction all the air that enters into the chimney is made to pass immediately above the fire, between it and the heated iron... as the back of the fire-place is bent a little forward above the grate... the heat is likewise reflected into the room with the greater force... [I]f the smoke is accidentally beat down the chimney by a sudden gust of wind, it will be catched by the sheet of Iron, and prevented from coming into the room."

"It is not known at what time chimneys began to be used. The writers of the 14th century seem either to have been unacquainted with chimneys, or to have considered them as the newest invention of luxury."

"The strong hold of Conway is further remarkable for exhibiting another domestic refinement, not found, except at , in any contemporary building. A hearth is recessed into the wall, and has a rising from it for the passage of the smoke into the air. It is true, that after this period, flued fireplaces were sometimes made in rooms that had been erected without them, but the chimney in Conway Castle, and a similar one at Kenilworth [Castle], appear as if they had formed part of the original edifices."