Popular Science Monthly/Volume 2/February 1873/The Warming of Houses
|THE WARMING OF HOUSES.|
By JOHN P. SEDDON, Esq.
THE usual appliances for warming houses, setting aside comprehensive systems, resolve themselves into open grates, close stoves, and, under special conditions, gas apparatus, and pipes for hot air or water for warming halls and passages.
For the whole of these certain general rules may be laid down:
1. More cannot be got out of any one of them than is put into it. This is an axiom which, truism as it appears, is necessary should be impressed upon the public mind, which is apt to assume that engineering skill can multiply the heating power of fuel indefinitely. Thus, materials like fire-clay, which are absorbent of heat and useful to prevent its escape, and retain it till needed, must abstract it first from the fuel before it can dispense it.
2. There are but 100 degrees of percentage. This simple fact should be kept in mind in considering methods of saving fuel, the inventors of which would otherwise persuade one that reference to coal-merchants is a work almost of supererogation.
3. Some proportion of the heat generated must be expended in maintaining a draught in the flue, which is to carry off the products of combustion. This is by no means unprofitably lost, since it promotes ventilation as well.
4. To minimize this proportion of escaping heat to as nearly as possible what is just necessary, and to take toll from it during its passage, as by warming the air which is to replace that abstracted by the flue, are the principal directions which efforts to economize fuel should take.
5. The products of combustion, being noxious, must be wholly removed, unless they can be chemically transformed. It is as barbarous to allow the fumes from gas to invade rooms, as it is to let the door be the sole outlet for peat-smoke in an Irish cabin, or as it was to provide only louvers in the roofs of the halls of our forefathers for the smoke of their wood-fires. The evil may be disguised, but the poison is the more insidious from being comparatively unfelt. The lungs of the living animals, as the leather of dead ones on the book-shelves, become corroded alike by its pernicious influence.
6. Warming and ventilation are so intimately connected that, although the latter is not my special subject upon this occasion, it is necessary that it should be kept in mind throughout while treating of the former. In fact, infusing heated air is a more economical and pleasanter mode of warming houses than direct radiation, and it is only by their capability of combining the two methods that open fires can maintain ascendency over stoves, and it is only by uniting proper ventilation with stoves that they ought to be tolerated.
Lastly, all appliances should be simple and as self-acting as possible. This is essential for those intended for the use of the poor, whose treatment of them is of the roughest, and who neither need nor understand any thing complicated. If there be a damper to be drawn, or a handle to be turned by them, neither will be drawn nor turned except occasionally the wrong way, and if there be any cover or part that is loose, it is safe to be lost. At the risk, therefore, of some waste, their scanty fuel must be consumed in the most primitive manner possible. With somewhat less force the same caution may be given to those who design apparatus for the upper classes. Every thing even for them should be as self-acting as possible, for, though individuals may for a time take a fancy to an ingenious arrangement that requires personal adjustment, they tire of it in time; servants in their succession are not to be drilled into its use, and the thing is soon left to itself, and failure is the inevitable result.
To proceed to the several appliances themselves:
In the race to attain economy, it must be acknowledged, at the outset, that close stoves completely distance open grates, and that they in their turn are as far ahead of all gas-apparatus as at present invented; and yet all have some advantages as well as disadvantages peculiar to themselves, to which it is worth giving some consideration.
In stoves, the heat from fuel can be almost wholly extracted and utilized, and even the little that escapes with the gaseous products of combustion is heavily taxed when its ultimate exit is by the few insignificant pipes, or diminutive chimney-stalks, which alone are suffered to peep above the roofs of houses on the Continent. English ideas of comfort will not, however, permit of the general introduction of the stove system into this country, and it is hardly to be desired that it should, unless great improvement be grafted upon that in vogue abroad, in which stuffiness is ever an accompaniment of warmth.
Our British privilege, however, of being able to poke the fire, although purchased dearly by its concomitant dust and the labor it entails upon servants, is not likely soon to be relinquished, and the luxury of an open fire is a fact which no theory can demolish.
Still, the grates in common use savor of barbarism, and much can and should be done to gain further refinement, economy, and immunity from nuisance. There is no need, for instance, that our roofs should be disfigured by the ugly and even comical flue terminals which Dickens satirized in one of his latest Christmas publications. We ought not to be subject to vexatious down-draughts in windy weather, nor to chimneys that smoke unless a door or window be open. Our drawing-rooms should not be invaded by sooty chimney-sweepers, and all ought not to have to scramble for a place near the fire in a room to be warm, nor when there to have to rotate like a smoke-jack to prevent being frozen on one side while we are scorched on the other.
Such evils are to be obviated by simple means, and yet ninety-nine out of every hundred Englishmen submit to them supinely if not patiently. Whole streets, occupied by men of means, have their skyline fringed with demon-like excrescences which tell a sure tale of internal discomfort. Such was the case with that in which my own residence is situated. When I took my house upon lease, though it had been well built by an eminent architect for his own use, yet, in common with all its neighbors, it displayed a grim array of tall-boys and tortuous contrivances as chimney terminals. All these I swept away at once, without inquiry, feeling that, whatever might be needed, they certainly could not be. I then introduced an air-pipe to each fireplace through the floors, and, as I expected, found no smoky chimneys to complain of, though my neighbors still grumble at theirs, as I do of their futile and unsightly expedients to remedy them.
So much depends upon the proper construction of fireplaces and their flues, without which no appliance in the shape of a grate can have fair play, that I shall in the first place describe the points to be attended to in the erection of these portions of a building, and in palliating evils in those which already exist.
The first essential to insure a good draught is that the flue should be sufficiently rarefied. For this purpose it is desirable that it should not be in an outer wall; but, if it be necessarily so, the enclosing wall should be thick (at least 9 in. between the flue and the outer air) or else it should be protected by a double casing, with intermediate hollow space. Materials which absorb damp should be avoided for the construction, as they tend to the evaporation and loss of the heat generated; and the interior of the flue should be well pargetted, to further prevent the suction of external cold by the up-draught within. Another important point is that the flue be not too large, or currents of cold air descending will interfere with the ascending heated air. In old buildings flues are found of large size—as 18 in. by 12 in.—with wide throats, funnel-shaped, diminishing upward. But the fuel used in them was wood, and abundant, and men were more hardy, and minded not the roaring of wind in the chimney, or cowered over the embers within the vast embrasure of the fireplace, which formed an inner room of itself. There are those who would revive these large flues, on the ground that no cowls decorate their terminals. If, however, we are to recur to the practice of our ancestors, we might as well revert to that of a still earlier age, when the stately hall of Penshurst had its fire upon a hearth in the centre, and the graceful wreaths of smoke thence found exit by the lantern in the roof. We must needs then have the same goodly logs as fuel, and a supply which will enable us to afford the blaze that alone would suffice to rarefy a cavern. The ordinary coal-fires of our apartments do not need a larger flue than a pipe of 9 in. in diameter. Mr. Richardson, in his work, states that the houses built by Cubitt in Belgravia have flues 9 in. by 9 in. only, while others erected later have them 14 in. by 9 in., and that these are distinguishable outside by the absence or presence of objectionable cowls respectively. Kitchen-flues must be larger, in proportion to their fires, or better, perhaps, doubled—a practice for which old precedents may be found, and which seems calculated to avoid down-draughts.
For the avoidance of that particular nuisance, however, special provision should be made in every flue. This may be done by an enlarged space, wherein the force of gusts of wind may expend itself upon, as it were, a cushion of air. If the first pipe above the chimney-mantel be a 9-inch pipe, let the next be a 15-inch one, and the flue above continued with 9-inch ones. A somewhat similar arrangement has been proposed by Mr. Boyd for brick flues. He discontinues the vertical flue a few feet above the mantel with an enlarged space or pocket, and carries an inclined one from the fireplace into this on one side, and the down-draught, thus meeting resistance at the bottom, eddies round the space, without being able to check the upward draught from below. Mr. Cubitt's continuation of the flue to the basement also obviously affords a resisting column of air to accomplish the same purpose. It may be impossible to make such cavities large enough to overcome the effect of every down-draught, but these provisions against them will generally secure this desired end if combined with ample provision of air to the fireplace.
The use of pipes for the lining of flues has the advantage of compelling a good and non-porous finish, which would otherwise be neglected by careless workmen, who often will not take the trouble to properly parget and core the flues in stone and brick walls. The interior of the pipes, however, should be rough, and by no means glazed, or their inability to give any means of adherence to soot will be found a nuisance, in consequence of its continual dropping. The old funnel-shaped throat left a large space above the grate filled with cold air, which checked the draughts. This depends much upon the grate itself; but, generally speaking, the flue should be contracted to its smallest size as soon as possible above the mantel. Iron frames for this purpose, serving as mantel-bars as well, such as Gibbs's registered fireplace-lintel, are useful appliances. A concrete block may be made of the shape required at perhaps the least cost. . . .
The construction of the fireplace itself is of the most importance. The contraction of the flue immediately over it is the first point to be looked to, and next the provision of a proper supply of air for the combustion of the fuel. To illustrate this in the simplest manner, I may refer to a small room with a large fireplace in it, belonging to a friend, which was complained of as simply uninhabitable by reason of the draughts that invaded it from all sides. A piece of iron pipe, with the lower end protruded through the outer wall, the middle brought through the fire, and the upper end open to the room, stopped all cause for complaint. The reason for this is so obvious that it seems hardly credible that a vast majority of dwellers in houses are enduring continual torture for want of this pipe or some equivalent simple appliance. One looks in vain along the walls of our streets for any signs of air-bricks or other inlets of air, and, with closed doors and plate-glass windows, one wonders where the air comes from to feed the fires within. There are but few available sources, which are these: 1. The joints of the window-frames and chinks round doors, through which cold blasts whistle as they are sucked in, so that these are pasted up, and as far as possible this means of supply intercepted. 2. Unused flues of other rooms down which air pours mixed with smoke; and 3. The soil and waste pipes, the water in the taps of which cannot hinder the precious element from coming even by such undesirable channels, in obedience to the powerful suction of the several fires in the house. These failing, there are positively no other sources. Then, fortunately, the fires begin to smoke, and doors and windows are perforce opened to abate that by far the smallest and least dangerous nuisance of the whole.
The remedy for this is to provide a sufficiently ample supply of pure, fresh air in such a manner that it may come in moderately warm, and from such quarter that it be felt as a draught. There are several means of doing this, each hotly maintained by its partisans to be the only fit and proper one. The bottom, the centre, and the top of the room, are each pointed out as being specially adapted for the purpose by those much-enduring laws of Nature, and the course of the currents of air, demonstrated by flights of the most obedient and flexible arrows. This certainly may be taken for granted: if openings be made in any or all of the positions indicated, the laws of Nature will make a beneficial use of them, but it will be capriciously, one moment as an inlet and one as outlet, as the occasion may need. The fire being the motive power of the currents, the direction that the air will take if it can will be in a straight line to the fireplace, and, therefore, to obviate disagreeable draughts, the air-inlets must not be placed so that currents thence must necessarily impinge upon the inmates of the room, as in the case of the undesigned ones of the chinks round the doors and windows. Again, they should not be so near and below the grate as to rush direct to feed the fire, and thus, not only not aid to ventilate the room, but absolutely take from the fire that valuable office. By far the best mode, in my opinion, is to introduce the air below the hearth, and carry it thence through warming-chambers at the back or sides of the grate, and allow it to issue into the room above the fire-place, or from the outer sides from the chimney-piece, so that it must ascend and mix with the air in the room before it finds its ultimate exit by the fireplace or outlet-flue. In fact, the fireplace itself should be the fountain of warmed fresh air to an apartment, since no draught thence can be annoying to any of the inmates of the room. The air may be brought, according to its position upon different floors, from below, by air-bricks inserted in the walls between the joists, or from above the roof by a flue constructed for the purpose; and if this flue be carried in close connection with the chimney-flue, whether in separate pipes, as by Mr. Jennings's method, by the use of Boyd's metal withes, or ordinary brick ones, the air drawn down by the suction of the fire will have the temperature considerably raised above that of the outer atmosphere, the coldness of which, entering by windows, is unendurable.—Builder.