PUBLIC Part III. Mr. Braidwood on Fires. Principle of Floors. Iron. APPENDIX III. MR. BRAIDWOOD ON FIRES. OPY of a letter from Mr. Braidwood to Henry Cole, CO 68, Watling Street, October 30, 1846. SIR, Having inspected the model of a room for the preservation of Records, in which you have adopted the dimensions I suggested, and having been asked by you for the reasons for recommending such dimensions, to enable you to submit them to the Right Honourable the Master of the Rolls, and to make any other suggestions, I have pleasure in acceding to your request. To make what follows intelligible, I must explain some of the difficulties of making any building fire-proof. In the first place I have assumed that a Record Office must be so built that no fire in any one compartment can by possibility affect another; also, that the safety of the building, as a whole, against fire must not depend on the care and attention of any one, or on any outward appliances. I am not aware of any incombustible material which can be used for the support of floors, so as to allow a tolerable size of apartment, with sufficient light, except iron. Iron, however, must be used with the greatest caution, as, of all building materials, it is one of the most rapidly and most seriously Fairbairn on affected by fire. Mr. Fairbairn, engineer of Manchester, in his interesting experiments on the strength of cast-iron, published in the Seventh Report of the British Association, page 409, states that, on raising the temperature of cold blast cast-iron from 26° to 190° Fahrenheit, the loss of strength was 15 per cent.; and in raising the temperature of hot blast from 21° to 190°, the loss of strength was 10 per cent. Taking the average of the above-mentioned examples, it gives a loss of 12 per cent. of strength, on a rise of temperature of 166o. The fusing point of cast-iron is differently stated in different works, but it may be safely taken as not less than 3000° Fahrenheit; therefore, according to the above experiments, less than one-half the heat required to melt cast-iron would completely destroy its strength. I have now by me two specimens of castiron which have been melted at fires which took place this year (22nd February and 10th September); and some time ago I sent to the Official Referees some pieces of cast-iron and wrought-iron PUBLIC melted also at a fire (7th September, 1844). RECORDS. App III. Mr. Braid wood on Fires. As iron pillars are much more exposed to the action of the Part III. draft, and, in consequence, the intensity of the heat, I did not think it advisable to recommend them. Iron ties are still more easily affected by the heat, as a comparatively slight rise of temperature will so expand them, as to prevent them acting as tiesin fact, make them totally useless, or rather worse, as what power they might exert would, in consequence of the expansion, be the reverse of ties. Iron girders, if of considerable length, are apt to unsettle the brickwork by their expansion, if heated to any extent. Again, it is a very common thing to have the mortar in the first course of bricks completely pulverized by the heat. In one in- Use of stance, a great part of the first or lowest layer of bricks in an arch Bricks. fell down of themselves (15th July, 1843); therefore, the brick arches in the proposed building ought not to be less than 9 inches thick. It is now a generally admitted principle by all who have turned their attention to the subject, that, as the cubic contents of any building or compartment of a building (if properly divided) increase, so does the intensity of the heat increase, and, of course, the loss of strength in the iron would increase in the same proportion. It must also be considered that, although a Record Office may be constructed without any combustible materials in the building itself, still, even in the size of the apartment proposed, say 27 × 17 X 15, there would be at least 12 tons of Records in Cubical many of the rooms of the above size, disposed so as to have a and Limits thorough draft round them in every direction for the purpose of of Spaces. preservation; but, at the same time, this thorough draft would cause the ignition to proceed with greater rapidity, and very much increase the intensity of the heat. For these reasons, I proposed that the bearing of the girders should not exceed 17 feet; to this extent they might be made, I have no doubt, perfectly secure, if protected from the effects of the heat, as they may easily be to a certain extent, and also that each compartment should not exceed 27 × 17 × 15 = 6885, the height being intended to give two sets of shelving. This appears to me the largest size of room that could be used with perfect safety. I would even advise the room to be divided into two, with iron window shutters, for the more precious description of Records. One very great advantage, from the small size of the rooms, would be that, should a fire take place, the loss would be in proportion to the size of the room. I may here state, that what are commonly called fire-proof buildings (cast-iron girders and brick arches) are not so, if the Contents PUBLIC Open Ventilation. compartments are large, and a sufficient quantity of combustible materials to raise the iron to a certain temperature be introduced. If, for any reasons independent of safety (which I am not aware of), it were thought expedient to have either the rooms larger, or the whole building three stories instead of two, I would prefer the latter alternative; but still it does not appear to me that the same safety or convenience would be obtained from three as from two stories. It has been suggested that, in case of fire, the upper floor might be reached by ladders. Such an arrangement appears very injudicious, as there would be always chances of the ladders not being ready, or not in good condition, when wanted. Respecting the mode of heating the building, I strongly recommend open fire-places (two in each room) for safety. There are many objections to heating by hot air or hot water: Ist. A considerable number of fires have been caused by both modes. 2nd. Either mode induces a general communication through the building, not only by means of the pipes, but it is next to impossible to pass a pipe which is alternately heated and cooled through brick or stone-work air-tight, owing to the contraction and expan sion of iron, without expansion joints, which are a considerable expense, and require constant attention. 3rd. The heat required for heating so great an extent of building must be generated in one or more furnaces, and these, with their flues, are such constant causes of risk and trouble, that no furnace or close fires should be permitted within any premises which are meant to be absolutely safe from fire. 4th. I have been given to understand that a thorough ventilation is believed to be the most efficient means of preserving Records; and it is submitted that two open fire-places in each room, with independent flues, would better effect that end than either hot air or hot water. These fires could be lighted at pleasure in any one or more rooms that might most require drying or draft; at present I am not aware that heating is at all necessary for the preservation of Records, except under peculiar circumstances, when the fires could be lighted. I have the honour to be, Sir, your obedient Servant, Superintendent of London Fire Engine Establishment, and HENRY COLE, ESQ., Carlton Ride. See Great Exhibition of 1851 and Kensington Museum (postea) for his remarks. A REPORT OF AN IMAGINARY SCENE AT UNIFORM PENNY POSTAGE. Council Chamber in Windsor Castle-Her Majesty is sitting at a large table, on which are lying the Parliamentary and Commissioners' Reports on Postage; Copies of the Post Circular; Annual Reports of the French and American Post-Offices-Her Majesty in deep study over "Post-Office Reform" by Rowland Hill-Lord Melbourne, at the Queen's right hand, is watching her Majesty's countenance. PENNY Part II. Selections. A.D. 1838-1841. HE QUEEN (exclaiming aloud).-Mothers pawning UNIFORM their clothes to pay the postage of a child's letter! POSTAGE. Every subject studying how to evade postage without caring for the law! Even Messrs. Baring sending letters illegally every week, to save postage! Such things must not last. (To Lord Melbourne.) I trust, my Lord, you have commanded the attendance of the Postmaster-General and of Mr. Rowland Hill, as I directed, in order that I may hear the reasons of both about this Uniform Penny Postage Plan, which appears to me likely to remove all these great evils. Moreover, I have made up my mind that the three hundred and twenty petitions presented to the House of Commons during the last session of Parliament, which pray for a fair trial of the plan, shall be at least attended to. (A pause.) Are you, my Lord, yourself, able to say anything about this postage plan, which all the country seems talking about? UNIFORM Part II. A.D. 1838-1841. Scene at Windsor. Lord Melbourne.-May it please your Majesty, I have heard something about it, but The Queen.-Heard! So I suppose has every one, from the Land's End to John o' Groat's house: I wish to ask your Lordship's advice upon it. Lord Melbourne.-May it please your Majesty, the PostmasterGeneral tells me the plan will not do; and that, to confess the truth, is all I know at present about the matter. Groom. Enter Groom of the Chamber. The Postmaster-General and Mr. Rowland Hill await your Majesty's pleasure. The Queen. Give them entrance. Enter Lord Lichfield and Mr. Rowland Hill, bowing. The Queen. I am happy to see my noble Postmaster-General and the ingenious author of the Universal Penny Post Plan. Gentlemen, be seated. My Lord Melbourne has told you why I wished for your presence on this occasion. I have been reading carefully, and with great interest, the late discussions and evidence on the postage question, and I now wish to hear what is my Postmaster-General's opinion on this plan, which I therefore beg you, Mr. Hill, to describe in a few words. Rowland Hill. With your Majesty's leave I will say nothing of the dearness and hardship of the present Post-Office rates, or of Post-Office management itself, but confine myself, according to your Majesty's commands, to the plan you have honoured me by noticing. My plan is, that all letters not weighing more than half an ounce should be charged one penny; and heavier letters one penny for each additional half ounce, whatever may be the distance they are carried. This postage to be paid when the letter is sent, and not when received, as at present. Lord Lichfield.-Please your most gracious Majesty, "of all the wild and visionary schemes which I have ever heard or read of, it is the most extravagant." "1 The Queen. You seem, my Lord, to adhere, not only to your opinions, but your very words. If I recollect rightly, the very same expressions were used a year and a half ago, by you, in the "Mirror of Parliament," 15th June, 1837. |