FIREPROOF DOORS.—IRON v. TIN.

New Zealand Times, Volume XXXIV, Issue 5612, 25 March 1879, Page 3

FIREPROOF DOORS.—IRON v. TIN.

(From the Insurance . Agent and Insurance Review.) ■ ; : “-■We called' attention’ in onr last number to. the fact that!wooden doors covered-with tin have proved more - effective in - resisting. the Spread of . flames than Iron doors. , -i The reason of this is obvious. Iron presents the same Weakness when used ,for -doors as when-em-ployed for the beams and supports of buildings. While it will hot burn; it is extremely susceptible to the influence of -boat in other ways, warping and bending to such an extent; as. to allow;, the fire! free, passage,besides being an hpcelleht' conductor, and thereby convoying heat enough’ to iiye. combustibles on the other side. ' The' Manufacturers Mutual, , ; of, Boston; has lately issued a [circular on this sub-, ject, confirming ;froin . facts in its own experi; ehce the superior value of; tin. Mr-Whitingi. theisecretary.'says’:^-’', “ I have usually visited the scene, of, all. fires reported to this ..office in which we yvere interested as underwriters, whether,the,damage was •nainih or littleand I . may, say . that,T,have never yet seen a well-made wooden tinned, door .which gave way to..the-fire , and Xhave.no 'recollection of any case,in which an iron door of-ordinary construction, subjected to a heavy(fire; has proved reliable. Among the many ‘picker fires (which have happehed in mills insured by this company since 1862, only one has proved destructive to.the mill, and,the door in ’ this! case dividing, the! picker : rbbm' from.the ''nfill was ofirdn| and. did not hold the fire at all, but immediately softened and warped outof, ‘shape, allowing' the! pre free passage to,the -mill.”’ ‘ , , j ‘ Mr. Woodbury, the inspector, relates _ thq’following, as the result of his examination in thd case of the late fire at the Pacific Mills:— " ;< “'At end,o£.ihe, steaming, room, “'where the'fire'originated, is’an ISin. brick fire Wall, in which are double doors made of 2in. ■plank*; and :.tirine’d-! on: both sides, put in, m-T 1 ani informed, at the instance Of.’Mr. Whiting,; within five years. The: flames were in direct ‘contact with. ;one , door during an hour or an hour and a half, ;in which timethe buildingdn ffii» (was destroyed’; but no flame entered the ""other room, and only a portion of the' paint on .the 'other door,’ ISin.-distant,’ was blistered. 1 ' tlpdn removing the. rtini from the door winch 'resisted the fire,' it was found that the wood--1 had been charred to the depth of three-eighths.: of.ah inch. A tinned wood door on the same floor, at the entrance to the picking building, ' .‘subjected to a somewhat less degree of heat,’ resisted all action of the fire. ■ <' ' ‘ On the westerly side of the pressing-room (the: corner room) is a sliding iron door, constructed of Jin. iron, and; heavily backed by 7-l6in. iron. The panels:: were 'about. 6in.; width, so .that , most of ,the door, is ll’-16in.:in 'tbickness.' This door is hung on; trucks,’and when .shut three sides are in iron grooves ; the’ "fire department of the Atlantic Mills threw a large amount ofwater in to. this room soon after alarm was given, and only a portion of the

floor-was'burned; .yet this door is'so badly warped that if: dan be moved only’.with great difficulty.” . V The appearance of the doors, and the'statements of the experienced persons present at the fire, are to the effect that wood doors covered with tin successfully;pesisted intense heat for a long time) and that iron doors of exceptionally good Econsfriiction Iwafped under a comparatively slight degree of heat. . The objections to iron doors are equally applicable to shutters. It is notorious that while these have, in many cases, proved powerless to prevent the; spread of the fire, the difficulty of opening them, haa seriously impeded; the 1 work of . extinguishment. .. Wooden shutters backed with tin would undoubtedly prove a far better safeguard. The same principle applies 'to all beams and supports. Wood will .not readily lose its shape or its; strength when subjected to hbat) If property’encased in a non-.comhus-tible) it cannot' btirii ; it will' slowly char, while its non-conducting powers will keep back the fire.;’ The use of iron,for. fire-proof purposes is- a'falb.oy which is fast being exploded. , . . , . ' .