TRUSSED METAL LATH FIRE TEST

TRUSSED METAL LATH FIRE TEST

Ira H. Woolson, E. M., adjunct professor of Mechanical Engineering at Columbia University, New York, recently submitted truss metal lath partitions to a test by both fire and water. Its purpose was to determine the effect of a continuous fire against the partitions for one hour, maintaining an average temperature of about 1700° Fahr. during the last half of the test. At the end of that time a stream of cold water was thrown against each partition for two and one-half minutes through a one and one-eighth inch nozzle at hydrant pressure, which at this location varies from twenty-five to thirty pounds. The test was conducted on a fair day, with a light wind from llie west and a temperature of from 75 to 80″ Fahr. It began at 11: 25 a. ttt.; the water was applied at 12: 28 p. in. The partition, when tested, was four weeks old. The test building was the standard size of the New York city building department, namely, nine feet by fourteen feet six inches on the outside. The foundation walls were twelve inches thick and three.feet high. Securely anchored in these was four-foot by fourfoot steel angle framework, to which the partitions were attached. The side walls were constructed the same as partitions in a building, and thev were the only part under test. The end walls and roof were made of concrete reinforced with the metal lath, and were thicker than tinpartitions They simply served to complete the building. Suitable draught openings and chimney lines were provided as shown in the drawings. The fire grate was on the level with the top of the foundation walls. The side walls, or partitions. were constructed of sheets of truss metal lath wired together, thus forming continuous sheets or layers filling the opening in the steel frame and attached to it on all sides. Upon these the partitions were built by plastering, first one side, which was allowed to set, and then the other. The total thickness of the partitions, including the finishing plaster coat on both sides, was two-inch to two and one-half inch. The two partitions were of different compositions, one being patent bag plaster, and the other, lime mortar, tempered with twenty per cent, of Portland cement. The temperature of the fire was obtained by an electric pyrometer couple suspended through the centre of the roof and banging about fifteen inches below the ceiling. The temperature was read every three minutes. The Log of Temperature Readings, with plotted curve for same, accompanies this article. The fuel used was dry cord wood supplemented by refuse boards. The frequency of firing was controled bv the temperature recorded. The water was applied by New York firemen. In applying the water through the door in the end of the building, it struck the partitions at an angle, and not with full force. The stream was thrown hack and forth over the whole surface of the partition as much as possible and not allowed to play continuously in one spot. The effects of the) test were as follows. Owing to a liberal supply of dry kindling wood, with a too generous applica-l lion of kerosene, the fire at the start was an intensely hot flash (1700“ l-ahr. recorded in three minutes), and it became necessary to throw on water to check the flames. The heat fluctuated for a few minutes, then gradually fell to 8oo°, and rose again gradually to about 1700° at the end of half an hour. The average for the last half hour was a little below 1700; but, as such high temperatures were recorded during the first half of the test, it was decided the average was satisfactory. During the fire the plaster partition bulged out considerably and cross cracks appeared, the larger of which opened about one sixteenth of an inch wide, and extended two-thirds of the distance across the partition surface in both directions. Similar cracks appeared in the cement partitions, but not so large, and very lithe, if any bulging took place At no time did any smoke or fire come through either of the partitions, nor were any openings to be seen through them After the water had been applied, it was noted that the piaster partition had suffered the worst. It was bulged outwards about one and one-half inch. On the inside the finishing plaster was practically all gone, and the “brown coat” was gone over the area attacked by the water T he metal lath showed in spots or speckles over this area, but the body of the partition was in good condition. T he cement partition was not bulged, and only about one-third of the “brown coat” was gone on the inside. The finishing coat was practically all gone. The metal lath was exposed over about one-sizth of the partition stir face. VV here the metal did show, the exposure was more complete than on the plaster side. This may have lieeu due to the fact that the water was put on the cement side first when it was hottest, causing a more sudden contraction of the metal and consequently cleavage between cement and lath, or the cement, having a stronger bond, may have broken cleaner from the metal when it was forced off by the water. On the whole, the cement partition was without doubt the more rigid of the two after thaAt. The accompanying photographs give the interior view of each partition after the test, also general views of the building before and after test.

TEST BUILDING TWO MINUTES AFTER TESTIING FIRE.INTERIOR VIEW SHOWING SOUTH PARTITION AFTER TEST.INTERIOR VIEW SHOWING NORTH PARTITION AFTER TEST.TRUSSED METAL LATH BUILDING AFTER THE TEST.

The new waterworks system at Constableville, N. Y., will have a storage reservoir, with a capacity of manv million gallons.

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