- Author
-
National Bureau of Standards
- Title
- Fire-Endurance Tests of Bar-Joist Floors With Ceilings of Perlite-Gypsum Plaster on Perforated Gypsum Lath.
- Coporate
- National Bureau of Standards, Washington, DC
- Report
-
Test 257; Test 260; Test 261; Test 266; TR10218-19; FP2982
December 12, 1950
23 p.
- Keywords
-
fire endurance tests
|
floors
|
ceilings
|
plaster
|
gypsum
|
joists
- Abstract
- Four fire-endurance tests have been made on steel Bar-joist floors with lightweight plaster ceilings. These tests were performed at the request of the Housing and Home Finance Agency in cooperation with the United States Gypsum Company. Two of the tests were exploratory in character and were made on 4 ft 4 in wide by 9 ft long floor specimens to develop information needed for the selection of the ceiling required for a test on a 13 ft 3 in wide by 17 ft 4 in long floor. The floors were built with 2-in. thick concrete floor slabs on open web type steel bar-joists. The plaster base for the ceiling construction was 3/8-in. perforated gypsum lath attached to steel furring channels by steel wire clips. A mill mixed perlite-gypsum plaster was applied in two thicknesses for the exploratory tests in an effort to arrive at the minimum thickness which would qualify the full scale specimen for a fire-resistance rating of one hour. Two thicknesses of plaster were applied for the full scale floor tests. The fourth and final test was that on the large floor that had previously been tested and to which a second ceiling, but of less thickness than the first, had been applied. 13 ft 6 in. wide by 17 ft 4 in. long, Test Nos. 272 and 281. Each had a ceiling of lightweight plasters on metal lath. The tests were made in cooperation with the Metal Lath Manufacturers Association to obtain data from which fire-resistance ratings were derived. The choices of the two types of lightweight plaster aggregates and the thicknesses selected were based on the results of three exploratory tests, Nos. 239, 240, and 241. For test No. 272, the plaster aggregate was vermiculite and for test No. 281, perlite. The plaster on one-half the ceiling of the first was from one manufacturer; that on the other half from another; and the ceiling of the second was covered with a mixture containing equal parts of plasters of the two manufacturers.