- Author
- Mitchell, N. D. | Ryan, J. V.
- Title
- Fire Tests of Steel Columns Encased With Gypsum Lath and Plaster.
- Coporate
- National Bureau of Standards, Washington, DC
- Report
- BMS 135, April 3, 1953, 16 p.
- Keywords
- columns | steels | fire tests | gypsum | plaster | fire endurance tests | steel columns | sand
- Abstract
- The results presented are those derived from fire-endurance tests of 16 steel columns encased with gypsum lath and gypsum plasters. The laths were wired into place; those on eight columns were of the 3/8-in. thick perforated type in a single layer, those on seven of the other eight columns were of two layers of the 1/2-in. thick plain type, and on the other a single layer. Six of the latter eight also had a layer of wire fabric to reinforce the plaster. Expanded perlite was used as the plaster aggregate for 13 columns, sand for two, and vermiculite for one. The thickness of the plasters ranged from 1/2 in. to 2 in. and those of the encasements from 7/8 in. to 2 1/2 in. The fire-resistance values indicated by the tests varied with the composition, reinforcement, and thickness of the protective coverings, and to some degree with the size of the column. The fire-endurance limits, as determined from the tests, ranged from 1 hr 23 min for a 10-in. steel H-section column protected with 3/8-in. perforated lath and 1/2 in. of sanded gypsum plaster to 4 hr 42 min for one protected with two layers of 1/2-in. lath, and a 1 1/2-in. thickness of perlite-gypsum plaster reinforced with wire fabric.