- Author
- Issen, L. A.
- Title
- Fire Endurance Tests of Residential Walls Containing Branch Circuit Wiring--Preliminary Findings. Final Report.
- Coporate
- National Bureau of Standards, Gaithersburg, MD
- Sponsor
- Department of Housing and Urban Development, Washington, DC
- Report
- NBSIR 78-1415, February 1978, 65 p.
- Distribution
- Available from National Technical Information Service
- Keywords
- fire endurance | fire tests | polyvinyl chloride | smoke | walls | wires | electrical codes
- Abstract
- Two fire endurance tests were performed to study the effects of branch circuit electric wiring and wiring devices on the fire resistance of a gypsum board and wood stud one-hour fire-rated wall. The tests simulated potential fire spread between (a) horizontally adjacent occupancies and (b) vertically adjacent occupancies. Each test wall assembly included both nonmetallic sheathed cable (type NM) and armoured cable (type AC), with ducted with a slightly positive pressure in the furnace, to represent the overpressure generated in room fires. The tests showed that the presence and penetrations of electric branch circuit cables and wiring devices lowered the fire resistance of a one-hour rated gypsum board and wood-stud wall by 13 minutes when based on flame penetration of the unexposed surface wallboard and by 23 minutes when based on flame penetration at the wiring devices. The tests showed no significant difference in the performace of the different cable types.