- Author
- Mawhinney, J. R. | Tamura, G. T.
- Title
- Effect of Automatic Sprinkler Protection on Smoke Control Systems.
- Coporate
- National Research Council of Canada, Ottawa, Ontario
- Journal
- ASHRAE Transactions, Vol. 100, No. 1, [pages unknown], 1994
- Sponsor
- American Society of Heating, Refrigerating and Air-Conditioning Enginers, Inc., NY National Fire Laboratory, Canada
- Report
- 94-12-3; RP-677,
- Keywords
- sprinklers | smoke control | experiments | crib fires | fuel load | fire tests | heat release rate | buoyancy | pressure | smoke production
- Identifiers
- one-story test room; ten-story tower; shielded fires; gas concentrations; smoke spread
- Abstract
- A series of experiments on the interactions of sprinklers with shielded fires and the corresponding effects on a zoned smoke control system was conducted. Testing involved two phases. In the first phase, large wood crib fires were conducted in a one-story test room equipped with sprinklers. The centers of the cribs were shielded from direct impingement by water spray so that burning continued in spite of the sprinklers. The room was instrumented so that fire conditions, including heat release rate; heat flux to walls; ventilation rate; temperature profiles; oxygen, carbon dioxide, and carbon monoxide concentrations; and buoyancy pressures, could be closely measured. Sprinkler discharge rates were also measured and converted to spray densities. The tests in the one-story room provided fundamental information about the interaction of sprinklers and partially suppressed fires, and the results were used for the design and interpretation of a second phase of testing. In the second phase of testing, shielded wood crib fire tests were conducted on the seventh floor of a 10-story experimental tower. The tower was set up to act as a zoned smoke control system, with mechanical exhaust of the fire floor and positive pressurization of the floors above and below the fire. The stairshaft was not pressurized, although it represented one of the zones to be protected against smoke entry. The tests demonstrated that a shielded, sprinklered fire will continue to burn at a reduced heat release rate until the fuel within the shielded area is consumed, producing smoke for the duration of the fire. Concentrations of carbon monoxide in the smoke may be dangerously high, depending on ventilation conditions of the fire. Radiant heat and temperatures were reduced to nonhazardous levels. Fire-induced buoyancy pressures were very low relative to the pressurization used to protect adjacent zones. Although the zoned smoke control system prevented smoke spread to adjacent pressurized floors, it did not prevent smoke spread into the stairshaft after the door to the fire floor was opened unless the stairshaft had been prepressurized by the opening of other doors. With the zoned smoke control system shut off, the buoyancy pressures were sufficient to cause smoke spread into adjacent zones. This paper discusses implications of the test results for the design of zoned smoke control systems and identifies areas for further research.