- Author
- Cooper, L. Y.
- Title
- Calculating Flows Through Vertical Vents in Zone Fire Models Under Conditions of Arbitrary Cross-Vent Pressure Difference.
- Coporate
- National Bureau of Standards, Gaithersburg, MD
- Report
- NBSIR 88-3732, May 1988, 16 p.
- Distribution
- Available from National Technical Information Service
- Keywords
- fire models | building fires | compartment fires | computer models | computer programs | algorithms | pressure differential | pressure effects | pressure vessels | zone models
- Abstract
- In typical compartment fire scenarios, ratios of cross-vent absolute pressures are close to 1. When such is the case, algorithms are available to predict the resulting cross-vent room-to-room flows. There are, however, important situations where this pressure condition does not prevail, for example, in fire scenarios involving relatively small penetrations in otherwise hermetically-sealed compartments of fire origin. It is important for a versatile compartment fire model have a capability of predicting vent flows for the entire range of possible cross-vent pressure conditions. This paper develops a unified analytic description for flows through vertical vents between pairs of two-layer room fire environments under conditions of arbitrary cross-vent pressure difference. The analysis, which takes advantage of generally useful modeling approximations, leads to a concise result which is not significantly more complicated than the result for simple, low-pressure-difference cases.