Wednesday, February 1, 2017: 9:45 AM-10:45 AM
Fundamentals and Applications
Chair:
Paul Turnbull, Siemens Building Technologies, Inc.
Technical Committee: 05.06 Control of Fire and Smoke
All three conference papers in this session focus on verifying modeling information with hands-on experimentation to validate the modeled results. In the first paper, differential pressures from shaft to building were measured in 15 different buildings. Comparing the experimental results to the modeled results, found that in most cases, hand-calculations underestimate differential pressures. In the second paper, experimentation with smoke movement through a high-rise shaft was undertaken and found that previous modeling methods did not match the experimentation results; so a new and improved method was proposed. In the third paper, a building fire was simulated and data on smoke movement in the shaft was captured. When compared to available modeling software, the experimental results were significantly different. More information about this research and their interesting results are up next.
1 Modeling of Stack Effect in High-Rise Buildings Under Winter Conditions: Evaluating the Validity of Field Observations (LV-17-C071)
To characterize the magnitude of stack effect in existing buildings, differential pressures measurements were taken in fifteen high-rise buildings during the winter of 2013. Four observations were made: (1) unless conservative leakage values are used, typical hand calculations may under-predict the shaft-to-building differential pressures, (2) introduction of cold air into pressurized stairwells cooled the stair, but temperatures remained significantly higher than ambient (3) introduction of cold air into pressurized stairwells caused significant pressure and increased door opening forces required at the bottom of the stairs, (4) pressurization of the stairwells increased pressure and stack effect flows via the elevator shafts.
2 Scale Modeling of Smoke Spread in High-Rise Shafts during Fires (LV-17-C072)
Driven by stack effect, smoke often spreads across a building through shafts, which becomes a major challenge for high-rise fire protections. It is therefore important to conduct research on the smoke movement inside high-rise shafts, for which scale modeling based on experiments in sub-scale models of full-size buildings is an important technique. In this paper, a new scale modeling method is developed based on a group of new dimensionless numbers based on the conservations of both heat transfer and mechanical energy for mechanical and natural venting systems of high-rise shafts.
3 Comparison of COSMO Smoke Management Software and Experimental Measurements of Smoke Properties During a Structural Fire (LV-17-C073)
A group of small-scale test sections consisting of acrylic and gypsum models with a single vertical shaft was used to simulate building fires. A propane burner on the first floor provided high-temperature gases that entered the shaft and moved to the upper floors via stack-effect forces under natural ventilation as well as mechanical exhausting conditions. Vertical variations of the pressure and temperature distribution were measured in the shaft. The locations of the Neutral Pressure Plane were determined based on pressure differences measured with different combinations of smoke mass flow rates and size of openings in the shaft.