NIST fire researchers Stephen Kerber and Roy McLane position a mounted fan outside the doorway of a 30-floor building in Toledo, Ohio. The positive pressure ventilation (PPV) experiment demonstrated that in a building with sprinklers, the fan, operating a
Photo credit: Courtesy NIST
Two researchers from the National Institute of Standards and Technology are working on a model of how to help save your building's occupants in the case of a high-rise fire.
The two research, Stephen Kerver and Roy McLane, went fairly low-tech in their approach. They mounted a fan on a trailer and positioned it outside an escape doorway/stairwell entrance of a vacant 30-floor office structure in Toledo, Ohio, and then turned it on. What they found, over some 160 tests using a variety of fans, was that a high-powered direct-drive fan (their unit ran at 3,500 rpm, which is fairly normal for these types of fans), could create positive pressure in the exit stairwell that would effectively keep smoke out away from the stairs, and subsequently aid those trying to escape from the building.
It's not that fans are anything new, or that the benefits of positive pressure haven't been thought about before. In fact, fans have been installed directly into high-rise facilities for such uses since the 1970s. Rather what the NIST researchers did was explore the use of portable fans, such that could arrive on a trailer with other fire equipment to a scene.
Among other findings:
â€¢ Fans are loud. Mobile fan units strong enough to create positive pressure can generate up to 110 decibels -- about the same as a loud car stereo system turned up all the way, or the noise of a chainsaw in operation.
â€¢ Fire and security command centers will need to be located away from such fans due to noise levels.
â€¢ Fans for this purpose would need to be certified depending on height of building.