NCJ Number
190328
Date Published
October 1999
Length
43 pages
Annotation
This document presents information concerning testing of Positive Pressure Ventilation (PPV) fans for use by emergency first responders in the event of a terrorist attack that employs Chemical Warfare Agents (CWA).
Abstract
PPV fans are common equipment to many firefighters. During fire fighting operations, PPV fans are used to clear smoke from burning buildings, so that quick rescues can be performed in these buildings. The Domestic Preparedness program investigated using PPV fans to reduce the concentration of CWA (or other HAZMAT vapors) in vapor-contaminated buildings. A scientific study was undertaken to measure and document how PPV fans reduced indoor vapor concentration in a specific building. Phase 1 of the testing examined the ventilation rates of a building in both the natural (without PPV) and forced air environments with PPV. The difference was used to determine the ventilation rate from using the PPV fans. Phase 2 examined the use of the fans in the same building during a live-rescue mission scenario. Standard MIST testing was used in this phase to determine the increased protection the firefighters received from using the PPV fans in addition to the protection they received from Bunker Gear. Results showed that the use of PPV fans at a site of terrorist activity where chemicals had been disseminated would significantly reduce the vapor levels inside the building and increase the safety of first responders who must enter the building to effect rescue operations. It was recommended that a hand-held pressure gauge be used by firefighters when determining the optimum distance from entry doors to place PPV fans in service at a building. Optimal distance is the fan location where the measured pressure inside the building is the greatest. Visual verification with streamers still provides a rough estimate for PPV location if portable pressure gauges are not available. 23 figures, 5 tables