Online News--Tiny Cell-Based Chemical Detectors Offer Protection Potential
A highly sensitive, inexpensive "lab-on-a-chip" that provides warning within seconds of even trace amounts of toxic chemicals in water was designed and demonstrated recently by National Institute of Standards and Technology (NIST) scientists and collaborators.
The prototype sensor system monitors the natural response of bacterial cells bound within the microscopic channels of a plastic microfluidics device--a miniaturized chemical and biochemical analysis system. In the presence of certain chemicals, the cells eject large amounts of potassium, which is detected with an optical sensor that changes color.
The prototype was demonstrated as part of an early warning system for industrial pollutants that interfere with sewage treatment, but it also has potential homeland security applications. It was designed in collaboration with scientists at Virginia Polytechnic Institute and State University (Blacksburg, VA) and Veridian Pacific-Sierra Research (Charlottesville, VA).
IRC-Designed CAF Fire Suppression System Finds Use in Aircraft Hangars
Researchers in the Institute for Research in Construction's Fire Risk Management program are investigating the use of a compressed-air foam fire suppression system in aircraft hangars.
In collaboration with Canada's Dept. of National Defence, researchers in the (Canadian) Institute for Research in Construction's (IRC) Fire Risk Management program are investigating the use of a newly developed compressed-air foam (CAF) fire suppression system in aircraft hangars. Because of CAF's fire suppression capability, low water requirements and easy cleanup, they believe the system has potential for providing fire protection in these buildings, as well as in other special applications.
If a fire occurs in an aircraft hangar, protecting the aircraft in the building from possible fuel spill fires is the first priority, while protecting the building itself comes second. NFPA Standard 409 for aircraft hangars specifies 90% fire control within 30 seconds and 100% within 60 seconds.
Using these criteria, IRC researchers developed a prototype CAF system for a 55-meter by 37-meter hangar using specially designed ceiling-level and floor-level nozzles to cover the hangar floor with foam rapidly. The overhead nozzles provide coverage of approximately 100 square meters in a circular pattern with a diameter of 11.3 meters. The low nozzles provide coverage of approximately 66 square meters in a circular pattern with a diameter of 9.1 meters.
IRC's system uses compressed air to generate foam, in contrast to current foam systems that incorporate aspirating nozzles and blower generators, and produces foam with substantial injection velocity. These characteristics are particularly important in buildings with high ceilings, such as aircraft hangars, where the injected foam must penetrate fire plumes to reach the seat of the fire.
IRC's patented CAF technology was recently licensed to a Canadian company for commercialization. The company plans to develop systems that utilize fixed piping and special nozzle technology to deliver the CAF to the area of the fire, providing a high level of fire protection with low water requirements.
Reprinted from the December 2002 issue of "Construction Innovation," a newsletter published by the IRC.