NanoMist® and Hybrid Mist behave like gas. Ultrafine water mist (<10 micron) technology is a potential alternative to clean agents in certain selected fire suppression applications. Droplets smaller than 10 microns begin to exhibit gas-like behavior with a superior ability to diffuse around obstructions without significant loss of mist due to plating and deposition. The ultra-fine mist disperses like a dense gas or as a total flooding agent unlike standard (or commercial) water mist systems (50-100 micron) and rapidly absorbs heat because of the huge surface area and the large vaporization rate of micron sized mist droplets. NanoMist droplets generated at ambient pressure have a relatively narrow droplet-size distribution whereas conventional pressure atomization generally yields broad droplet-size distributions.
Figure below shows NanoMist or NanoMist Hybrid mist flow inside the room. The mist behaves like a dense gas dispersing from the discharge location.
If the mist discharged with high velocity, the volume will be filled with a swirl flow of NanoMist or NanoMist Hybrid (co-flow of air and nitrogen) as shown below:
NanoMist has the following unique features:
Similar to gaseous agents, NanoMist® applications involve areas with obstructions and non-line of sight locations.
High cooling power of water mist (2.25 MJ/liter of water) while behaving like a pseudo gas.
Tolerance to reasonable leaks since NanoMist® water-mist can be continuously discharged.
Little or no collateral damage in the event of a false discharge because of the small amount of water usage.
Environmentally friendly water fog without chemical agents.
In NRL sponsored total flooding work, calculations were carried out to design total flooding fire tests in a 28 m3 compartment for an ultrafine water mist and experiments were conducted.
The ultrafine water mist was able to successfully extinguish all pool fires.
The average extinguishment time of a 120 kW heptane fire was around 5 min with six mist units operating at a total of 0.66 l/min. The extinguishment time decreased with increasing mist injection rate. The addition of a simple obstruction required slightly more mist input to extinguish the fire.
A 70 kW methanol fire was extinguished in approximately 8 min. The measured volume of water consumed by the misters differed from the predicted rates used in the computer model.
Another independent study was conducted at Warner Safety Equipments Trdg. Est. Dubi, UAE on total flooding in 22 m3 room. The objective of this work was to investigate the gas-like nature of UFM in a 22-m3 fire test compartment, treating NanoMist as a gaseous agent and using corner telltales at various heights. In addition to low velocity NanoMist, some “high-momentum” discharge scenarios demonstrating the ability to increase the mist “throw” height/distance and accelerated transport process are also illustrated.
All four telltales at the floor level are extinguished within 2-3 minutes using approximately 1.4 LPM NanoMist. This extinction time in a 22 m3 room gives an extinction concentration of 0.130-0.19 L/m3 (130-190 grams/m3).
All telltales at the 50% of room height level are extinguished within 4 minutes using about 1.4 LPM. This gives an extinction concentration of 0.250 L/m3 (250 grams/m3). Telltales at the 70-75% of room height level are extinguished within 6-7 minutes.
The results of simulated raised floor tests indicate the near gaseous nature of UFM in its ability to reach hidden areas in a typical total flooding situation. This feature of UFM to reach non-line-of-sight shows its possible use in “hidden area” fires.
NanoMist® agent demonstrates the gas-like total flooding behavior in a room of 22 m3.
The test results also showed the ability of the UFM agent to pass around obstacles and extinguish telltales located in corners and hidden areas. The observed high-speed discharge behavior indicates the ability to accomplish faster mist transport and the potential to accomplish quicker extinction of fires in a total flooding context.
Some of test scenarios and photographs of Navy sponsored total flooding CFD simulations and experimental tests and another independent study are presented here.
NanoMist or NanoMist Hybrid System Flooding
NanoMist Total Flooding Tests -Outside Laboratory Tests
NFS Company Patent on Electronics Cooling - Prevent Overheating
NanoMist Small-Enclosure Electronic Space Fire Study by NRL/Hughes Associates
NanoMist Fire Protection Agent - Publication
NanoMist Electronic Space Fire Study by NRL/Hughes Associates Scaled-up Tests