Firefighter 101 teaches us that to sustain any fire requires heat, oxygen and fuel. Take away one of the three and the fire goes out. However, take away two of the three and it goes out quicker.
That is the idea behind Victaulic’s Vortex Hybrid Fire Extinguishing System, utilizing water mist and nitrogen in a combined suspension to cool the hazard and remove oxygen that supports combustion, said Ian MacInnis, Vortex sales manager.
“It is not water mist or inert gas alone,” MacInnis said. “It’s a mixture of both. Hybrid suppression is the new name coined by the NFPA.”
Starting with the water mist side of the equation, Vortex releases a water droplet of approximately 10 microns in size, eliminating any significant wetting of equipment or surrounding space. The ultra-fine water particles feature a heat-absorbing surface area 90 times greater than those generated by standard sprinklers.
A swirling distribution pattern fills the hazard space at 40 miles per hour, extinguishing the fire with a minimum use of water.
“We can engineer all the way from .26 gpm of water coming from each emitter to creating more or less a fog at 1.06 gpm,” MacInnis said. “It’s a very small amount of water but it’s enough to extinguish the fire.”
Most water mist systems use between five to eight gallons per minute, causing significant wetting. Atomizing the water via Vortex reduces that amount to one gallon per minute, requiring very little cleanup and no containment.
The nitrogen side of the equation involves bringing the oxygen level of the affected area down to the neighborhood of 14 percent, too low for fire to survive but not low enough to suffocate anyone.
“When we started testing we used compressed air to atomize the water,” MacInnis said. “We found it was easier to get nitrogen to do our testing than it was to get compressed air. Nitrogen is used everywhere. Every gas supplier has big cylinders of it available.”
The cost savings of switching to nitrogen provided the bonus of supplemental suppression by reducing the oxygen level in the hazard area, MacInnis said.
Misting systems have a difficult time extinguishing smoldering fires typical of data rooms and machine spaces, MacInnis said. Fires inside server cabinets or beneath tables cannot be reached by direct spray. But combining water mist with inert nitrogen proves extremely effective against these threats.
However, MacInnis uses more rigorous industrial emergencies as an example of what the Vortex system can accomplish.
“Say you have a pickling and annealing line in a steel mill,” he said. “That can be a very volatile fire, probably involving exposure to hydrofluoric acid. In that situation we are going to use a bit more water while we inert the oxygen level.”
The major upgrade for this type of fire would be polyvinylidene fluoride (PDVF) emitters designed for caustic environments.
“It has proven very efficient at putting out those HF fires,” MacInnis said.
Vortex is applicable to Class A, B and C fires, MacInnis said. The water supply is self-contained and requires no additional piping. It can activate immediately upon detection of a fire without having to wait for evacuation. The system seamlessly integrates with existing alarm and detection systems.
Unfortunately, the initial product rollout in 2008 coincided with a nationwide economic downturn, MacInnis said.
“What we did was to pick and chose our spots when we first released it,” he said. “It wasn’t a mass release. That allowed us to make a few tweaks to our system since then.”
Nitrogen leakage is notoriously hard to prevent, MacInnis said. The solution was to update the valves on the nitrogen cylinders and keeping the manifold unpressurized until necessary.
“So now we have an electrical release on a primary discharge head that opens the first cylinder,” MacInnis said. “The other cylinders are daisy-chained together. The back pressure from the first cylinder discharging opens the others, filling the manifold.”
The release pressure of 3,000 psi is reduced to 30 psi by the time the nitrogen reaches the emitters, he said.
“There is a very large orifice in the emitter for the nitrogen and then a number of small orifices around it,” MacInnis said. “The water dribbles out those holes at about five psi. The nitrogen rockets out the big orifice at supersonic speed while the water is very low velocity, low pressure.”
The design of the emitter further pulverizes the water droplets into a mist that takes away the heat needed to sustain combustion.
Vortex is used companies specializing in aircraft and automobiles, telecommunications, energy and aerospace, MacInnis said. The system protects 6.6 million cubic feet in totalflooding applications for more than 250 projects.
The problem in marketing Vortex is that customers are adverse to publicity about the success, MacInnis said.
“We know about many fires that we have extinguished,” he said. “But talking about them specifically gives the insurance companies a free pass to raise rates.”