"Although SF6 is slated to remain the largest market shareholder in coming years owing to superior functional attributes, the fact that it is one of the key greenhouse gases and has substantial atmospheric lifetime
as well as the global warming potential is making room for potential alternatives to SF6, which are relatively less popular in the dielectric gases landscape," says a senior research analyst at the company.
The system, which utilises a flow of super-pressurised nitrogen to spread an anti-fire agent over a designated area, comes with a considerably low environmental impact due to its zero-ozone depleting potential and short atmospheric lifetime
The GWP of a gas depends on three factors: atmospheric lifetime
of the species, the absorption of the infrared radiation by a given species and the spectral location of its absorbing wavelengths.
'If you release something with an atmospheric lifetime
of, say, four months at 50 or 60-degrees north, by the time it gets down to the tropics --particularly to these regions of the tropics where the majority of stratospheric exchange takes place--because of their short lifetimes, a lot of it will have reacted away, broken down lower in the atmosphere before they get the chance to get into the stratosphere.' Therefore, despite general awareness of these compounds for decades, it has always been anticipated that they would contribute only a small amount of chlorine to the stratosphere.
Although HFCs cause a greenhouse effect that's thousands of times more powerful than carbon dioxide's, their average atmospheric lifetime
is roughly 15 years - unlike carbon dioxide, which can persist in the atmosphere for centuries.
The atmospheric lifetime
of [H.sub.2]S is limited by the hydroxyl radical to between 4.3 and 12.3 h (Spedding and Cope 1984; Hynes and Wine 1989; Wang and Howard 1990).
"The existing material has an atmospheric lifetime
of 13 years.
Buchwitz said: "The interpretation of the pattern is not trivial as the atmospheric lifetime
of CO2 is very long (many years).
The Honeywell material, which should be available in sample quantities later this year, is a non-flammable liquid that the company says will offer performance benefits comparable to those of other fluorocarbons, but with a low global-warming potential, in addition, the blowing agent will have an atmospheric lifetime
of just a few days.
Explaining the products he says Novec 1230 fluid is a highly efficient fire extinguishing agent offering a long-term, sustainable technology that has the greatest margin of safety for use in occupied spaces, has a global warming potential of 1, zero ozone depletion potential and the lowest atmospheric lifetime
for halocarbon alternatives -- five days.