Posts Tagged ‘nitrous oxide gas’

Monday, June 6, 2011 @ 05:06 PM gHale

Sometimes there are better ways to conduct safety tests and officials at the University of California at San Diego feel doing a test without a potent greenhouse gas is the way to go.

UC San Diego and the University of California Office of the President convinced state regulators to drop a requirement that UC campuses use a greenhouse gas in a required laboratory safety test. The change gained approval by the California Occupational Safety and Health Administration (Cal-OSHA).

The state ruling grants UC campuses the ability to permanently stop using sulfur hexafluoride (SF6) gas in the required tests of newly retrofitted energy-efficient laboratory fume hoods.

UC San Diego will immediately switch to nitrous oxide gas, a less environmentally hazardous alternative. The ruling does not apply to the California State University system or other colleges, universities, companies and research institutes in California.

Fume hoods are standard equipment in most research labs. They provide safe working areas for laboratory workers and researchers who must handle hazardous solvents and other volatile materials. The fume hoods continually ventilate through air ducts with powerful fans. The continuous flow of room air into the hoods to roof-top vents requires constant heating or cooling to maintain needed room temperatures.

UC San Diego officials wanted to seek the variance because of the university’s concern SF6 is 22,800 times more potent than carbon dioxide in warming the Earth’s lower atmosphere. Each 20-minute test of a single fume hood using SF6 releases the equivalent of about 10 metric tons of carbon dioxide. The substitute, nitrous oxide, has about 1 percent of the global-warming impact of SF6.

“This change represents a victory for common sense, as well as a significant reduction in UC San Diego’s carbon-equivalent footprint,” said Ray Weiss, a distinguished research professor of atmospheric chemistry at Scripps Institution of Oceanography at UC San Diego. “Nitrous oxide is still a significant greenhouse gas, which also plays a role in the depletion of stratospheric ozone, so I hope that we will not rest on our laurels and that we will continue to lead the University of California to even more benign testing procedures.”

The colorless, odorless SF6 gas is non-toxic to humans, but Weiss noted in addition to its strong greenhouse-gas effect it remains in the atmosphere for thousands of years. Nitrous oxide degrades after 120 years in the atmosphere.

The state Occupational Safety and Health Standards Board approved the variance application after research by Technical Safety Services Inc. showed nitrous oxide worked just as well as SF6 and there would not be a compromise in worker safety.

“We confirmed the safety and efficiency of using nitrous oxide as a substitute for a very bad greenhouse gas,” said Larry Wong, program manager of UCOP’s Office of Environment, Health and Safety. “We also are doing the research necessary to change the national consensus standard on this kind of test on hundreds of thousands of fume hoods in the nation.”

 
 
Archived Entries