Sulfur-containing odorants: facts and figures
Because natural gas does not have its own innate odor, sulfur-containing odorants have been added to it in the past to warn of the risk of explosion. In light of environmental considerations, however, this practice no longer defensible today. Although critical voices were still making themselves heard when Gasodor S-Free came on the market in 2001, this environmentally friendly, sulfur-free odorant has since been put to successful use.
“We were convinced of the ecological and technical advantages of Gasodor S-Free from the very beginning,” says Markus Königshofen, divisional head of network services for EVI Energieversorgung Hildesheim, the energy supply company for Hildesheim, Germany. “After six years of testing under actual working conditions, we now see that the decision we made was a good one.” EVI did pioneering work in 2003: the company was the first municipal energy service provider in Germany to stop using sulfur-containing odorants and switch over to environmentally friendly Gasodor S-Free. By using Gasodor S-Free, the company hoped to do its part to protect the environment while providing a high level of safety. Financial benefits also made the product attractive: “Over the long haul, Gasodor S-Free is more economical than traditional odorants, because we don’t have to use as much,” Königshofen explains. The only real challenge turned out to be the process of introducing the new product.
Factors influencing the implementation process
Six months prior to introducing Gasodor S-Free, EVI provided intensive training for the police and fire departments, installers and for all company employees, teaching them how to work with the new odorant. Shortly before switching over, EVI sent all of its customers informational letters containing scratch-and-sniff patches that allowed recipients to test the new product. EVI also staged a large promotional event in the Hildesheim pedestrian zone. “We set up an odor machine and let passersby test the new product,” Königshofen reported.
“People clearly identified Gasodor S-Free as a warning.” These steps ensured that EVI’s customers would be able to recognize the new warning smell as soon as it was introduced into the natural gas supply. “Effective public relations work is an indispensable part of the implementation process,” Königshofen knows. Also supporting this view is a study produced last year by the German Technical and Scientific Association for Gas and Water (Deutscher Verein des Gas und Wasserfachs e.V., or DVGW) that addressed the subject of recognizing the new natural gas odorant. In summary, the study concluded that “... switching to a sulfur-free odorant did not have a negative impact on customer response; the public recognized Gasodor S-Free as a warning of the presence of gas. An extensive information campaign should be carried out prior to changing odorants in order to sensitize gas customers to the difference in smell between sulfur-free and sulfur-containing products.” EVI switched over to the environmentally friendly odorant in February of 2003 – and its supplier and customer businesses have been running smoothly ever since.
Sustainable design
Jörg Müller, Global Category Manager Gas Odorization at Symrise, is pleased with this long-term success: “With Gasodor S-Free,” he says, “we’ve developed a product offering a lot of advantages for suppliers, gas customers and the environment.” Because it contains no sulfur, Gasodor S-Free is more environmentally friendly than traditional odorants, and its intense warning smell guarantees a high level of safety. It is also more economical, because it results in less odorant loss than is the case with sulfur-containing products. The advantages of Gasodor S-Free are no secret anymore, as its use is also increasing outside of Germany, in countries such as Austria, the Czech Republic, Slovakia, Russia and China. “It’s an upward trend,” says Müller. “Every day we get new inquiries from energy service providers.” Over the past year, he adds, new emission regulations have sparked growth in demand by about ten percent in Germany alone. “It’s been over eight years, and Gasodor S-Free is continuing to gain acceptance.”
That is not how it looked during the introductory phase, however. Critical voices were raised over and over again, and an entire industry initially seemed poised to turn its back on a global innovation. At that time, Heribert Kaesler, an engineer and the head of the Gas Quality Competence Center of E.ON Ruhrgas AG, spoke out in favor of using Gasodor S-Free. “The time was right to develop an environmentally friendly yet safe alternative to sulfur-containing odorants,” says Kaesler. E.ON Hanse began using the product in three German provinces beginning in 2007.
In the past, sulfur-containing odorants have repeatedly been confused with day-to-day odors. The most recent example occurred in May 2008, when a suitcase that supposedly smelled of gas caused an uproar at the Cologne/Bonn airport. Airport personnel noticed the odor while loading luggage and alerted security and the police. An inspection of the suitcase revealed that it merely contained large quantities of meat marinated in garlic. The heat had apparently caused the garlic marinade to produce a gas-like odor.
Suitability testing
Before Gasodor S-Free was launched on the market, the sulfur-free odorant was subjected to extensive scientific suitability studies by the DVGW Research Center at the Engler-Bunte Institute. In addition to assessing the character and intensity of the odorant, these studies also examined numerous technical aspects of the product such as its sorption behavior on piping materials and questions of measurement technology. Multiple field tests were also conducted in cooperation with the gas industry to assess product suitability in actual applications. Dr. Frank Graf, an engineer and the department head responsible for the tests at the DVGW Research Center, summarized the studies saying, “The results of the research program did not indicate any drawbacks to using Gasodor S-Free as opposed to the sulfur-containing odorants used in Germany.”
Plus, Professor Robert Hess of Swiss institute WT Consulting GmbH demonstrated that the sulfur-free odorant shows no cause for concern regarding respiratory tract sensitization. He verified this in a study that simulated an everyday situation: switching on a gas burner. Before the gas lights, acrylates – a component of the Gasodor S-Free odorant – escape, and these can be slightly allergenic, but only at certain concentrations. The acrylate concentrations determined in this simulation were found to be comparable with acceptable workplace exposure limits.
Values established for the surrounding air lay well below one one-thousandth of accepted workplace limits. The study concluded that, “Given these conditions, current data on human beings provide no reason to anticipate sensitization, specifically of the respiratory tract.”
Environmentally safe?
Environmental protection is one of the greatest challenges of our time. One potential solution to this problem is Gasodor S-Free, which sets new standards in natural gas odorization – it is, after all, the world’s first DVGW type-tested sulfur-free odorant, and is environmentally safe while meeting highly sophisticated safety, economic and technical demands. EVI and E.ON Hanse became environmentally conscious pioneers when they decided to use Gasodor S-Free. Numerous other service providers have followed their example over the years, and demand for sulfur-free odorization is on the rise throughout the world – and not just for reasons of ecology.
This article appeared in Sicherheitsingenieur, issue 4/2009
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