Frequently Asked Questions

1. How long has Gasodor® S-Free been around?

Development of Gasodor® S-Free began in the 1990s. It was first implemented in 2001 as part of a pilot project in Phillipsburg, Germany, after years of extensive research. At that time Gasodor® S-Free was the world’s first sulfur-free odorant.

2. Who developed Gasodor® S-Free?

Scientists from Symrise GmbH (and/or its predecessor Haarmann und Reimer GmbH) developed Gasodor® S-Free in collaboration with DVGW (the German Technical and Scientific Association for Gas and Water) and the E.ON Ruhrgas AG company. Today, Gasodor® S-Free is produced by Th. Geyer Ingredients and is DVGW certified.

3. What is Gasodor® S-Free made of?

Gasodor® S-Free is a mixture of two acrylates and one pyrazine. The materials were selected because their odor is unpleasant, yet they are non-toxic and readily distribute in natural gas. Gasodor® S-Free is sulfur-free, which makes it significantly more environmentally friendly than materials containing sulfur, such as THT or mercaptans.

4. Is Gasodor® S-Free safe?

Absolutely. If an odorant is to be safe, it is important that people recognize its smell as a warning. To ensure that this would be the case, DVGW subjected the material to extensive testing. The results were unequivocal: 80 percent of the test participants claimed that Gasodor® S-Free reminded them of gas. There is no risk of confusing its odor with day-to-day smells.
Another important indicator of the safety of an odorant is the frequency with which customers report actual or suspected gas leaks. To test this, the Engler-Bunte Institute (Karlsruhe) reviewed reporting data for networks that had switched over to Gasodor® S-Free in order to determine whether the reporting frequency had changed. Fewer reports would indicate that consumers are less likely to perceive Gasodor® S-Free as a warning odor. The results? The study showed that after switching to Gasodor® S-Free, the number of leak reports that gas companies received was the same or larger than before the switch. (Source: energie wasser praxis magazine, vol. 09/2008) In other words, the public does indeed perceive Gasodor® S-Free as a warning odor.
Increases in reporting could be due to the comprehensive information campaigns carried out when providers switch to the new odorant.

5. Where is Gasodor® S-Free being used?

Gasodor® S-Free is aready being used in a number of German cities and municipalities, such as Hamburg, Kiel, Dortmund and Würzburg. The new odorant has been introduced in urban and rural areas alike, and is being used increasingly in Austria and China. Pilot projects for testing Gasodor® S-Free are currently being conducted in other countries as well.

6. Is Gasodor® S-Free environmentally safe?

Yes, particularly when compared to sulfur-containing odorants such as THT. Burning THT produces sulfur dioxide, which is known to cause environmental damage. Combustion of natural gas generates roughly 600 tons of this harmful gas each year. Sustainable reduction of sulfur emissions is a known goal of both national and international environmental policies. Gasodor® S-Free will help us reach this goal.

7. Is Gasodor® S-Free cheaper than other odorants?

As it turns out, Gasodor® S-Free is attractive from an economic perspective as well. Odorant loss is relatively low with Gasodor® S-Free, and the minimum amount of odorant required to do the job is significantly less than is the case for traditional substances. Overall, this means having to use less odorant than before. Some suppliers using Gasodor® S-Free have reported that switching odorants has yielded long-term savings.

8. What issues need to be considered when introducing Gasodor® S-Free?

An important factor in switching over to Gasodor® S-Free is informing the public in plenty of time – the more familiar the odorant is, the better the public will be at recognizing it. Disseminators such as fire departments, police, heating and cooling technicians, the media, etc., absolutely must be informed and integrated into the process. Odorant samples can be requested from WVGW (the DVGW publishing company) for distribution among the population.

9. Are there other applications for Gasodor® S-Free?

Yes, such as fuel cells, which require natural gas that is absolutely free of sulfur. Natural gas fueling stations could also be operated with natural gas containing Gasodor® S-Free. This represents an area where sulfur-free Gasodor® S-Free could make a major contribution toward compliance with legal sulfur limits.