Linde Gases, a division of The Linde Group, today announced that it has been awarded ISO 17025 accreditation for its specialty gases mixtures used for environmental testing of volatile organic compounds (VOCs).

While many liquid VOC standards have been previously certified, this is the first time any industrial gases company has achieved such validation for VOC mixtures in a gaseous state, and in so doing Linde has enabled a significant leap forward in legal metrology.

VOCs are insidious and highly noxious chemicals that exist within the ambient air - both in the outdoor environment and within buildings. Many are carcinogenic in nature and are directly attributable to serious human health problems, including diseases of the respiratory tract, even when exposure is limited to very low levels.

“During the US energy crisis in the 1970s, a trend emerged to seal up buildings and make them airtight”, said Mike Hayes, Head of Premium Specialty Gases, Linde.

“In the process that kept a lot of VOCs trapped within office environments - from copier toners, carpet fibres, and plastics and adhesives used in furniture manufacture - and they have been making people sick.”

Additionally, when VOCs emitted into the ambient air react with nitrogen dioxide, a common pollutant from automotive emissions and other combustion processes - from refineries, distilleries and cement kilns, for example - they form ground level ozone. Ozone is a powerful oxidising agent, exposure to which has been associated with adverse health effects including asthma and decreased lung function.

With ever increasing environmental testing around the world, there are a growing number of federal and state agencies demanding an unequivocal “baseline” or “anchor” standard for VOC samples against which laboratories can reliably compare the samples they have for analysis. In other words, they require that the environmental sample they are testing can be accurately and assuredly compared to a guaranteed, “known” sample.

“With this accreditation, Linde has raised the bar yet again for gaseous standards for VOC detection. Until now, one could argue that there existed a level playing field of imprecision for gaseous standards used for legal metrology purposes,” said Stephen Harrison, Global Head of Specialty Gases and Specialty Equipment, Linde.

“To explain further, there was never anywhere to plant a flag in order to state what one part per million (ppm) of benzene, for example, actually looked like. Through years of technical innovation and advanced analytical and blending methods Linde has become the first to develop traceability procedures to prove one ppm of benzene - or indeed any other VOC - in a gaseous state, and guarantee a previously unattained level of precision.”

The international accreditation of Linde’s gaseous VOC standards is likely to have a significant impact on legal metrology - or the science of measurement as laid down by law. Cases involving environmental matters could often be dismissed due to the measurement standards used being contested. Linde can now provide that undisputable, known standard which can be held up in a court of law. Additionally, regulatory authorities will have the baseline guarantee needed to effectively write legislation requiring VOC testing to this level of quality.

“This ISO 17025 accreditation proves our technical competence in manufacturing these gaseous standards,” continues Hayes. “However, the fact that we are scoring significant numbers of commercial contracts for these environmental standards - including our 15th consecutive contract with the US EPA - elevates this accreditation announcement beyond the realms of theoretical excellence to a badge of confidence we wear daily.”