Gold Standard in Quality

Many of our HiQ^® specialty gas facilities are certified to the latest ISO 9001 standards and follow additional specific programs such as the ones described in the ISO 6141, ISO 6142, ISO 6143, ISO 6144 and ISO 6976 standards detailing the preparation of calibration gas mixtures.

Dedicated specialty gas facilities are also accredited to the following standards:

ISO 17025 Testing and calibration laboratories

Many of our specialty gases facilities are accredited to ISO 17025. This standard enables laboratories to demonstrate that they operate competently and generate valid results, thereby promoting confidence in their work both nationally and around the world.

ISO 17034 Competence of reference material producers

Our most advanced specialty gas facilities are accredited to ISO 17034. This standard provides the highest level of quality assurance and allows us to confidently state that the methods used to manufacture and attest our certified reference materials are accurate, consistent and documented. That means that the reference material composition is always traceable to the International System of Units (SI) using validated measurements.

The certificates of analysis (COA) we issue always follow the latest update to the ISO 6141 standard. Based on actual analyses, they present all the certified concentrations of components and their uncertainties, the confidence level and the shelf-life. Our COAs thus fulfill all your quality assurance requirements. All of our specialty gas products are quality-controlled and come with a COA if applicable or requested.

We also supply certificates of conformity (COC). These clearly state the specification to which a product is manufactured. They do not contain actual analysis results, but are linked to individual samples. They thus provide limited metrological traceability, but help in documenting the material used in a specific process.

A batch certificate is available if a higher degree of traceability than that offered by a COC is required. This is based on a limited number of samples - taken from the same production batch - which are tested to specification. The results from the analyzed cylinders are applied to the entire batch in the form of a batch certificate.

The gas industry plays a vital role in the metrological chain in gas analysis, producing several patterns that are used in the calibration and validation of instruments and equipment.

In the production process of a calibration gas mixture, we use the most reliable reference materials from international metrology institutes like NIST (National Institute of Standards and Technology, US), the VSL (Van Swinden Laboratorium, the Netherlands), the NPL (National Physical Laboratory, GB) and the PTB (Physikalisch-Technische Bundesanstalt, Germany).

In addition to this, we support the development of both theoretical and experimental research at any level of uncertainty in any field of science and technology, engaging in discussion forums and participating in external inter-laboratory proficiency testing schemes. These processes help to assure the trustworthiness of the analysis beyond the equipment and/or the analysts involved.

We also run regular internal proficiency testing schemes to ensure that all our specialty gases production sites and laboratories are aligned with each other and are able to deliver reliable and consistent products in terms of purity, accuracy, stability and certification.

In order to deliver the exact accuracy you need, we have established proper production and quality assurance processes. This ensures that the requested concentrations are within a pre-defined blending tolerance and that the analytical uncertainty during the lab analysis is always minimized to achieve the measurement precision you need.

The illustration below depicts an example of ±5% blending tolerance and ±2% analytical uncertainty in the case of a requested concentration of 2% and a delivered analytical result of 2.05%: 

As an established gas company and trusted supplier of high-purity gases in many countries, we have developed advanced production and purification methods to ensure that our customers always get gases with the right purity level for their applications. We understand that purity and accuracy are essential in the world of specialty gases and always aim to match or even surpass our customers’ expectations in this area.

Many high-purity gas cylinders are accompanied by a certificate of conformity, confirming that the maximum limits for impurities have not been exceeded. A certificate of analysis is available on request. In many cases, the purity level may even exceed the specified value.

The following table illustrates some typical purity classifications. At Linde, high-purity gases typically include level 5.0 and above.

Metrological traceability has become a key issue for many industries that need to establish a relationship between their measurements and an element of a recognized national/international measurement system. This need for traceability may be to establish compliance with regulatory requirements – for example in the field of air quality control and emissions monitoring - or simply to gain trust in the performance of instruments and materials supplied.

Our broad accreditation scope and footprint can ensure metrological traceability for many of the specialty gases we offer. We can also certify traceability for non-accredited gases.

As part of the production process for our gas mixtures, we implement state-of-the-art technologies for cylinder pre-treatment and passivation. Complementing our precise filling methods, this allows us to deliver stable mixtures - within predefined ranges and uncertainties - even when they contain reactive components such as hydrogen sulfide, hydrogen chloride, ammonia or sulfur dioxide at low ppm or ppb levels. The relevant shelf-life is stated in the certificate of analysis.

Through EffecTech - a Linde company - we provide inspection and performance evaluation services for process gas chromatographs and gas quality measurement systems in accordance with the international standards ISO 17020 and ISO 10723. Our highly trained and experienced staff provide fast and effective solutions and support to help you meet your fiscal, regulatory, contractual, safety and environmental gas measurement obligations. Validations of this kind are often beneficial for factory/site acceptance tests, fiscal metering and custody transfer requirements (based on the natural gas composition), greenhouse gas emissions trading, network entry agreement requirements (biomethane, LNG), and storage connection agreements. The services are independent, and recommendations can be regarded as objective, reflecting industry best practice.

For more information on the products and services offered by Linde company EffecTech, visit Performance Evaluations and Inspections.

EffecTech - a Linde company - organizes regular proficiency testing schemes to provide participating ISO 17025-accredited laboratories with an objective way of assessing their performance (bias, stability and repeatability) through a series of inter-laboratory comparisons. We offer both specific proficiency testing schemes - for the LNG industry and for stack emissions testing service providers, for instance – and on-demand proficiency testing scheme designs to suit individual customer requirements.

For more information on the products and services offered by Linde company EffecTech, visit Proficiency Testing Schemes.