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This section explains the small amount of data processed for contact messages and basic technical insight into use of the Gas Composition Converter.
Composition data
Composition calculations run locally in your browser. The entered gas composition and calculated conversion results are not sent to a calculation server.
Browser identifier and usage record
The site stores a random anonymous browser identifier in your browser. After the first valid conversion in a browser session, the site may record that the converter was used, together with the identifier, country, input basis, and application build.
This information is used only for technical audit and simple usage insight. It does not include the entered composition, calculated results, IP address, or user agent, and it is not used for advertising, cross-site tracking, or profiling.
Contact messages
Messages sent through the contact form are delivered by email and handled like ordinary email correspondence sent directly to the maintainer.
The contact form uses Cloudflare Turnstile to check that it is submitted by a human visitor, and the message may be processed by the configured email delivery provider.
Disclaimer
This disclaimer applies to the current public version of the Gas Composition Converter and to all use of the site, its calculations, outputs, examples, explanations, and related information. Use of the site and any result from it is entirely at your own risk.
Use at your own risk
The converter and all information on this site are provided for general technical information and preliminary evaluation only. The site is provided "as is" and "as available", without warranties of any kind, express or implied.
No guarantee is made that any calculation, result, explanation, example, reference value, or user interface message is accurate, complete, current, suitable for your intended use, or free from errors.
No professional or certified advice
The converter does not provide legal, contractual, regulatory, compliance, safety, engineering, operational, laboratory, or commercial advice. It is not a certified analysis, calibration service, engineering opinion, design approval, or substitute for qualified professional judgement. Use of this site does not create a consultant, laboratory, client, advisory, or similar professional relationship.
You are responsible for checking the input data, understanding the applicable standard, verifying the converted composition independently, and deciding whether the result is appropriate for your specific technical, contractual, regulatory, safety, or commercial context.
Method limitations
The converter implements a limited part of the gas-composition conversion procedures described in ISO 14912:2025. It currently converts complete compositions between mole, mass, and volume fractions for the available components. It does not currently implement concentrations, uncertainty propagation, phase assessment, or grouped pseudo-components.
Calculations use Annex C second pressure virial data from 0 °C to 30 °C. The procedures assume a homogeneous and stable gas mixture under conditions well outside its condensation region. All components must be completely gaseous when volume fractions are used. The converter does not determine whether these conditions are satisfied for a particular mixture.
Independent verification required
Before relying on any result for engineering, analytical, operational, contractual, regulatory, safety-critical, financial, or other consequential decisions, you must verify the result by independent means and, where relevant, by a qualified professional, accredited laboratory, approved software, or the applicable official standard.
Limitation of liability
To the fullest extent permitted by applicable law, the creator, operator, contributors, and affiliates of this site shall not be liable for any direct or indirect loss, economic loss, loss of profit, loss of revenue, business interruption, loss of data, contractual loss, operational loss, property damage, personal injury, consequential damage, special damage, punitive damage, or any other loss or damage arising from use of, inability to use, or reliance on this site or its results.
If applicable law does not allow a particular exclusion or limitation, the liability is limited to the maximum extent permitted by that law.
Changes
The site, calculation code, user interface, examples, documentation, and disclaimer may be changed, corrected, limited, suspended, or discontinued at any time without notice.
Free access is not guaranteed permanently. The site operator may introduce paid access, subscription plans, usage limits, or other access conditions in the future.