Products by Type

High Purity Mixtures

Our database of gas products contains over 30,000 individual product recipes all of which are maintained to ensure best filling and analytical procedures are followed. We can also create customised products to your specification.

Our gas mixture recipes are written by BOC technical experts within strict guidelines to provide you with the gas product required for each purpose.

Gas mixtures are used as integral components of industrial processes and as calibration gases. The calibration gases are the most diverse group, often containing reactive components at trace level concentrations.

We can utilise gravimetric and volumetric filling techniques, filling by weight or pressure respectively and have the ability to specify analysis results with tight analytical tolerances and uncertainty values. Visit our Technical Advice pages for further information.

High Quality Gas Mixtures

Specific instrument calibration mixtures

An instrument is called specific because it measures one specific substance and cannot be used for others. Specific instruments are normally calibrated with a zero gas and a span gas. Zero gas is normally a pure gas not containing the component to be measured, and as similar to the matrix of the measured sample as possible. Normally this is synthetic air or nitrogen. The span gas is optimal a mixture of 90% of measured value of component in matrix (if measuring 50 ppm span calibration point will be 0.9 x 50=45 ppm.) Therefore our standard mixtures have concentrations correlating to 90% of typical measuring values.

General instrument calibration mixtures

An instrument is called general when the instrument can be used to analyse a wide variety of chemical substances. General instruments like gas chromatographs are often calibrated by creating a calibration line or curve covering the intended measuring area. Therefore our standard products are points at such a line or curve. In addition to this many of the points represent 90% of full scale for a substance specific instrument.

Threshold monitor mixtures

To avoid and warn for occupational or fire hazards special monitors are used. These are specific instruments that are set to alarm when a pre-set concentration of the substance monitored is reached. High quality gas mixtures for these types of applications have typically half and full time weighted threshold limit value concentration for the substance in air (if this is not possible nitrogen is used) or for flammable products typical concentrations are 20, 40, 50, and 60% of Lower Explosion Limit (LEL).

Liquid mixtures

Most liquefied hydrocarbon mixtures are supplied with additional head space pressurisation using a high purity inert gas such as helium to prevent the lighter hydrocarbon components from separating after final production. To maintain composition during use, the mixture may be supplied in a cylinder using a dual port valve to allow additional pressure to be introduced as required to keep the head space pressure consistent.

General mixtures

BOC can produce gas mixtures blended to suit your individual requirements.

Nationally recognised gas mixtures are produced and stocked by BOC for use across many market sectors. Our product portfolio includes mixtures for use in the following industries: environmental, automotive, G-Test Gases, lighting, petrochemical, laser, food packaging, laboratory and research, Healthcare and law enforcement. Please visit our products by industry page for further information.

We hold a wide variety of common gas mixtures in stock around the UK. With 315 cylinder vehicles and 72 retail outlets, BOC provides unrivalled national coverage.

If you have any questions regarding mixture production, call 0800 02 0800 or email us