In many cases speciality gases and mixtures are unique “one-off” products developed for a specific customer application and they require a great deal more product engineering compared to the standard industrial or medical gas products. For this reason, they are not always “off the shelf” items and can even take several weeks to produce in the most complex of cases.
Where a raw material of the required purity cannot be sourced, the gas producer must buy the highest purity available and introduce additional purification processes in-house to achieve an end product of a sufficiently high purity.
Finally, the level of quality control associated with speciality gas production is far higher than with industrial and medical gases. Sophisticated laboratory instrumentation is used to analyse and verify the constitution of many products and customers are then provided with a certificate declaring the analytical results.
As many as 200 different multi-component gas mixtures are often required at a large refinery complex. These are all “made-to-order” and therefore require fairly lengthy production, certification and delivery lead times in comparison to the standard “off-the-shelf” industrial gases range. To facilitate timely repeat ordering of these complex gas mixtures, plant instrument tag numbers can be used to allow personnel to reference exactly where the mixtures are deployed in the different sections of the plant.