As currently configured, the test tends to give inconsistent results when PD-680 is used. Basically, the test involves diluting a sample of hydraulic fluid with solvent, filtering the diluted sample, and then comparing the color of the filter with various color standards. These inspection kits are usually supplied as aerosol cans. All of the components in these systems, that are in contact with the oxygen or mixed breathing gas, are cleaned to exceptionally high levels to avoid endangering the users. Currently, CFC-113 is the primary solvent used for the cleaning of all gas system applications.
Contractors can typically recycle the solvent to a very high level of purity.
The actual recycling process can either be done on site or at the contractors remote facility. If the solvent recycling is done off-site, then shipping of the spent solvent must be arranged. In some cases, the contractor can provide this service. In all cases, the spent solvent is analyzed for impurities to allow the contractor to estimate the amount of solvent which can be reclaimed. There are basically three options for this service.