How To Ensure Quality Of Medical Gas Systems

medical gas systems

Particulate contamination and odour tests may have been carried out prior to filling with the working gas, particularly if the system has been left for some time before use.

Oxygen, helium/oxygen mixture, nitrous oxide, and nitrous oxide/oxygen mixtures discharged during the process must be released to a safe place. These tests are not required on a vacuum system for any work including modifications or new works.

The oil, water, carbon monoxide and carbon dioxide, sulphur dioxide and oxides of nitrogen tests can be carried out with detector tubes, but advances in detection technology have produced a range of suitable alternative instruments. The use of detector tubes giving a quantitative response is recommended, but if other equipment is used for validation purposes, it must provide a level of repeatability, resolution and accuracy at least equivalent to that of detector tubes and must be calibrated to appropriate Standards.

An electronic dew-point meter should be used in preference to water content measurements.

However, it is recommended that the use of polytest tubes be considered as an optional general test for contamination of pipelines on a representative sample of terminal units.

All sources of supply should be tested for quality before the pipeline distribution system is filled with the working gas. This test is not intended as a test of certificated gases but is to ensure that supply source equipment (manifolds, compressors, VIEs etc) does not compromise the quality of such gases when delivering them to the pipeline systems.

The plant test point and a representative sample of terminal units distributed throughout the pipeline systems should be tested for total water content. The water content must not exceed 67 vpm (equivalent to an atmospheric pressure dew-point of approximately –46°C). The typical water content of medical gas cylinders is normally below 5 vpm.