Cleaning ensures oxygen systems don’t go out with a bang

Elizabeth Norwood, senior chemist at MicroCare, outlines the importance and techniques of cleaning oxygen systems and components to ensure the devices perform at their best.

Cleaning is a critical step to assure medical device parts work safely and effectively. Almost all components require cleaning during manufacture to remove particulate, residues, and other soils. This is particularly important for components that transport, store, and dispense pure liquid oxygen. Medical oxygen system cleaning requires great care and attention since any residual contamination left on parts or inside the system could cause a catastrophic explosion. 

What contamination?

Production contamination is anything that could potentially cause combustion, auto-ignition or affect the purity of the medical oxygen system. The contaminants vary from dust and production debris like metal particulate, to more challenging residues like hydrocarbon-based greases and oils, and inorganic pollutants such as water-based cutting oils and other acids and solvents. These contaminants, which are often not visible to the naked eye, can have a significant effect on the performance and reliability of oxygen system parts and must be precision cleaned before inspection, assembly, and packaging.

Why clean?

Any particles or residue left behind during the production of the oxygen system components may impede the operation of sensors, valves, regulators, meters, and controls. Soils can also negatively impact other components like hoses, tubes, and pipes. Any remaining contaminants on these parts also add a significant combustibility risk as they create friction in moving parts which generates both heat and a fuel source. In addition, the materials used within an oxygen system become easier to ignite because their flammable ranges start to expand as their auto-ignition temperatures drop. In an oxygen-rich environment, any remaining contaminant can suddenly and spontaneously combust causing an explosion. Therefore, it is critical that every single component within the system is perfectly cleaned and dried.

In addition to the risk of explosion or unreliable device operation, manufacturers must also adhere to industry specific standards and regulations. One of the primary standards for manufacturing oxygen systems is ASTM G93 - 03(2011). This standard guides the cleaning processes or methods and specifies cleanliness levels for the materials and equipment used in oxygen-enriched systems.

Meeting the requirements 

Vapour degreasing is a recommended parts cleaning process that is used extensively within the medical manufacturing industry since it provides effective oxygen system components cleaning while maintaining compliance and meeting regulatory standards. 

Vapour degreasing is a closed-loop industrial cleaning process. It consists of a top-loading machine composed of two chambers, the boil sump and the rinse sump that are filled with a low-boiling, non-flammable cleaning fluid. 

In the boil sump, the fluid heats and the parts are then immersed and cleaned in the fluid. Once cleaned, the parts are mechanically transferred to the second chamber for a final rinse in a pure, uncontaminated fluid. The oxygen system parts come out perfectly clean and dry and immediately ready for the next step in the process (or packaging). Vapour degreasing is a simple engineered process that is consistent, repeatable, easy to document, and easier to validate, making it an excellent cleaning method to use in a cleanroom environment. 

Importantly the cleaning fluid used within the vapour degreaser has many advantages. They are engineered to have multiple chemical properties that are beneficial to medical oxygen system cleaning. For example, they typically have a low surface tension and a very low viscosity, allowing them to easily penetrate and clean complex assemblies, intricate shapes, and delicate parts. They also dry quickly leaving no residue. Most vapour degreasing fluids also are very dense and up to 40% heavier than water, which aids in dislodging particulate from the parts. They are also non-flammable, so you are not adding to the safety risk when cleaning.

New improvements in cleaning fluid technology mean that modern vapour degreasing is also an environmentally sound option. Most modern vapour degreasing fluids meet local and national air quality regulations and operator safety requirements, making them the sustainably sound option for precision cleaning.

Don’t be hasty

The process of cleaning medical oxygen system parts during manufacture must be investigated and planned with precision. Any particulate or residue left behind can cause explosive results!

A vapour degreaser, when used with modern, non-flammable cleaning fluid delivers quality precision cleaning results. It is safe, fast, and effective for tackling many other manufacturing concerns, from environmental impact to process validation and worker safety.