OXYGEN CLEANING PROCEDURE
OXYGEN CLEANING PROCEDURES
Historically, solvents such as 1,1,2-trichloro-1,2,2-trifluoroethane and 1,1,1-trichloroethane have been the chemicals of choice for NASA, the Department of Defense and the aerospace industry in cleaning non-breathable oxygen systems and components, including hoses. The U.S. Environmental Protection Agency classified and regulated these chemicals as Class I (most harmful) ozone depleting substances. In the mid 1990’s, in response to the U.S. Clean Air Act and Montreal Protocol, aerospace organizations began replacing these Class I ozone depleting chemicals with less harmful hydrochlorofluorocarbons (HCFC), which are still ozone depleting substances (Class II). Two common HCFCs are 1,1-dichloro-1-fluoroethane (HCFC-141b) and 1,3-dichloro-1,1,2,2,3-pentafluoropropane (HCFC 225g). The Class II solvents provide only a temporary solution, however, because the Clean Air Act and Montreal Protocol have set finite caps and phase-out dates for their manufacture. Other qualified solvents, such as hydrofluoroethers, are not ozone depleting but are limited in the applications in which they can be used. Flexline will monitor these developments to assure our ability to deliver timely cost effective cleaned for industrial oxygen hoses.
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2.0 OXYGEN CLEANING PROCEDURES
2.1.1 This procedure is specifically directed at insuring freedom from combustible oils, greases or other matter that would provide a source of ignition in service with oxygen or other fluids that critically support ignition. All components requiring Oxygen Cleaning shall be processed according to the following guidelines. This procedure occurs after the hose assembly has been welded, leak tested and dried per Flexline standard FLX-010C
2.1.1 The work order must specify that the product requires Oxygen Cleaning CGA G-4.1 Hose assemblies that normally would have an adapter present will have the adapter cleaned separately and then installed prior to shipment.
2.1.2 Cleaning, inspection, assembly and testing of Oxygen Cleaned products will be done at the cleaning station.
2.1.3 Assemblies are thoroughly flushed with clean nonflammable solvent degreaser in sizes ¼” through 2”. Sizes 2.5” and up are immersed in a bath of nonflammable solvent degreaser. Proper safety equipment must be worn at all times when in proximity to or use of solvent. These include appropriate mask and gloves.
2.1.4 All Solvent product can filtered and re-used as per manufacturer’s recommendation unless the color has changed from the control vial.
2.1.5 All Oxygen Cleaned parts are to be dried in the oven in the assembly shop for at least 20 minutes prior to packaging.
2.1.6 All assemblies/parts are to be visually examined after the oven drying process. Any visible contamination, residue, or FOD on or in the part will be cause for rejection. Parts failing inspection are to be re-cleaned using the same cleaning process.
2.1.7 Detailed cleaning and quality control procedures should be agreed upon between Flexline and its customer if cleaning requirements exceed CGA G-4.1.
2.1.8 Certifications should be prepared for the cleaned assemblies, kept on file and forwarded to the purchaser with the following information:
• The Part number of the item
• Its purchase order number
• Its invoice number
• The cleaning specification
• The dates of inspection for cleanliness
• The method of inspection
• The inspector’s signature and date signed
2.1.9 Larger size hoses must be handled with care at all times and by all personnel so as not to put their hands inside the assemblies.
2.1.10 Clean protective caps are to be inserted onto or into the hose assembly ports to prevent contamination. The product is then tagged per the customer’s requirements, bagged in a new plastic bag and sealed. For large assemblies, stretch wrap will provide sufficient sealing.
2.1.11 The Cleaning Certification sign off on the work order is to then be filled out and signed by the appropriate personnel and resigned by the shipping personnel that package the assemblies for shipment. The unit cannot be shipped if the certification is not fully and completely filled out.
3.0 DISPOSAL OF CLEANING FLUID
3.1.1 Flexline is committed to a zero environmental impact model.
3.1.2 All spent Solvent product is to be isolated in the rear metal shop area in the drum marked for this purpose.
3.1.3 The Assembly Shop manager is responsible for periodically checking the level of spent cleaner and informing the president of the company when the drum is near full.
3.1.4 The president of the company is responsible for contacting the proper disposal company, arranging for the pick up and documentation of the safe disposal of the material. Documentation is to be stapled to the disposal invoice and kept for 10 years.