Ground Support Pressure Systems Certification and Recertification
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11.3.1. Ground Support Pressure Systems Recertification Test Requirements. Testing requirements for recertification of components and systems are as follows:
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11.3.1.1. Vessels and packaging designed to 49 CFR specifications shall be retested to DOT requirements.
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11.3.1.2. All systems shall be hydrostatically tested at ambient temperatures to 150 percent of the system MOP or pneumatically tested at ambient temperatures to 125 percent of the system MOP with the concurrence of the PSWG and Range Safety.
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11.3.1.3. Vessels designed to ASME Code, Section VIII, Division 2 that are prohibited from hydrostatic testing to 150 percent of the MOP shall be hydrostatically tested to 125 percent of system MOP at a minimum.
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11.3.1.4. Cryogenic systems shall be retested in accordance with 11.2.3.2 of this volume.
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11.3.1.5. 100 percent visual inspection of all joints and connections shall be performed before and after hydrostatic or pneumatic pressure tests. Parts that indicate a change in volume, permanent deformation, leakages, or cracks shall be rejected.
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11.3.1.6. 100 percent visual inspection of the external surfaces of a vessel and system and 100 percent of the internal surfaces for vessels shall be performed.
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11.3.1.6.1. Any sign of corrosion, dents, or other damages shall be identified and annotated on permanently maintained recertification documents.
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11.3.1.6.2. For corroded areas, the corrosion shall be removed.
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11.3.1.6.3. Using ultrasonic testing (UT), the entire surface area affected by corrosion shall be measured and the remaining wall thickness determined.
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11.3.1.6.4. Wall areas that are below the minimum required thickness and other unacceptable findings shall be fixed before placing the system back into service.
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11.3.1.6.5. The susceptibility effects of corrosion such as cracking, delamination, or intergranular attack should be addressed.
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11.3.1.7. All weld joints on vessels and systems with pressure greater than 500 psig or containing a hazardous fluid shall be 100 percent volumetrically and surface inspected.
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11.3.1.7.1. Radiographic examination shall be used to the maximum extent possible.
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11.3.1.7.2. UT shall be used if radiographic testing (RT) is determined to be ineffective.
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11.3.1.7.3. Surface and volumetric testing shall be performed after the hydrostatic/pneumatic pressure test.
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11.3.1.8. All components and systems shall be leak checked and functionally tested.
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11.3.1.9. Leaks shall be repaired and components that do not function properly shall be repaired or replaced before starting the subsequent recertification period.
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11.3.2. Ground Support Pressure Systems General Recertification Requirements
Requirements for performing recertification are found in NASA-STD-8719.17 and the following:
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11.3.2.1. The recertification period for vessels and systems shall comply with local requirements and shall not exceed the shortest period resulting from or determined by the following criteria:
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11.3.2.1.1. The shortest service life shall be determined based on the system and components design performance parameters, operational requirements, and inspection and test results.
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11.3.2.1.2. Twenty years for systems and for vessels that can be 100 percent inspected both internally and externally.
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11.3.2.1.3. Ten years for systems and for vessels that cannot be 100 percent inspected internally but can be 100 percent inspected externally.
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11.3.2.1.4. Five years for systems and for vessels that cannot be 100 percent inspected either internally or externally.
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11.3.2.1.5. Manufacturer recommendations.
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11.3.2.1.6. Recertification of cryogenic vessels shall be accomplished at a minimum of every 20 years with an internal inspection every 10 years.
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11.3.2.3. Portable or mobile vessels used for transportation and/or storage of pressurized or hazardous commodities shall be designed, maintained, and recertified in accordance with 49 CFR or applicable codes.
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11.3.2.4. Inspections and maintenance shall be performed on hazardous pressure systems and integrated portable or mobile vessels in accordance with local requirements and a system inspection and maintenance plan developed by the system operator approved by the PSWG, Range Safety and the Center Pressure Systems Manager.
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11.3.2.5. The hazardous pressure system operator shall retain all documentation generated as a result of the recertification effort and place a copy of this documentation in the system certification and recertification file located at the ranges.
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11.3.3. Ground Support Pressure Systems Certification
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11.3.3.1. Ground Support Pressure Systems Certification Files General Requirements
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11.3.3.1.1. Certification files shall be maintained and updated in an appropriate configuration management system acceptable to the responsible pressure systems manager. These files shall be available at the payload processing facility and launch site area and accessible for PSWG and Range Safety review. Vessels and systems, including mobile and portable systems, that do not have current certification files shall be deactivated and removed from service.
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11.3.3.1.2. Certification files shall be updated within 90 calendar days of completion of periodic inspections and tests.
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11.3.3.1.3. Updated information shall include any changes to the current certification files and the following:
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11.3.3.1.3.1. Temperature, pressurization history, and pressurizing fluid for both the tests and operations.
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11.3.3.1.3.2. Results of any inspection conducted, including the name of the inspector, inspection dates, inspection techniques used, location and character of defects, defect origin, and defect cause.
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11.3.3.1.3.3. Maintenance and corrective actions performed from the time of manufacture throughout operational life, including refurbishment.
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11.3.3.1.3.4. Sketches and photographs to show areas of structural damage and extent of repairs.
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11.3.3.1.3.5. Certification and recertification tests performed, including test conditions and results.
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11.3.3.2. Ground Support Pressure System Certification Data
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11.3.3.2.1. The certification file for each hazardous pressure system shall contain all the data required to justify system certification.
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11.3.3.2.2. The data shall include, but not be limited to, the following:
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11.3.3.2.2.1. Design calculations for stress, fatigue, and other items that verify compliance with applicable code requirements such as ASME, ANSI, and DOT.
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11.3.3.2.2.3. In-process fabrication and construction inspection plans and results.
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11.3.3.2.2.4. Pressure vessel manufacturer data reports (ASME Form U-1 or Form U-1A).
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11.3.3.2.2.5. Specification drawings and documents for all components.
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11.3.3.2.2.6. If available, maintenance manuals for all components.
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11.3.3.2.2.7. If available, component operating manual.
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11.3.3.2.2.8. As required, a cross-sectional assembly drawing of the component to assess the safety aspects of the internal elements.
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11.3.3.2.2.9. System operating and maintenance plans and procedures.
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11.3.3.2.2.10. Certification that welding and weld NDE meet applicable standards such as ASME and ANSI.
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11.3.3.2.2.11. Unique qualification and acceptance test plans and test reports.
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11.3.3.2.2.12. Certification documentation showing that vessels are designed, fabricated, and tested in accordance with ASME Boiler and Pressure Vessel Code, Section VIII, Division 1/Division 2 or 49 CFR.
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11.3.3.2.2.13. Certification that all components, including pipe and tube fittings have successfully passed a hydrostatic or pneumatic pressure test.
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11.3.4. Ground Support Pressure System Analyses. An engineering analysis shall be performed as follows:
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11.3.4.1. A stress analysis of all vessels and piping shall be available for evaluation or performed to verify that stresses are within allowable limits of current codes, standards, and regulations as identified in this volume and NASA-STD-8719.17.
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11.3.4.2. The number of stress cycles experienced by the vessel during the certification period shall be determined.
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11.3.4.3. Using fracture mechanics analysis, the cyclic limits for vessels with pressures greater than 2,500 psig, burst-before-leak failure mode, or corrosive and/or toxic fluids shall be determined.
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11.3.4.4. The safe-life analysis shall be performed under the assumption of pre-existing cracks. This does not imply that cracks are allowed. All unacceptable indications shall be repaired. The safe-life analysis shall be conducted in accordance with the following requirements:
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11.3.4.4.1. The analysis shall show that the vessel will service at least 4 times the cycles expected during the recertification period.
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11.3.4.4.2. The analysis shall calculate and evaluate the results from the worst combination of crack sizes (refer to NASA-STD-5009 Nondestructive Evaluation Requirements for Fracture-Critical Metallic Components MSFC-STD-1249, Standard NDE Guidelines and Requirements for Fracture Control Program, for guidance) and locations such as boss transition area, heat affected area, weld joint, and membrane section within the vessel.
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11.3.4.4.3. The appropriate stress component in the vessel shall be used in the analysis.
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11.3.4.4.4. The initial flaw size used in the safe-life analysis shall be based on either the hydrostatic test pressure or the detection limits of the appropriate NDE techniques. Flaw shapes (a/2c) ranging from 0.1 to 0.5 shall be considered.
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Refer to NASA-STD-5009 and ASME Section VIII for guidance.
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11.3.4.4.5. Calculated cycles to failure shall be based on the maximum and minimum operating pressure.
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11.3.4.4.6. A linear elastic fracture mechanic parameter (stress-intensity factors) shall be used to determine critical crack sizes. The most conservative deformation mode shall be used to determine the appropriate stress-intensity factors (fracture toughness) as appropriate for the parent, weld, and joint materials.
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11.3.4.4.7. Fracture mechanics shall only be used to predict the subcritical crack propagation life before unstable crack growth.
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11.3.4.4.8. The safe-life analysis results shall be reduced by a factor of 4 in conjunction with assuming the most conservative bounds on material properties and crack growth data for the vessel environment.
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11.3.4.4.9. Failure mode determination shall consider any potential hazardous are classification concerns per Attachment 3 of this volume.
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11.3.4.4.10. Vessels subject to stress corrosion (sustained stress) shall show that the corresponding applied stress intensity during operation is less than the threshold stress intensity in the intended environment.
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11.3.4.4.11. Corrosion allowance and the remaining wall shall be determined based on MIL-HDBK-729, Corrosion and Corrosion Prevention Metals.
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