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ASME PVHO-2-2016 pdf download

III-1 GENERAL This Mandatory Appendix sets forth the requirements for establishing and maintaining Quality Assurance Programs to control the quality of work performed by the repairers of severely damaged windows used in Pressure Vessels for Human Occupancy in accordance with this Standard. III-2 ORGANIZATION (a) The window fabricator required to comply with this Standard shall have a documented organizational structure, with responsibilities, authorities, and lines of communication clearly delineated in writing for activi- ties affecting quality. Persons or organizations responsi- ble for the Quality Assurance Program shall have authority and organizational freedom to (1) identify problems affecting quality (2) initiate, recommend, or provide solutions to quality problems, through designated channels (3) verify implementation of solutions (4) control further processing, delivery, or assembly of a nonconforming item, deficiency, or unsatisfactory condition until proper corrective action has been taken (b) The necessary scope and detail of the system shall depend on the complexity ofthe workperformed and on the size and complexity of the fabricator’s organization (including factors such as number and experience level of employees and number of viewports produced). III-3 QUALITY ASSURANCE PROGRAM (a) A documented program for the assurance of qual- ity of activities, items, and services shall be planned, implemented, and maintained in accordance with speci- fied requirements of this Standard. (b) The program shall apply to activities, materials, parts, assemblies, and services that affect the quality of the windows. It need not apply to other activities, products, and services at the same location. (c) The program shall identify the PVHO activities to which it applies. (d) The program shall provide for indoctrination and training of personnel to assure compliance with this Standard. 26 (e) Management shall, at least annually, assess the program and take corrective action, if necessary. III-4 QUALITY ASSURANCE MANUAL (a) The Quality Assurance Programshall be described in a Quality Assurance Manual. (b) The Quality Assurance Manual shall provide a mechanismtodocumentissuance and revision,and shall include a method to identify and/or highlight the revisions. III-5 DRAWING, DESIGN, AND SPECIFICATION CONTROL (a) The window fabricator shall establish procedures to assure that window Design Drawings and all applica- ble documents and requirements of this Standard rela- tive to the design of windows are received from the designer and are correctly translated into fabrication specifications, drawings, procedures, and shop instruc- tions for the windows. (b) Procedures shall be established for the review, approval, release, distribution, and revision of fabrica- tion documents. III-6 PROCUREMENT CONTROL (a) Applicable requirements necessary to assure com- pliance with this Standard shall be specified or included in documents for procurement of materials, items, or services to be used by the window fabricator. (b) The procurement of materials, items, and services shall be controlled by the fabricator to assure confor- mance with specified requirements. (c) These controls shall include, but not be limited to, any of the following, as appropriate: (1) source evaluation and selection (2) appraisal of objective evidence of quality fur- nished by the supplier, including all necessary material certification documents (3) inventory control (4) material identification
IV-1 WINDOW REPAIR TEST REQUIREMENTS A testofthe tensile strengthofa sample bond between previously cured acrylic window material and the mate- rial used to perform spot cast repair shall be made. (PVHO-2 Form IV-1-1, Material Testing Certification for Repair by Spot Casting, shall be completed when repair by spot casting is performed.) Samples for the balance of testing shall be taken from an integral part of a separate casting made for that purpose. Where more than one specimen is used in the test procedure, the average of the test values shall be used to meet the requirements of the minimum physical properties shown. Samples are to be cut so that no surface of the test sample is closer to an unfinished cast surface than the normal trim line. Where possible, test samples shall be cut from the central portion. The test methods shall be as follows: (a) The test for the tensile strength of a sample bond shall be per ASTM D638, with the bond face located as close to the center of the gauge length as practical. (b) Tests for compressive strength of the spot cast material shall be per ASTM D695. (c) Tests for the presence of an ultraviolet absorber (ultraviolet transmittance) shall be made using a mono- chromator having a bandwidth of 10 nm or less, and a photometer having reproducibility of +1% of full scale. Report the value of one specimen 1 ⁄ 2 in. (12.5 mm) thick- ness nominal, with both faces polished. (d) The following procedures are recommended for the measurement of residual acrylic monomer. A sample of suitable size shall be obtained and analyzed for unpolymerized methyl methacrylate and unpolymer- ized ethyl acrylate monomers using gas liquid chro- matographic techniques (as described in Snell and Otto, Encyclopedia ofIndustrial Chemical Analysis, Interscience, 1972, Vol. 4, pp. 211–217, and Vol. 16, p. 99; or one giving equivalent results). Samples for testing are to be cut so that the center point of the analyzed piece is no closer to the original edge or surface of the casting than the thickness divided by two. The following (from Cober and Samsel, SPE Transactions, Gas Chromatograph, A New Tool for Analysis ofPlastics, April 1962, pp. 145–151) is a suitable procedure. The instrument shall be a Beckman GC-2Agas chromatographwitha hydrogenflame detec- tor, or equivalent, and a 6 ft (1.8 m) column of 1 ⁄ 4 in. (6.0 mm) stainless tubingoperatedat212°F(100°C). Pack thecolumnwith25% diethyleneglycoladipate polyester (LAC-2-R-446, Cambridge Industries Co.) and 2% phos- phoric acid on an 80-100 mesh Celite filter aid. The 29 acrylic to be analyzed shall weigh approximately 2.0 g and shall be dissolved in exactly 50 ml of methylene chloride. Inject a 3 ?L aliquot of the plastic-solvent solu- tion into the gas chromatographic apparatus. Compare the areas of the resulting peaks with the areas produced by the injection of a standard solution. Prepare the stan- dard solution by dissolving 20 mg to 30 mg of pure monomers in 50 ml of methylene chloride. Acrylic that does not dissolve shall be analyzed by swelling the plastic and extracting the soluble portion. Place a solid piece of insoluble acrylic about 1 g and 20 mL of methylene chloride in a glass bottle, and place on a shaker for 24 hr. After 24 hr, the fluid portion shall be analyzed for monomeric methyl methacrylate and monomeric ethyl acrylate (in accordance with the proce- dures set forth in the preceding paragraph). See also Tables IV-1-1, IV-1-2(a), and IV-1-2(b). All repaired windows shall be annealed after all machining and machine polishing have been completed, hereafter referred to as the final anneal. All annealing shall take place in a forced circulation air type oven. The final anneal and (any other anneals performed prior to the final anneal) shall be in accordance with Tables IV-1-2(a) and IV-1-2(b). Time and temperature data for all annealing cycles shall be entered into PVHO-2 Form IV-1-2, Annealing Process Certification. Also, a copy ofthe final anneal’s time/temperature chart shall be attached.

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