Browsing by Author "Buchanan, Vanessa"
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Item Elaborated Odor Test for Extended Exposure(46th International Conference on Environmental Systems, 2016-07-10) Buchanan, Vanessa; Henry, Emily; Harper, SusanaConcerns were raised when incidental exposure to a proprietary bonding material revealed the material had an irritating odor. The NASA-STD-6001B document describes a supplemental test method option for programs to evaluate materials with odor concerns (Test 6, Odor Assessment). In addition to the supplemental standard odor assessment with less than 10 seconds of exposure, the NASA White Sands Test Facility (WSTF) Materials Flight Acceptance Testing section was requested to perform an odor test with an extended duration to evaluate effects of an extended exposure and to more closely simulate realistic exposure scenarios. With approval from the NASA Johnson Space Center Industrial Hygienist, WSTF developed a 15-minute odor test method. WSTF performed this extended-duration odor test to evaluate the odor and physical effects of the bonding material configured between two aluminum plates after the safety of the gas was verified via toxicity analysis per NASA-STD 6001B Test 7, Determination of Offgassed Products. During extended-duration testing, odor panel members were arranged near the test material in a small room with the air handlers and doors closed to minimize dilution. The odor panel members wafted gas toward them and recorded their individual assessments of odor and physical effects at various intervals during the 15-minute exposure and posttest. A posttest interview was conducted to obtain further information. Testing was effective in providing data for comparison and selection of an optimal offgassing and odor containment configuration. The developed test method for extended exposure is proposed as a useful tool for further evaluating materials with identified odors of concern if continued use of the material is anticipated.Item High Risk Spacecraft Materials Offgassing(2024 International Conference on Environmnetal Systems, 2024-07-21) Buchanan, Vanessa; Silva, Emmanuel; Padilla, Julio; Greene, Benjamin; Reys, Ilse; Harper, SusanaNASA-STD-6001B Determination of Offgassed Products (Test 7) provides the offgassing characteristics under standardized conditions for materials and assembled articles to be located within habitable spacecraft environments. Experience with Test 7 has found certain material types above many others to be of high risk for offgassing undesirable compounds aboard spacecraft. Formaldehyde and acrolein are historically high T value offgassed components of the offgassed compound target list because they have low spacecraft maximum allowable concentration (SMAC) values assigned by the JSC Toxicology Group. Carbon disulfide, benzene, acrylonitrile, and furan are additional target compounds of concern due to their lower thresholds of toxicity as determined by the JSC Toxicology Group. Materials offgassing siloxanes are also of concern due to their degradation effects on environmental control and life support system (ECLSS) components and performance. Spacecraft materials and articles defined in this manuscript as high risk were identified after examining and condensing data for these compounds of concern from approximately 3000 tests performed over 30 years. Summaries of high risk material and article types based on highest Multi-purpose Crew Vehicle (MPCV) T values are also presented. Historical analysis shows high risk components are produced largely from test materials and articles in the general categories of electronic/powered components, foams, paints/coatings/films, adhesives/tapes, epoxy/resins, liquids/gels, Nomex� with surface treatments, markers/pens/inks, dry film lubricants, thermoplastics, hygiene items (deodorants, lip balms), and silicone rubber. These data are intended to be a resource for spacecraft materials and processes managers, designers and toxicologists. High risk materials and articles intended for use aboard spacecraft should be tested in accordance with NASA-STD-6001B Test 7.Item History of NASA's Odor Assessment (Test 6)(51st International Conference on Environmental Systems, 7/10/2022) Greene, Benjamin; Buchanan, Vanessa; Tapia Harper, SusanaNASA's Odor Assessment (Test 6) for nonmetallic materials and assembled articles for spacecraft has evolved since the Apollo program in 1966 to meet various habitable spacecraft nonmetallic programmatic requirements. The purpose of Test 6 is to determine if the odor from a material or assembled article is objectionable or revolting on an odor-characteristic scale of 0 to 4. Samples of the toxicity-screened test atmosphere from a conditioned specimen container are administered to an Odor Panel of qualified human research subject volunteers using a syringe and mask, and are assigned a scored odor characteristic of undetectable (0), barely detectable (1), easily detectable (2), objectionable (3), or revolting (4). The odor from a material or assembled article is objectionable or revolting if an average rating of 2.5 or higher is assigned by an Odor Panel. This manuscript presents the history of Test 6, beginning with the Apollo spacecraft nonmetallic materials selection guidelines and test requirements from 1966, in which tests were performed in oxygen atmospheres, and follows the odor test through Skylab, Space Shuttle, International Space Station, and Orion nonmetals testing, and acceptance requirements.Item History of NASA’s Determination of Offgassed Products (Test 7)(49th International Conference on Environmental Systems, 2019-07-07) Greene, Benjamin; Buchanan, Vanessa; Harper, Susana TapiaNASA’s Determination of Offgassed Products (Test 7) from materials and assembled articles for spaceflight has evolved since the Apollo program for over 50 years to meet various habitable spacecraft non-metallic programmatic requirements. Now mandated by NASA STD-6016A Standard Materials and Processes Requirements for Spacecraft, all nonmetallic materials used in habitable flight compartments, with the exception of ceramics, metal oxides, inorganic glasses, and materials used in sealed containers must meet the offgassing requirements in NASA-STD-6001B Test 7. This manuscript presents the history of Test 7 beginning with the Apollo spacecraft nonmetallic materials selection guidelines and test requirements in 1967, in which tests were performed in mostly oxygen atmospheres, and progressing through Skylab, Space Shuttle, International Space Station non-metals testing and acceptance requirements with milder test environments, and now imposed on Commercial Crew Transportation, Space Launch System/Project Orion programs, and other NASA-funded programs. This review of the history of Test 7 presents the reader with a perspective on the development and changes undergone since inception to the present. Related NASA standard tests (some now former, discontinued, combined, or supplemental) including Test 6 (Odor Assessment), Test 16 (Determination of Offgassed Products from Assembled Articles), and Test 12 (Total Spacecraft Cabin Offgassing) are discussed in context.Item NASA-STD-6001B Test 7: Impact of Test Methodology and Detection Advancements on the Obsolescence of Historical Offgas Data(47th International Conference on Environmental Systems, 2017-07-16) Buchanan, Vanessa; Harper, Susana; Woods, Brenton; Beeson, Harold; Perez, Horacio; Ryder, Valerie; Pedley, Michael; Tapia, Alma StephanieNASA-STD-6001B states “all nonmetals tested in accordance with NASA-STD-6001 should be retested every 10 years or as required by the responsible program/project.” The retesting of materials helps ensure the most accurate data are used in material selection. Manufacturer formulas and processes can change over time, sometimes without an update to product number and material information. Material performance in certain NASA-STD-6001 tests can be particularly vulnerable to these changes, such as material offgas (Test 7). In addition, Test 7 analysis techniques at NASA White Sands Test Facility were dramatically enhanced in the early 1990s, resulting in improved detection capabilities. Low level formaldehyde identification was improved again in 2004. Understanding the limitations in offgas analysis data prior to 1990 puts into question the validity and current applicability of that data. Case studies on Super Koropon® and Aeroglaze® topcoat highlight the importance of material retesting.