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This time, the entire 11 1/2-inch width of the foam chunk rather than just a corner during previous tests hit the wing, putting maximum stress on the suspect area.
I'm curious about this gun. Doesn't the piece of foam need to be shaped to fit the barrel ... or not?
[Federal Register: November 15, 2001 (Volume 66, Number 221)] [Rules and Regulations] [Page 57511-57523] From the Federal Register Online via GPO Access [wais.access.gpo.gov] [DOCID:fr15no01-18] ----------------------------------------------------------------------- ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 82 [FRL-7101-1] RIN 2060-AH99
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EPA received a comment from the National Aeronautics and Space Administration (NASA) regarding the use of specific plastic foam products for the space shuttle. NASA identified one particular product, BX-250, a foam which is part of the thermal protection system of the Space Shuttle External Tank and which uses CFC-11 as a blowing agent. NASA stated that ``although extensive efforts have been made and continue to be made to replace this material, no viable alternative has been identified.'' NASA requested that EPA revise the proposed rule to provide an exemption for CFC-blown foam products in applications that are associated with space vehicles. NASA suggested that EPA consider using the same language that EPA has previously adopted under 40 CFR part 63, subpart GG (40 CFR 63.742) for the National Emissions Standards for Hazardous Air Pollutants (NESHAPs) program. NASA provided EPA with additional information concerning its proactive pursuit of potential alternative blowing agents.
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Since human space flight safety is of paramount importance to NASA, prior to implementing any new material, that material must undergo a rigorous development and qualification program for which no suitable substitute has yet been identified. NASA requested that EPA consider using the language at 40 CFR 63.742:
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Space vehicle means a man-made device, either manned or unmanned, designed for operation beyond earth's atmosphere. This definition includes integral equipment such as models, mock-ups, prototypes, molds, jigs, tooling, hardware jackets, and test coupons. Also included is auxiliary equipment associated with test, transport, and storage, which through contamination can compromise the space vehicle performance. [[Page 57518]]
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EPA agrees that an exception is necessary, but EPA disagrees with NASA's proposed language. This language is far broader than what EPA concludes is actually necessary based on an evaluation of the information NASA presented. If EPA were to simply exempt all foams used for any applications associated with space vehicles EPA could be exempting products where there are already suitable substitutes. NASA only provided information concerning one particular type of foam used in applications associated with the Space Shuttle External Tank. Therefore, based on that information, through this action, EPA will modify Sec. 82.66(c) to provide an exemption for foam products manufactured with or containing Class I substances that are used as part of the thermal protection system of external tanks for space vehicles and will add the definition of space vehicles found at Sec. 63.742 to Sec. 82.62. The exemption will be limited to the use of CFC-11 as a blowing agent and where no other CFCs are contained in the foam product. Although EPA did not propose this exemption or the additional definition, they are logical outgrowths of the comment submitted by NASA and thus it is appropriate to proceed to final action without providing any additional proposal or opportunity for further comment.