M
mlorrey
Guest
http://www.lockheedmartin.com/data/assets/8385.pdf<br /><br />See page 4<br />The above document is the smoking gun of what I've been saying: ET foam application processes were changed due to the Montreal Accord banning CFCs. It was after these changes took place that the serious problem of large foam chunk losses started happening. Here is the text, in case the document disappears:<br />"Environmental Protection Agency<br />In 1987, the United States and 45 other<br />nations adopted the "Montreal Protocol on<br />Substances that Deplete the Ozone Layer."<br />Under the Protocol, class I ozone depleting<br />compounds, such as Chlorofluorocarbon<br />11 known as CFC 11 -- the Freon-based<br />blowing agent used in the production of<br />the External Tank's foam -- was to be<br />phased out of production by the end of<br />1995. Production of these compounds<br />after 1995 is allowed only by "Essential<br />Use Exemption" and must have Montreal<br />Protocol approval.<br />After extensive testing the External Tank<br />Project proposed hydro chlorofluorocarbon<br />HCFC 141b as the CFC 11<br />replacement. HCFC 141b is a blowing<br />agent more environmental regulation<br />compliant. At the same time, the<br />Environmental Protection Agency allowed<br />the External Tank program to continue use<br />of stockpiled supplies of CFC 11until<br />HCFC 141b was certified for use on the<br />Space Shuttle and phased in.<br />However, in 1999, the EPA proposed to<br />expand its regulations by implementing a<br />ban on nonessential products that release<br />class I ozone-depleting substances under<br />section 610 of the Clean Air Act. Under the<br />proposed rule, sale and distribution of BX<br />250, used to insulate part of the External<br />Tank, would have been banned because it<br />contains CFC 11. NASA asked the EPA to<br />revise the proposed rule to provide an<br />exemption for BX 250 and other foam<br />containing CFC