I have found that if you go to the OEM of the product you want the spec for, they usually have it and may fax it to you.
I recently got an SAE spec for the testing of aircraft seats from Weber Aircraft (an aircraft seat manufacturer).
Nigel Waterhouse
n_a_waterhouse@hotmail.com
A licensed aircraft mechanic and graduate engineer. Attended university in England and graduated in 1996. Currenty,living in British Columbia,Canada, working as a design engineer responsible for aircraft mods and STC's.