When generating a saturation curve is it assumed that the Almen test strip has 100% coverage at T1? Can anyone show me where it is written that it must have coverage, or that it's not required?

It is not likely that an Almen strip will show 100% coverage at time T1 since it must continue to increase curvature an additional 10% at double the time. I do not know of any specification that refers to the strip receiving 100% coverage at time T1.

Jack,
I share your belief that the test strip might no exibit 100% coverage at T1. However there are a few Major Aerospace Companies that do not believe this to be the case. Perhaps in the next revision of AMS-2430 this issue could be clarified.

Walt,
I offered wondered if there is a terminolgy problem here. When someone says a strip must be covered 100% there could be two interpretations. Suppose the strip is only peened on half of it's length, i.e. 1.5 inches covered from one end to the middle. Obviously it's not 100% covered. In another case suppose it's peened over it's entire surface but more than 2% is left unpeened with these areas being evenly distributed over the surace of the strip.
It's my understanding that the first example is what is requested by 100% coverage. The second example may, or may not occur at peening exposure time T1. Pete Bailey has done numerous experiments to substantiate that some strips peened at exposure time T1, depending upon the intensity and shot size, do NOT exhibit 98% or more coverage.
It would seem counter-productive to insist on two criteria for "intensity" determination from the saturation curve and from inspection of the strip for coverage.
Perhaps a better place to address this problem is in SAE J443, use of the Almen strip, not just AMS 2430. This way any other spec referring to J443 will receive the benefit.