pnorder,
The ASTM has several standards for the testing of fiberglass tanks and pipes.
You could find the standard designations going to www.astm.org and searching for "fiberglass tank".
Only the titles are shown there. The standards can be purchased in the same website.
regards
zakk,
I think a construction worker could apply easily a force of 100 lbs. provided he has enough room and a good point to react. If he can not, he always can use a longer wrench.
AEF