lutan1,
Just saw your post and question. I live in the US, and work in the papermaking industry. We have an in house confined space rescue team, and that is the same limits we use. Pretty sure that is what US OSHA recommends also. Refer to their web site www.osha.gov
Thanks Kenneth- it got me curious as I've noticed that some of the TLV's (TWA, STEL, Peak) for some exposures are different, which I found really interesting...