Does IEEE 1584 say anything specific about how often or under what conditions the Arc Flash study should be updated or reviewed ?

Don't think so, but the 70E does.

70E says % yrs.

70E says 5 yrs.

Yep, or if any major changes are made to the system.

IEEE 1584 does not specify a time frame. It just provides the "how to" for the calculations

Thanks Zog, Thanks Jim,

So we should go by 5 Years per 70E or if a major change takes place.
Any other idea ?

To clarify:

The study is "updated" if there are any major changes

It is to be "reviewed" periodically not to exceed 5 years to check for major changes i.e. utility, configuration etc. that could affect the results.

It helps if someone keeps track of any setting changes (from test reports if testing is performed) and any similar changes. Depending on the utility, verification of their fault data could be simple. Just request updated information to see if there was much of a change.

Years ago I headed up this group at a large public utility and I can tell you first hand, if we had a new substation going on line, fault currents in the area could increase dramatically and no one would know. Other areas of the system that had no major construction would see the fault currents remain fairly constant.

It is also a good idea to see if they can give you minimum fault currents such as during a line out so you can evaluate the impact on the tripping time i.e. lower fault current may lead to higher protective device clearing times and greater incident energy.

Thanks for the clarifications.