Dave:
I have to agree with Pierre, and have a few 'others' for your consideration:
Best solution for a NEW install is to get the quartz restrike option installed in the HID fixtures when ordering.
A common solution used widely here is:
Install a time delay (off) on the exit/emergency circuit that starts the set time delay upon restoration of normal power. (usually 10 to 15 min). That allows the HID's to re-strike.
Some guys install fluorescent channels in the egress areas as needed that 'light' instantaneously upon power restoration. This is dependent on the size of the jobsite, and some customers don't like the additional fixtures.
We usually install a phase loss monitor relay at the LP, that the exit/em circuit(s) are wired to, in case of only a phase loss, and not a full power fail.
Again, the ultimate solution needs a lot of 'answers' to find a solution. Don't despair, there's always a Code compliant answer!
