Does anyone know what the maximum time delay allowed between the first and second stage of a two stage fire alarm system is?

All interested parties should get together and decide the shortest acceptable time to carry out the aims why a delay is necessary.  The signal should automatically change to an audible fire warning, in at least the relevant alarm zone, after a pre-set period, unless manual stopped at the control equipment. The period for the staff to investigate (the pre-set time) should not normally exceed six minutes then go into full alarm depending on the evacuation procedure.