I didn’t want to scare anyone by adding more information to my previous post about stairwell re-entry, but I do get questions about how to accomplish this. The stairwell re-entry requirements state that the stair side lever must unlock on fire alarm or on a signal from the fire command station depending on the code (there is always free egress from the non-stair side). I have seen stair doors that had been retrofitted with card readers and electric strikes. If these doors are required by code to meet the stairwell re-entry requirements, an electric strike is not an acceptable way to do this.
An electrified product that unlocks upon fire alarm is a fail-safe product, and openings in an egress stair are fire-rated. Electric strikes used in fire-rated frames have to be fail-secure, so that they remain positively latched during a fire. A fail-safe electric strike might allow the latch to be pushed past the keeper by the pressure of a fire, and the door would not be latched.
For stairwell re-entry, a fail-safe electrified lockset or exit device trim is required, so the door will be unlocked, but not unlatched upon fire alarm. The Schlage nomenclature for a fail-safe lockset is “EL” or “electrically locked”. When you remove the electricity from an “EL” lock, it is no longer locked. It’s a little confusing since Von Duprin uses “EL” to mean something completely different (electric latch retraction), but if it was easy everyone would do it, right?