The codes surrounding stairwell reentry address the requirements that allow building occupants to leave a stairwell during a fire if the stair becomes compromised by smoke, or if the stair is impassable because of firefighting efforts and equipment. In many buildings, stairs doors are locked on the stairwell side in order to prevent unauthorized access from the stairwell to the tenant floors. But in an emergency, stair doors may need to be remotely unlocked in order to allow people to leave the stairwell if necessary and find another exit or wait for assistance. It’s important to note that in almost all cases, doors leading to the stairs need to allow egress as required by the model codes. Stairwell reentry refers to the locking and unlocking of the hardware on the stair side of the door.
The 2003 edition of the International Building Code (IBC) and previous editions of other model codes allowed some stair doors to be mechanically locked on the stair side; NFPA 101 – The Life Safety Code still allows some stair doors to be mechanically locked if certain criteria are met. At that time, enforcement of the requirements for remote unlocking was somewhat inconsistent, but a fire at the Cook County Administration Building in Chicago brought attention to the issue and resulted in more vigilant enforcement as well as changes to the IBC. This fire, in October of 2003, resulted in the deaths of 6 people who were unable to leave the stairwell when it became filled with smoke, firefighters, and equipment. A detailed report on this fire is available from the National Institute of Standards and Technology (NIST).
The stairwell reentry requirements of the IBC and NFPA 101 vary. The IBC is more stringent, and requires all lockable stair doors to be capable of remote unlocking via a switch at the fire command center or other approved location. NFPA 101 currently allows stairs serving 4 stories or less to be mechanically locked on the stair side, but the IBC does not include this exception. NFPA 101 also includes a section on “selected reentry” which allows doors serving some floors to be mechanically locked, while doors to other floors must allow reentry. The IBC does not include similar “selected reentry” requirements, and because the IBC is the most common building code used in the US, the requirements of the IBC pertain to most buildings.
The hardware most frequently used to meet the stairwell reentry requirements is a fail-safe electromechanical lockset or fail-safe lever trim for fire exit hardware. In some cases, particularly retrofit applications, electromagnetic locks are used in addition to the positive-latching hardware required for fire door assemblies. All of these products will unlock the door on the stair side when firefighters actuate the switch at the fire command center. These locks are also unlocked upon power failure, and can be unlocked automatically by the fire alarm system as required by NFPA 101. Electric strikes are not typically allowed on stair doors that require reentry, because fail-safe electric strikes are not listed for use on fire door assemblies; fail-secure electric strikes must be used for fire doors, and these strikes will not facilitate automatic reentry.
Keep in mind that the doors required to provide for stairwell reentry are the interior doors between the stairwells and the tenant floors. These model code requirements do not apply to the exit discharge, which is typically the door swinging out of the stairwell at the ground floor. Some local jurisdictions may ask for discharge doors to have the ability to be unlocked remotely for firefighter access, but this is not required by the model codes and can create security problems if doors unlock upon power failure and allow free access to the building.
The video below includes more information about stairwell reentry, and there is also a Decoded article that can be downloaded for reference. This blog post addresses some of the FAQs about this topic. If you want to get a head start on what’s coming next, this post covers some stairwell door changes to the 2024 IBC. After watching the video and reviewing these materials, please proceed to the review questions below.
1. The IBC requires which lockable stair doors to be remotely unlocked on the stair side by a switch at the fire command center?
- All lockable stair doors must be remotely unlockable, with the exception of the discharge door.
- Doors leading to stairs serving more than 4 stories are required by the IBC to be remotely unlockable.
- The IBC requires the stair door at every 5th level to be remotely unlockable.
- None of the above
2. Which of the following products are commonly used to meet the stairwell reentry requirements?
- Fail-safe electrified lock
- Fail-safe trim for fire exit hardware
- Electromagnetic lock with a passage set for positive latching
- All of the above
3. Which code allows mechanical locks (without remote release) on the stair side of some stair access doors if certain criteria are met?
- International Building Code (IBC)
- International Fire Code (IFC)
- NFPA 101 – The Life Safety Code
- All of the Above
- None of the above
Answers: 1 – A, 2 – D, 3 – C