Fail Safe vs. Fail Secure

One of the biggest challenges our industry constantly wrestles with is how to achieve a balance between safety and security. How do you keep occupants safe in an emergency without compromising the security of a building? This conflict frequently plays out in discussions of fail safe vs. fail secure products, and confusion about which type to use is not uncommon. Installing the incorrect electrified hardware can be a costly mistake to rectify so it’s critical to have a thorough understanding of the fire, life safety, and building codes that apply.

Let’s begin with some basic definitions:

• Fail safe products are unlocked when power is removed.  Power is applied in order to lock the door and prevent access.
• Fail secure products are locked when power is removed.  Power is applied in order to unlock the door and allow access.

With a few exceptions (which we will discuss later), most products provide free egress regardless of whether they are fail safe or fail secure. Only the secure side or key side of the door is affected by the access control system.

While some products are only available fail safe and others fail secure, many are available in either form and the codes regulating their use in various applications are not always as clear as one would hope. To help clarify things, we’ll examine each type of electrified hardware and look at not just the code requirements, but also the logic behind each as it’s easier to remember the rules if you have a firm understanding of them.

Electric Strikes

An electric strike replaces the regular strike for a lockset or panic hardware.  For a single door it mounts in the frame, and for a pair it mounts in the inactive leaf or on a mullion.  The lockset or panic hardware allows free egress at all times, except in the case of double-cylinder institutional function locks.

The spring-loaded keeper on the electric strike controls the latchbolt of the lock/panic.  When access is allowed, the keeper is free and the latchbolt can be pulled through the keeper so the door can be opened.  When the strike is secure, the keeper secures the latchbolt and prevents the door from being opened.  In most cases, a key can be used to retract the latchbolt from the secure side of the door to allow access if a manual override is needed.  Because the lock or panic hardware functions independently of the electric strike, occupants can exit by turning the lever or pushing the touchpad of the panic hardware, regardless of whether the electric strike is fail safe or fail secure.

NFPA 80 - Standard for Fire doors and Other Opening Protectives states that electric strikes may be used on fire door assemblies “where provided for in the published listings.”  Electric strikes listed for use on a fire door assembly must be fail secure, and a fire alarm contact may be required to ensure that the door is positively latched during a fire.  Fail secure electric strikes should be specified in almost all applications, except when access is required upon fire alarm. 

Outside of stairwell re-entry, there are very few situations where access upon fire alarm is required. Electric strikes may not be used on stair doors that are required to meet the requirements for stairwell reentry upon fire alarm, because electric strikes on fire doors must be fail secure, and stairwell re-entry requires a fail safe product.  A common concern is ensuring that firefighters are able to gain access to the building, but their method for gaining access is the same whether the door has a mechanical lockset, electric strike, electrified lock, or electrified panic hardware. That might be a key or other credential in the key box, or they may force the door using tools.

The primary reason that electric strikes on fire doors MUST be fail secure is so the door is positively-latched in the event of a fire to maintain the compartmentalization of the building and deter the spread of smoke and flames.  There are also serious security implications to having an unlocked building or area, allowing free access every time there is a power failure.  A breach of security can be extremely dangerous to building occupants, along with the potential for loss or damage.  That’s not a situation for which you want to be held liable.

Electromechanical Locks

An electromechanical lock is a lockset that has been electrified, so that it can be controlled by a card reader, remote release, or other access control device.  Although most electromechanical locksets allow free egress at all times, there are double-cylinder electromechanical locksets that do not allow free egress, which should not be used on any door that is part of a required means of egress. 

A fail secure electromechanical lockset is locked on the secure side when there is no power to the lock.  To unlock it, power is applied and the lever can then be turned to retract the latch.  The latch remains projected until the lever is turned.

A fail safe electromechanical lockset is locked when power is applied, and unlocked when power is removed.  When power is removed, the lever can be turned to retract the latch.  Fail safe electromechanical locks are typically used for stairwell doors providing re-entry.  The lock is constantly powered when the lever on the stair side is locked.  During a fire alarm, the lever on the stair side is unlocked (power removed) either by the fire alarm or a signal from the fire command center, depending on which code has been adopted.  Building occupants may then leave the stairwell to find another exit if necessary.  The stair doors would also be unlocked during a power failure.  The locks always allow free egress into the stairway.

Electrified Panic Hardware Trim

This refers to the outside lever on panic hardware or fire exit hardware.  It is similar to an electromechanical lock in that the power controls whether the outside lever can be turned or not.  Free egress is always available by pushing the touchpad or crossbar of the panic hardware, and the latch remains projected until the lever is turned.

Because most doors are not required to allow access upon activation of the fire alarm, fail safe electrified trim for panic hardware is used primarily for stairwell doors providing re-entry. Keep in mind that while the stair discharge door is not typically required by code to unlock upon fire alarm, the door between the stairwell and the roof MAY be required/desired by some code officials to be fail safe, allowing building occupants to reach the roof during a fire.  However, this is not currently a requirement of the International Building Code or NFPA 101 – The Life Safety Code.

Electric latch retraction (EL)

This function is commonly used on panic hardware or fire exit hardware.  From a security/locking perspective, EL devices are only available fail secure, so when power is applied the latch retracts automatically and stays retracted as long as power is applied.  When power is removed the latch is projected, securing the door.  Again, free egress is provided by pressing the touchpad of the panic hardware. 

Fire doors are sometimes equipped with EL devices as they allow push/pull function during normal use, and provide positive latching during a fire alarm.  A signal from the fire alarm system to the power supply is needed to ensure that the door is latched during a fire.

EL devices are often used on doors that also have automatic operators, so the latch is retracted before the door begins to open.  Electric strikes can perform this function as well.  Fail safe or fail secure products can be used in this application, but fail secure is the better choice unless access is required upon fire alarm. 

Electromagnetic Locks

An electromagnetic lock is an electromagnet that mounts on the frame, with a steel armature mounted on the door.  When power is applied to the magnet, it bonds to the armature, securing the door.  Electromagnetic locks are only available fail safe, so when power is removed, the electromagnetic lock is unlocked.

Unlike other types of electrified hardware, mag-locks do not provide free egress without the external release devices required by code in order to unlock the door.  An electromagnetic lock that is released by door-mounted hardware, such as a request-to-exit switch in panic hardware, is required to unlock upon loss of power.  If the electromagnetic lock is released by a sensor, it must be unlocked by a push button located beside the door, upon actuation of the fire alarm/sprinkler system, and upon loss of power.

When in Doubt, Check the Codes

When struggling to strike a balance between safety and security, understanding the relevant codes for each type of hardware will make the process easier. Installing the appropriate fail safe or fail secure hardware will ensure the effectiveness of fire doors, protect the occupants’ safety, reduce liability and prevent costly replacement of non-compliant products.

Lori Greene, AHC/CDR, CCPR, FDAI, is Manager, Codes & Resources, for Allegion. Visit her blog at www.iDigHardware.com.