Showing posts with label NFPA 252. Show all posts
Showing posts with label NFPA 252. Show all posts

Tuesday, March 1, 2022

Fire Codes Apply for Electromagnetic Locks

 Fire Codes Apply for Electromagnetic Locks

An electromagnetic lock (EM Lock) is essentially an electromagnet in a housing mounted on the door frame, and a steel armature mounted on the door wing. When the magnet is energized, it bonds to the armature and locks the door. To allow access or egress, a switch must be provided to de-energize the electromagnet. It can be difficult to determine which set of code requirements to follow. However, code compliance is crucial when this product is used in an access- or egress-control system. Unlike most locks, electromagnetic locks typically require external release devices such as motion sensors or request-to-exit switches to allow building occupants to exit. In addition, secondary means of releasing the mag-lock are often mandated by the codes, and the requirements vary depending on the type of locking system used.

Prior to the 2009 edition of the International Building Code (IBC), the set of code requirements typically used for doors equipped with electromagnetic locks was the section called Access-Controlled Egress Doors. The 2009 edition added a second set of requirements that could be used, called Electromagnetically Locked Egress Doors. Either of these two sets of requirements can now be used, depending on the application.

The basic difference between these two sections is that the original section, Access-Controlled Egress Doors, required a sensor and push button as release devices, while the new section, Electromagnetically Locked Egress Doors, allows a door-mounted release device instead. This could be panic hardware or a latchset with a request-to-exit (RX) switch, or a bar with an electronic touch sensor.

A building could have several AHJs (Authorities Having Jurisdiction), and more than one code may be enforced for a particular project. The most commonly used model codes in the U.S. are the International Building Code (IBC), the International Fire Code (IFC), and NFPA 101 – The Life Safety Code, but state and local codes sometimes include modifications that affect the use of electrified hardware. It’s usually best to follow the most stringent set of requirements that have been adopted in the project’s jurisdiction.

Here is a summary of the requirements for both sections from the 2009 IBC:

1008.1.4.4 Access-Controlled Egress Doors

·        Applies to entrance doors in a means of egress and entrance doors to tenant spaces.

·        Allowed in Use Groups - A (Assembly), B (Business), E (Educational), I-2 (Institutional - Hospitals & Nursing Homes), M (Mercantile), R-1 (Residential - Hotels, Motels, & Boarding Houses), and R-2 (Residential - Apartments & Dormitories).

·        A sensor must be mounted on the egress side to detect an occupant approaching the doors. Doors must unlock upon a signal from the sensor or loss of power to the sensor.

·        Loss of power to the lock must unlock the doors.

·        A manual unlocking device (push button) shall result in direct interruption of power to the lock – independent of the access control system electronics. When the push button is actuated, the doors must remain unlocked for 30 seconds minimum. The push button must include signage stating “Push to Exit” and must be located 40” to 48” vertically above the floor and within 5’ of the doors. Ready access must be provided to the push button.

·        If the building has a fire alarm/sprinkler system/fire detection system, activation of the system must automatically unlock the doors. Doors must remain unlocked until the system has been reset.

·        Entrance doors in buildings with an occupancy in Group A, B, E or M shall not be secured from the egress side during periods that the building is open to the general public.

1008.1.9.8 Electromagnetically Locked Egress Doors

·         Applies to doors in a means of egress and doors to tenant spaces. The 2009 IBC includes a limitation to doors “not otherwise required to have panic hardware,” which was removed in the 2012 edition.

·        Allowed in Use Groups - A (Assembly), B (Business), E (Educational), M (Mercantile), R-1 (Residential - Hotels, Motels, & Boarding Houses), and R-2 (Residential - Apartments & Dormitories).

·          The door must be equipped with listed hardware mounted on the door leaf, which incorporates a built-in switch to directly release the electromagnetic lock and unlock the door immediately.

·         The release device must have an obvious method of operation, and must be readily operated with one hand under all lighting conditions.

·            Loss of power to the listed hardware must automatically unlock the door.

·          When the new section was added to the 2009 IBC, the technical committee made a change to the proposed language which caused some confusion. A limitation to doors that are “not otherwise required to have panic hardware” was included in the 2009 edition, but it appears that this was not the intent. The limitation was removed and the intent clarified in the 2012 edition of the IBC, and as long as the switch in the panic bar releases the mag-lock, a door required to have panic hardware can be equipped with a mag-lock.

·        With the addition of Section 1008.1.9.8 – Electromagnetically Locked Egress Doors, the door-mounted release device can be used instead of the sensor and emergency push button. Note that this section does not require the mag-lock to release upon activation of the fire alarm or sprinkler system when a door-mounted release device is used. But there are a few issues that are still unclear, even with the 2012 changes.

·           The door must unlock upon loss of power to the “listed hardware,” which in this case is the door-mounted release device. Loss of power to some types of request-to-exit switches will not unlock the mag-lock. We may see a future change to the language so that loss of power to the electromagnetic lock is required to unlock the door, but the code currently addresses the release device.

·        I-2 occupancies (Institutional – Hospitals & Nursing Homes) are not included as acceptable locations for electromagnetically locked egress doors. This use group was added to the Access-Controlled Egress Doors section in the 2009 edition of the IBC, so hopefully the new section will catch up and include the I-2 use group in the future.

·        UL 305, the UL Standard for Panic Hardware, doesn’t address the use of panic hardware to release an electromagnetic lock. There is also a section of the IBC which states that certain doors shall not be equipped with a latch or lock unless it’s panic hardware. This should be changed to reflect the use of a mag-lock released by panic hardware.

The following summaries address each type of system where a mag-lock might be used, and the related model code requirements:

Sensor Release: A sensor automatically unlocks the electromagnetic lock to allow egress.

This is the most common type of system where electromagnetic locks are used. In past editions of the model codes, the applicable section referred to “access-controlled egress doors” which often gave the impression that the requirements applied to all doors with an access control system. A typical access control system which controls access but utilizes a lever handle or panic hardware to allow free egress is not required to comply with this section. The intent is for this section to apply only to electrified locks that are released by a sensor, and the title of this section has been changed in the model codes to clarify the intent.

For these systems, a sensor on the egress side of the door opening must detect an approaching occupant and unlock the door. The door must also unlock upon loss of power to the sensor or locking system, upon activation of the building fire alarm or automatic sprinkler system (until manually reset), and upon actuation of an auxiliary switch – typically a push button. This switch must be located 40-48 inches above the floor and within 5 feet of the door, must be readily accessible, and must be marked “PUSH TO EXIT.” Pushing the button must directly interrupt power to the lock, independent of the other electronics, and the door must remain unlocked for at least 30 seconds.

Recent editions of the IBC/IFC and NFPA 101 include virtually identical egress requirements for these systems, and all of these model codes currently require the UL 294 listing for these applications. It’s important to note that when this type of system is installed on a door that is required by code to have panic hardware, the panic hardware is required in addition to the electromagnetic lock.

Door-Hardware Release: A switch in the door-mounted hardware releases the electromagnetic lock to allow egress.

This type of system typically utilizes a request-to-exit (RX or REX) switch in the lever handle, panic hardware, or sensor bar mounted on the door. Again, the requirements of the IBC/IFC and NFPA 101 are very similar. The model codes require the hardware mounted on the door to have an obvious method of operation, and to be readily operable with one hand and under all lighting conditions. Operation of this door-mounted hardware must directly interrupt power to the electromagnetic lock, and the door must unlock immediately. The door must also unlock upon loss of power to the locking system, and the UL 294 listing is required by the current model codes. Note that this section does not require an auxiliary push button beside the door, or for the door to unlock upon activation of the fire protection system, although some local codes or AHJs may mandate these additional safety overrides.

Delayed Egress: Doors are locked to delay egress for 15 seconds under normal operation but allow immediate egress during an emergency.

There are two types of egress:

·        Free means that someone can exit an egress door without any delay by using only a single motion, such as turning a lever or pushing on a panic bar.

·        Delayed means that there’s a timed delay before someone can pass through the egress door and exit. Typically, this delay is 15 seconds.

Delayed egress is used to:

·        Discourage casual use of certain doors, so pedestrians can’t leave a premises or steal merchandise.

·        Deter elopement of patients, children or inmates from a protected area of a facility.

·        Make possible access control in both directions through selected openings.

Often, delayed egress systems include panic hardware with delayed egress circuitry, but electromagnetic locks are also available with this function. The lock includes an integral timer which allows the door to be opened 15 seconds after an attempt to exit is made – or 30 seconds when approved by the AHJ. The activation switch may be part of the mag-lock, or the timer may be initiated by an external RX switch.

To ensure free egress in an emergency, delayed egress locks must unlock immediately (no 15-second delay) upon activation of the fire protection system or sprinkler system, and upon loss of power. The capability of allowing immediate egress by a switch at the fire command center or other location may also be required.

Under normal operation, the delayed egress lock prevents egress until a force of 15 pounds, maximum, is applied for not more than 3 seconds; an audible alarm will sound in the vicinity of the door, and in 15 seconds the door will unlock to allow egress. After the device has been released by an attempt to exit, it must be rearmed manually - current codes do not allow delayed egress locks to rearm automatically.

Doors with delayed egress locks must also include signage stating, “PUSH UNTIL ALARM SOUNDS. DOOR CAN BE OPENED IN 15 SECONDS.” When a delayed egress lock is installed on an inswinging door, or when an AHJ approves a 30-second time delay, the signage must reflect the applicable operation. Specific requirements for the signage can be found in the model codes, and current codes also require the UL 294 listing for delayed egress locking systems.

The model codes include some additional limitations based on the use group or occupancy classification. For example, past editions of the IBC/IFC prohibited the use of delayed egress locks in assembly, educational, and high hazard occupancies, but the 2018 editions include exceptions for doors serving classrooms with an occupant load of less than 50 people, and for secondary exits from courtrooms. Delayed egress locks are allowed in those locations when the jurisdiction has adopted the 2018 edition of the model code, or when approve by the AHJ.

Controlled Egress: In health care facilities where patients require containment for their safety or security, doors may be locked in the direction of egress under normal operation but must allow emergency egress.

The IBC and IFC allow this application to be used in some health care units in hospitals, nursing homes, and other Group I-1 and I-2 facilities. These units might include memory care, maternity, pediatrics, or other areas approved by the AHJ. NFPA 101 includes these requirements in the chapters that cover new and existing health care facilities, and the code allows the doors to be locked where patients’ special needs require specialized protective measures for their safety or security.

According to the IBC and IFC, the building must have an automatic sprinkler system or automatic fire detection system, and activation of these systems must unlock the doors to allow egress. Loss of power must also automatically unlock the controlled egress doors, as well as a switch that directly breaks power to the lock - located at the fire command center, nurses station, or other approved location. A building occupant must not be required to pass through more than one door equipped with a controlled egress lock before entering an exit. The automatic-release requirements listed here do not apply to areas used for psychiatric treatment, or hospital units where listed infant abduction systems are installed.

All clinical staff members must have the ability – including keys or credentials – to unlock the doors for emergency egress, and these procedures must be included in the facility’s emergency plan. Training and drills are crucial in order for staff to be familiar with the egress protocols. Systems used for controlled egress must be listed to UL 294, and emergency lighting must be present at doors equipped with these locks. The requirements of NFPA 101 would not change the type of locks used in these systems (fail safe electrified locks), but the Life Safety Code does include slight variations to the required safety systems and procedures.

Stairwell Reentry: Stairway access doors may be locked on the stair side but must unlock to allow building occupants to leave the stairwell if it becomes compromised during a fire.

The IBC and IFC require all stairwell doors that are lockable on the stair side to have electrified locks that can be remotely released by a switch at the fire command center, or other approved location. (Note: Stair discharge doors may be locked to prevent access to the stairwell but must allow free egress.) For high-rise buildings, the IBC and IFC require the stairwell to be equipped with a two-way communication system if doors are electrically locked. Consult the IBC/IFC for exceptions related to buildings with a single exit stair.

The NFPA 101 requirements for stairwell reentry differ from the IBC and IFC, so it’s very important to refer to the adopted code to verify what is required. For example, NFPA 101 allows doors to be mechanically locked on the stair side when serving four stories or less – the IBC and IFC require these doors to be electrically locked, or never locked. NFPA 101 also exempts some occupancies from the reentry requirements, and includes a section detailing the criteria for “selected reentry” – which allows some doors to be mechanically locked and others to allow reentry.

If mag-locks are used on fire-rated stair doors, the door must be equipped with additional latching hardware to maintain the fire rating. In addition, the mag-locks must meet the applicable requirements on the egress side – sensor release, door hardware release, delayed egress, or controlled egress. Fail-safe electrified locks or fail-safe trim for fire exit hardware is commonly used; fail safe electric strikes are not listed for use on fire door assemblies.

Elevator Lobby Egress: Doors secure the elevator lobby and prevent access to the tenant space but must allow emergency egress from the lobby.

Currently, the IBC and IFC require each elevator lobby to have code-compliant egress via at least one exit. This could include direct access from the lobby to an exit stairwell, or free egress from the lobby to a corridor that leads through a tenant space to an exit. This means of egress must not be restricted, except with a delayed egress lock (most occupancy types) or an exit alarm.

NFPA 101 does allow egress through elevator lobby doors to be restricted during normal operation, if the doors allow emergency egress. The application must be allowed by the applicable occupancy chapter. For example, Chapter 11 (Special Structures and High-Rise Buildings) allows elevator lobby exit access doors to be locked “in other than newly constructed high-rise buildings.” Therefore, this application would not be allowed by NFPA 101 in new high-rise buildings.

The building must have a fire alarm and sprinkler system, and the lobby must have a smoke detection system. Activation of any of these systems (except by manual pull stations), or loss of power must automatically unlock the doors to allow egress. The doors must remain unlocked until the system is manually reset.

The elevator lobby must have a two-way communication system connected to a central control point that is constantly staffed by people who can provide emergency assistance. The electrified hardware must be listed to UL 294, and any latch-releasing hardware on the door must comply with the egress requirements of NFPA 101.

Because the IBC and IFC do not include a section similar to NFPA 101 regarding elevator lobby doors, some cities and states have modified the IBC/IFC to allow these doors to be electrically locked. These modifications typically require fail safe locks which unlock automatically upon activation of the fire protection system, as well as communication between the elevator lobby and a security desk or other location.

Security Interlock: Two or more doors are interlocked so that when one door is opened, the other door cannot be opened; commonly used on clean rooms and high-security applications.

Mag-locks are often used in security interlocks, but this application is not currently addressed in the model codes except when related to a prison sallyport. This type of system could impede egress, so each application must be approved by the AHJ, and additional safety features may be required. For example, to avoid entrapment in the room or vestibule, the AHJ may require emergency override switches in both locations, as well as an override switch on the exterior that is controlled by a key or credential. These switches will allow the doors to be unlocked for access or egress if one door is in the open position, preventing the use of the other door. In most security interlocks, the locks are automatically unlocked upon activation of the fire protection system, to allow free egress. Consult the AHJ to determine what is required.

In most cases, only one of these sections will apply to a particular door opening equipped with a mag-lock. The exception would be a stairwell door that must meet the stairwell reentry requirements on the stair side but would have one of the other applications on the egress side. Remember, refer to the applicable model codes and any state or city modifications to determine whether additional limitations apply, and consult the AHJ if more information is needed.

Code Comparisons - Occupancy Classifications

I-Codes. Until the 2018 edition of the IBC, delayed-egress locks were allowed in all use groups except A – assembly, E – educational and H – high hazard. Beginning with the 2018 edition, delayed-egress locks are allowed on the secondary exits that serve courtrooms (typically assembly occupancies) if the building has a sprinkler system. The 2018 edition also allows delayed-egress locks on classroom doors in educational occupancies if the calculated occupant load served by the door is fewer than 50 people. This gives schools an option if they’re looking for a way to prevent elopement of young children or students who have special needs.

NFPA. The NFPA codes are less restrictive and allow delayed-egress locks in areas of low and ordinary hazard contents, although the Life Safety Code includes restrictions depending on the occupancy. For example, delayed-egress locks aren’t permitted on the main entrance or exit doors that serve assembly occupancies, and they also are prohibited on airport jetway doors. Lodging or rooming houses can have only one door that has a delayed-egress lock per escape path, and residential board and care facilities are permitted to have delayed-egress locks only on exterior doors. The other occupancy classifications aren’t subject to similar limitations.

Code Comparisons - Required Fire Protection System

I-Codes & NFPA. Both sets of model codes require buildings that have delayed-egress locks to be equipped throughout with an automatic sprinkler system or approved automatic smoke- or heat-detection system. This requirement allows either type of system, although the change to the 2018 IBC that applies to courtrooms specifically requires a sprinkler system.

Code Comparisons - Activation Time

I-Codes & NFPA. Both sets of model codes require the delayed-egress timer to begin when a force of 15 pounds is applied for no more than 3 seconds. Prior to the 2015 edition of the IBC, the timer was required to begin after someone attempted to exit for 1 second. The activation time required to initiate the 15-second (or 30 second) timer is permitted to be less than 3 seconds, but it can’t be more than 3 seconds.

Code Comparisons - Automatic Release Delay

I-Codes & NFPA. When the timer is activated, the model codes require the delayed-egress lock to release in the direction of egress after 15 seconds; the AHJ might approve a time delay of 30 seconds. After that period, the door will be unlocked in the direction of egress, and another attempt to exit will allow the door to be opened.

Code Comparisons - Rearming After Activation

I-Codes & NFPA. When the timer of a delayed-egress lock is activated and the lock allows egress after 15 (or 30) seconds, the model codes require the lock to be rearmed manually.

Code Comparisons - Audible Alarm

I-Codes & NFPA. Both sets of model codes require an audible alarm to sound when a delayed-egress lock is activated, but the codes don’t mandate a specific type of alarm. Some products incorporate a continuous alarm, while others have an intermittent sound or even a verbal countdown.

Code Comparisons - Signage Requirements

I-Codes. Signage must state "PUSH [PULL] UNTIL ALARM SOUNDS. DOOR CAN BE OPENED IN 15 [30] SECONDS.” These signs are required for doors equipped with delayed-egress locks (see exception for Group I) and must be mounted above and within 12 inches of the door exit hardware. Beginning with the 2015 edition, signage is required to comply with the visual character requirements of ICC A117.1 – Accessible and Usable Buildings and Facilities. In Group I – institutional occupancies, the AHJ may allow signage to be omitted for certain types of treatment areas.

NFPA. The required text for the signage is the same as that required by the I-Codes: “PUSH [PULL] UNTIL ALARM SOUNDS. DOOR CAN BE OPENED IN 15 [30] SECONDS.” The NFPA codes require signage for delayed-egress locks to be readily visible, with letters not less than 1 inch high, a stroke width of one-eighths of an inch and a contrasting background, durable and located on the egress side of the door adjacent to the release device.

Code Comparisons - Action Upon Alarm Activation

I-Codes. When the fire alarm or sprinkler system is activated, delayed-egress locks must allow immediate egress automatically. This ensures that building occupants can exit quickly during a fire.

NFPA. The NFPA codes are more specific regarding the types of system activation that must unlock the delayed-egress locks for emergency egress. These doors must unlock with no delay in the direction of egress upon the activation of a sprinkler system, not more than one heat detector or not more than two smoke detectors.

Code Comparisons - Remote Release

I-Codes. To allow immediate egress when necessary, the I-Codes require delayed-egress locks to be capable of being deactivated by a switch at the fire command center or other approved locations.

NFPA. Remote release isn’t mandated by the section of the Life Safety Code that addresses delayed-egress locks.

Code Comparisons - Action Upon Power Failure

I-Codes & NFPA. When power fails, both sets of codes require delayed-egress locks to unlock immediately in the direction of egress. A common question about delayed-egress locking systems is whether battery backup is allowed in the power supply of the electrified hardware. The model codes don’t address this specifically, so it often is left up to the AHJ to decide whether delayed-egress locks must release upon loss of the main power to the building or continue to delay egress on standby power. However, based on the requirements of NFPA 72 – National Fire Alarm & Signaling Code, I don’t recommend using independent battery backup in the power supply of the delayed-egress lock. If the fire-alarm system and delayed-egress locks are powered by two different standby power systems, the hardware might not interface properly with the fire alarm after the loss of main building power. Using the same standby power source for the fire-alarm system and delayed-egress locks is preferred.

Code Comparisons - Emergency Lighting

I-Codes & NFPA. Emergency lighting is required by both sets of model codes, on the egress side of the door on which a delayed-egress lock has been installed. It’s important to check for the presence of emergency lighting before you install delayed-egress hardware.

Code Comparisons - Quantity of Locks per Egress Path

I-Codes. For most use groups, only one delayed-egress lock is allowed per egress path. This has changed from past editions of the I-Codes, where a building occupant could encounter only one delayed-egress lock before going through an exit. In Group I – institutional occupancies, such as hospitals, nursing homes and day care facilities, the I-Codes allow two doors that have delayed-egress locks per egress path, with a maximum combined delay of 30 seconds. In Group I-1, Condition 1 and Group I-4, the exception permitting two doors that have delayed-egress locks mandates that the building is equipped with a sprinkler system throughout.

NFPA. For most occupancy classifications, the NFPA codes don’t restrict the number of delayed-egress locks per egress path. Only in lodging or rooming houses does the Life Safety Code limit delayed-egress locks to one device per escape path.

Required Listings

I-Codes & NFPA. Both sets of model codes require delayed-egress locking systems to be listed to UL 294 – Standard for Access Control System Units. If a delayed-egress lock will be installed on a fire-door assembly, it also must be listed to UL 10C – Positive Pressure Fire Tests of Door Assemblies or NFPA 252 – Standard Methods of Fire Tests of Door Assemblies. In addition to the other listings, panic hardware that has delayed egress as a feature must be listed to UL 305 – Standard for Panic Hardware (I-Codes & NFPA) and in some cases BHMA A156.3 – Exit Devices (NFPA only).

If you are a system integrator or access automation installer or even a distributor, it is important to know how to select the best code application for access system on behalf of the customer. Majority of the datasheets and catalogues are not really useful unless you already know what you are getting into. If need any further information contact us on ssaintegrate@gmail.com.

Further Reading

For more on codes and delayed-egress locks:

IBC sections for Delayed Egress:

·        2021 – 1010.2.13

·        2018 – 1010.1.9.8

·        2015 – 1010.1.9.7

·        2012 – 1008.1.9.7

·        2009 – 1008.1.9.7

NFPA 101 sections for Delayed Egress Electrical Locking systems: 7.2.1.6.1

Sunday, December 2, 2018

Christmas trees placement within buildings

Christmas trees placement within buildings

We explain this through NFPA 1, Fire Code (2018 edition). 10.13 indicate Combustible Vegetation.

10.13.1 Combustible vegetation, including natural cut Christmas trees, shall be in accordance with Section 10.13.

10.13.1.1 Christmas tree placement within buildings shall comply with Table 10.13.1.1.

10.13.2 In any occupancy, limited quantities of combustible vegetation shall be permitted where the AHJ determines that adequate safeguards are provided based on the quantity and nature of the combustible vegetation.
10.13.3 Provisions for Fire Retardance for Artificial Vegetation.
10.13.3.1 Artificial vegetation and artificial Christmas trees shall be labeled or otherwise identified or certified by the manufacturer as being fire retardant.
10.13.3.2 Such fire retardance shall be demonstrated by each individual decorative vegetation item, including any decorative lighting, in an approved manner.
10.13.4 Vegetation and Christmas trees shall not obstruct corridors, exit ways, or other means of egress.
10.13.5 Only listed electrical lights and wiring shall be used on natural or artificial combustible vegetation, natural or artificial Christmas trees, and other similar decorations.
10.13.6 Electrical lights shall be prohibited on metal artificial trees.
10.13.7 Open flames such as from candles, lanterns, kerosene heaters, and gas-fired heaters shall not be located on or near combustible vegetation, Christmas trees, or other similar combustible materials.
10.13.8 Combustible vegetation and natural cut Christmas trees shall not be located near heating vents or other fixed or portable heating devices that could cause it to dry out prematurely or to be ignited.
10.13.9 Provisions for Natural Cut Trees.
10.13.9.1 Where a natural cut tree is permitted, the bottom end of the trunk shall be cut off with a straight fresh cut at least 1∕ 2 in. (13 mm) above the end prior to placing the tree in a stand to allow the tree to absorb water.
10.13.9.2 The tree shall be placed in a suitable stand with water.
10.13.9.3 The water level shall be maintained above the fresh cut and checked at least once daily.
10.13.9.4 The tree shall be removed from the building immediately upon evidence of dryness.
10.13.10 Exterior Vegetation.
10.13.10.1 Cut or uncut weeds, grass, vines, and other vegetation shall be removed when determined by the AHJ to be a fire hazard.
10.13.10.2 When the AHJ determines that total removal of growth is impractical due to size or environmental factors, approved fuel breaks shall be established.
10.13.10.3 Designated areas shall be cleared of combustible vegetation to establish the fuel breaks.



Sunday, February 25, 2018

Fire doors rating

Fire doors rating
Definition of a Fire Door - a door assembly, which is designed to hold back fire and smoke for a designated period and has been tested under conditions for door assemblies described in British Standard 476 Part 22; Fire Door Guidance -British Standard 8214-2008 (Code of Practice for Fire Door Assemblies).


Fire doors are made up of various components. The door itself is usually made from a solid timber frame, but they can sometimes be covered again in fire-resistant glass.

When I’m asked, “What is the required rating for a door in a particular wall?” nine times out of 10 my answer is, “It depends.” (This is the standard answer for nearly everything code-related.) In the Life Safety Code, required ratings for doors and other opening protective (e.g., windows) depend on the required hourly, fire-resistance rating of the barrier in which the opening is located and the function the barrier is serving.

Not all fire barriers are created equal. A door in an exit enclosure fire barrier will probably require a different rating than a door in a similarly rated corridor or hazardous area enclosure. Or a smoke barrier. Or a smoke partition. Or a shaft enclosure. (You get the idea.) At first glance it may seem convoluted, but the code does a good job of consolidating the opening protective rating requirements in one location. In the 2018 edition, you’ll find the required door rating in Table 8.3.3.2.2 (what I’ll refer to as “the table”). In the 2015 and earlier editions, the required ratings were located in Table 8.3.4.2. Prior to the 2003 edition, there was no handy consolidated table. If you’re using the 2000 or earlier edition, you’ll have to sort through a series of requirements and exceptions to determine the required door rating. (If you’re using the 2000 or earlier edition, you’re using a code that’s some 20 years out of date, and it might be time to join the rest of us in the 21st century. But I digress.)
To use the table, you’ll first need to establish the fire barrier’s purpose as required by the code. The table lists the purpose under the heading “Component.” Components include:
  • ·        Elevator hoistways
  • ·        Elevator lobbies
  • ·        Vertical shafts
  • ·        Horizontal exits
  • ·        Exit access corridors
  • ·        Other fire barriers
  • ·        Smoke barriers
  • ·        Smoke partitions

This is where the table has, at times, caused some confusion. Some have misinterpreted it as prescribing minimum fire-resistance ratings for various fire barriers. For example, the bottom row addresses smoke partitions. The second column specifies fire-resistance ratings for smoke partitions (half hour and one hour). Some have been led to believe that based on the table, all smoke partitions must have a minimum fire resistance rating of a half hour. This is not the case for smoke partitions or any of the other components listed in the table.
How can I find out more about an existing fire door?

Each fire door is labeled with a permanent label that must remain legible. Fire-rated frames may have a label or embossment from a listing agency. The door and frame labels contain a wealth of information, including the manufacturer, length of time the component is designed to resist fire, whether the opening is to be equipped with fire exit hardware, and whether the door carries a temperature rise rating or is a smoke door assembly.

Fire door labels usually include a number allowing manufacturers to access more information about the door’s original construction. Frame labels may state a fire resistance duration longer than that of the door. In this case, the assembly’s rating will be the lower of the two. Some hardware, such as fire exit hardware, will also be labeled, but the information on the label is typically less detailed.
The requirements for smoke partitions are located in Section 8.4; you’ll find no fire-resistance rating requirement there. Smoke partitions require a rating only where required by another section of the code. An example would be corridor walls in new, large, residential board-and-care occupancies, which require a half-hour rating (32.3.3.6.2). Once it’s determined that the smoke partition requires a fire-resistance rating, then refer to the table to determine the required fire-protection rating of any doors. In the case of a half-hour rated smoke partition, doors must have a one-third hour, or 20 minute, fire-protection rating. In short, use the table to determine the required opening protective rating when a barrier is required by another section of the code to have a fire-resistance rating.
Fire barriers having a one-hour rating might require one-hour doors, three-quarter-hour doors, or one-third-hour doors. Again, it depends on the barrier’s application. Fire barriers having a two-hour rating generally require one-and-a-half hour doors. Fire barriers with a rating exceeding two hours are rarely required by the code, except for a few occupancy separation fire barriers involving relatively hazardous occupancies.
I sometimes get the question, “Why does the code allow a 20-minute door in a one-hour barrier? Why not just require a one-hour door?” This would certainly make life easier when applying the code, but it also might require a more expensive door than is actually needed for life safety. Where the code requires 20-minute doors, it’s usually in a barrier that the committees primarily wanted to be smoke resistant. Before the days of smoke partitions, which first appeared in the 2000 edition, when a committee wanted a smoke resistant barrier (e.g., a corridor wall), it was simpler to mandate a one-hour barrier than to come up with criteria to evaluate smoke resistance. Since they really wanted a nominal degree of fire resistance, rather than mandating a substantial one-hour door, they were comfortable with a 20-minute door, which would inherently resist the passage of smoke.
Other reasons for the difference in fire barrier ratings and door ratings are the tests used to establish the ratings. You might have noticed I refer to the fire-resistance rating of a fire barrier, whereas a door has a fire-protection rating. Fire barrier assemblies are tested at a lab using a standard like ASTM E119, Standard Test Methods for Fire Tests of Building Construction and Materials, which yields a fire-resistance rating. Fire doors are tested using a standard like NFPA 252, Standard Methods of Fire Tests of Door Assemblies, which yields a fire-protection rating. Comparing the ratings from the different tests is not an apples-to-apples comparison. An hour’s worth of fire resistance (fire barrier) is not necessarily equivalent to an hour’s worth of fire protection (fire door).

And although it’s not a very scientific reason, this is the way the code has done it for many years and it seems to work. To this point, there has been no compelling reason to change the approach. If it’s not broken, there’s no need to fix it.


Remember Fire resisting glass can withstand exposure to the heat condition in a fire test for at least 60 minutes before it reaches a temperature high enough to soften it. This is mainly because, with clear FR glazing, nearly 50 per cent of the incident heat is transmitted through the glass by radiation.

Where can I find the code requirements for fire doors?

National Fire Protection Association (NFPA) 80, Standard for Fire Doors and Other Opening Protectives, is referenced by the International Building Code (IBC), International Fire Code (IFC), NFPA 101, Life Safety Code, and other codes and standards. NFPA 105, Standard for the Installation of Smoke Door Assemblies and Other Opening Protectives, addresses smoke doors and is also referenced in these publications.

Some fire door requirements are included within the applicable building or fire code, but NFPA 80 and 105 are referenced for many of the detailed requirements. For product-specific issues, the manufacturer’s listings must be referenced. For example, to find out the maximum fire door size available from a particular manufacturer,

The increased use of sprinklers has resulted in reduced requirements for temperature-rise doors. The 2012 IBC requires doors in interior exit stairways/ramps and exit passageways to have a maximum transmitted rise in temperature of 232 C (450 F) above ambient at the end of 30 minutes of exposure, but also includes an exception stating temperature-rise doors are not required in buildings equipped throughout with an automatic sprinkler system.

For the convenience of building occupants, how can fire doors be held open in a code-compliant manner?

Fire doors must be closed during a fire to compartmentalize the building and prevent the spread of smoke and flames. The intent is to protect the means of egress and allow building occupants time to evacuate safely. If fire doors are blocked or wedged open, they will not be able to do their job and protect the building and its occupants.


What is positive-latching, and is it required for all fire doors?

Hardware on fire door assemblies has to have an active latchbolt to prevent the pressure caused by a fire from pushing the door open and allowing smoke and flames to spread. A springlatch found in a standard lockset or latchset is considered an active latchbolt; some fire door configurations require a specific ‘latch throw’ (i.e. dimension of latch projection).

A deadbolt is not an active latchbolt, because it can be held retracted. An electromagnetic lock does not provide a positive latch, because there is no latching mechanism and the locking is accomplished when the electromagnet bonds to the steel armature. Electric strikes used on fire doors must be fail-secure—that is, when power is cut, the latch is securely captured behind the strike keeper. A fail-safe electric strike could allow the door to become unlatched, so such strikes may not be used on fire doors.
How is fire exit hardware different from panic hardware?

When panic hardware is used on fire doors, it must be fire exit hardware, which bears labels for both panic and fire resistance. A door with fire exit hardware will also have an additional label, indicating it is equipped with fire exit hardware. Fire exit hardware does not incorporate a mechanical dogging feature—the means to hold the latch retracted using a key, thumbturn, or Allen wrench. For fire doors where a ‘push/pull’ condition is desired, fire exit hardware with electric latch retraction may be used, as long as the latch projects automatically upon fire alarm, to secure the door.

Some vertical rod fire exit hardware for pairs of doors can be installed ‘less bottom rod’ (LBR). These devices use the top rod and latch only, with no bottom rod or latch. The advantage is there is no floor-mounted strike, and no bottom rod or latch to become damaged by carts or traffic. This configuration can sometimes cause a reduction in security, because it may be more easily defeated with only one latching point at the top of the door. In most cases, doors with LBR devices are required to have an auxiliary fire pin, which mounts in the edge of one door and projects into a hole in the edge of the other door if there is a fire.

Do fire doors need smoke gasketing? Are smoke doors also fire doors?

NFPA 80 and NFPA 105 do not specifically state fire doors and smoke doors require smoke gasketing. The key is to check the applicable code or standard, such as the International Building Code, for a limitation on air infiltration, typically a reference to UL 1784, Air Leakage Tests of Door Assemblies, as the test standard.


For fire doors and smoke doors in certain locations, the limit for air infiltration is 0.02 m3/(s • m2) or less as tested at a pressure of 0.02 kPa (3 cfm per square foot or less as tested at a pressure of 0.10 inch of water)—for most door sizes, this cannot be achieved without smoke gasketing. The requirements for smoke doors and fire doors depend on where they are used. For example, smoke barriers, smoke partitions, exit enclosures, and corridors all have varying requirements for smoke and fire resistance, and the applicable code sections must be consulted to see if a limit on air infiltration is established.

Thanks for reading, and as always, stay safe.