If you have designed a building of Type II, III, IV or V construction, you probably considered the allowable building area, which depends on the construction type, occupancy classifications, presence of fire sprinkler systems, and a few other criteria.
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One common way to increase the allowable area for a building is to use a frontage increase. The frontage increase provision in the IBC, found in Section 506.3, recognizes the safety benefits of having open space directly adjacent to a building. When a fire department or other emergency responders arrive to a site, there is an increased level of effectiveness when those personnel can access a large portion of the building exterior.

There is no requirement for a building to use the frontage increase provisions of IBC Section 506.3, but when used, the following requirements apply:

• A minimum of 25% of the building perimeter must be adjacent to a public way or open space
• To count as frontage, the open space must be either on the same lot or a dedicated public space. Open space on an adjacent lot does not count.
• The width of the open space must be at least 20 feet, measured at right angles from the building exterior wall to: (1) the closest interior lot line, (2) the entire width of the public way, or (3) the exterior face of a building on the same property.
• The open space must be accessed from a street or fire lane

The frontage calculation can be performed by hand, but I recommend the building frontage calculator. If you want to do the calculation on your own, here are the steps:

1. Determine the weighted average of the width of open space (W). 

This value, W, is determined by the following equation:

2. Determine the total building perimeter, P.
3. Solve IBC Equation 5-5 to determine the frontage increase factor. 

Using the frontage increase provisions of IBC 506.3 is a common way to increase the allowable area of a building. There is no requirement to use these provisions, but when you do, the requirement described above do apply.
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When working with architects, I frequently see code summary sheets with a frontage calculation for Type I buildings that have an unlimited allowable area. Since there is no requirement to take a frontage increase, I typically remind architects they don’t need to perform the frontage calculations if the building already has an unlimited allowable area. This saves time and also prevents possible permit review comments on a code provision that wasn’t needed in the first place.

​NFPA 285 is the “Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Wall Assemblies Containing Combustible Components.” How’s that for a title? Despite the lengthy name, the goal of the test is quite simple – to understand how fire will spread on an exterior wall. In this article, we’ll briefly review the history of NFPA 285, discuss the criteria for the rest, and then review when compliance with NFPA 285 is required in the IBC.

The NFPA 285 standard was first published in 1998 and is currently on it’s 4th edition, published in 2019. But the origins of NFPA 285 go all the way back to the 1970s, when foam plastic insulation became a popular choice for energy conservation in (or on) exterior walls. Based on work by the Society of Plastics Industry, the first test for flammability characteristics of an exterior wall was developed. This test was named UBC 17-6 and was first adopted by the Uniform Building Code (UBC) in 1988. This same test was later renamed as UBC 26-4 [1].

UBC 17-6/UBC 26-4 was a massive, full-scale test, consisting of a two-story exterior wall, totaling 24 feet in height (12 feet for each story). The test evaluated both vertical and lateral flame spread on nonload-bearing exterior walls containing foam plastics. Several wall assemblies containing foam plastics passed the test and, starting with the 1988 UBC, could be used as exterior wall assemblies in Type I, II, III and IV construction. A few years later, a modified test, using a smaller scale was adopted as UBC 26-9.
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10 years after the first adoption UBC 26-4, NFPA released the first edition of NFPA 285, entitled “Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Non-Load-Bearing Wall Assemblies Containing Combustible Components.” This version of NFPA 285, published in 1998, is the same as the UBC 26-9 test.
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Notice the difference in the name between the 1998 version of NFPA 285 and the 2019 version. The “nonload-bearing” restriction has been removed, now allowing load-bearing walls to be tested (although the standard itself does not require the application of a live load during testing).

The NFPA 285 testing criteria is nuanced, with variations based on the materials used in the wall assembly and the thickness of certain components in the wall assembly. For a full explanation of the acceptance criteria, review Section 10.2 of the 2019 edition of NFPA 285.

Generally, the acceptance criteria involves the following:

Flame propagation on the exterior face of the wall assembly

1. ­Vertical flame spread of less than 10 feet above the window opening in the test
2. Lateral flame spread of less than 5 feet from the centerline of the window opening
3. Temperature less than 1000 F at a point 10 feet above the window opening

Flame propagation through combustible components and insulation
Depending on the materials used in the exterior wall assembly, there are various temperature requirements that must be met. These include:

1. Limitations on temperature within exterior wall panels containing combustible components
2. Limitations on temperature within the air cavity between exterior wall panels and the wall itself

These temperature requirements apply both vertically and laterally and are measured by thermocouples placed above and to the side of the first story window opening.

Temperatures in the second story

1. The temperature in the second story room cannot rise more than 500 F above the temperature at the start of the test, measured 1-inch from the interior side of the wall assembly

Flame Propagation to second story

1. Flames cannot spread to the inside of the second story room

Flame propagation to adjacent horizontal spaces

1. Flames cannot spread horizontally beyond the side walls of the test

In the 2021 IBC, there are a number of triggers for NFPA 285 compliance. If you are using an earlier version of the code, the requirements are fairly similar, but refer to the corresponding sections in the applicable code edition for the specific details.
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Water Resistive Barriers (IBC 1402.5)
Exterior walls in buildings of Type I, II, III or IV construction that are greater than 40 feet above grade plane must comply with NFPA 285 if they contain a water-resistive barrier. There are two key exceptions:

1. If the water-resistive-barrier is the only combustible component in the exterior wall and the wall has a brick, concrete, stone, terra cotta, stucco or steel covering meeting the thickness requirements in IBC 1404.2.
2. If the water-resistive-barrier is the only combustible component and it:
   1. Has a peak heat release of less than 150 kW per square meter, a total heat release of less than 20 MJ per square meter and an effective heat of combustion of less than 18MJ/kg when tested per ASTM E1354 with an incident heat flux of 50 kW per square meter.
   2. Has a flame spread index of 25 or less and a smoke-developed index of 450 or less as determined by ASTM E84.

For this section, fenestration products, flashing of fenestration and water-resistive-barrier flashing are not considered to be part of the weather-resistive-barrier. If any of these materials are combustible, the exceptions above do not apply.

Metal Composite Materials (MCMs) (IBC 1406.10.3)
Exterior walls containing MCMs in buildings of Type I, II, III or IV construction that are greater than 40 feet above grade plane must comply with NFPA 285. Note that the 2021 IBC has removed several exceptions that existed in previous editions regarding the height of the MCM panels and the area of wall covered by the panels.

High-Pressure Laminates (HPLs) (IBC 1408.10.4)
Exterior walls containing HPLs in buildings of Type I, II, III or IV construction must comply with NFPA 285. There are two key exception for when HPLs are installed 40 feet or less above grade plane:

1. When the fire separation distance is 5 feet or less and the area of HPLs does not exceed 10% of the exterior wall surface area.
2. When the fire separation distance is greater than 5 feet. In this case, the area of HPLs is not limited.

Mechanical Equipment Screens (IBC 1511.6.2)
Compliance with NFPA 285 is one of three possible code paths for providing combustible mechanical equipment screens on the roof decks of buildings of Type I, II, III or IV construction.

Foam Plastic Insulation (IBC 2603.5.5)
Exterior walls containing foam plastic insulation in buildings of Type I, II, III or IV construction of any height must comply with NFPA 285. There are several exceptions:

1. One story buildings where the foam plastic has a flame spread index of 25 or less, smoke-developed index of not more than 450 and is covered by at least 0.032” of aluminum or 0.015” of corrosion-resistant steel and the building is fully sprinkler protected per NFPA 13. This exception only applies to foam plastic insulation with a thickness of 4” or less.
2. When the foam plastic insulation is covered on each face by minimum 1” of masonry or concrete and one of the following conditions is met:
   • No airspace between the insulation and concrete/masonry cover.
   • The insulation has a flame spread index of 25 or less per ASTM E84 and the maximum airspace between the insulation and concrete/masonry cover is 1”.

​Fireblocking (IBC 718.2.6, Exception 3)
Fireblocking is not required in exterior walls when the exterior wall covering complies with NFPA 285.

​Wall Assembly vs. Wall Components
NFPA 285 tests wall assemblies as a whole. Individual components of the wall are not considered, rather the entire exterior wall assembly is evaluated for compliance with the standard.

Deviation from NFPA 285 Assemblies
The use of Engineering Judgements (Ejs) for NFPA 285 compliance is a well-debated topic in the design industry. On one hand, it can be impractical to test an exterior wall assembly with every possible variation of material and component (remember that NFPA 285 is a full-scale test of a specific wall assembly). But on the other hand, it can be difficult to judge how variation from a tested assembly will impact performance.

While there are many exterior wall assemblies that have passed the NFPA 285 test, in my experience, many designers choose an assembly that has not been specifically tested. Many manufacturers of exterior wall products will obtain a testing report from ICC Engineering Services (an ICC ES Report, or something similar from another testing agency) that claims the product would pass NFPA 285 if tested. These reports, which essentially amount to a generalized EJ, are typically based on substituting one or more products into a wall assembly that has passed NFPA 285.

If the EJ route is chosen, the EJ should be provided by a qualified design professional, such as a licensed fire protection engineer with experience in the evaluation of exterior wall assemblies.

NFPA 285 vs. ASTM E119
NFPA 285 is different from ASTM E119, the test most commonly used to establish fire-resistance ratings for wall assemblies. This means that if your exterior wall is required to have a fire resistance rating, it also needs to have been tested per ASTM E119. Unfortunately, there are many walls that have a fire-resistance rating per ASTM E119 but do not pass NFPA 285. Similarly, there are walls that comply with NFPA 285 but may not be tested to ASTM E119.

This means that if your exterior wall is required to have a fire resistance rating and comply with NFPA 285, there are at least four potential code paths available:

1. Provide an exterior wall assembly that has been tested to ASTM E119 for the required fire-resistance rating and has also passed NFPA 285
2. Provide an exterior wall assembly that achieves the required fire-resistance rating using the prescriptive fire resistance method (IBC 721) or calculated fire resistance method (IBC 722) and has also passed NFPA 285.
3. Provide a wall that uses an IBC ESR report (or similar) to achieve compliance with one or both of the testing requirements.
4. Obtain an Engineering Judgement (EJ) to achieve compliance with one or both of the testing requirements.

Note that the acceptance of the last two items will vary by jurisdiction. In my experience, most AHJs are satisfied by an ICC ESR report, but the acceptance of EJs can vary greatly. See the section below for more on Ejs.

Finding NFPA 285 Wall Assemblies
To my knowledge, the best place to find wall assemblies that have been tested to NFPA 285 is the UL database. You can search “FWFO” in the UL directory to find the list, or checkout the database below of all UL-listed assemblies.

A mixed occupancy building is any building that contains two or more occupancy types as defined by the IBC. The code requirements for mixed occupancy buildings are found in IBC Section 508, Mixed Use and Occupancy. Nearly every building contains multiple uses, but fewer contain multiple occupancy types (remember, there is a difference between use and occupancy). Assuming your building does have two or more of the occupancy types found in IBC Chapter 3, you have three available approaches:

• Accessory
• Nonseparated
• Separated

Link: IBC Nonseparated Mixed Occupancy Height/Area Calculator
Link: IBC Separated Mixed Occupancy Height/Area Calcualtor

​​Note that these options are not exclusive, as the IBC specifically states that you can use a combination of these approaches in your building design. It’s common to use both the accessory and nonseparated approaches together to avoid providing a rated separation between occupancies.
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Building designers are also free to use any of these approaches, as there is no requirement stating one approach or the other must be used. I have talked with many building owners who believe they have to provide a rated separation between occupancy types (the separated occupancy approach). The code allows any of the mixed occupancy approaches to be used, so the only situation where a separated approach is required is when the design cannot comply with the other approaches.

​An accessory occupancy approach can be used when one of the occupancies in the building is ancillary to the main occupancy. A common example of an accessory occupancy approach is a conference room located within an office building. Another is an exercise room provided for residents of an apartment building.

In order to be considered an accessory occupancy, the aggregate area of accessory spaces must be less than 10% of the floor area of the story in which its located. The area of the accessory occupancy must also be less than the allowable area for that occupancy type found in IBC Table 506.2, using the nonsprinklered “NS” value.

The main advantage of using the accessory occupancy approach is that the allowable height, area and number of stories of the building is based on the main occupancy of the building. Using the example above, an office building that classifies the conference room as an accessory occupancy would only need to comply with the height/area requirements for a Group B occupancy, not Group A.

Accessory occupancies do not require a rated separation from the main occupancy, unless there are Group H, I-1, R-2, or R-3 occupancies present, in which case the special separation requirements forum in IBC Chapter 4 still apply.

By far, the most common misunderstanding of the accessory occupancy approach is that other code requirements beyond the allowable height/area can be ignored. Outside of the allowable height and area, all of the code requirements for the accessory occupancy still apply to that portion of the building. Continuing with the example above, if the conference room is a Group A-3 occupancy, even if it is considered accessory, all of the code requirements for Group A occupancies still apply to the conference room. So, the travel distance, common path of egress travel, and dead-end corridor lengths of this conference room would all need to comply with the requirements for Group A occupancies.
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Any fire protection requirements found in IBC Chapter 9 would also apply to the accessory occupancy. If IBC Chapter 903 requires a sprinkler system for the accessory occupancy, that would still apply, even if a sprinkler system was not required for the main occupancy.

In a nonseparated occupancy approach, there is no requirement for a fire rated separation between adjacent occupancies.

The key limitation to the nonseparated occupancy approach is the allowable height, area and number of stories are limited by the most restrictive requirements of the occupancies in the building. So, if one of the occupancies in the building is limited to two stories per IBC Table 504.4, the entire building is limited to two stories, even if the other occupancy types are permitted additional stories. Check out our calcualtor that quickly shows you the height/area requirements for this approach.

Similarly, the most restrictive fire protection requirements for the occupancies involved must be applied throughout the entire building (or nonseparated area). So, if a building has two occupancy types and one of them requires a voice fire alarm system, the system would need to be provided for the entire building.

If the building falls within the allowable height, area and number of stories for all the occupancy types involved, and you can meet the fire protection requirements of the most restrictive occupancy, a nonseparated approach is the easiest from a design standpoint. There is no requirement to provide a rated separation between nonseparated occupancies, unless there are Group H, I-1, R-2, or R-3 occupancies present, in which case the special separation requirements forum in IBC Chapter 4 still apply.
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Outside of the Chapter 9 fire protection requirements and height/area requirements, other code requirements are applied individually to each occupancy type in the building.

With a separated mixed occupancy approach, a fire rated separation is typically provided between adjacent occupancy types per IBC Table 508.4.

The main advantage to a separated occupancy approach is that the allowable height, area and number of stories for the building are applied individually to each occupancy. Going back to the previous example of a building where an occupancy is limited to two stories in height, the building could be taller, with other occupancies on the upper stories, as long as there is a rated separation between the second story and areas above.
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The allowable area is based on the sum of the ratios of the actual floor area for each occupancy divided buy the allowable floor area of that occupancy. The sum of these ratios cannot exceed one for any given floor and three for the entire building (assuming an NFPA 13 sprinkler system). This approach typically allows for a larger total building area than the other mixed occupancy approaches (check out the calculator for this if you need further assistance).

Other code requirements, such as egress or fire protection requirements are applied individually to each occupancy. If the separated approach is being taken in conjunction with one of the other approaches (accessory or nonseparated), the most restrictive fire protection requirements from Chapter 9 are applied to the total nonseparated occupancy area.
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A common point of confusion is that in some cases, the separated occupancy approach can be taken without providing a rated separation between occupancies. IBC Table 508.4 shows that occupancy types of similar hazard level have a required separation level of “N,” meaning there is no separation requirement. For example, a building containing both Group B and M occupancies could take the separated occupancy approach but not actually provide any rated separation between the occupancies. This is a little confusing to understand, but essentially, the code views certain occupancies as similar hazard levels and allows these areas to be continuous to one another without a rated separation.

The IBC offers three approaches to mixed occupancy buildings: accessory, nonseparated and separated. One or more of these approaches must be used in any building containing two or more occupancies. The IBC does not require any of these approaches specifically, rather a designer can choose from any of the three approaches that best suit the design goals.

In almost every building, owners or tenants have a need for some level of security or access control. The IBC covers a wide range of door locking and control techniques, but the shear number of sections and underlying requirements can be tough to digest. Many folks have trouble knowing which code sections apply, and even if the correct section is identified, it can be a challenge to understand the requirements.

In this post, I take a number of these door locking requirements and translate them into (hopefully) more clear and concise language. I also provide some general commentary on my experience in using each type of door/locking arrangement. References are provided to the last 3 editions of the IBC.

Click one of the door/lock types in table below to jump to that section.

Many designers don't realize that a revolving door can be used in an egress path, as long as certain requirements are met.

All revolving doors must meet the following requirements, but be sure to check out the paragraph below this one for additional requirements for egress/non-egress doors.

1. Comply with BHMA A156.27 and the manufacturer's instructions.
2. Each revolving door must have "breakout" capability per BHMA A156.27 and have an aggregate width of at least 36 inches.
3. A revolving door must be at least 10 feet from the top or bottom of stairs and escalators. A dispersal area must be provided between the stair/escalator and the revolving doors.
4. The revolving door speed (in RPMs) cannot exceed the maximum rpm as specified in BHMA A156.27. Manual revolving doors must comply with Table 1010.1.4.1(1). Automatic or power-operated revolving doors shall comply with Table 1010.1.4.1(2).
5. An emergency stop switch is required near each entry point of power or automatic operated revolving doors within 48 inches of the door and between 24 inches and 48 inches above the floor. The activation area of the emergency stop switch button must be at least 1 inch in diameter and red in color.
6. Each revolving door must have a side-hinged swinging door that complies with IBC 1010.1 in the same wall and within 10 feet of the revolving door.
7. Revolving doors cannot be part of a required accessible route.

Revolving Doors in Egress Components must meet the following requirements:

1. Count towards no more than 50% or required egress width or capacity.
2. Each door counts towards a maximum of 50 occupants when performing egress calculations.
3. Maximum breakout force of 130 pounds.

Revolving doors that are not egress components must have a breakout force of 180 pounds or less. A breakout force of more than 180 pounds is permitted if the breakout force reduces to 130 pounds or less under one of the following conditions:

1. Door power failure
2. Sprinkler system activation
3. Smoke detector activation with 75 feet of the revolving doors
4. Activation of a manual control switch in a clearly identified location

Power operated doors are common in building entrances, as well as in occupancies where people may struggle to open a door by themselves, such as a Group I-2 nursing home.

Any egress door that is operated or assisted by power must have the capability to be manually opened or closed. The forces required to open the doors must comply with IBC 1010.1.3 door opening force requirements, except the force to set the door in motion must not exceed 50 pounds. The door must have the capability to open from any position to the full width of the opening when a force is applied on the egress side.

Power-operated swinging doors, power-operated sliding doors and power-operated folding doors must comply with BHMA A156.10. Power-assisted swinging doors and low-energy power-operated swinging doors must comply with BHMA A156.19. (2018 and Beyond): Low-energy power-operated sliding doors and low-energy power-operated folding doors must comply with BHMA A156.38.

Exceptions to the above requirements:

1. Group I-2 occupancies
2. Special purpose horizontal sliding, accordion or folding doors (see related section in this article)
3. For a biparting door in the emergency breakout mode, a door leaf located within a multiple-leaf opening is exempt from the minimum 32-inch single-leaf requirement, provided that a minimum 32-inch clear opening is provided when the two biparting leaves meeting in the center are broken out.

Special purpose doors, such as horizontal sliding doors, are most commonly used in situations where a fire door is needed in an egress path but there is a desire to have the door normally open, or perhaps concealed. A sliding or folding fire shutter would fall into this category. These are the only type of doors in this article that specifically require an integrated standby power supply, typically provided as a battery pack above the door.

Horizontal sliding, accordion or folding doors can be used in all occupancies except Group H when allowed by Exception 6 of IBC 1010.1.2. Use of these doors requires the following:

1. The doors are power operated and are capable of being operated manually in the event of power failure.
2. The doors are openable by a simple method from both sides without special knowledge or effort.
3. The force required to operate the door cannot exceed 30 pounds to set the door in motion and 15 pounds to close the door or open it to the minimum required width.
4. The door must be openable with a maximum force of 15 pounds when a force of 250 pounds  is applied perpendicular to the door adjacent to the operating device.
5. The door assembly must comply with the applicable fire protection rating and, where rated, must be:
   1. Self-closing or automatic closing by smoke detection in accordance with IBC 716.2.6.6.
   2. Installed in accordance with NFPA 80.
   3. Comply with IBC 716.
6. The door assembly must have an integrated standby power supply.
7. The door assembly power supply must be electrically supervised.
8. The door must open to the minimum required width within 10 seconds of the operating device.

Locking of egress doors in educational occupancies has been a hotly-debated topic in recent code cycles. Some argue that being able to lock a classroom door from the inside is necessary to protect occupants during certain emergency situations. Others argue that this actually poses a greater risk to occupants inside the classroom. The requirements for such locking arrangements are provided below.

In Group E occupancies, Group B educational occupancies and (2021 only) Group I-4 occupancies, egress doors from classrooms, offices and other occupied rooms with locking arrangements designed to keep intruders from entering the room are permitted with the following requirements:

1. The door is capable of being unlocked from outside the room with a key or other approved method. Remote door unlocking is permitted in addition to the key.
2. The door is openable from within the room per IBC 1010.2
3. Modification are not permitted to listed panic hardware, fire door hardware or closers.
4. (2021 only) Modifications to fire doors assemblies must be in accordance with NFPA 80.

Secutiry grilles are an important part of building security systems, particularly in retail spaces such as a shopping mall. The IBC allows security grilles in Group M occupancies, as well as Groups B, F and S.

In Groups B, F, M and S, horizontal sliding or vertical security grilles are permitted at the main exit and must be openable from the inside without the use of a key, special knowledge or effort when the space is occupied. The grilles must remain secured in the full-open position anytime the space is occupied by the general public. Where two or more means of egress are required, no more than half of the exits or exit access doorways can be equipped with security grilles.

Group I-1 and I-2 occupancies include assisted living facilities, nursing homes, hospitals, psychiatric treatment centers, all facilities where people receiving care may​ require some level of containment. There are many situations where allowing a care recipient to freely exit may actually endanger that person or others. The IBC recognizes this risk and provides an avenue to provide locking control on egress doors in such occupancies.

Electric locking systems are permitted in Group I-1 and I-2 occupancies where the clinical needs of the care recipient require their containment. In order to use this code provision, the building must be either fully sprinkler-protected or equipped throughout with smoke detectors and meet all of the following requirements:

1. The door must unlock upon actuation of the sprinkler or smoke detection system.
2. The door must unlock upon power loss.
3. The door must have an unlocking switch, located at the fire command center, nursing station or other approved location, that directly breaks power to the lock.
4. No more than one controlled egress door before reaching an exit
5. Door unlocking procures must be included and approved in the required Fire Code emergency planning (see IFC Chapter 4).
6. All clinical staff must have a key or other means to operate the locked door
7. Emergency lighting is required at the door.
8. The door locking system must be UL 294 listed.

Exceptions: Items 1-4 above do not apply to the following situations:

1. Areas where persons require restraint or containment as part of the function of a psychiatric treatment area or (2021 only) cognitive treatment area.
2. Where a listed egress control system is used to reduce child abduction risk from nursery and obstetric area of a Group I-2 hospital.

Using a delayed egress system is one of the most common approaches to achieve some level of access control on an egress door. They provide a deterrent to occupants using the door unless there is a true need (e.g. a fire emergency), but still allow for full egress use after the delay period. A key limitation of delayed egress systems is they are limited by occupancy , for example, Group A spaces cannot use delayed egress systems, regardless of the occupant load.

Where permitted:

2015:
Delayed egress locking systems are permitted in any occupancy except Groups A, E or H when the building is fully sprinkler protected per NFPA 13 or provided with smoke/heat detection throughout.

2018 and Beyond:
Delayed egress locking systems are permitted in the following situations when the building is fully sprinkler protected per NFPA 13 or provided with smoke/heat detection throughout.

1. Group B, F, I, M, R, S and U
2. Group E classrooms with an occupant load less than 50
3. In courtrooms, on other than the main exit doors, when the building is fully sprinkler protected per NFPA 13.

The delayed egress locking system must meet all of the following requirements:

1. The delay electronics must allow immediate and free egress upon actuation of the sprinkler system or fire detection system.
2. The delay electronics must allow immediate and free egress upon power loss.
3. The delay electronics must have the capability to be deactivated from the fire command center or other approved location.
4. When an effort is applied to the egress door hardware for not more than 3 seconds, an irreversible process must star that allows for the egress door to open in 15 seconds or less. The irreversible process must activate an audible signal near the door. Once the delayed egress door has been deactivated, the door can only be rearmed by manual means.
   1. Exception: Where approved by the AHJ, a delay of not more than 30 seconds is permitted.
5. The egress path cannot pass through more than one delayed egress locking system.
   1. 2015 Exception: In Groups I-2 or I-3, the egress path can pass through up to two delayed egress locking systems if the combined delay is 30 seconds or less.
   2. 2018 Exception: In Groups I-2 or I-3, the egress path can pass through up to two delayed egress locking systems if the combined delay is 30 seconds or less. In Groups I-1 or I-4, the egress path can pass through up to two delayed egress locking systems if the combined delay is 30 seconds or less and the building is fully sprinkler protected per NFPA 13.
   3. 2021 Exception: In Groups I-1 Condition 2, I-2 or I-3, the egress path can pass through up to two delayed egress locking systems if the combined delay is 30 seconds or less. In Groups I-1 Condition 1 or I-4, the egress path can pass through up to two delayed egress locking systems if the combined delay is 30 seconds or less and the building is fully sprinkler protected per NFPA 13.
6. A sign must be provided on the door and located above and within 12 inches of the door exit hardware:
   1. For doors swinging in direction of egress, the sign must read “PUSH UNTIL ALARM SOUNDS. DOOR CAN BE OPENED IN 15 [30] SECONDS.”
   2. For doors swinging in against the direction of egress, the sign must read “PULL UNTIL ALARM SOUNDS. DOOR CAN BE OPENED IN 15 [30] SECONDS.”
   3. The sign must comply with the visual character requirements in ICC A117.1.
   4. Exception: Where approved in Group I occupancies, the sign is not required where care recipients have a clinical needs requiring restraint or containment as part of the function of the treatment area.
7. Emergency lighting must be provided on the egress side of the door.
8. The delayed egress systems must be UL 294 listed.

Electrically locked doors using a sensor release are frequently used in situations where it is helpful to have an egress door unlock prior to an occupant physically reaching the door. Note that this type of door release functionality can be used in conjunction with an electromagnetic locking mechanism (Mag Lock).

Where Permitted:

2015:
Sensor release locks are permitted on any egress door in Groups A, B, E, I-1, I-2, I-4, M, R-1 or R-2 occupancy.

​2018 and Beyond:
Sensor release locks are permitted on any egress door except in Group H occupancies.

Sensor release locks must be installed and operated per the following requirements:

1. Sensor installed on egress side of door to detect an occupant approaching the door and cause the electric lock system to unlock.
2. Door unlocks upon loss of power or signal to the sensor.
3. Door unlocks upon loss of power to the lock or locking system.
4. Doors can be unlocked from a manual device located 40” to 48” above the floor and with 5 feet of the doors. The unlocking device must be readily accessible and be clearly identified with a “PUSH TO EXIT” sign. The unlocking device must directly interrupt power to the lock independent of other electronics and keep the door unlocked for at least 30 seconds.
5. Door unlocks upon activation of the building fire alarm system and remain unlocked until fire alarm system is reset.
6. Door unlocks upon activation of the sprinkler system or fire detection system and remain unlocked until the fire alarm is reset.
7. Door lock system must be UL 294 listed.
8. (2021 Only) Emergency lighting must be provided on the egress side of the door.

Electromagnetically locked egress doors, commonly referred to as “Mag Locks” are permitted in Group A, B, E, I-1, I-2, M, R-1 and R-2 occupancies. Use of such locks requires a built-in switch on the door and compliance with the following:

1. Hardware is affixed directly to the door leaf and has an obvious method of operation under all lighting conditions.
2. Hardware can be operated with one hand.
3. Operating the door hardware immediately interrupts power to the Mag Lock and unlocks the door immediately.
4. Door unlocks upon lows of power to the locking system.
5. Where panic or fire exit hardware is required, operation of that hardware also releases the Mag Lock.
6. Lock system must be UL 294 listed.

Starting in 2018, the Mag Lock section above was expanded to any electric locking system with a door hardware release. The requirements here are essentially the same as the Mag lock requirements from 2015.

Door hardware release of electric locking systems on egress doors is permitted in all occupancies except Group H and requires compliances with the following:

1. Hardware is affixed directly to the door leaf and has an obvious method of operation under all lighting conditions.
2. Hardware can be operated with one hand and meets IBC unlatching requirements.
3. Operating the door hardware immediately interrupts power to the lock and unlocks the door immediately.
4. Door unlocks upon lows of power to the locking system.
5. Where panic or fire exit hardware is required, operation of that hardware also releases the lock.
6. Lock system must be UL 294 listed.

Correctional and detention facilities are permitted to have locked egress doors when occupants are required to have controlled movements for security purposes. Such doors must have an egress control devices that unlocks the door manually and by at least one of the following means:

1. Activation of the building sprinkler system
2. Actvaition of a manual fire alarm pull station
3. A signal from a constantly attended location.

In the 2015 IBC, use of this provision is limited to Groups A-2, A-3, A-4, B, E, F, I-2, I-3, M and S occupancies within correctional and detention facilities. In 2018 and beyond, use of this section is permitted in any building within a correctional and detention facility.

Generally, interior stair doors must be openable from both sides without the use of a key or special knowledge, though the following exceptions allow you to lock the stair door:

1. Stair discharge doors can be locked from the outside (must be unlocked in direction leaving the stair).
2. Stair doors in high rise buildings complying with IBC 403.5.3 (see section below).
3. (2015 Only): In stairs serving 4 stories or fewer, stair doors can be locked from the inside provide they have the capability of being simultaneously unlocked (without unlatching) by a signal from the fire command center or location inside the main entrance of the building.
4. (2018 and Beyond): Stair doors can be locked from the inside provide they have the capability of being simultaneously unlocked (without unlatching) by a signal from the fire command center or location inside the main entrance of the building.
5. Stair doors in Group B, F, M and S occupancies where the only interior access to a tenant space is from the exit stair can be locked from the inside of the stair (must be unlocked in direction of egress).
6. Stair doors in Group R-2 dwelling units where the only interior access to the unit is from the exit stair can be locked from the inside of the stair (must be unlocked in direction of egress).

In high rise buildings, stairway doors can be unlocked from the stairway side provided they have the capability of being unlocked (without unlatching) by a signal from the fire command center. when this provision is used, a telephone or other two-way communication system connected to a constantly attended location is required on every fifth floor in every stairway with locked doors.

Panice and fire exit hardware itself does not involve locking a door. Rather, panic or fire exit hardware can be used in conjunction with one of the locking arrangement described in this article. 

In the A/E world, there is much confusion regarding the definition of fire protection rating and fire resistance rating when designing doors, windows, transoms, sidelights and other openings in rated construction. These terms are often used interchangeably by mistake, but they represent two very different types of assemblies. A third term, "fire rating", is often used as well, making the distinction even more confusing. In this article, we'll review the differences between fire resistance ratings and fire protection ratings and show you how to determine the requirements for your specific situation. All code references are to the 2018 IBC.

Before distinguishing between fire-resistance-rated assemblies and fire-protection-rated assemblies, it's important to note that both of these are types of fire-rated assemblies. So if someone refers to a fire-rated glazing assembly, they could be potentially referring to either a fire-resistance-rated assembly or a fire-protection-rated assembly. The majority of the requirements for either type of assembly come from IBC Table 716.1(2).

Fire-resistance-rated assemblies are those that have been tested to ASTM E119 or UL 263. This is the same test that is used for rated wall, floor and ceiling assemblies. Therefore, if you have a door, window, shutter or any other type of openings protective that is tested to ASTM E119 or UL 263, it is treated no differently than a rated wall or floor. There are no limitations to the area or location where you can provide such opening protectives. 

Functionally, these tests measure an opening protective's ability to stop the transmission of smoke/flames AND to limit the transmission of radiant heat. In order to pass ASTM E119 or UL 263, assemblies must limit the temperature rise on the non-fire side of wall/floor to 250 degrees or less.

Any fire-rated glazing assembly, whether a fire-resistance-rated assembly or fire-protection-rated assembly, is required to be labelled per IBC 716.1.2.2.  The markings for these assemblies are shown in IBC Table 716.1(1) and replicated in the table provided below. For fire-resistance-rated glazing, you are looking for markings containing either a "W" or "F". If the marking does not contain either of these letters, the assembly is not fire-resistance-rated. Fire doors are required to be labelled per the requirements of NFPA 80.​

Fire Doors
In interior fire doors that require a 1-hour rating or greater, fire-protection-rated glazing is permitted in the door vision panel up to 100 square inches. The glazing in the door vision panel is required to pass the hose stream test and bear the "D" and "H" markings. The duration (in hours) of the required rating depends on the type and rating of the wall itself - specific requirements are provided in IBC Table 716.1(2). If a vision panel greater than 100 square inches in area is desired, the vision panel must be fire-resistance-rated glazing and bear the "W" marking. Additionally, vision panels exceeding this area in exit stairways, ramps and passageways must meet the maximum temperature rise criteria of 450 degrees after 30 minutes and bear the "T" marking. There is an exception for this temperature rise criteria if the building is fully-sprinkler protected in accordance with NFPA 13 or 13R. Finally, sidelights and transoms adjacent to fire doors that require a 1 hour rating or greater are required to have a fire-resistance-rating equal to that of the wall itself; fire-protection-rated glazing is not permitted in these.

If the fire door requires a 45 minute rating or less, fire-protection-rated glazing is permitted in the door vision panel up to the maximum size tested. There is no requirement for fire-resistance-rated glazing in such doors. Sidelights and transoms adjacent to these doors are required to have a fire protection rating of either 20 or 45 minutes depending on the location. Refer to IBC Table 716.1(2) for the specific requirements.

Fire doors in rated exterior walls have slightly different requirements. If the exterior wall has a rating greater than 2 hours, the fire door is required to have at least a 90-minute rating and a fire-protection-rated vision panel is permitted up to 100 square inches in area. Any sidelights and transoms are required to have a fire-resistance-rating the same as the wall itself.

Exterior walls rated 2 hours or less are permitted to have fire-protection-rated glazing in the door vision panel, sidelight and transom. The rating requirement for these elements is the same as the door itself.

Fire Windows
Fire-protection-rated glazing is permitted in certain fire windows in interior wall assemblies, up to a maximum rating of 45 minutes. Fire windows in fire walls and fire barriers (excluding atrium separation, incidental use separations and occupancy separations) are required to have fire-resistance rated glazing. Refer to the table below, based on requirements form IBC Table 716.1(3). Note that walls allowing fire-protection-rated glazing can be provided with fire-resistance-rated glazing as indicated, but this is not required.

*except those noted in the next row
​
Fire-protection-rated glazing is permitted in all fire windows in exterior walls, as described in the table below. IBC Table 705.8 provides requirements for opening protectives in exterior walls, so be sure to refer there as well. Depending on the fire separation distance, you may be permitted to have unprotected openings in a rated exterior walls. Conversely, if the fire separation distance is less than 3 feet, you are not permitted to have any openings in the exterior wall, even if they have a fire protection rating. Fire-resistance-rated glazing is always permitted since it must meet the same test criteria as the wall itself.

There are two types of fire-rated openings protectives: fire-resistance-rated and fire-protection-rated assemblies. Fire-resistance-rated assemblies have to meet the same test criteria, ASTM E119 or UL 263, as a rated wall or floor assembly. Since the test is the same, there are no size or location limits for where you can provide fire-resistance-rated protectives. Fire-protection-rated assemblies are tested to lesser criteria and are limited in size and location. Full requirements for both types of assemblies are found in IBC Table 716.1(2).

If you have been involved in the design or installation of a fire alarm system, whether as an architect, engineer, or owner, you have probably asked the question, "Is a strobe required here?" Like all engineering questions, the answer depends on a number of factors. In this post, I will walk through the code path step-by-step to help you understand where fire alarm strobes are required.

The starting point for determining strobes requirements is the applicable building code for your jurisdiction. If you are in the United States, this is most likely based on the International Building Code (IBC). For projects located elsewhere, this could be NFPA 5000. Buildings owned or operated by the government could also be subject to other requirements, such as the GSA PBS-P100 or UFC 3-600-01. You may also be in a jurisdiction that enforces NFPA 101, which also has requirements for fire alarm systems.

Assuming the applicable code is the IBC (all references here are to the 2018 IBC), your first step is to check Section 907.2 to determine if a fire alarm system is required for your building. This section requires a fire alarm system based on occupancy type and other building criteria, such as classification as a high-rise building. In some instances, 907.2 requires a manual fire alarm system (pull stations) and in others a smoke detection system. For the purposes of this article though, the main concern is whether any type of fire alarm system is required at all. That's because, according to IBC 907.2, if a fire alarm system is required by Sections 907.2.1 through 907.2.23, occupant notification is required.

Fire alarm equipment required outside of Section 907.2 such as duct smoke detectors or elevator emergency operations would not trigger a requirement for strobes.

In addition to the occupancy requirements above, IBC 907 provides requirements for specific building situations.

Once you have determined that a fire alarm system is required, you'll want to flip ahead a few pages to determine which rooms require strobes. The starting point is IBC 907.5.2.3:

Public Uses Areas and Common Use Areas
Strobes are required in public and common use areas, with the exception of employee work areas, which are permitted to be provided with spare circuit capacity to account for future addition of strobes if needed for hearing-impaired employees. Public use and common use are defined terms in the IBC:

Common Use: Interior or exterior circulation paths, rooms, spaces or elements that are not for public use and are made available for the shared use of two or more people.

Public Use Areas:  Interior or exterior rooms or spaces that are made available to the general public.

Examples of spaces that fall under one of these categories are: lobbies, corridors, circulation areas, meeting rooms, conference rooms, assembly areas, public or shared restrooms, retail spaces, and classroom. This is by no means an exhaustive list, so you'll need to consider each space in your building to verify if it falls under the definition of public use or common use.

Groups I-1 and R-1
Strobes are required in a certain percentage of dwelling and sleeping units in Group I-1 and R-2 occupancies. Refer to the table below, replicated from IBC Table 907.5.2.3.2.

Group R-2
Group R-2 occupancies requiring a fire alarm system must have the capability to support strobes appliances in the future. The intent is that the fire alarm system has the capability to be modified if a hearing impaired occupant were to  move into the sleeping or dwelling unit.

The final step is to review other documents that could drive strobe requirements. One common question is whether or not ADA Accessibility Guidelines (ADAAG) or NFPA 72 require strobes in certain rooms. Neither of these documents actually require a fire alarm system or strobes to be installed at all. When a fire alarm system is provided, however, ADAAG brings in requirements for where visible notification is required. Similarly, NFPA is only applicable when the IBC or other applicable codes require a fire alarm system.

Assuming you are required to provide a fire alarm system, the requirements of NFPA 72 would apply (ADAAG would also apply, assuming your building is required to comply with the Americans with Disabilities Act (ADA), which is a longer discussion for another article). In most cases, if you provide a fire alarm system and a strobe layout that complies with the IBC and NFPA 72, you will meet the requirements of ADAAG.

The general process for determine strobe requirements is:

1. Determine if a fire alarm system is required for your occupancy and/or specific building situation in the applicable codes.
2. If a fire alarm system is required, determine if visible notification (strobes) are required. The most common drivers are:
   1. Public use and common use areas
   2. Group I-1 and R-1 sleeping/dwelling units
3. Check other requirements. These could be additional local codes/standards, particularly amendments or additional requirements to NFPA 72 or ADAAG.

New on the blog today is an occupant load calculator based on factors from the 2015, 2018 and 2021 editions of the IBC. Check it out at the link below!

This week, the ICC Committee Action Hearings (CAH) kicked off, where proposed code changes for the 2024 ICC Codes are heard by the various ICC committees. In yestereday's session, the IBC General committee heard several proposed changes related to occupied roofs and the classification of high-rise buildings. In recent code cycles, there have been several key changes to occupied roof requirements, but none of these have addressed whether an occupied roof over 75' would trigger classification of a high-rise building.

As a quick reminder, the 2021 IBC currently defines a high-rise building as "A building with an occupied floor located more than 75 feet above the lowest level of fire department vehicle access."

While previous code editions have remained silent on the issue, the ICC website does have two articles addressing high rise classification due to an occupied roof.

This article, authored by ICC staff member Chris Reeves, clearly states that an occupied roof is not intended to count as a floor for the purposes of evaluating the high-rise building definition. Another article, authored by ICC staff member Kimberly Paarlberg, states "What has not yet been clarified is if an occupied roof is considered an occupied floor when determining if the building does or does not have to meet the high-rise provisions in the code..."

While the two articles above are both informal opinions from ICC staff, it appears the 2024 IBC will now address this issue directly. During today's hearing, the IBC General Committee voted in favor of proposal G15-21, which is copied below:

Revise as follows:
[BG] HIGH-RISE BUILDING. A building with an occupied floor or occupied roof located more than 75 feet (22 860 mm) above the lowest level of fire department vehicle access.

This proposed change to the definition of a high-rise building would require any building with an occupied roof above 75' to meet all of the high-rise building requirements.  Several proposals, including G12-21 and G14-21, were aimed the other way, attempting to clarify that an occupied roof would not trigger a high-rise classification. Both of these were disapproved by the committee.

When a building is classified as a high-rise, there are numerous additional requirements, including:

• Hard Body Impact requirements for stairway and hoistway walls in Risk Category III and IV buildings (IBC 403.2.3)
• Minimum SFRM bond strength of 430 psf (up to 1,000 psf for buildings higher than 420') (IBC 403.2.4)
• Voice fire alarm system (IBC 403.4.4)
• Fire command center (IBC 403.4.6)
• Smoke removal (IBC 406.4.7)
• Additional standby and emergency power requirements (403.4.8)
• Smokeproof enclosures (most commonly stair pressurization) for exit stairways (IBC 403.5.4)

Do you agree with the General Committee on this issue? Should an occupied roof above 75' trigger the classification as a high rise building? Please share your thoughts in the comments section!

If you disagree with this viewpoint, there is still time to have your opinion heard before the change is codified. The ICC code development process includes a public comment period, which will be open between May 24 and July 2. Any one is free to submit a comment on this issue or any other proposed changes moved forward by ICC committees. The ICC Public Comment Hearings (PCH) will take place between September 22-29 in Pittsburgh (also open to the public).