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!

The 2021 IBC includes several changes that impact Group I-2 occupancies. These changes build upon updates from 2018 edition and continue with the sub-grouping of occupancies into either Condition 1 or 2 that started in the 2015 edition. As a quick reminder, IBC 308.3 defines these as:

Group I-2, Condition 1: "facilities that provide nursing and medical care but do not provide emergency care, surgery, obstetrics or in-patient stabilization units for psychiatric or detoxification, including but not limited to nursing homes and foster care facilities."

Group I-2, Condition 2: "facilities that provide nursing and medical care and could provide emergency care, surgery, obstetrics or in-patient stabilization units for psychiatric or detoxification, including but not limited to hospitals."

The 2021 IBC provides two changes related to corridors doors in Group I-2 occupancies.

First, Section 407.3.1.1 has been added for corridor doors that are not required to have a fire protection rating. Generally, Group I-2 corridor walls are not required to have a fire-resistance rating unless they are part of an enclosure for an exit or vertical opening, or if they are separating an incidental use room that requires a rating per IBC 509.4.

This new section now addresses the following:

• Solid doors, which are now specifically required to have close fitting operational tolerances, head and jamb stops
• Dutch-style doors, which are now specifically allow, but must have the following features:
  • An astragal, rabbit or bevel at the meeting edge of the upper and lower sections
  • Latching hardware on both the upper and lower sections
  • Hardware that connects the upper and lower sections, allowing them to function as a single leaf
• Makeup air: when used to provide makeup air for exhaust systems (per Section 1020.6 Exception 1), doors are now specifically permitted to have either louvers OR up a 2/3" bottom gap

​Second, Section 407.6.1 has been added for automatic-closing doors on hold-opens. Previously, these doors were only required to close upon actuation of a smoke detector or loss of power to the hold-open or smoke detector. Now, these doors must also close upon activation of the fire alarm system or sprinkler system.

Section 407.4.4.3 has been revised and no longer considers the number of doors or care suites in the path of exit access. Previously, this code section limited exit access to not require passage through more than three doors before reaching the corridor. Now, the code does not provide a maximum number of doors and simply limits care suites to no more than 100' of travel to reach a corridor. When a care suite requires two exit access doors, the second exit access door must lead directly to a corridor, exit or adjacent care suite.

The 2021 IBC makes an organizational change to requirements for nursing home cooking facilities, moving the requirements for the cooking appliances into a separate section. This builds upon a change in the 2018 edition, which provided specific provisions to allow cooking facilities to be open to the corridor in Group I-2, Condition 1 occupancies.

Under the 2021 IBC, these requirements are now organized as follows:

Nursing Home Cooking Facilities (407.2.6): In Group I-2, Condition 1 occupancies, spaces containing a cooking facility with a domestic cooking appliance are permitted to be open to the corridor when all of the following criteria are met:

• No more than 30 care recipients in the smoke compartment containing the cooking facility (or served by the facility)
• No more than one cooking facility per smoke compartment
• A clearly delineated corridor space is provided
• The cooking facility can not obstruct access to the exit
• The cooking appliance must comply with 407.2.7

Domestic Cooking Appliances (407.2.7): In Group I-2 occupancies, cooking appliances in domestic cooking facilities must comply with the following:

• Appliances limited to ovens, cooktops, ranges, warmers and microwaves
• Domestic cooking hood installed in accordance with IMC 505 provided over cooktops and ranges
• Cooktops and ranges protected with Section 904.14.1, which requires either a fire extinguishing system in the hood OR a burner that is listed to prevent ignition of cooking oils. While the code does not give a specific standard for the listing, any appliances listed to the new Section 60A in UL 858 would meet this criteria. In the US, electric burners sold after April 2019 are required to meet this criteria.
  • This requirement does not apply for cooktops and ranges used for care recipient training or nutritional counseling purposes
• A fuel/electrical power shutoff for the cooking equipment is provided in a staff-only area
• A timer is provided that automatically deactivates the equipment in 120 minutes or less
• A fire extinguisher is provided within 30 feet of each domestic cooking appliance

The 2021 IBC includes several changes related to Group I-2 occupancies. These changes build upon provisions enacted during past cycles and include changes to corridor doors, care suite arrangement and nursing home cooking facility requirements.

As more and more states move to adopt the 2018 IBC, it's important to know about a few code updates that impact the design of occupied roof spaces. And if you're jurisdiction is on the ball and already adopted the 2021 IBC, there are a few additional items that apply to you.

In the 2015 IBC and prior editions, the code remained silent in regards to occupied roof decks and requirements for allowable height and area.  Under the 2018 IBC, there are now specific provisions addressing this issue.

First, IBC 302.1 has been updated with specific requirements for classifying an occupied roof space:

This section limits the occupancy on an occupied roof to those allowed on the story immediately below the roof. So if your building construction type allows an assembly occupancy on the top story, you are also permitted an assembly occupancy on the roof. The code does offer two major exceptions:

1. If your building if fully sprinkler-protected (NFPA or 13R) and you have fire alarm notification on the occupied roof, you are permitted to have any occupancy on the occupied roof.
2. If your building is Type I or II construction, you are permitted to have assembly occupancies on the roof of parking garages.

Take the image below for an example, a 4 story building consisting of Type IIIA construction. If the building is fully sprinkler protected in accordance with NFPA 13, a Group A-3 occupancy would per permitted on Level 4. As long as occupant notification is provided on the roof, the 2018 IBC now explicitly allows a Group A-3 occupancy on the roof.

The 2021 IBC updates Section 503.1.4 to explicitly clarify that an occupied roof should not be included when determining building height or number of stories per IBC 504. Language was also added to clarify that this only applies when penthouse and other rooftop structures, when present, comply with IBC 1511. This further supports the notion described above that an occupied roof should not by itself trigger a classification as a high-rise building.

Additionally, the 2021 IBC clarifies that the Exception 1 to 503.1.4 for occupant notification would only require a voice fire alarm system on the roof if the system is required elsewhere in the building. In other words, if you aren't required to have a voice fire alarm in the building, you don't have to provide it on the roof in order to use Exception 1.

Finally, the 2021 IBC updates Section 1511.2.2, Use Limitations for Penthouses, to specifically allow "ancillary spaces used to access elevators and stairways" to be considered part of a penthouse. This means that a stair or elevator tower to the roof will not force an occupied roof to be classified as a story, even though those elements are taller than 48" from the roof surface.

In the last year or so, there have been several fire incidents during the construction of wood-framed residential buildings. Recently, in January 2021, a fire at the Ely at Fort Apache apartment complex in Las Vegas completely destroyed the building, racking up an estimated $25-30 million in damages. Or last year, a Jacksonville, Florida grew so large that it shut down a portion of nearby Interstate 295 and forced the local fire department to deploy 45 apparatus, including 14 engines and seven ladder trucks. In both of these cases, as well as other similar fires, there were two clear similarities:

• The building construction included wood structural members (Type III, IV or V construction)
• The building sprinkler systems were not yet active

In large, wood-framed apartment buildings, the window of time between enclosure of the structure and the building sprinkler system being functional is a clear vulnerability. The presence of a huge fuel load without an active fire sprinkler systems is a dangerous situation, where a single ignition source can lead to horrific fire losses. 

According to a recent NFPA report, between 2013 and 2017, "fires in structures under construction caused an average of four civilian deaths, 49 civilian injuries, and $304 million in direct property damage annually." In the same report, it is noted that three out of every four construction fires occur in residential buildings. During the 5 year timeframe in the report, 42% of the direct property damage was caused by fires starting from electrical distribution and lighting equipment.

Fires in wood buildings are certainly not a new development, but over the last several building code cycles, various code changes have been enacted that allow for larger and more complex wood buildings. For example, in the 2015 IBC, the "podium" concept, where a wood-framed buildings can be constructed on top of a Type IA podium, allowing for an overall larger building, was expanded to allow multiple levels of Type IA construction beneath the podium. More recently, in the 2021 IBC, Type IV construction has been significantly expanded to now include three different sub-categories (Types IV-A, IV-B and IV-C), allowing for substantially taller and larger heavy timber buildings.

Without a doubt, there are numerous benefits to wood-framed construction. Reduced carbon emissions, faster construction and reduced building costs - all are positive reasons for designers to choose wood buildings. But the very nature of wood being a combustible material brings inherent risks, particularly during construction where fire protection systems are not yet in place.

While recent code changes have allowed for larger and more complex wood buildings, requirements for safeguards during construction have evolved as well. For example, in the 2021 IBC, Chapter 33 has been updated with a few notable changes:

• Updated requirements for water flow to construction sites of buildings of Type III, IV and V construction. Depending on the size of the building and the fire separation distance, the flow requirements start at 500 gpm and continue up to the full required fire flow for the building when constructed (IBC 3313).
• Updated requirements for fire watch during construction, specifically authorizing the fire code official to require a fire watch for buildings exceed 40 feet in height when the area per story exceeds 50,000 square feet (IBC 3315.1).

NFPA 241, Standard for Safeguarding Construction, Alteration, and Demolition Operations, does provide requirements that are often more stringent than IBC Chapter 33. But many jurisdictions do not adopt or enforce compliance with this standard.

Apart from the model codes, many local jurisdictions have enacted their own requirements. In addition to requirements for protection during construction, I am also seeing local requirements for pursuing phased occupancy, where building owners want to occupy a portion of a building while other areas are still under construction. For example, Fairfax County, VA publishes a standard operating procedure document for phased occupancy that institutes a variety of building and site requirements that have to be met before phased occupancy can be considered.

But even with national and local codes addressing the issue, the magnitude of these fire losses does force you to ask: Is enough being done?

What trends are you seeing in your area? Does your local building or fire department have any specific requirements for fire protection during construction or phased occupancy, particularly for wood buildings?  While I don't think there is a one size fits all solution to such a problem, I'm very interested in hearing a variety of perspectives from across the country. Please share in the comment section below!

While working in the early phases of a project, a mechanical engineer recently asked for an estimate of the required stair pressurization system fan capacity. On this particular project, I am planning to do a CONTAM analysis, but won't start that portion until later in the Design Development phase.

Since I wanted to give the mechanical engineer an estimate for sizing purposes, I put together a quick calculator to estimate the fan size. Check it out at the link below!