NFPA 1: Fire protection ratings and fire resistance ratings, what is the difference? #FireCodefridays
Today's blog was written by Val Ziavras, a Fire Protection Engineer at NFPA. Special thanks to Val for her contribution to this blog and discussing one of the many subjects addressed in the Fire Code!
Fire-resistance-rated assemblies play a vital role in fire safety. However, an assembly is only as good as its weakest point - the openings. How do you know if an opening in a fire-resistance-rated assembly is protected appropriately, or if the opening is even permitted?
Not all openings are created equal. Door openings, for example, usually can't be avoided as they are needed for the movement of people and equipment throughout the building, and for security and privacy. Windows or transom openings, on the other hand, are not necessary for the building to function; they tend to be installed for aesthetics, environmental reasons, or other architectural purposes. To understand the requirements for opening protectives, it is required for one to first understand the difference between a fire-protection-rating and a fire-resistance-rating. Although often used interchangeably, they are different.
Most opening protectives (assemblies protecting openings in a fire-rated assembly) have a fire-protection-rating whereas the wall/floor/ceiling assembly has a fire-resistance-rating. There are some exceptions where an opening protective may also be fire-resistance rated, but it is not the majority. There are a number of tests that will result in a fire-protection-rating, such as NFPA 252 and NFPA 257. When a product has a fire-resistance-rating it has been tested to ASTM E119 or ANSI/UL 263. If the opening protective is being tested as a wall; it will be subject to the same fire test as the wall itself. NFPA 252, NFPA 257, and ASTM E119 all expose the test specimen to a fire-based on the standard time- temperature curve.
A big difference between the tests is the performance criteria. For products undergoing a test resulting in a fire-protection-rating, some amount of openings, specifically around the glazing, are permitted and there are no limitations on the amount of heat transferred from one side to the other. Products tested to ASTM E119 are held to different test criteria based on their performance needs. There can be no passage of flame or gases hot enough to ignite cotton waste on the unexposed side and the temperature on the unexposed side of the wall cannot increase more than 250OF above the original temperature.
To properly protect an opening in a fire-resistance-rated assembly, the proper fire-protection-rating is required. Section 12.7.6 of NFPA 1 addresses opening protectives in fire-rated assemblies. It should be carefully noted that this table DOES NOT require the fire-resistance-ratings. The fire-resistance-rating will be mandated somewhere else in the Code and Section 12.7.6 will provide the required fire-protection-rating of the opening based on that mandated fire-resistance-rating. Wherever the Code refers to a fire-protection-rated door assembly or fire door assembly, it is referring to the entire assembly. If any single component is not properly provided, installed, and functioning, the assembly is not a fire-protection-rated assembly. For example, if a listed fire door leaf and frame are installed with positive latch and hinges but the required self-closing device is omitted, the assembly cannot be considered a fire door assembly and is not considered to have any fire-protection-rating.
For example, a new exit stair enclosure that connects 2 stories would require a 1-hour fire-resistance-rating based on how the Code requires exits be protected. Table 18.104.22.168.2 provides the minimum fire-protection-rating of the openings in “Vertical shafts, including stairways, exits, and refuse chutes”. Based on the Code requirement for a 1-hour fire-resistance-rating, the table tells us that opening protectives must have a minimum 1 hour fire-protection-rating.
How does this impact a fire inspector? AHJs are responsible for confirming that openings have been properly inspected, tested, and maintained and met the provisions as referenced in NFPA 80, Standard for Fire Doors and Other Opening Protectives (also extracted into NFPA 1, Section 12.4). An inspection of an opening protective will determine if the proper opening has been installed; the proper fire-protection-rating being one of the first pieces of information that an inspector will look at on the label on the opening protective. The inspections themselves, required annually, may be done by a person also serving as a fire inspector, by a facility manager/facility staff, or by someone who is in a role specific to the inspection, testing and maintenance of openings.
NFPA offers a plethora of resources related to protecting and inspecting fire-rated opening protectives including training and online learning. A recent article in NFPA Journal highlights the importance of clearances and gaps around fire door installations, particularly in health care occupancies. It also addresses the connection between the maximum gaps permitted by NFPA 80 versus the criteria tested for by NFPA 252 and how proposed research and testing can further the knowledge on the performance of opening protectives and their impact on building and life safety. NFPA offers annotated handbooks on the 2010, 2013, and 2016 editions of NFPA 80 if you are in a role where you require expanded knowledge of the standard, in addition to the application for fire-rated openings in NFPA 1.
Thanks for reading, stay safe!
Please visit www.nfpa.org/1 to view the free access version of NFPA 1 2018 edition. Follow along on Twitter for more updates and fire safety news @KristinB_NFPA. Looking for an older #FireCodefridays blog? You can view past posts here.