AUTHOR: Valerie Ziavras

Sprinkler Supervision: What Does it Mean?

Automatic Sprinklers have proven to be highly effective over the years. Recent statistics show that sprinklers operated 92% of the time in fires that were considered large enough to activate sprinklers. The leading cause of sprinklers failing to operate is because the sprinkler system had been shut off. In fact, that is the reason cited in three out of every five incidents where sprinklers failed to operate according to the U.S. Experience with Sprinklers Report. One way to prevent shut-off of sprinkler systems is through sprinkler supervision. What is sprinkler supervision and why is it necessary? A sprinkler system has a number of control and isolation valves which allow portions of the system to be shut down for things like maintenance, testing, or rehabilitation work. These valves allow for the rest of the system to remain operational while the necessary work is completed in a specific area. It isn’t uncommon to see a main control valve which controls water to the entire system as well as a floor control valve on every floor. This way, if rehabilitation work is happening on the second floor, the isolation valve on the second floor can be closed and that portion of the system can be worked on. The system would remain operational on the remaining floors. While the benefit of being able to isolate certain parts of the system is obvious, there can be risks associated with it. Valves can remain shut after the work is complete, or, valves can be accidentally, or intentionally, shut thus rendering portions of the system useless. This is where sprinkler supervision is important. Sprinkler supervision is intended to ensure the overall integrity of the piping system by providing a method to verify all control and isolation valves are fully open. What does supervision mean in NFPA 13, Standard for the Installation of Sprinkler Systems? NFPA 13 provides the designer with options of how to monitor the isolation and control valves. The options are: Electrical supervision that reports to either Central station, proprietary, or remote station signaling service Local signaling service that will cause the sounding of an audible signal at a constantly attended point Valves locked in the correct position Valves located within fenced enclosures under the control of the owner, sealed in the open position, and inspected weekly as part of an approved procedure If you want to learn more about NFPA 13 and sprinkler supervision, check out this article. Any of the above means of supervision is acceptable per NFPA 13 for all valves except floor control valves in high-rise buildings and valves controlling flow to sprinklers in circulating closed loop systems. In those two special cases, NFPA 13 requires that those valves be electrically supervised. What does supervision mean in NFPA 101, Life Safety Code and NFPA 1, Fire Code? The Life Safety Code does not provide the designer the same options for supervision that NFPA 13 does. Instead, the Life Safety Code requires that all supervised sprinkler systems be electrically supervised. The supervisory signal must be reported either at a location within the protected building that is constantly attended by qualified personnel or at an approved, remotely located receiving facility. It is important to note, that there are instances where the Life Safety Code does not require electrical supervision and instead permits supervision in accordance with NFPA 13. In these cases, such as what is seen in the extinguishment requirements for existing mercantile occupancies, the Life Safety Code requires an “approved automatic sprinkler system” in specified locations. Since the word “supervised” is not included, the electrical supervision requirements specific to the Life Safety Code do not apply, and the sprinkler system is permitted to be supervised in accordance with NFPA 13. Since the Fire Code extracts the automatic sprinkler system provisions from the Life Safety Code, the same requirements for electrical supervision apply to any sprinkler system that is required to be supervised by the Fire Code. Why is there a difference? Not all Codes require electrical supervision like the Life Safety Code and Fire Code do. For instance, NFPA 5000, Building Construction and Safety Code, only requires electrical supervision when specifically called for, otherwise any form of supervision permitted by NFPA 13 is acceptable. The electrical supervision required by the Life Safety Code is a vital component. In many cases, by providing a supervised automatic sprinkler system, other modifications to building design are permitted. For example, in most occupancies, a sprinklered building is permitted to have a longer travel distance and a longer common path of travel when electrically supervised. Other trade-offs include different allowable construction types or reduced fire resistance rating of fire barriers. NFPA 13 also recognizes the improved reliability of electrically supervised sprinkler systems through trade-offs like the Life Safety Code does. One example is that, when determining the water supply duration requirements for hydraulically calculated systems, the lower duration values are permitted to be used where the waterflow alarm devices and supervisory devices are electrically supervised. This means that for an ordinary hazard occupancy, the water supply duration for an electrically supervised system would be permitted to be 60 minutes instead of 90 minutes. These types of allowances found in NFPA 13 and the Life Safety Code, are based on the assumption that the automatic sprinkler system is going to perform as expected. To increase the probability of this occurring, electrical supervision is required so that any time a valve is closed, somebody, either a qualified person on site or an approved remotely located receiving facility is made aware of the system impairment.

Complying with the Life Safety Code: There's More to It Than You Think

I know I'm not the only one who walks into a building and immediately starts looking around to see what kind of life safety features a building has. When I'm looking around, I'm usually comparing what I see to what I know is required per NFPA 101, Life Safety Code. Sometimes, I have to remind myself that although what I see doesn't align with what is required by Code, the building may still be compliant. Determining compliance isn't always just following the applicable occupancy chapter requirements. Rather, two compliance options are recognized by the Code; prescriptive-based and performance-based. Both options offer equivalent levels of protection and one method is not preferred to the other. While we will focus on performance-based code compliance as it applies to the Life Safety Code, other codes, such as NFPA 5000, Building Construction and Safety Code and NFPA 1, Fire Code, also allow for performance-based designs. The prescriptive-based option is what most people associate with compliance, looking through the Code and determining what requirements apply to your specific situation. However, sometimes this option is too limiting, and the performance-based option will be applied. This is especially true for complex buildings or buildings with unique functions and features. The Stratosphere Tower in Las Vegas, Nevada (pictured above) comes to mind. The tower rises over 900 ft (274 m) above grade with ten floors and outdoor amusement rides in the upper portion of the tower “pod”. At the base of the tower is a casino building. The occupant load of some of the floors in the pod would have required three remote exit stairs to go from the top all the way to the base of the building. The physical area of the structure isn't big enough to provide remotely located stairs and the height of the building makes the use of stairs as a means of evacuation somewhat impractical. Through the performance-based design compliance option, the Stratosphere Tower uses typical exit stairs for the occupied floors (floors 3-10) discharging to areas of refuge on the lowest two floors of the pod as part of its primary evacuation method. The areas of refuge serve no other purpose and consist entirely of noncombustible construction. The floors serving as areas of refuge are open to the surrounding exterior environment so that natural ventilation occurs, and a mechanical ventilation system is not required to keep the areas free of smoke. While a single stair is provided from the area of refuge to grade, the primary evacuation route from the area of refuge involves the elevators. The elevator evacuation system is capable of moving the maximum 2600-person occupant load of the pod to the base building in under 1 hour. As you can see, this fire protection strategy departs from the typical approach. Another example is the crown of the Statue of Liberty where visitors can now go up and look out onto New York City. For these unique situations, the prescriptive-based compliance option would have eliminated the design flexibility, that was imperative for the design of these buildings. Therefore, the performance-based option was applied. In addition to the two compliance options recognized by the Code, there is also an equivalency clause found in Chapter 1 that allows alternative systems, methods, or devices to be used when they are approved as equivalent by the authority having jurisdiction. Goals and Objectives In order to allow for two equivalent compliance options, a common understanding of the minimum level of life safety needed to be established. This allows for performance-based designs to be evaluated against similar criteria that a prescriptive-based approach is assumed to meet. This is done through the goals and objectives, found in Chapter 4. The primary goal of the Life Safety Code is to keep occupants reasonably safe from fire and in addition to fire, to keep occupants safe from comparable emergencies (such as explosions), hazardous materials, and crowd movement. The objectives compliment the goals and strive to provide more quantitative expectations than that of the goals. For example, to help clarify the expectation around the primary goal of life safety from fire, the first objective of the Code states that “a structure shall be designed, constructed, and maintained to protect occupants who are not intimate with the initial fire development for the time needed to evacuate, relocate, or defend in place.” Without these objectives, the goals could be interpreted differently. Perhaps someone thinks occupants should be reasonably protected from fire for 10 minutes while someone else thinks 2 hours. The objectives play an important role in providing appropriate context for the goals. Option #1 Prescriptive-Based Code Compliance The prescriptive-based option is the method people are most familiar with. In this approach, the design is in accordance with the core chapters and the appropriate occupancy chapter(s).  The requirements outlined in these chapters and the resultant level of life safety is deemed to meet the goals and objectives of the Life Safety Code. For most buildings, this is the approach taken because the requirements are practicable to apply. However, there are situations where the structure is so unique, or the functionality of the space is so unusual that the prescriptive-based approach is too limiting. In this case, designers can use the performance-based option. Option #2 Performance-Based Code Compliance As mentioned above, the intent behind the performance-based option is to provide design flexibility. Designs utilizing this option must comply with Chapters 1 through 5. Chapter 5 states that if a design, for each design fire scenario, assumption, and design specification, meets the performance criterion, then it shall be considered to meet the objectives. The performance criterion states that any occupant who is not intimate with ignition shall not be exposed to instantaneous or cumulative untenable conditions. The annex material provides four different methods that could be used to show a design meets this performance criteria. One of the methods described is to perform calculations for each design fire scenario proving that each room or area will be fully evacuated before the smoke and toxic gas layer in that room descends to a level lower than 6 ft. The performance-based design needs to successfully handle different fire scenarios. NFPA 101 provides 8 specific scenarios, covering a wide range of situations, that must be assessed. One design fire scenario that must be considered is a fire that starts in a normally unoccupied room and addresses the concern of a fire in such an area migrating into the space that potentially holds the greatest number of occupants in the building. In addition to the eight specified design fire scenarios, there is a requirement that the design fire scenario be as challenging as any that could occur in the building, but shall be realistic, with respect to any of the following: initial fire location; early rate growth in fire severity; or smoke generation. This usually requires at least one, if not more design fire scenarios to be added to the eight already required for evaluation. The intent of including these nonspecific scenarios, as opposed to only the specified scenarios found in Chapter 5, is to capture those scenarios in which initial fire location, early rate of growth in fire severity, or smoke generation poses a greater problem than those conditions captured by the required scenarios. Performance-based design requires that the designer and authority having jurisdiction (AHJ) agree that the goals and objectives of the Life Safety Code have been met and that the desired level of safety is provided. The AHJ may require an independent third-party review of the performance-based design. As you can see, the selection of design fire scenarios as well as the evaluation of the scenarios is not a simple process. Therefore, performance-based design is usually reserved for unique situations where design flexibility is important. Equivalency Clause The equivalency clause found in Chapter 1 permits alternative systems, methods, or devices as approved as equivalent by the authority having jurisdiction to be recognized as complying with the Life Safety Code. It is not intended to serve as a waiver of compliance, but instead requires that a level of safety is provided that is equivalent to that required by the prescriptive-based provisions. When employing the equivalency clause, it is important to clearly identify the prescriptive-based code provision being addressed, to provide an interpretation of the intent of the provision, to provide an alternative approach (proposed design), and to provide appropriate support for the suggested alternative (evaluation of proposed designs). One example where equivalency may be granted is using a newer edition of a standard. If your jurisdiction follows the 2018 edition of NFPA 101, then the 2016 Edition of NFPA 13, Standard for the Installation of Sprinkler Systems, would be the referenced standard for the installation of sprinklers. As a designer, you may want to use the 2019 edition, and could ask the AHJ to approve an alternative design as equivalent that uses the 2019 edition of NFPA 13. If you found this article helpful, subscribe to the NFPA Network Newsletter for monthly, personalized content related to the world of fire, electrical, and building & life safety
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Determining Sprinkler Requirements for High-Rise Buildings

The summer of 2017 saw a number of deadly high-rise fires, including the Grenfell Tower fire and the Marco Polo fire. While deadly incidents like these are usually the result of a combination of failures, these buildings had one major thing in common: they were both unsprinklered. These events led to a review of the high-rise sprinkler requirements for the 2021 edition of NFPA 101, Life Safety Code. While a blanket retroactive sprinkler requirement for high-rise buildings still isn't proposed, a number of technical committees did modify the requirements for their respective occupancies. These proposed changes include: The installation of sprinklers is required in all existing high-rise ambulatory health care occupancies within 12 years of the adoption of the Code. Existing apartments, without a previously approved engineered life safety system, must be sprinklered by January 1, 2033. The installation of sprinklers or the installation of an engineered life safety system is required in all existing high-rise industrial occupancies within 12 years of the adoption of the Code.   The technical committees responsible for the changes noted above carefully considered the impact retroactive requirements have on existing buildings. Sometimes, as is the case with retroactive sprinkler requirements, the benefits far outweigh the costs.   A common misconception is that NFPA 13, Standard for the Installation of Sprinkler Systems, dictates which buildings must have sprinklers.  However, the requirement for a building to be sprinklered will be dictated by a code such as a building code, life safety code, or fire code and the standard (NFPA 13) will tell you how to install the sprinklers. When determining if a building is required to be sprinklered it is important to review the requirements from all applicable codes in your jurisdiction. Just because one of the codes doesn't require sprinklers, doesn't mean the same is true of the others. In the case of differing requirements, the most restrictive of the codes would apply. As each of these codes serves a different purpose and has a different scope, it can lead to the difference in requirements.   We'll look a little more closely at how the sprinkler requirements for high-rise buildings differ between the current editions (2018) of NFPA 1, Fire Code and NFPA 101. High-rise buildings are defined by NFPA 1 and  NFPA 101 buildings where the floor of an occupiable story is greater than 75 ft above the lowest level of fire department vehicle access. When looking at your local requirements, it is important to verify how your jurisdiction defines a high-rise building as many jurisdictions may modify the definition.   2018 Fire Code, NFPA 1 The Fire Code is intended to address firefighter life safety and building protection in addition to occupant life safety.  The high-rise building sprinkler requirements are straightforward. All new high-rise buildings must be protected with sprinklers throughout and all existing high-rise buildings must be sprinklered within 12 years of the adoption of the Code.   2018 Life Safety Code, NFPA 101 The Life Safety Code is primarily concerned with occupant life safety. Like the Fire Code, the Life Safety Code requires that all new high-rise buildings be protected with sprinklers throughout. The differences between the codes arise in existing high-rise buildings. Instead of a blanket requirement retrofit requirement, the Life Safety Code relies on the individual occupancies to determine the extent of, if any, sprinkler protection that is required. If an existing occupancy chapter requires sprinkler protection, the requirement will be found in either the “Extinguishment Requirements” subsection (XX.3.5) or the “Special Provisions” section (XX.4). Many existing occupancy chapters specifically require high-rise buildings to be sprinklered: Assembly Educational Day-care Health care Detention and correctional Hotel and dormitories Residential board and care - large facilities Although mercantile does not specifically call out existing high-rise buildings, there is a good chance they would be required to be sprinklered based on the general sprinkler requirements.   Ambulatory health care, apartments, and business occupancies require either a sprinkler system or an engineered life safety system. An engineered life safety system (ELSS) must provide a similar level of safety as an automatic sprinkler system. It can include protection features such as a partial sprinkler system, smoke detection, compartmentation, or other types of fire and life safety systems. It must be developed by a professional engineer and approved by the Authority Having Jurisdiction (AHJ).   Others, such as industrial and storage occupancies do not require sprinklers or an engineered life safety system due to the relatively low occupant load that is typical of these occupancies. (maybe add a sentence reminding readers about 101 mandating sprinklers only when they are installed for the protection of people not property)   The high-rise sprinkler requirements in the Fire Code and the Life Safety Code are an example of two Codes with differing requirements. To summarize, both require all new high-rise buildings to be sprinklered throughout. The Fire Code requires all existing buildings to be sprinklered within 12 years of its adoption date while the Life Safety Code is occupancy specific. As mentioned above the differences can be attributed to the different scopes and purposes.   A number of cities have passed legislation independent of the codes requiring the retrofit of some or all high-rise buildings with sprinklers. Has your city?  Are you interested in learning more about retrofit? If so, let us know in the comments section!   If you found this article helpful, subscribe to the NFPA Network Newsletter for monthly, personalized content related to the world of fire, electrical, and building & life safety.
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Many Factors to Consider When Providing Access to Roofs with a Photovoltaic System Installed

The use of renewable energy is on the rise and one popular source is photovoltaics (PV). Section 11.12 in the 2018 Edition of NFPA 1, Fire Code covers everything related to PV installations from marking to rapid shutdown to accessways. There are a number of things to consider when installing a PV system on the roof of a building, but perhaps the most popular topic for questions has to do with the required pathways. Providing proper pathways is extremely important because firefighters need access to the roof for firefighting operations. Often, there is confusion about the size and location of the required pathways. The pathway requirements are different for PV arrays installed on one- and two-family dwellings and townhouses than they are for all other buildings. Here, we will focus on the pathway requirements for all those other buildings. There are essentially three types of pathways that are required. The first type ensures firefighters will be able to get on the roof and are often called perimeter pathways. The second type of pathway ensures that firefighters can move around the roof once they have gained access. These are referred to as “other pathways” in the Code. The final type of pathways provide access to areas for ventilation. The size of the perimeter pathways is going to depend on the building size. For any building with a length or width greater than 250 ft (76.2 m), a minimum 6 ft (1829 mm) pathway is required on all sides. If both the length and width are 250 ft (76.2 m) or less, then the pathway is only required to be a minimum of 4 ft (1219 mm). The images below show what these pathways look like in plain view. The “other pathways” required by the Code allow firefighters to move around the roof as needed. These types of pathways are required under three different conditions. The first is to provide straight line access to ventilation hatches and/or roof standpipes. Wherever ventilation hatches and standpipes are located a pathway of at least 48 in (1219 mm) must be provided.  A 48 in (1219 mm) pathway around all roof access hatches must also be provided. In addition to the pathway around the roof access hatch, at least one 48 in pathway must be provided from the roof access hatch to the roof edge or parapet. The last type in this group is to ensure that there is a pathway every 150 ft (46 m). The 150 ft distance cannot be exceeded in either the length or the width of the building. This essentially limits the PV array to a maximum size of 150 ft by 150 ft (46 m by 46 m). The final category of pathways required are for smoke ventilation. The third type of pathway listed in the “other pathway” paragraph, which limits the array size to 150 ft by 150 ft (46 m by 46 m), will be used to provide ventilation options. The width of this pathway will depend on what, if any, type of ventilation options If there aren't any ventilation options provided (such as skylights or smoke and heat vents) then the pathway must provide a minimum 96 in. (2438 mm) between array sections. If there are existing roof skylights or dropout smoke and heat vents are provided on at least one side    of the pathway, then the pathway must only be a minimum of 48 in (1219 mm) wide. A 48 in. pathway is also permitted where there are 48 in. by 96 in. (1219 mm by 2438 mm) venting cutout options every 20 ft (6096 mm). The last type of required pathway for venting is where nongravity-operated smoke and heat vents are provided. For those, a 48 in. (1219 mm) pathway must be provided around the vent.   It is not uncommon to see PV systems connected to energy storage systems (ESS). This allows the energy generated from the PV system to be stored and used later on when it is needed. For more information on ESS take a look here and at NFPA 855. There are many components to ensuring a PV system is installed correctly. Here we've focused on the pathway requirements for buildings other than one- and two-family dwellings and townhouses. Other requirements such as marking requirements and requirements for rapid shutdown can all be found in NFPA 1, The Fire Code, Section 11.12. If you found this article helpful, subscribe to the NFPA Network Newsletter for monthly, personalized content related to the world of fire, electrical, and building & life safety.

As Businesses Prepare to Re-open, New NFPA Checklist Helps Building Owners and Facility Managers Ensure Fire and Life Safety for all Occupants

During the lockdown policies that have been in place over the past couple of months, many of the ongoing inspection, testing, and maintenance (ITM) activities typically required by locally enforced codes and standards may not have been completed for a variety of reasons. Regardless of the level of ITM performed while occupancies have largely remained vacant, it is imperative that building owners and facility managers verify the performance of all building fire protection and life safety systems prior to reoccupation. As the federal government and many states begin allowing businesses to reopen, NFPA has developed a checklist to help building owners and facility managers prepare, ensuring that fire protection and life safety systems in commercial and multi-occupancy residential buildings are properly checked and functioning. This new resource addresses the factors that should be confirmed by a qualified person before re-opening a building to ensure the safety of all its occupants. Based on the assumption that the building was in compliance prior to being closed, the checklist provides some initial steps to help make sure the occupancy is safe enough to reopen until a qualified professional can complete the regularly scheduled ITM of all fire protection and life safety systems. This process should be completed as quickly as possible. Any alterations to the building that adhere to public health guidelines, such as the installation of physical barriers or automatic door openers, will need to be evaluated as well to ensure that they are properly designed and installed and do not negatively impact the fire protection and life safety systems currently in place. The newly available checklist reflects the latest in a series of COVID-19 related resource developed by NFPA to address fire and life safety issues, concerns, and challenges that have emerged over the past couple of months. Additional resources are added to the NFPA website as they are developed. Visit the NFPA coronavirus landing page to access all newly released documents, as well as existing COVID-19 related information, guidelines, and resources provided to date.

How to Calculate Occupant Load

A fundamental concept of model building codes, fire codes, and life safety codes is that a means of egress is designed to accommodate all occupants of a building. Knowing how to determine the total occupant load of a building is an integral part in determining if the building meets that basic concept. It can be difficult to estimate how many people are going to use a space within a building so most model codes that address egress design will provide requirements for how to estimate this number. If you are working with NFPA 101, Life Safety Code, Table provides occupant load factors for different uses found in a building. Occupant load factors are chosen based on how the space is used and not the occupancy classification of the space. For example, it isn't uncommon for a business occupancy to have spaces that would fall under “business use”, as there will almost always be spaces used for non-business purposes also within the building. A conference room within the business occupancy wouldn't be considered an assembly occupancy unless it was determined to have an occupant load of 50 or more people. For the purposes of determining the occupant load, that conference room has an assembly use. Once the occupant load factor has been determined based on the use of the space, it is then used to calculate the occupant load of that space. Calculating occupant load can be thought of in three steps: Select an occupant load factor Determine the size of the room Apply the occupant load factor to the space There is a common misconception that the calculated occupant load is the maximum number of occupants the space can contain. Instead, the calculated occupant load is actually the minimum number of expected occupants. If the designer, building owner, or other involved party knows the expected number of occupants may be higher than the calculated number of occupants, then that number should be used as the occupant load. If, for example, the building owner knows there will be 5 people working in a storage room that has a calculated occupancy of 3 people, the design needs to be based off of the expected occupant load (5 people). Now, if the building owner says there will only be 1 person in the storage room that has a calculated occupancy of 3 people, the design needs to be based off of the calculated occupant load (3 people).   For a detailed step-by-step explanation of calculating occupant load and to learn about changes to some of the occupant load factors for the current edition (2018), download your free fact sheet! 

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