Topic: Fire Protection Systems

A Guide to Fire Alarm Basics – Off-Premises Signaling and Supervising Stations

A fire alarm system is a crucial part of the overall fire protection and life safety strategy of a building. A fire alarm system serves many functions and the differences between the functions can be a bit confusing, so I created a visual guide to fire alarm basics. The objective of this blog series is to discuss some of the major components and functions of a fire alarm system. For an overview of the entire system take a look at my Guide to Fire Alarm Basics Blog. This blog will take a deeper dive into fire alarm system off-premises signaling and supervising stations. When talking about fire alarm systems, the term premises includes the entire area monitored by the fire alarm, this could include the entire building or even an entire campus. Off premises signaling is important because it allows signals from the fire alarm system to be sent to a constantly attended location (supervising station or a public communication center) to ensure the proper response. The purpose of off-premises signaling is to provide dedicated, 24-hour monitoring for a fire alarm and signaling system and to initiate the appropriate response to those signals. In the case of a fire alarm condition (fire detected in the building), the appropriate response usually includes the dispatching of the local fire department or fire brigade. In the case of a supervisory condition, such as a closed sprinkler valve, the appropriate response might be the notification of designated maintenance personnel or outside contractors.   If a fire alarm and signaling system is sending signals off premises, it is either (1) sending signals through a Public Emergency Alarm Reporting System, or (2) the fire alarm system is part of a Supervising Station Alarm System. Regardless of the system, in today’s world they all consist of a type of transmitter at the protected premises that uses a transmission and/or communications channel and pathway to send signals to a receiver at the supervising station or public communications center.     A Public Emergency Alarm Reporting System (PEARS), otherwise known as a Municipal Emergency (Fire) Alarm System is a communication infrastructure, other than a public telephone network that is used to communicate with a communication center. Typically, this communication infrastructure is owned, operated, and controlled by a public agency. The system itself does not include the fire alarm control unit or any of the equipment that is located on the protected premise, instead, it starts at the transmitter and ends at the public communication center.   One way the interface between the fire alarm control unit and the PEARS is completed is using a master fire alarm box, which is an addressable manual pull station on the PEARS system that has an interface circuit that allows a fire alarm control unit to actuate the master box when the system initiates a fire alarm signal. Large municipalities usually locate the communications center at a facility designed for the purpose. Small communities often locate the communications center at the fire station, police station, sheriff’s office, or a private agency that has been contracted to provide public emergency communications services. NFPA 1221, Standard for the Installation, Maintenance, and Use of Emergency Services Communications Systems, provides requirements for the installation, performance, operation, and maintenance of communications systems and facilities.     If off-premises signaling is provided by a private company, it is most likely completed using a supervising station alarm system.  A supervising station alarm system consists of everything connected to the supervising station, including the protected premises fire alarm control unit and devices.   Supervising Station Alarm Systems are further divided into three specific types. They are Central Station Service Alarm Systems Proprietary Supervising Station Alarm Systems Remote Supervising Station Alarm Systems.     A Central Station Service Alarm system consists of a remotely located supervising station that is listed for central station service to UL 827 Central-Station Alarm Services and, in addition to monitoring, it provides several other services including record keeping and reporting, testing services, and runner service. This can either be required by code or some insurance companies for certain occupancies. This option can also be chosen by a building owner who wants to have a single contract with a provider who supplies monitoring as well as inspection, testing, and maintenance and other services required of central stations.     A Proprietary Supervising Station Alarm System consists of a supervising station under the same ownership as the protected building that it supervises. These can be useful to owners who have very large buildings or a campus or for owners who have numerous buildings in many locations and who are able to dedicate the space and staffing levels to accomplish this. Proprietary supervising stations can be located on the same premises as the fire alarm system or at another location; these are most often used by large airports, industrial plants, college campuses, large hospitals, and retail chains, among other facilities. An example of this is a big box store that has a dedicated location that monitors all of its store locations. Additional fire alarm services including record keeping, equipment installation, inspection, testing, and maintenance are the responsibility of the owner and can be accomplished in-house or be contracted out to an outside contractor.   A Remote Supervising Station Alarm Systems consists of a constantly attended location that receives signals from various protected premises typically owned by different parties. Unlike central station fire alarm systems, contracts for this service are typically limited to the monitoring and recording of signals from the fire alarm system. Additional services including equipment installation, inspection, testing, and maintenance are the responsibility of the owner. This is an option for owners who are not required or do not want to provide central service and for whom a proprietary supervising station does not make sense. It also may be common for a municipality to operate a remote supervising station as a way to receive signals at their communication center if they are not utilizing a public emergency alarm reporting system.  There are many different methods that can be used for the fire alarm control unit to communicate to the supervising station, and NFPA 72 outlines the requirements for four different types that are permitted in new installations, which includes both wired and wireless methods. Want to learn more? Like I noted in the beginning of this blog, if you are interested in learning more about fire alarm basics, take a look at my Fire Alarm Basics Blog. I will be updating this series over the next few months to add a deeper dive into different portions of the fire alarm system. 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.
Sprinkler pipe

Modifications To Existing Sprinkler Systems

With many businesses rethinking how their office spaces will be utilized post-pandemic, a significant number will likely undergo renovations or redesigns. Add this to regular tenant fit outs, including shell space in newly constructed buildings, and there are sure to be thousands of existing sprinkler systems  requiring modifications to adequately protect redesigned spaces. This often raises the question as to what extent the sprinkler system must be brought up to date with the latest standard, whether the system needs to be recalculated, and how extensive the testing of the modified system must be. Fortunately, the 2019 edition of NFPA 13 dedicated a chapter to the requirements for these instances for the first time and that information will carry over to the soon-to-be-issued 2022 edition. Change of use/occupancy For the purpose of this discussion, we will focus on situations where the use or occupancy classification of the space is not being changed. Where that is the case a more complex analysis is likely required to determine the impact of changes to design densities, areas of operation, and several other possible changes. NFPA 25, Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems places responsibility on the owner for ensuring an evaluation be conducted in these instances, many of which go beyond the reconfiguration of office space where the space protected is likely to remain a light hazard occupancy. General When a building is undergoing a renovation or a remodel of its space the removal or addition of walls, partitions, and ceilings can negatively impact the effectiveness of the originally designed sprinkler system. In these instances, numerous sprinklers must often be relocated or added in order to appropriately protect the reconfigured space. This does not necessarily mean that the entire system must be reevaluated to ensure complete compliance with the latest edition of the standards. In fact, portions of the existing system that are not subject to the modifications can be considered previously approved under the retroactivity clause of NFPA 13, Standard for the Installation of Sprinkler Systems and do not need to be evaluated. Whenever additions or modifications are made to an existing system, enough of the existing system must be indicated on the plans to make all conditions clear for the AHJ to evaluate. This means that one of the first steps taken in these instances should be to gather as much of the existing plans and calculations, as is available. A more complex analysis might be required for the entire system if the original design basis cannot be confirmed. Hydraulic calculations While some have argued that minor modifications should not impact the system demand significantly enough to require calculations, NFPA 13 does require calculations be provided to verify that the system design flow rate will be achieved. Previous editions of the standard included an annex note indicating that it was not the intent to require a full hydraulic analysis of the existing sprinkler system, in addition to the new sprinkler layout. This note has been removed in recent editions. This still does not necessarily require a full set of hydraulic calculations particularly if the modifications are made in a part of the system that is not the most hydraulically demanding. In this case the modified portion of the system can be hydraulically calculated back to the branch line or riser to the point where original calculations are used to show that the design flow rate can be met.  This is not entirely clear in reading the standard especially without the previous annex note to point to so it is certainly worth checking with the local AHJ to determine what they will accept for these instances. Hydrostatic testing Newly installed sprinkler systems must be hydrostatically tested to check for leaks at a pressure of at least 200 psi (14 bar) for a period of at least 2 hours. When existing systems are modified such that the work affects less than 20 sprinklers, the system only requires testing at the system working pressure. Where the modification affects more than 20 sprinklers, that portion of the system must be isolated and tested at 200 psi (14 bar) for 2 hours. If the new work cannot be isolated, the testing can be done at system working pressure even if the modifications involved more than 20 sprinklers. In general, existing portions of the system do not need to be subjected to a new hydrostatic test. Striking a balance  Many buildings are routinely undergoing changes that can impact the fire sprinkler system and require modification of the system to adequately protect the space as it evolves. The provisions for existing system modifications in NFPA 13 are intended to ensure that the space has adequate coverage, the system demand can still be met, and the workmanship ofthe job has been completed well enough. This is meant to strike the appropriate balance between ensuring that the changes are not simply ignored, not throwing the entire latest standard out, and saying everything must be brought up to those requirements.
A sprinkler head

NASFM is helping NFPA Spread the Word About Home Fire Sprinklers

The effectiveness of home fire sprinklers is undeniable. Sprinklers respond immediately to fires, meaning they fight a fire before firefighters even arrive. In most cases, this reduces a significant amount of property damage and can even save lives. However, from 2010-2014, home fire sprinkler systems were only found in seven percent of all home fires, according to NFPA. It is imperative to spread the word about home fire sprinklers as they truly have the power to save lives. Jon Narva, the director of external relations at the National Association of State Fire Marshals (NASFM), sat down with Home Fire Sprinkler Coalition (HFSC) president, Lorraine Carli, to talk more about this subject as a part of a video series created to celebrate the 25th anniversary of HFSC. Educating the public about home fire sprinklers is a huge objective for NASFM. Narva emphasized this point, stating that what is necessary to get more people to install home fire sprinklers is to “focus on education, that has to remain key and continuing to develop the programs to help the marshals get the word out, not just to the firefighters or first responders in their state, but to all the stakeholders as well,” he said. NASFM is playing a huge role in promoting home fire sprinklers because of how effective they are at stopping a fire before it engulfs a home. Home fire sprinklers are “really a no-brainer,” Narva said. “NASFM’s mission is to protect human life, property, and the environment and that describes home fire sprinklers.” According to Narva, home fire sprinklers can also help reduce safety risks in any community. “Community risk reduction really takes a look at the whole picture of all the risks that are out there,” he stated. “If we can reduce the fire risk through fire sprinklers, we’re able to dedicate resources to higher risk or more recent risk areas and protect the community overall.” To help promote home fire sprinklers, NAFSM worked with HFSC to develop programs that give people incentives for installing home fire sprinklers. Listen to the full interview with Narva and Carli to learn more about why it is so important to educate the public about home fire sprinklers:   If you missed any of the previous interviews, including Carli’s most recent discussion with Kevin Quinn, the 1st vice chairman at the National Volunteer Fire Council, find the full video series on HFSC’s website.   Help NFPA and HFSC celebrate its 25th anniversary this year; share the facts about the affordability, reliability, and effective protection of home fire sprinklers. For additional information, visit the Home Fire Sprinkler Coalition and the Fire Sprinkler Initiative websites.
Kevin Quinn

Home Fire Sprinklers Reduce Risks for Volunteer Firefighters

There are 1.1 million firefighters nationwide, 67 percent of which are volunteers. The National Volunteer Fire Council (NVFC) represents the interests of volunteer fire, EMS, and rescue services. Kevin Quinn, the first vice chairman at the NVFC, sat down with Home Fire Sprinkler Coalition (HFSC) president, Lorraine Carli, to talk more about why home fire sprinklers are important to the volunteer firefighters as a part of a video series created to celebrate the 25th anniversary of HFSC. In the video interview, Quinn emphasizes the importance of home fire sprinklers as they save numerous lives, “by knocking those fires down before they become that deadly, whether it be for residents, or for firefighters, volunteers and career alike,” he said. Quinn mentions while every home should be equipped with home fire sprinklers, they are especially important in rural areas. Of all the country’s volunteer firefighters, many are in rural areas. “Water supply is an issue for rural areas and there’s a little bit more of a response time,” Quinn said. “So, the home fire sprinklers are going to be impactful on those residential homes that have protection.” Home fire sprinklers stopping a fire before it can spread puts firefighters at much less risk and reduces injuries from fighting structure fires. However, it also prevents firefighters from inhaling carcinogens from fires, reducing their risk of cancer. Cancer in firefighters is a serious issue. According to Two studies from the National Institute for Occupational Safety and Health, they find that: Firefighters face a nine percent increase in cancer diagnosis. Firefighters also face a 14 percent increase in cancer related deaths compared to the general US population. In the video, Quinn states that the NVFC helped put together the Lavender Ribbon Report, which is 11 of the best practices to reduce exposure and minimize any kind of additional risk put on firefighters. “Volunteers are your neighbors helping others,” Quinn said. “They give up so much and dedicate so much and we appreciate each and every one of them for what they do. But we also have to let them realize that there are other means such as home fire sprinklers that will help protect them, their communities, and their families.” Listen to the full interview with Quinn and Carli to learn more about how home fire sprinklers reduce risks for volunteer firefighters:   If you missed any of the previous interviews, including Carli’s most recent discussion with Mike O’Brian, a fire chief from the Brighton Area Fire Authority and a board member on the International Association of Fire Chiefs, find the full video series on HFSC’s website.   Help NFPA and HFSC celebrate its 25th anniversary this year; share the facts about the affordability, reliability, and effective protection of home fire sprinklers. For additional information, visit the Home Fire Sprinkler Coalition and the Fire Sprinkler Initiative websites.

A Guide to Fire Alarm Basics – Emergency Control Functions

A fire alarm system is a crucial part of the overall fire protection and life safety strategy of a building. A fire alarm system serves many functions and the differences between the functions can be a bit confusing, so I created a visual guide to fire alarm basics. The objective of this blog series is to discuss some of the major components and functions of a fire alarm system. For an overview of the entire system take a look at my Guide to Fire Alarm Basics blog. This blog will take a deeper dive into the emergency controls of a fire alarm system.     The fire alarm control unit can be used to control the function of other systems such as elevator recall, automatic door closers, smoke control systems, and so on. The most common way that the fire alarm can do this is through the use of a control circuit and a relay.     A control circuit is essentially a notification appliance circuit (NAC) that is used to send power to a relay instead of notification appliances. A relay is a switch that is open and closed electromechanically and allows the fire alarm control unit to operate emergency control functions. As seen above, power sent from the fire alarm control unit will energize an electro-magnet coil, which will cause the switch, which is controlling power coming into the common terminal (C) to move from the normally closed (NC) position to the normally open (NO) position. This switch can then be used to control other systems.   The control outputs from a fire alarm control unit can also be sent out on a signaling line circuit (SLC) to an addressable output module, which can open or close a contact based on information sent from the fire alarm control unit on the SLC to the COMM terminals. This is beneficial because multiple output modules can be controlled by the same SLC, which can control each module separately. For example, all output modules controlling all of the door hold opens in a building could be on the same SLC, but based on the specific input to the control unit, only specific doors can be closed. If all of these modules were on the same control circuit, the control unit would only be able to close all the doors.      The fire alarm control unit can also be used to send a signal to the elevator controller to initiate elevator recall or shutdown. The fire alarm control unit will send a signal to send the elevator to the designated level (typically street level) when a smoke detector on any floor lobby or in the elevator machine room detects smoke, if smoke is detected in the designated level lobby the elevator will be sent to the alternate level (typically the level above the designated level). This is done to protect any of the occupants in the elevator by ensuring that they exit the building and do not go to a floor that has a fire on it.   If the elevator hoist way, pit, or machine room is required to have sprinklers, the fire alarm control unit is used to cut power to the elevator via a shunt trip prior to sprinkler activation to protect occupants. This is done by either placing a heat detector with a lower response time index (RTI) next to the sprinkler or by using a waterflow switch next to the sprinkler. The lower RTI means the heat detector would activate before the sprinkler, if a waterflow switch is used, it would need to have a 0 second time delay.     Many building designs include the use of large open spaces such as atriums that connect multiple floors of a building. To keep occupants safe in the event of a fire, a smoke control system may be needed to maintain the level of smoke above the occupants as they are exiting the building. These systems may be composed of exhaust fans and makeup air openings that are all controlled by a separate smoke control panel. The fire alarm control unit is responsible for sending a signal to the smoke control panel to initiate smoke removal when specific smoke detectors, pull stations, and waterflow alarms within the protected space are actuated. Additionally, the fire alarm control unit may be responsible for closing specific fire doors and dampers to enclose the smoke control zone. Want to learn more about smoke control systems? Check out this blog.    If a fire were to start within a building, an important objective is to contain the fire and products of combustion within an enclosed space for as long as possible. This is accomplished through construction that can resist the passage of fire. In most buildings these fire-resistant barriers can be found in corridor walls, and shafts (including stairwells). Openings within the fire-resistant construction need to be protected with fire doors. For these doors to be effective they need to be closed, so they are equipped with automatic closers. In some cases, the fire alarm can be used to hold these doors open with an electro-magnet door holder. Upon alarm, the fire alarm control unit will send a signal to cut power to the electro-magnets allowing the door to close.    A key piece of documentation for the fire alarm system is known as the input/output matrix. This table outlines all the outputs from the fire alarm control unit when a given input is received. Above is a portion of the input/output matrix outlining elevator recall. An example shown on this chart would be when the fire alarm control unit receives an input from the 1st floor elevator lobby smoke detector (row 6) it will activate the NAC circuit 1 and NAC circuit 2 as well as send a signal to the elevator controller to recall the elevator to the alternate level. This document is key to the proper design of a fire alarm system and is also a crucial when performing testing to ensure that all of these systems are working as intended. When a fire alarm control unit controls another system, it is known as system integration. It is crucial that the fire alarm system along with all integrated systems are tested properly. For more information on integrated fire protection and life safety system testing take a look at this fact sheet on NFPA 4. Go here for an interactive learning module on integrated system testing. Want to learn more? Like I noted in the beginning of this blog, if you are interested in learning more about fire alarm basics, take a look at my Fire Alarm Basics blog. I will be updating this series over the next few months to add a deeper dive into different portions of the fire alarm system. 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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