AUTHOR: Shawn Mahoney

A Guide to Fire Alarm Basics – Initiation

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 initiation portion of a fire alarm system. The main function of the initiation portion of a fire alarm system is to report the status of a protected space or the existence of a fire. The components include all devices and circuits that send a signal to a fire alarm control unit (FACU) such as heat detectors, smoke detectors, carbon monoxide detectors, water flow switches, manually actuated devices, and pressure switches. Depending on the system, the signal from an initiating device can create an alarm condition or a supervisory condition. Based on the type of detectors and FACU, the signals can be sent over an initiating device circuit (IDC) for conventional systems, or a signaling line circuit (SLC) for addressable systems. Conventional initiating devices are typically detectors that use a switch contact to short both sides of the initiating device circuit together. By doing so, the initiating device causes an increase in current flowing through the circuit, which the FACU interprets as an alarm signal. Once one device shorts the circuit, no other device on that circuit or “zone” can send a signal. Because of this, any device on the circuit or “zone” will put the entire zone into an alarm state. Zones are typically designed to enable someone to easily identify an area where the alarm is located, for example, in a school you may have a gymnasium zone circuit and an auditorium zone circuit that each contain multiple devices. Addressable devices are either initiating devices or control/notification appliances that are capable of communicating a unique identification number or address to a control unit via a signaling line circuit. This identification consists of a binary string of 1s and 0s that indicate the address or location of that device on the circuit. When the FACU polls an initiating device, the initiating device responds with its status (Normal, Alarm, ect.) and address. The device address allows for the location of the detector to be identified at the FACU. When one initiating device is activated on a signaling line circuit, the FACU is still able to poll the other devices unlike a conventional initiating device circuit. Additionally, some addressable initiating devices are able to also transmit to the FACU a range of values of smoke density, temperature variation, water level, water pressure changes, and other variables. And then the control unit software determines the set points for initiation of an alarm, supervisory, or trouble signal. These types of initiating device circuits are known as analog addressable as they are able to tell the FACU their address and their value.   Ionization smoke detectors utilize a small amount of radioactive material to ionize air molecules into positively and negatively charged molecules that create a small electric current. The introduction of smoke into that ionized air will reduce the amount of current and cause an alarm signal.   Photoelectric smoke detectors utilize a light source and a photosensitive cell. When smoke enters the chamber, light scatters and is picked up by the photosensitive cell, causing an alarm signal. A beam smoke detector is like a photoelectric detector, except it is designed to cover a large area. A transmitter and receiver or reflector are placed to create a light beam across a space, when the amount of light being received by the receiver or reflected to the transmitter falls below a certain percentage, an alarm signal is sent. A non-restorable fixed temperature heat detector utilizes solder that holds up a plunger. The solder melts at a specific temperature and causes the plunger to drop, which shorts the contacts and causes an alarm signal.   A restorable fixed temperature heat detector utilizes two metals that have different thermal expansion coefficients. At a specific temperature, these metals will bend and cause the plunger to short the contacts, which causes an alarm condition. When the metal cools it will bend back in the other direction and restore itself.     A rate-of-rise detector utilizes an air chamber and a diaphragm. When a fire causes the air in the chamber to expand faster than it can escape out the vent, the increased pressure forces the diaphragm to close the contacts and initiate an alarm signal. This rate-of-rise detector also contains a fixed temperature plunger that will operate if the temperature exceeds the determined temperature.     An analog addressable heat detector utilizes a thermistor element to constantly monitor the temperature. The response criteria, which can be a temperature above a specified level, or a specific rate of rise in the temperature, is programmed at the FACU.   There are many different types of carbon monoxide (CO) detectors. One example of a CO detector is a Colorimetric detector. Like a photoelectric smoke detector, this detector contains a light source and a photocell that are constantly measuring for light being reflected from a chemical detector. In the presence of carbon monoxide, the chemical detector will change to a black color and light will no longer be reflected to the photocell, which will result in an alarm signal.   Sometimes called manual fire boxes, pull stations, or call points, manually actuated initiating devices initiate an alarm signal when there is an input from a person, such as pulling a lever or pushing a button. These can require multiple actions to initiate such as lifting a cover or breaking glass prior to actuating the device.   Flow switches are installed inside the piping of a sprinkler system and have a vane that moves with the flow of water. When water begins to flow within the pipe, the vane operates a switch that initiates an alarm.     Pressure switches are installed on sprinkler systems to monitor for a change in water pressure. A signal will be sent to the FACU when there is an increase in water pressure, which means that water is flowing though the sprinkler alarm valve. 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.

Introduction to Seismic Protection for Sprinkler Systems

We rely on a sprinkler system within a building to protect both the building and occupants during a fire. After a building is subject to a seismic event, such as an earthquake, there is an increased possibility for a fire to occur.  For a building that is in an area subject to seismic activity, it is crucial to provide seismic protection to ensure the sprinkler system installed remains capable of protecting the building and occupants after a seismic event. What does Seismic Protection Include? Chapter 18 of the 2019 edition of NFPA 13, Standard for the Installation of Sprinkler Systems, provides requirements for the general protection of fire sprinkler systems against damage resulting from seismic activity. The requirements are based on a comprehensive approach of providing not only bracing but also flexible connections, pipe clearance to structural members, pipe restraint, and restrictions on the types of hangers and fasteners used. It is the intent of NFPA 13 for the sprinkler system to coordinate movement from a seismic event with the building structure. The sprinkler system and the building are to move as one unit, which traditionally is accomplished with sway braces connecting the system piping and the structure. Where the building is expected to move, the sprinkler system must be able to accommodate that motion. For example, where there is a seismic joint within a building that can create differential (or opposing) movement of the structure, the sprinkler system also must have a seismic joint so that the system is not damaged from the movement. Additionally, proper clearance around the piping needs to be provided to allow for movement, this includes when piping is run through walls and partitions. Example of a Seismic Loop at a Seismic Joint. (Courtesy of Anvil International) When is Seismic Protection Required? Not all areas are subject to seismic activity or expect significant seismic forces if an event were to occur. As such, not all fire sprinkler systems require seismic bracing. Usually, the local or state building code will drive the need for seismic bracing. The authority having jurisdiction and the system designers and/or technicians should agree early in the project whether protection against seismic damage will be required. Seismic Bracing A fire sprinkler system requiring seismic protection is held in place within a building with some combination of sway bracing, restraint hangers, and pipe stands. These components should be laid out in such a manner that all potential horizontal movement expected from an earthquake is controlled. Successful bracing of fire protection systems involves determining the appropriate force factors, tentative placement of sway bracing, determining the loads to braces, and verifying the loads can be carried by the sway brace components. Sway bracing is provided to prevent excessive movement of system piping. Shifting of large pipe because of an earthquake has led to the pull-out of hangers and the fracture of fittings. With some exceptions, seismic bracing is required at the following locations: Top of the system riser All feed and cross mains or other piping regardless of size Branch lines 2½ in. (65 mm) in diameter and larger (lateral bracing only) NFPA 13 contains requirements for both lateral (perpendicular to the piping) and longitudinal (parallel to the piping) horizontal braces (shown below). The maximum spacing of lateral braces of 40 ft (12 m) is based on the strength of the piping as a beam under the uniform load of its expected horizontal “weight.” Longitudinal braces are required at a maximum spacing of 80 ft (24 m).   Lateral Sway Bracing (Drawings courtesy of AFCON)     Longitudinal Sway Bracing (Drawings courtesy of AFCON)   Lateral and longitudinal braces shown above are “two-way” braces, that is, they prevent piping from moving back and forth in a single direction. Four-way bracing, shown below, requires the simultaneous application of lateral and longitudinal bracing. Two Typical Four-Way Sway Brace Assemblies (Drawings courtesy of AFCON)   As with system hangers, sway braces must be attached directly to the building structure. Fasteners and structural elements at the points of connection must be adequate to handle the expected loads. Sway Bracing Calculations Sway braces need to be designed to withstand forces in tension and compression of the system. To properly size and space the braces, it is necessary for the designer to complete a calculation (sample calculation form shown below). This calculation includes: Determining the seismic coefficient Cp Choosing the brace shape and size based on the system piping and the structural members that will support the braces Determining the total load tentatively applied to each brace by the water filled system piping in the “zone of influence” (see examples of load distribution to bracing below) Determining if the total expected loads are less than the maximums permitted Checking to see if the fasteners connecting the braces to the structural members are adequate to support the expected loads.  Sample Seismic Bracing Calculations (NFPA 13)     Examples of Load Distribution to Bracing (NFPA 13)   Summary A sprinkler system installed in a building that is subject to seismic activity may require seismic bracing by the local or state building code . If required, Chapter 18 of NFPA 13 outlines requirements for the seismic bracing, which includes bracing, flexible connections, pipe clearance to structural members, pipe restraint, and restrictions on the types of hangers and fasteners used. The design of required seismic bracing must also include calculations based on the specific piping to be installed in the system. I hope this blog served as a good introduction into seismic bracing, are you interested in seeing a deeper dive into the specific calculations? Have you completed these calculations for a project of your own? Let us know in the comments below. IF you would like to learn more about seismic protection, take a look at the commentary and supplemental information found in chapter 18 of the NFPA 13 Handbook. 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

A Guide to Fire Alarm Basics

A fire alarm system is a crucial part of the fire and life safety of a building and its occupants. There are many functions that are served by the fire alarm system and it all may be a bit confusing to someone new to fire alarms, so I decided to create a visual guide to fire alarm basics. The objective of this blog is to share that visual guide and to discuss some of the major components and functions of a fire alarm system. See larger image   FACU - Fire Alarm Control Unit The fire alarm control unit serves as the brain of the fire alarm system by monitoring all the inputs and controlling all the outputs. Some may also refer to this as a fire alarm control panel or fire alarm panel. The different types of conditions that can be seen at the fire alarm control unit are Alarm, Supervisory, and Trouble, these conditions can also result in a signal being sent to the supervising station. Alarm – An alarm condition means there is an immediate threat to life, property, or mission. An example of this would be a smoke detector sending a signal to the fire alarm control unit that there is a presence of smoke, which would initiate notification to the occupants to evacuate. Trouble - A trouble condition means there is an issue or fault with the fire alarm system. An example would be a break in an initiating device circuit. This would show up as a trouble signal on the control unit. Supervisory – A supervisory condition means there is an issue with a system, process, or equipment that is monitored by the fire alarm control unit (see supervision section). An example of this would be a sprinkler system valve being closed, this would show up as a supervisory signal on the control unit. Here is a blog discussing some of the places you may find a fire alarm control unit. Initiation The initiation of a fire alarm system includes all the devices and circuits that send a signal to a fire alarm to provide the status of a protected space or the existence of a fire. Initiation devices include, but are not limited to heat detectors, smoke detectors, water flow switches, manually actuated devices, and pressure switches. Depending on the system, the signal from an initiating device can create an alarm condition or a supervisory condition. Based on the type of detectors and fire alarm control unit, the signals can be sent over an initiating device circuit (IDC) for conventional systems, or a signaling line circuit (SLC) for addressable systems. For more information regarding fire alarm initiation, take a look at this blog I created diving deeper into fire alarm initiation.   Supervision It is possible to utilize a fire alarm system to monitor the condition of other systems, processes, or equipment that are related to the building’s fire and life safety as well as crucial to the mission of the building. Supervision can include but is not limited to valves on fire protection systems, other fire protection systems such as kitchen hood suppression systems, valve room or storage tank temperatures, and fire pump condition issues with these systems would provide a signal to the fire alarm control unit via an initiating device circuit (IDC) for conventional systems, or a signaling line circuit (SLC) for addressable systems and would create a supervisory condition at the fire alarm control unit.   Power It is important that a fire alarm system be provided with reliable power so it can operate during any emergency. Primary Power Primary power to the fire alarm system can be provided by the electric utility, an engine-driven generator (this is not a standby generator, however, it is a site generator meeting the requirements in NFPA 72® Fire Alarm and Signaling Code®), and Energy Storage System, or a cogeneration system. Secondary Power Secondary power to the fire alarm system can be provided via properly sized batteries, batteries and a standby generator, or an Energy Storage System.   Notification A fire alarm system is able to provide notification to alert the occupants and in some cases on site emergency forces. Notification is provided via visible and audible notification appliances. The visible notification is typically provided via strobes, and audible notification is provided by either speakers, which can provide different tones and voice signals, or horns, which can only provide a single tone. The fire alarm control unit provides the signal to the notification appliances via a notification appliance circuit (NAC).   Emergency Control Functions The fire alarm control unit can be used to control the function of other systems such as elevator recall, 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.     Communication to Supervising Station Supervising stations monitor the premises and include Central Station Service, Proprietary Supervising Stations, and Remote Supervising Stations. The communication method to those supervising stations is done with the communication methods shown below. Based on the types of signals received from the fire alarm control unit and the type of supervision station, the supervising station may alert the emergency forces or dispatch a runner service to fix a trouble to supervisory condition. For more information on fire alarm supervision check out this blog.  I hope you found this guide to fire alarm basics informative, would you be interested in some more guides on other fire protection and life safety topics? If so, let me know in the comments below what systems or concepts you would be interested in. 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.
Rolling fire door

How is a rolling fire door inspection different than a swinging door?

So, you are used to inspecting swinging fire doors per NFPA 80, Standard for Fire Doors and Other Opening Protectives as required by NFPA 101®, Life Safety Code® and are comfortable with those requirements, but you have come across a rolling fire door. Let’s take a few minutes to review some unique aspects to inspecting a rolling fire door. Rolling steel fire doors come in various sizes and can be used for different applications. The term rolling steel fire door as used by most manufacturers refers to a product that is intended for use in relatively larger openings. Such products generally utilize larger slat designs and more substantial guides for securing the assembly to the wall. Many manufacturers use the term counter fire door in reference to products that are typically designed for use on smaller openings such as counters. Their construction is similar to the product that is manufactured as a rolling steel fire door except that the assemblies typically use smaller slat designs and formed steel sections for guides. NFPA 80 does not differentiate between these products. NFPA 80 requires that door openings and their surrounding areas be kept clear of anything that could obstruct or interfere with the free operation of the door. This is something that is very important to pay attention to with rolling fire doors because it is very easy for someone to unknowingly place furniture under a rolling fire door that would obstruct it from closing, which would render the entire assembly useless. Because of this, operators of a facility should be trained to know the areas where they cannot place items that could interfere with the rolling fire door. Just as with swinging fire doors, rolling fire doors are required to be inspected, tested, and maintained in accordance with NFPA 80, which includes an annual inspection. During this inspection, the rolling door needs to be drop-tested twice. The first drop is done to ensure that the assembly is in proper operation and fully closes, the second drop is to ensure that the entire assembly including the automatic closing device was reset correctly in accordance with the manufacturer’s instructions. Make sure you check any fusible links, release devices, and any other moveable parts to ensure that they are not painted or coated with materials that could interfere with the operation of the assembly. Some of the items that need to be inspected are similar to those for a swinging fire door, such as: the label ·open holes, breaks or damage modifications missing or broken parts auxiliary hardware that can interfere with the operation of the door, In addition, there are other items that need to be checked on a rolling fire door. The first is to make sure that the curtain, barrel, and guides are aligned, level, plumb, and true, this is necessary to ensuring that all the components of the assembly work together properly. Next you will need to ensure that all the expansion clearances outlined in the manufacturers listing are maintained. This is different than a swinging fire door because NFPA 80 does not provide those clearances, they need to be provided from the manufacturer and should be located in the listing. Mechanisms that are utilized for the automatic operation of the rolling fire door such as smoke detectors or fusible links need to be inspected to ensure that they are operational. If the rolling fire door relies on the fire alarm for operation, it may be required to initiate a fire alarm and confirm that it operates in accordance with the fire alarm input/output matrix. One additional difference between a swinging fire door inspection and a rolling fire door inspection is that you will need to confirm that the rolling fire door has an average closing speed of not less than 6 in./sec (152 mm/sec) or more than 24 in./sec (610 mm/sec), which means you will need to measure the total length the door must close and record the amount of time it takes to close in order to calculate the average time. Clearly, there are some differences with inspecting a rolling fire door as compared to a swinging fire door. As a result, I recommend taking a look at chapter 5 in NFPA 80 to find all of the specific requirements before performing an inspection. Let me know in the comments if you have had any experience with inspecting rolling fire doors. Are there any other things that you pay attention to or have come across?

Fire Pump Electrical Safety for Service Personnel

Fire pumps are an important component in fire protection systems as they provide the required water pressure that these systems need to operate. Requirements for the installation of fire pumps are covered in NFPA 20 Standard for the Installation of Stationary Pumps for Fire Protection. In order to ensure the availability of power to fire pumps, NFPA 20 discourages the installation of a disconnecting means and features that limit overcurrent protection in the power supplies to electric motor-driven fire pumps. The lack of an overcurrent protection device is something that becomes important to consider when discussing the Inspection Testing and Maintenance of these fire pumps. In order to make sure that fire pumps remain operational, NFPA 25 Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems outlines the minimum requirements for inspection, testing, and maintenance (ITM) of water-based fire protection systems, including fire pumps. When performing required ITM on the fire pump equipment, the lack of overcurrent protection devices discussed earlier subjects service personnel to an unusual exposure to electrical shock, arc flash, and arc blasts. Because of these dangers, some important changes were made to the 2020 edition of NFPA 25 and all the way back through the 2011 edition via tentative interim amendment to reduce the need for a service person to open up the fire pump controller to take the measurements or perform inspections if the controller could not be placed in an electrically safe work condition. The changes that have been made to NFPA 25 now require the safe work practices within NFPA 70E Standard for Electrical Safety in the Workplace®, or an equivalent such as Canada’s CSA Z462 Workplace Electrical Safety, to be applied in addition to legally required precautions when testing or maintaining fire pump controllers. Additionally, the tests and inspections in chapter 8 that would have required a service person to open up the energized fire pump controller to take measurements or inspect connections have been alleviated if they cannot be completed without opening an energized controller. These include, but are not limited to: Printed circuit board inspections Cable and wire inspections Plumbing parts inspection inside of electrical panels Inspection of controls and power wiring connections Testing accuracy of pressure gauges and sensors Reading current pressure for fire pumps that use electronic pressure sensors to control the fire pump operation Recording electric motor voltage and currents (all lines) Testing alarm sensors within the fire pump controller (instead they can be tested at an alternative location) It may be possible for some of these readings to be taken on an energized controller if external means are provided. Additionally, some of these inspections can be completed if the fire pump controller can be placed in an electrically safe work condition. Per NFPA 70E, this would include de-energizing the circuit, lockout/tagout of the isolation device for the controller, and confirming that the controller is in a zero energy state. In order to de-energize the controller, an isolation switch in the fire pump controller - located in a separate compartment than the other controller components - can be used. It should be noted that fire pumps are permitted to have a disconnecting means per NFPA 20 and NFPA 70® National Electrical Code® (the NEC), but due to the cost of adding such a large disconnecting means, they are not typically provided. Without a disconnecting means, it becomes much more difficult to de-energize the fire pump controller for work. The philosophy of NFPA 70E is to complete work on de-energized equipment, which aligns well with the requirements in NFPA 25, but if there is a need to complete work, inspect, or test an energized controller, precautions need to be made in order to protect the service person from shock, arc flash, and arc blast. There is far too much involved in NFPA 70E to cover everything in this blog, but I can give a brief overview of the options when working on an energized fire pump controller. NFPA 70E requires that a qualified service person complete a risk assessment before performing a task to determine if a hazard exists, how likely the hazard is to cause injury, how bad the injury could be if it were to happen, and what measures should be taken to protect themselves. This last part often includes the use of personal protective equipment or PPE. To determine the proper level of PPE, the service person would need to either utilize the PPE Category Method or an Incident Energy Analysis. The PPE category method is outlined in NFPA 70E, however this method relies on the clearing time of an upstream overcurrent protective device (OCPD). Since many fire pumps are supplied directly from a service and have no upstream OCPD, the service person would need to reference the information determined from an Incident Energy Analysis. This means that an incident energy analysis will have to have been performed prior to any service personnel opening an energized cabinet to perform any testing. To aid the worker in selecting PPE based on the Incident Energy Analysis, NFPA 70E requires that the owner label the equipment with the following: Nominal system voltage Arc flash boundary At least one of the following: Available incident energy and the corresponding working distance, or the arc flash PPE category Minimum arc rating of clothing Site-specific level of PPE Keep in mind that only service personnel that meet the definition of a qualified person in NFPA 70E can perform this task. That means that they have demonstrated the skills and knowledge related to construction and operation of the fire pump controller and they have also received the necessary safety training to be able to identify the hazards and take the appropriate steps to reduce the risk from the electrical hazards present. Without this labeling, the service worker cannot make a determination for safe work practice on the equipment without further assessment of the incident energy associated with the installation that needs to be provided by the owner. If the worker is able to complete the Incident Energy Analysis, or the fire pump controller is provided with an overcurrent protection device and the PPE Category Method is performed, then the service person can complete the work if they are qualified, have training in 70E and the equipment they are using, and are using the proper PPE and precautions. In conclusion, NFPA 25 alleviates some of the inspection, testing, and maintenance on a fire pump if they cannot be completed without opening an energized fire pump controller. If there is a need to complete work inside of an energized fire pump controller, the owner of the controller and service worker will need to follow NFPA 70E to determine the proper safeguards and PPE needed when completing the work. Under no circumstances should a service person engage in work on energized equipment without determining and using the proper level of PPE and obtaining the proper level of training. If you haven’t done so already, download the new Electrical Safety in the Workplace fact sheet that came out recently.

Ensuring the Operation of Your Fire Alarm System During Loss of Primary Power

We rely on a fire alarm system to constantly monitor for hazardous conditions (such as fire, smoke, carbon monoxide, and even combustible and toxic vapors) within a building, and notify the occupants so they can exit the building safely, notify first responders, and even activate systems to mitigate the hazard such as fire suppression or ventilation. The fire alarm system needs to be able to operate continuously during the life of a building, this includes times in which primary power to the building is lost. Secondary Power Supply Fire alarm systems are provided with a secondary source of power in order to remain operational after loss of primary power. The most common forms of secondary power supplies are batteries or an emergency generator. Secondary power supplies are designed to provide enough capacity to power the entire system for 24 hours on standby and then operate the system for at least 5 minutes under emergency conditions (15 minutes for mass notification systems). If a generator is used for secondary power, batteries are still required, but only need to provide capacity for 4 hours, this gives time to get the generator operational if there is an issue. In order to ensure that the secondary power supply is always available, the fire alarm system itself is able to monitor for the presence of voltage and monitor the battery charging system, and will then annunciate a trouble signal if there is an issue with the power supply or charging system. Battery Inspection Testing and Maintenance Although the system can monitor some aspects of the secondary power supply, there is some inspection, testing, and maintenance (ITM) that needs to be completed to ensure that the secondary power supply is reliable. For ITM specific to the generator, refer to the blog that I wrote on Maintaining your Emergency Power Supply. Batteries need to be inspected semiannually to confirm that the connections are tight and there is no corrosion on the connections. When inspecting, the batteries need to be checked for damage such as cracks in the case, bulges, or leaking. The batteries need to be marked with the month and year of manufacture (not the date of installation), this information is important for tracking the batteries age. If the battery's age exceeds the manufacturer's replacement date, the battery needs to be replaced. The batteries and charger need to be tested semiannually; these tests include: Measuring the temperature to ensure that the battery is not 18F (10 C) above ambient temperature Measure the voltage to ensure that the battery and charger are still operational Measure the voltage at each cell of the battery to confirm each cell is greater than 13.26 volts Measure the internal ohmic value of each battery and compare to previous tests to ensure that the battery does not have 30% or more conductance or 40% or more resistance or impedance than previous tests or is outside the manufacturer's acceptable ranges. Every three years the batteries need to either be replaced or a load test needs to be conducted. Load tests are conducted by putting a known load on the battery for a given time (found from the battery manufacturer). The battery is discharged until it reaches its end voltage. Based on the known load and the time taken to discharge you can then calculate the capacity of the battery and apply any adjustments for temperature. The battery must be replaced if the capacity is less than 80% of its rated capacity. Secondary Power Operation All the requirements for ITM above focused on the batteries themselves, but there are some tests that need to be completed in order to make sure that the entire system will operate under secondary power. First, if the system is supplied by an emergency generator, power will need to be transferred to the generator monthly to ensure that the transfer switch and generator will be able to supply the fire alarm. Additionally, all primary power to the system needs to be disconnected annually so the required standby and alarm current to the system can be measured and compared to the available battery capacity. Remember, these batteries need to be able to provide the 24 hour standby and 5 (or 15) minutes of alarm or 4 hours of standby if there is also an emergency generator. Finally, the system needs to be operated under secondary power in alarm for at least 5, or 15 minutes depending on the system type. Do you have any instances in which you needed to replace the fire alarm batteries because they failed testing? Was there a time in which you relied on the secondary power during an outage? Let me know in the comments below. If you found this article helpful, subscribe to the NFPA Network Newsletterfor monthly, personalized content related to the world of fire, electrical, and building & life safety

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