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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.

NFPA Today

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.

Join NFPA as we Celebrate 125 Years of Protecting People and Property; Anniversary Conference Series Kicks off on May 18 with Electrical Program

NFPA is celebrating its 125th anniversary this year and we want to commemorate this momentous milestone with you! Since our founding in 1896, NFPA has been devoted to eliminating death, injury property, and economic loss due to fire, electrical, and related hazards. Working side-by-side with our members, colleagues, and countless other fire and life safety advocates from every industry across the globe, we have had a major impact on the public’s safety – we’re proud of the strides we have made over the past few decades in reducing the fire problem worldwide.  So it is with great excitement we’re announcing NFPA will be hosting a series of events and initiatives throughout the year that pay homage to the Association and its long history of dedication and collaboration. Key to the celebration is the launch of a virtual 125th Anniversary Conference Series that replaces the traditional in-person 2021 NFPA Conference & Expo. The series features 10 one-day programs for building, electrical, and life safety professionals and practitioners that collectively offer more than 100 informative education sessions, engaging content, industry roundtable discussions, networking opportunities, live chat sessions, and exhibitor demonstrations. Led by leading industry experts, the program sessions cover a broad range of topic areas from the impact of new technology on codes and standards and the use of data to drive safety, to community risk reduction and public education strategies aimed at protecting people and property. The sessions are designed to help you adjust to changing industry needs and more effectively and efficiently perform your daily work. The online conference series runs from May 2021 through March 2022 and will be available on demand during the year to allow for more schedule flexibility.  For those in the electrical industry, you do not want to miss the first program of the series that kicks off on May 18. The “Empowering Electrical Design, Installation, and Safety” one-day program has two learning tracks and nine sessions that focus on issues related to design and installation, new and emerging technology, and workplace safety in the electrical landscape. Whether you attend the live event in May or view the content on demand, the program will help you sharpen your skills and improve your knowledge as you earn CEU credits. Find out more on our webpage. With so much to celebrate, we hope you’ll join us for this year-long, unique educational opportunity. A safe world is our priority, and we look forward to our continued progress, working with all of you, during the next 125 years and beyond! Visit nfpa.org/conferenceseries to learn more about the series, the electrical program, and to see the full roster of upcoming events.

Fire Break

A wildfire burning at night

Burn Survivor Shares Her Story About Importance of Being Prepared for and Living Safely with Wildfire

In just the past few years, the U.S. has seen the average number of acres burned in wildfires rise exponentially. The country has watched as 40,000 structures have been destroyed, 100 lives were lost, and countless families were impacted as a result of a wildfire event in their community. Allyson Watson knows first-hand what it means to suffer at the hands of a wildfire. Forced to evacuate her home during one of the worst wildfire seasons in the history of southern California, Allyson was involved in two separate car accidents trying to flee her family home when a wildfire engulfed her community. Suffering 2nd and 3rd degree burns over 85 percent of her body as a result of the accidents, Allyson spent years recovering from her injuries. The Phoenix Society for Burn Survivors recently shared Allyson’s story on their website. As a burn survivor her journey is one of perseverance and resilience, and she credits her family and friends with helping her through the emotional and physical aspects of her recovery. As she grew stronger, Allyson’s bravery and passion spurred her on to advocate for wildfire safety, raising awareness and educating others in wildfire-prone areas about the importance of being prepared for a fire including having an evacuation plan and initiating retrofits and maintaining ignition-resistant properties. Allyson’s story is a powerful reminder about the need for better policies if we want to lower community wildfire risk. NFPA recently launched Outthink Wildfire™, an initiative that aims to drive more policy change across all levels of government to stem the tide of losses from wildfire. With so much loss, it is time for the country to take a stand, demand a new approach, and pursue a better course of action that will help us live more safety with wildfire. NFPA believes if the policy actions laid out in Outthink Wildfire are followed, we can end the destruction of communities from wildfire in the next 30 years. We are grateful to Allyson for sharing her story with us.  Read more about her journey and Outthink Wildfire on the Phoenix Society’s website.

NFPA Journal explores how we can collectively Outthink Wildfire™

The new Spring NFPA Journal is out and its feature article takes an in depth view on NFPA’s bold new strategy for ending the destruction of communities by wildfire in 30 years.  To Outthink Wildfire™, we can’t simply do what we’ve always done to address the problem.  What is needed are new approaches, new tactics, and a new resolve to use what we’ve learned about the risks of the wildland/urban interface (WUI) over the past 50 years to create a new blueprint for addressing the nation’s wildfire crisis.  The article explores the five key action policies for this new call to action, provides relevant examples about where the challenges are and where they are being solved, and calls on you to make a difference.  I enjoyed the privilege of collaborating with NFPA’s Wildfire Division Director, Michele Steinberg, on this article and hearing her excitement for the vision of Outthink Wildfire™.  When the NFPA Journal’s feature article was released earlier this week, she explained, “We can’t wait any longer, hoping that a specific industry or agency will take the first step to changing future outcomes. By taking a holistic approach and inviting decision-makers and stakeholders to engage in the solutions together, we can strengthen the arguments in favor of sustainable building and land management. Together, we can come to consensus on the solutions to provide better protection of the people and places at risk from wildfire destruction.” I share her excitement.  Recent destructive wildfires bring into stark focus that the continued loss of life, property, and local economic vitality is unacceptable.  The challenges in social equity from this risk are unacceptable and a holistic approach is truly needed to outthink wildfire.  This will require a generational shift that seeks changes over the natural life cycle of existing homes and public demand, just as the progressive response to urban conflagrations in the 19th and 20th centuries achieved.  Ultimately, we need to make the loss of communities to wildfire a lesson of history, not a part of our future. Learn more about the Outthink Wildfire™ action policies and their call to action for your community

Safety Source

Massive blaze at apartment building in New York underscores critical importance of an educated public

Last week, a massive blaze at six-story apartment building in Queens, NY displaced approximately 240 residents and injured six people. According to Daniel Nigro, commissioner of the New York City Fire Department (FDNY), the door to the apartment unit where the fire began had not been closed when the resident exited, a misstep that contributed to the fire’s rapid spread. The door was open," Commissioner Nigro said. "The occupant fled, left the door open. We've stressed over the years the seriousness of that if you do unfortunately have a fire in your home or apartment, how important it is to close that door. The fire (traveled) out to the hallway, the units were unable to make a quick advance." Much research has been done in recent years underscoring this point, including fire tests by Underwriters Laboratories which show that closing doors upon exiting a fire can make a substantive difference in slowing its spread. Nigro also noted that a delay in calling 911 exacerbated the furthered the fire’s spread and the damage incurred. According to an FDNY video posted on the department’s Facebook page, residents smelled smoke and smoke alarms were sounding, but no one called the fire department for 10 minutes. This delayed response reflects a complacency around fire that can lead to devastating outcomes. In a broader context, incidents like this reinforce the critical importance of the NFPA Fire and Life Safety Ecosystem, a framework that identifies the components that must work together to minimize risk and help prevent loss, injuries, and death from fire, electrical, and other hazards. If any component is missing or broken, the Ecosystem can collapse. In this incident, an educated public – one of the eight components of the Ecosystem – wasn’t in place and directly contributed to the magnitude of the fire and the damage it incurred. NFPA offers a wealth of public education resources that address the fundamentals of home escape planning and practice, including the importance of promptly responding to the sound of smoke alarms and the smell of smoke. We also have a safety tips sheet that provides specific guidance for people who live in apartment buildings and high-rise structures. Share this information with your communities to help ensure that people know what to do in a fire situation and have the skills to help minimize the extent of a fire’s impact on people and property.
Man varnishing a chair

As warmer weather approaches, NFPA offers 6 key tips to safely tackle spring cleaning

Melted snow, budding trees, longer days: they’re all signs that the warmer months are fast-approaching -  and for many of us, these seasonal hallmarks are reminders to start spring cleaning in and around our homes. As people power up their lawnmowers, rake up debris, touch up chipped paint, and take on myriad projects to get their homes and yards ready for the months ahead, following are six key practices and supporting recommendations to help minimize the risk of fires and associated hazards: Properly use and store gasoline Use gasoline only as motor fuel, never as a cleaner or to break down grease. Only store gasoline in a container that is sold for that purpose and never bring it indoors, even in small amounts. Never store gasoline containers in a basement or in the occupied space of a building. Keep them in a detached garage or an outdoor shed. Make sure the container is tightly capped when not in use. Carefully dispose of rags with paint and stain The oils commonly used in oil-based paints and stains release heat as they dry. If the heat is not released in the air as the rags dry, the heat is trapped, builds up and can cause a fire. Never leave cleaning rags in a pile. When you’re finished using the rags, take them outside to dry, keeping them well away from the home and other structures. Hang rags outside or spread them on the ground and weigh them down so that they don’t blow away. Put dried rags in a metal container, making sure the container is tightly covered. Fill the container with a water and detergent solution, which will break down the oils. Keep containers of oily rags in a cool place out of direct sunlight and away from other heat sources. Check with your town for information on how to properly dispose of them. Use/store flammable and combustible liquids with care Flammable and combustible liquids should not be used near an open flame. Never smoke when working with these liquids. If you spill liquids on your clothing, remove your clothing and place it outside to dry. Once dry, clothing can be laundered. Keep liquids in their original containers. Keep them tightly capped or sealed. Never store the liquids in glass containers. Feel free to use and/or share our Safety with Oily Rags tip sheet (PDF), which includes the above tips and more. Inspect grills to ensure they’re in good working order Inspect your grill (PDF) carefully and make sure it’s free of grease or fat buildup. Clean out any nests, spider webs, or other debris you may find. For propane grills, check the gas tank hose for leaks before using it for the first time each year. Keep debris well away from your home Every year, wildfires (PDF) burn across the U.S., with more and more people living in communities where wildfires are a real risk. Dispose of branches, weeds, leaves, pine needles, and grass clippings that you have cut to reduce fuel for fire. Remove leaves, pine needles, and other flammable material from the roof, gutters, and on and under the deck to help prevent embers from igniting your home. Remove dead vegetation and other flammable materials, especially within the first 5 feet of the home. Move construction material, trash, and woodpiles at least 30 feet away from the home and other outbuildings. Clean out your clothes dryer Make sure the air exhaust vent pipe for your dryer (PDF) is not restricted and that the outdoor vent flap will open when the dryer is operating. This includes making sure the outdoor vent flap is not covered by snow. Move things that can burn, such as boxes, cleaning supplies and clothing, away from the dryer. Clothes that have come in contact with flammable substances like gasoline, paint thinner, or similar solvents should be laid outside to dry, then can be washed and dried as usual.

Fire Sprinkler Initiative

Help Spread the Word About the Life-Saving Benefits of Home Fire Sprinklers During Home Fire Sprinkler Week May 16 – 22, 2021

The Home Fire Sprinkler Coalition (HFSC) is celebrating its 25th anniversary this year! To commemorate this great milestone, HFSC is developing new innovative tools and materials to support community outreach. One example is the popular Home Fire Sprinkler Week campaign set to launch on May 16 – 22, 2021. A project of HFSC and the NFPA Fire Sprinkler Initiative, this week-long campaign is the perfect opportunity to get the tools you need to help further the life-saving educational message of home fire sprinklers. Building on the great success of last year’s event, Home Fire Sprinkler Week will again go digital in 2021. The campaign is designed to help you virtually share messages and resources every day of the week on both a website and social platform such as Facebook, Twitter, Instagram, and LinkedIn. If you’re a member of the fire service, take advantage of materials and more social media graphics to share during the week or at any time of the year. Additional assets you will be able to use during the Week include: A brand new HFSW digital campaign to reach younger homebuyers to help emphasize the need for home fire sprinklers in communities A new video to highlight the green benefits of installing home fire sprinklers With each day of the campaign, you will find a different theme and related content like videos and graphics with posts, to share. You can choose one message or share all messages on any given day. The daily themes are: Monday, May 17: Fire is Fast Tuesday, May 18: Fire Sprinklers Are Part of Fire-Safe Communities Wednesday, May 19: It’s Easy to Live with Home Fire Sprinklers Thursday, May 20: Fire Sprinklers are Smart and Green Friday, May 21: Protect What You Value Most As we ramp up to Home Fire Sprinkler Week, stay tuned to the HFSC website for more campaign information and resources. We look forward to you joining us on May 16!

Home Fire Sprinkler Coalition Expands Stipends to Canadian Fire Departments to Support Home Fire Sprinkler Outreach, Extends Application Deadline for US Fire Department Stipends

The Home Fire Sprinkler Coalition (HFSC) announced they will award C$500 stipends to 20 qualifying Canadian fire departments that demonstrate a plan to share the importance of home fire sprinklers with their community during Home Fire Sprinkler Week (HFSW), which runs from May 16-22. Only departments that are part of HFSC’s BUILT FOR LIFE program are eligible to receive the stipend. The application link is available here, and the deadline is March 31. Additionally, the deadline for the $300 stipends to American fire departments has been extended to March 10. That application link is available here. Some options for outreach programs to qualify for the stipend include, but are not limited to, conducting a virtual Home Fire Sprinkler contest, producing a banner or canopy tent to display Home Fire Sprinkler graphics, setting up a monitor in the community to play HSFC educational videos, or building an NFPA 13D display to explain how a home fire sprinkler works. Additional ideas include boosting a Facebook post to reach a larger audience or conducting a virtual Home Fire Sprinkler contest and awarding prizes. Read the announcement here for more information. To learn more about home fire sprinklers and how to increase the number of homes being built with sprinklers in your community, visit the Home Fire Sprinkler Coalition and the Fire Sprinkler Initiative.

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