These are the Top 25 Fire Alarm Acronyms You Must Understand to Do Your Job

By Andrew Erickson

May 19, 2023

If you're new to the world of fire safety or are simply curious to learn more, you've probably come across a series of acronyms that have left you scratching your head.

I'm here to help you unravel the tangled web of fire alarm lingo, one scary "TLA" (Three-Letter Acronym!) acronym at a time.

Let's dive into some of the most common and important acronyms in the fire alarm industry:

  1. NFPA - The "National Fire Protection Association" is a non-profit organization that creates and maintains standards and codes for usage and acceptance by local government legal bodies responsible for fire safety. The best known of these standards is NFPA 72, the National Fire Alarm and Signaling Code, which provides comprehensive requirements for all aspects of fire alarm systems, including installation, performance, inspection, testing, and maintenance. NFPA 72 is a guiding light for us at Digitize because it dictates that standards that our fire alarm monitoring systems must follow.
  2. AHJ - The "Authority Having Jurisdiction". The AHJ is the organization, office, or individual responsible for enforcing the requirements of codes and standards. In the context of fire safety, the AHJ could be a fire marshal, a building inspector, or another local or state authority. They have the power to approve or deny fire safety system plans and installations. You'll commonly find AHJ modifications to the core NFPA codes. These adjust precisely what you'll need to do to be compliant in your local area.
  3. FACP - Your "Fire Alarm Control Panel" is the brain of the fire alarm system. This panel controls the functions of the system, from receiving information about potential fires from detectors to activating alarms to alert building occupants. It's a critical component of any fire alarm system. When I started at Digitize (as we brought it into the DPS Telecom family of companies), "FACP" was the one acronym I heard about almost daily. That's because these devices, commonly known as "fire panels", are what feed directly into our Prism LX central monitoring server.
  4. NAC - "Notification Appliance Circuit" refers to the circuit that powers the audible and visual alerting devices—like bells, horns, and strobes—in a fire alarm system. This circuit receives signals from the FACP and then notifies occupants about an emergency situation. This is one of many types of wiring that must be monitored and protected by each of your fire panels to ensure that it will function as intended in an emergency.
  5. EOLR - An "End of Line Resistor" is a resistor that's placed at the end of a circuit as a way of monitoring the circuit for integrity. In a fire alarm system, it ensures that the wiring is intact and the system will work as expected when it's needed. Coming from the related-but-different world of general-purpose remote monitoring devices, I am used to binary/discrete inputs. An EOLR is an ingenious way to accomplish "trinary" (3-state) monitoring with just one wire pair. Electricity is (1) flowing freely to indicate an alarm, (2) flowing very slightly to indicate normal status, or (3) not flowing at all to point to wiring trouble that must be addressed.
  6. DACT - A "Digital Alarm Communicator Transmitter" is a device that communicates alarm signals to the central station. It is used in the fire alarm system to automatically dial a pre-programmed phone number in the event of an alarm situation, sending a signal to a central monitoring facility. Many DACT devices today are based on LAN or radio instead of traditional dialers. The DACT is distinct from the local notifications (both on the fire panel itself and using notification devices) provided by the FACP directly.
  7. UL - "Underwriters Laboratories" is a safety consulting and certification company that performs safety testing on a wide range of products, including fire alarm systems. A product that has been "UL listed" has met certain safety standards and is deemed safe for use. "UL" is the most common lab used in the industry, so that term is the most commonly heard. That's what makes it important to remember that other government-approved labs (most notably ETL) accomplish the same function for certifying the safety and reliability of fire-alarm-related systems. Digitize, for example, uses ETL.
  8. NICET - The "National Institute for Certification in Engineering" is a non-profit organization that certifies individuals for their knowledge and experience in engineering technologies, including fire alarm systems. Having a NICET certification means a technician has demonstrated competency in the design, maintenance, and testing of fire alarm systems. A combination of technician qualifications and the proven track record of the equipment manufacturer are both things you should consider when you make your purchasing decisions.
  9. FAI - "Fire Alarm Interface" is a term used to describe the connections and interactions between the fire alarm system and other systems in a building, such as the HVAC system, elevators, and security systems. Because your fire-alarm infrastructure must be a strong monitoring backbone, other building systems sometimes hitch a ride on that convenient infrastructure. This is acceptable only to the extent that it complies with relevant fire codes and does not interfere with fire alarm operation.
  10. CO - "Carbon Monoxide." In the context of fire safety, CO refers to carbon monoxide, a deadly gas that is often produced in fires. Some fire alarm systems include CO detectors to protect occupants from this potential hazard. CO detection is the most significant detection that has been added more recently to the classic combination of heat and smoke detection. You saw it get added to many state and local codes in the last 10-20 years.
  11. HVAC - "Heating, Ventilation, and Air Conditioning" (HVAC) systems can play a significant role in the spread of smoke and fire. Many fire alarm systems are designed to interface with the HVAC system to help control the fire and smoke spread. You don't want to "fan the flames" during an active fire. As another example, the HVAC Controller made by Digitize's parent company DPS Telecom has a "Smoke Mode" that turns off the HVAC system at any time that the smoke detector has been triggered (which can also be via smokeless heat exceeding 135 F).
  12. ANSI - The "American National Standards Institute" is a non-profit organization that oversees the development of voluntary consensus standards in the United States, including those related to fire safety and fire alarm systems. You're likely also familiar with ANSI if you've ever researched protective safety glasses. These often proudly proclaim ANSI compliance.
  13. FM - "Factory Mutual" is an insurance company that provides commercial and industrial property insurance. They also provide approval standards for various fire protection equipment, ensuring their effectiveness and reliability. As I always say: If you want to understand risk, listen to an insurance company. They know how much things are likely to cost, and they reward you when you achieve lower risk.
  14. ADA - "Americans with Disabilities Act." In terms of fire safety, ADA comes into play by requiring visual alarms for the hearing impaired and ensuring that all safety equipment is accessible and usable by people with disabilities. This is why red fire alarm speakers also tend to have flashing strobes.
  15. VOIP - "Voice Over Internet Protocol." In the context of fire alarms, VOIP refers to a method of transmitting alarm signals over the internet, rather than traditional phone lines. This can offer benefits like cost savings and redundancy. It's also a necessity when true POTS lines are no longer offered.
  16. POTS - "Plain Old Telephone Service." Contrasting VOIP, POTS refers to traditional analog telephone service. Many fire alarm systems have traditionally used POTS lines to communicate with monitoring centers, though this is becoming less common.
  17. LPCB - The "Loss Prevention Certification Board" is an international certification body that sets standards and provides approval for fire protection and security products and services, ensuring they meet high-quality benchmarks. Although "LP" is often used in the context of theft, it of course also relates to fire losses.
  18. VESDA - A "Very Early Smoke Detection Apparatus" (VESDA) is a type of aspirating smoke detection system. It's designed to detect smoke at the earliest possible stage, often used in high-risk or high-value environments where early detection is critical.
  19. CID - A "Central Station Identifier" code is a specific type of alarm signal sent to a central station that identifies the type and location of an alarm event, allowing for the quick dispatch of emergency services. This is superior to the "old days", when non-addressable fire panels indicated, at best, a generic zone alarm.
  20. RTP - A "Remote Test Panel" is a remote interface for the fire alarm system, often installed at an easily accessible location. It allows authorized personnel to conduct tests and monitor system status without having to directly access the primary fire alarm control panel. The allows you to "be in several places at once" when managing a fire or during routine maintenance and testing.
  21. LED - A "Light Emitting Diode" is commonly spoken as an "LED light". In the fire alarm industry, LED lights are often used in alarm indicator devices. Their high visibility, energy efficiency, and long lifespan make them an ideal choice. You wouldn't want a burned-out lightbulb to impede the effectiveness of your fire alarms.
  22. IDC - An "Initiating Device Circuit" (IDC) is the pathway through which signals are sent from initiating devices—such as manual pull stations or smoke detectors—to the Fire Alarm Control Panel. These are the wires (or perhaps radio waves) that you must protect.
  23. RAC - A "Remote Annunciator Control" provides a secondary location from which you can control and observe the fire alarm system. It's essentially a remote control panel, offering improved convenience and increasing safety.
  24. ECS - Your "Emergency Communication System" is designed to communicate emergency information throughout a building or area. These systems can interface with a fire alarm system to provide coordinated emergency information. You're most likely to have these in medium to large facilities.
  25. NEC - The "National Electric Code" is a set of rules and guidelines in the United States for safe electrical design, installation, and inspection to protect people and property from electrical hazards. It applies to fire alarm installations because they are electrical devices with wiring involved.

You must understand these acronyms to do your job

Remember, these acronyms are more than just jargon. They're an essential part of understanding how fire alarm systems work and ensuring that they're used correctly and effectively.

Whether you're a new professional in the alarm industry or a building owner looking to improve your building's safety and maintain compliance, being familiar with these terms is critical.

Call Digitize for help now

At Digitize, we're engineers. We live and breathe fire safety. If you have a question, just give us a call.

Speak with an engineer now by calling 1-800-523-7232 or emailing

Andrew Erickson

Andrew Erickson

Andrew Erickson is an Application Engineer at DPS Telecom, a manufacturer of semi-custom remote alarm monitoring systems based in Fresno, California. Andrew brings more than 17 years of experience building site monitoring solutions, developing intuitive user interfaces and documentation, and...Read More