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Fire Alarm and Mass Notification

Updated: Jan 21

Mass Notification Systems (MNS) is designed to protect, alert, and inform your most critical resources, your people, by providing the right message, to the right people, at the right time.

In Fire Protection, a mass notification system is a system that is required by NFPA 72 code Fire Alarm and Signaling), a code adopted and mentioned in the IFC (International Fire Code) and IBC (International Building Code), to deliver an intelligible audio message to everyone for fire and non-fire emergencies. Having a proper system is more critical today than ever. By code, a mass notification system must reach everyone. NFPA 101 (Life Safety) and NFPA 72 code state that announcements must be heard over ambient sound levels and not have conflicting signals. Further, provisions in the code are made available to override a fire system's standard applications in the case where a fire alarm is the wrong signal or course of action. Think of active shooter situations where a fire alarm may worsen the immediate crisis.


Underwriters Laboratories (UL) and NFPA developed a standard to help building owners, property managers and contractors, know if a product or system can connect with a fire alarm control panel and meet the standard for mass notification. This standard is the UL 2572 standard and should be required on any audio product working with a life or fire system. The UL requirements are very stringent with a battery of tests from mechanical connections to all electrical, EMI, EMC, ESD, environmental tests and even software reviews. Mass notification systems can annunciate a fire alarm. Still, they also need to suppress the fire alarm in a non-fire emergency such as an active shooter situation.


An average smoke alarm is required to sound at 85 decibels from a distance of 3 metres - it will be much louder at close range. Hearing protection becomes necessary in an industrial environment at 85 decibels as sustained exposure could result in hearing loss.

The standard fire alarm signal, which does have some advantages, is generated at a 3,000 Hz frequency with a sound level output at 75 to 90 dB (decibels). A 520 Hz tone is a waveform that repeats 520 times per second.

Visible notification appliances are required to be located throughout the building or area. They must be of a type, size, intensity and number to ensure the intended audience, regardless of its orientation in the space or room, sees the strobe's light.

Individual employee work areas such as offices and workstations are not required to have visual strobes unless accommodating hearing-impaired employees, and they must contain audible alarms and notifications.


For many years NFPA 72, National Fire Alarm and Signaling Code has required as a minimum that smoke alarms be installed inside every bedroom (even for existing homes) in addition to requiring them outside each sleeping area and on every level of the house. (Additional smoke alarms are needed for larger families.)

Automatic fire detectors shall be provided in boiler and furnace rooms, trash-collection rooms, shops, laundry rooms, mechanical and electrical rooms, storage rooms and similar areas. Automatic smoke detectors shall be provided in all common areas and interior corridors, serving as a necessary egress means.


Most mains powered smoke alarms draw about 0.4 watts. This means a total power consumption over one year of 3.5kWh, costing you around $0.70 per unit per year.

Code requirements mandated that smoke alarms be hardwired directly into the home's electrical system and provided with a backup battery to keep the unit functioning during a power failure. Smoke alarms powered by batteries alone are allowed if the home was built before building codes required hardwired units.


It is recommended you test your alarms at least once a month to ensure they are working correctly. If a nine-volt battery powers your smoke alarms, the battery should be replaced every six months, while the alarm itself should be replaced once every ten years.

Hardwired smoke alarms are more dependable as they are connected to a power supply. Once the alarm sounds, it will not stop until turned off. In case of power interruptions, they have battery backups for continuous operation. Battery-powered smoke alarms depend solely on the batteries.

All smoke Alarms also have a red light that flashes momentarily every 40-60 seconds to indicate they are operating visually. ... The flashing red light gives a visual indication that the smoke alarm is functioning correctly. It also shows a working battery is connected to the smoke alarm.


There are two types of smoke alarms in general use for home smoke alarms: photoelectric and ionization. These smoke alarms sense the presence of smoke differently. The type of smoke produced by fire depends on the kind of fire. Flaming fires have a different type of smoke than smouldering fires.


Most fire detectors will detect carbon monoxide rather than natural gas. Again, carbon monoxide is considered a more significant threat: Though natural gas is more volatile, it is also more easily detected without a detector.


10 Years Smoke Alarm Requirements

The National Fire Protection Association (NFPA) recommends every smoke alarm be replaced after ten years, and those regular batteries are replaced every six months. With 10-year sealed battery alarms, battery replacements and late-night battery chirps are eliminated for a decade.


In most cases, we recommend using a smoke detector over a heat detector. This is because a smoke detector will typically detect a fire more quickly than a heat detector. But in some areas, a smoke detector may not be appropriate.


Manual and Automatic Alarm Devices

There are two main categories that fire alarm systems fall under: manual and automatic. A manual system requires a person's attention to activate it (a lever at a pull station), whereas an automated system is triggered automatically (via smoke or heat detection).


Conventional Fire Alarms


Conventional fire alarms include several different "zones" that are hardwired to your central control panel. These systems allow you to put separate fire alarms in each section of your building and monitor if an alarm is broken.


Addressable Fire Alarms


These fire alarms are also called "intelligent systems" as they monitor the fire alarms in your building. Addressable alarms allow you to choose between automatic and manual alarms. Each alarm installed in this system has its address, which will enable you to see which alarm is working and which are failing. Addressable fire alarms are more expensive because of the monitoring features.


Hybrid Fire Alarms


Hybrid alarms combine the hardwired zone features of conventional fire alarms with the addressable fire alarms' addressable loops into a single panel. This combined technology fits some of the settings better than either the addressable or the conventional alarm.


When choosing a new commercial fire alarm, it is vital to select the alarm that is right for your space. For more information on installing a commercial fire alarm


The fire alarm control panel must be located in an enclosed room, i.e. mechanical, riser room, etc. Prior approval of location should be obtained from the Fire Department.


The "brains" of the fire alarm system is the main control panel, which can be installed at the front entrance to a building or in an electrical room. If the board is installed in a secure room – such as an electrical room, there will typically be a small panel known as an annunciator at the front entrance.


Fire alarm panels continuously monitor and indicate the state of the fire alarm system. For the majority of scenarios, there are three possible states.

  • Normal: "Normal" means that all appliances, devices, circuitry and wiring are functioning correctly and that there are no active alarms.

  • Alarm: This status indicates an active alarm.

  • Trouble: If open or short wiring develops in the circuits that connect the initiating devices and the fire alarm panel, or if the system's phone line connection isn't working, the system will go into a "trouble" state, in which the control panel will display.

Initiation devices initiate alarms, and, just like alarm panels, they can be either addressable or non-addressable. Some initiation devices, like water flow switches, are traditionally non-addressable but connect with addressable modules. The controls can have specific addresses that let them communicate with addressable systems.

There are many types of initiation devices. In addition to water flow switches, initiation devices can also be:

  • Pull stations

  • Duct detectors

  • Smoke detectors

  • Beam detectors

  • Heat detectors

  • Tamper switches

  • Air aspirating detectors

Conventional panels represent a building as a series of regions known as detection zones. When a smoke detector or pull switch in a zone activates, the electrical current to the fire alarm panel changes. The control panel indicates that a device somewhere in that zone has been activated.


Commonly Heat detectors work in a similar way to an electrical fuse; the detectors contain a heat-sensitive eutectic alloy; when a specific temperature is reached, the alloy turns from a solid to a liquid which in turn triggers the alarm. Ionization Smoke detector generally contains two chambers.


Sometimes, building codes require the integration between fire alarm systems and other technology. However, in other cases, integration is optional and voluntary, such as integration with lighting systems, HVAC systems, door locks and security systems. While these systems have historically needed independent network communications, they can now operate on a shared infrastructure, saving you money and streamlining processes.

Some examples of functions and systems commonly interfaced with fire alarm systems are:


  • Extinguishing systems such as automatic sprinkler systems

  • Power interruption and elevator recall

  • Smoke management

  • HVAC fan and damper controls

  • Door unlocking and door release

  • Security systems

  • Mass notification systems

  • Monitoring of fire extinguishers


According to the National Fire Alarm and Signaling Code, some of the above are "fire safety functions" meant to improve occupants' life safety or control the spread of fire. You can choose to integrate other functions or systems for various reasons, such as operational benefits, information sharing and cost savings.


Commercial Fire Alarms with PSB Fire Engineers


At PSB Fire Engineers, we offer various portable fire extinguishers, fire alarms, and sprinkler systems to keep commercial kitchens safe. PSB Fire Engineers provides the highest quality alarm systems to keep your business safe from fires and carbon monoxide poisoning. We offer fire suppression systems as well to help keep commercial fires controlled should they break out. Our trained engineers will work with you to determine which air sampling smoke detection system is best for your business. We will also help install and maintain the system for your commercial building.


Are you looking for help solving your facility's fire protection system, fire fighting system, and fire safety issues? Installation, Service & Maintenance, Upgrading & Repair? Connecting with an experienced Fire Protection Consultant at PSB Fire Engineers can help. At PSB Fire Engineers, we understand that your unique building needs unique fire protection systems. Our team is equipped to ensure you receive the fire protection you need to keep your facility and people safe from harm.


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