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Fire Alarm -- Installation

AFA Manual RTU Riser Verify are all words or acronyms used inside the fire alarm industry. These words and acrnyms should not be used to explain what is happening during a fire.
These are words used for "Insider-Speak"; those working in the fire alarm industry are going to understand most of the words. During a fire, the people reading the descriptions on the fire alarm panel don't know Insider-Speak. Make sure the words used on the fire panel descriptions are words that are understood by the "Common Person".
Douglas Krantz -- Fire Alarm Engineering Technician, Electronic Designer, Electronic Technician, Writer

It's the Volunteer Firefighter that Reads the Panel

By Douglas Krantz

I suppose it was used because the technician programming the fire alarm system was totally familiar with the acronym AFA and what it means. But still, in an elementary school the acronym AFA (Automatic Fire Alarm) shouldn't have been programmed into the zone descriptions for fire alarm system.

The trouble is that even after seeing that description on the panel for years, the head custodian at the school still asked me what "AFA 1st Floor West Corridor" meant. He had no idea what an AFA was supposed to be. The term "AFA" wasn't relevant to him.

Automatic Fire Alarm (AFA) Devices

First though, just a as a refresher, let's look at the difference between an Automatic Fire Alarm (AFA) Device and a Manual Fire Alarm Device.

With an automatic fire alarm device, no one is needed to activate the fire alarm system; it's automatic.
  • People can be asleep
  • People can be working in another part of the building
  • People don't even have to be present at all

Without anyone, the fire alarm system will still activate if, using an Automatic Fire Alarm Device, it detects the presence of fire, or at least what the AFA Device interprets as the presence of fire.

The AFA device can be:
  • Smoke detectors that detect smoke from a fire and sound the alarm
  • Heat detectors that detect heat from a fire and sound the alarm
  • Flame detectors that detect the flickering light from a fire and sound the alarm
  • Waterflow switches that detect that water is suppressing a fire and sound the alarm

Automatic Fire Alarm (AFA) Devices are devices that activate the fire alarm system without human intervention.

Manual Fire Alarm Devices

Unlike Automatic Fire Alarm Devices, Manual Fire Alarm Devices don't do anything until a person activates it. In other words, someone has to manually activate the fire alarm system. Running down the hall, banging on doors, and shouting "fire" is a form of a manual fire alarm system.

For the fire alarm system, Pull Stations are a common form of manual fire alarm devices.

Single Action -- The fire alarm system is activated when the glass is broken and the button pops out, or when the lever is pulled.

Double Action -- Before the actual manual station is able to be pulled a glass cover has to be broken or a door has to be pushed out of the way.

Pre-signal -- To reduce false alarms, once the lever has been pulled but before the fire alarm system sounds the alarm, some manual pull stations only activate a light or a sounder somewhere else so a person with a key can investigate first.

Manual Fire Alarm Devices are devices that require human activation.

AFA and Manual are technical words that, to those working in the fire alarm industry, carry specific meaning.

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The thing is, though, the descriptions used in a fire alarm panel aren't for those in the fire alarm industry. The descriptions are for:
  • Fire Fighters -- They put out fires
  • Custodians and Caretakers -- They clean buildings
  • Building Engineers -- They maintain buildings
  • Building Management or Office Personnel -- They run businesses, schools, hospitals, etc.

Relevant Descriptions

These are all examples of people who have to deal with the fire alarm system but have not been trained in the technical aspects of a fire alarm system. Let's keep our descriptions relevant to those who are required to deal with the fire alarm system.


Douglas Krantz

Describing How It Works

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Electrical Flow

On this website, most references to electrical flow are to the movement of electrons.

Here, electron movement is generally used because it is the electrons that are actually moving. To explain the effects of magnetic forces, the movement of electrons is best.

Conventional current flow, positive charges that appear to be moving in the circuit, will be specified when it is used. The positive electrical forces are not actually moving -- as the electrons are coming and going on an atom, the electrical forces are just loosing or gaining strength. The forces appear to be moving from one atom to the next, but the percieved movement is actually just a result of electron movement. This perceived movement is traveling at a consistent speed, usually around two-thirds the speed of light. To explain the effects of electrostatic forces, the movement of positive charges (conventional current) is best.

See the explanation on which way electricity flows at