frank cinker
Member
- Location
- Pennsylvania
What is the difference between a coded fire alarm system and a fire alarm system that is not coded?
Coded Fire Alarm System
- Thread starter frank cinker
- Start date
- Status
- Location
- Massachusetts
Frank I think coded goes back to the days when individual pull stations worked like master boxes.
A coded pull station would have a spring wound wheel that sent out a the number of the pull station via the bells.
Here is one
Pull 4 - 3 would cause the bells to ring 4 times, pause, ring three times than long pause and start over.
An early form of addressable devices we use now.
A coded pull station would have a spring wound wheel that sent out a the number of the pull station via the bells.
Here is one
Pull 4 - 3 would cause the bells to ring 4 times, pause, ring three times than long pause and start over.
An early form of addressable devices we use now.
goldstar
Senior Member
- Location
- New Jersey
- Occupation
- Electrical Contractor
Most of the FA systems that you'll probably run into today are of the non-coded type. With the ongoing sophistication of electronic devices and communication systems, locating the area(s) that are affected by a fire or smoke condition are accomplished a lot faster than they were years ago. Depending on where you are working you may still run across coded FA systems. The basic intent of a coded system was to audibly identify what area an alarm was initiated in by sounding a coded signal over the bells (or gongs) in a building (i.e 2 - 3 - 2, 2nd floor, stair 3). Typically, a coded system would have been used for a facility like a hospital where fire brigade personnel may be working anywhere throughout the building.
If you look at the photos that Bob posted you'll notice that there was a "test key" feature built into the station. Turning the key to the "box" position and activating the station would allow the spring-wound motor to operate the station without causing an alarm. Turning the key to the "gong" position would rap the gongs one time each time you turned the key to the right. They also made "pre-signal" type manual stations whereby activating the station would only sound an alarm signal in a designated area (i.e a boiler room or mechanical space or floor). These type stations were predominantly used in situations where false alarms would probably cause panic and confusion if activated on a general alarm basis (i.e the Port Authority Bus Terminal in NYC during rush hour). If, after pre-signal activation, authorized personnel responding to this alarm determined that there was truly a fire or smoke condition, they could insert a general alarm key and re-activate the station.
Many of today's fire alarm systems are computerized, have graphic annunciation, voice evacuation or pre-recorded messages on selected floors to organize the safe evacuation of a building.
I know this is a small overview but I hope this helps.
Phil
Gold Star Electric
New Jersey
If you look at the photos that Bob posted you'll notice that there was a "test key" feature built into the station. Turning the key to the "box" position and activating the station would allow the spring-wound motor to operate the station without causing an alarm. Turning the key to the "gong" position would rap the gongs one time each time you turned the key to the right. They also made "pre-signal" type manual stations whereby activating the station would only sound an alarm signal in a designated area (i.e a boiler room or mechanical space or floor). These type stations were predominantly used in situations where false alarms would probably cause panic and confusion if activated on a general alarm basis (i.e the Port Authority Bus Terminal in NYC during rush hour). If, after pre-signal activation, authorized personnel responding to this alarm determined that there was truly a fire or smoke condition, they could insert a general alarm key and re-activate the station.
Many of today's fire alarm systems are computerized, have graphic annunciation, voice evacuation or pre-recorded messages on selected floors to organize the safe evacuation of a building.
I know this is a small overview but I hope this helps.
Phil
Gold Star Electric
New Jersey
- Location
- Illinois
- Occupation
- retired electrician
I just finished a coded system. It is a large industrial complex with ~15 different buildings. The alarm system is plant wide and the coded signal lets you know what building the alarm originated in. It is an electronic system and the code is computer generated. The panels talk to each other via a Class A fiber communications loop. The two main fire alarm computer panels at the main gate and the fire brigade building, have more detailed location information. The zone or in the case of the new addressable smoke detectors the exact location.
Don
Don
peteo
Senior Member
- Location
- Los Angeles
One of the early methods used CODED Wheels locally, dedicated lines and relays which printed on paper tape. This McCulloch system terminated at a central office, referring to a communications utility space or 'central station, ' what we still call a monitoring facility.
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