CODE & STANDARD REFERENCES
What is a protected premises (local) fire alarm system?
In this series, we are focusing on different types of fire alarm systems. In our last video, we discussed the most common types of fire alarm systems in the industry. Today, we’re gonna focus on protected premises fire alarm systems which include (1) building fire alarm systems, (2) dedicated function fire alarm systems, and (3) releasing fire alarm systems.
BUILDING FIRE ALARM SYSTEMS
Building fire alarm systems are basically your bells and whistles as they say. You will most likely not see the fire alarm control unit, which is typically installed within a closet, but you will see the strobes and/or speakers as they are usually marked fire.
NFPA defines a building fire alarm system as a system or portion of a combination system that consists of components and circuits arranged to monitor and annunciate the status of a fire alarm or supervisory signal and to initiate the appropriate response to those signals.
The NFPA 72 handbook provides further clarification that the definition of a fire alarm system includes fire alarm systems whose sole purpose is to provide a specific function or functions such as a sprinkler supervisory service. These systems fall under the defined term dedicated function fire alarm system.
Dedicated function fire alarm systems are defined as a protected premises fire alarm system installed specifically to perform emergency control functions where a building fire alarm system is not required.
A releasing fire alarm system is defined as a protected premises fire alarm system that is part of a fire suppression system which provides control inputs. These inputs relate to the fire suppression systems sequence of operations and outputs for other signaling and notification.
At this point, you may be asking when is a fire alarm system required, well the answer to that can be found in our multipart series on occupancy related fire alarm system requirements, which can be accessed in our content library or by clicking the fire alarm link to the right of this video.
Please remember, NFPA 72 does not provide the requirements for when or where to install a fire alarm system. Those decisions are found in your locally adopted building and fire codes. However, it does provide the how if indeed a fire alarm system is required. Think of it as theimulti-page instruction book that comes along with the giant present you open on Christmas morning. We’ve all been there.
Let's get into a dedicated function fire alarm system.
FIRE SPRINKLER MONITORING SYSTEM
By far, the most common is a fire sprinkler monitoring system. If your state, county, or local ordinances require an automatic fire sprinkler system for all new construction like we have here in California, then this is the most typical fire alarm system you will encounter.
At a minimum, this dedicated function fire alarm system consists of a fire alarm control unit or FACU, a smoke detector in the same room as the FACU or directly mounted above it in the event there is no ceiling, such as in a warehouse, supervisory switches for all valves controlling water supply to the sprinkler system, which generally include the backflow prevention or OS&Y valves and the butterfly valve on the fire sprinkler riser, a water flow device, and a communicator for the transmission of signals to a supervising station.
The purpose of this system is to monitor the position of the valves and report sprinkler waterflow to the right party. If someone were to try and shut off a valve, the system would transmit a supervisory signal to the supervising station warning them that someone is tampering with the system. In the event of a water flow through the fire sprinkler system pipe, an alarm signal would be transmitted to the supervising station advising them of a potential fire within the building. The system will also send trouble signals to the supervising station in the event of any open ground or short in the system wiring.
ELEVATOR RECALL SYSTEM
Another type of dedicated function fire alarm system is an elevator recall system, which uses automatic smoke detection inside elevator lobbies and landings as well as in hoist ways and elevator machine rooms to recall elevators to the primary floor. The primary floor is typically the first and or ground floor of a building or to an alternate floor in the event of smoke detection at the primary floor.
ELEVATOR RECALL SYSTEM
Now for releasing systems.
Releasing Service fire alarm systems are dedicated to the control of a fire suppression system or other fire protection systems and our specifically listed by a (NRTL) nationally recognized testing laboratory for a specific use case. Single interlock or double interlock pre-action fire suppression systems are a common example of a releasing service fire alarm system and consist of automatic smoke detection or linear heat detection within the protected space. Upon actuation of the automatic detection devices, the fire alarm control unit will trigger the opening of a deluge valve which will release water into the fire suppression system piping network, which is typically dry, to avoid damaging equipment such as a server room or for protection of freezer storage units. Other examples are clean agent releasing fire alarm systems for the protection of high value assets.
In summary, a dedicated function fire alarm system and a releasing service fire alarm system are part of a protected premises and local fire alarm system whose sole purpose is to provide a specific function or functions, such as fire sprinkler monitoring, elevator recall, or the releasing service of fire suppression systems. It is important to remember that these systems are not part of a manual or automatic fire alarm system as required by the model codes. Dedicated function and releasing service fire alarm systems do not include occupant notification.
When a fire alarm system is not required, these Dedicated Function and Releasing Systems stand on their own. Including them doesn’t mean that the whole building now needs a fire alarm system.
On the other hand - in the event a fire alarm system is required by model codes, then our sprinkler monitoring system, elevator recall, and even the releasing of fire suppression system components would be integrated into a single fire alarm control unit, which has the appropriate listings for a complete building fire alarm system.
In our next video, we will discuss municipal fire alarm systems.
Until next time, I am Al Yakel and this is Meyer Fire University.
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