How many horn strobes on a circuit?

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firealarm guy

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Good evening all, I am renovating the fire alarm system in a 12 unit apartment building out here in atlanta, ga. i am taking out the old 5 zone panel and adding a firelite ms9050. The whole building currently has 12 horn onlys and 3 horn strobes on each floor breezeway. I need to add additional 8 horn/strobes and 8 strobe onlys. Do you guys think that this panel can handle this or do i need a power supply? Thanks in advance. Also this panel has 2 nac circuits at 2.5 amps each.
 

iwire

Moderator
Staff member
Location
Massachusetts
It sure won't have the battery capacity needed.


You really need to know the current rating of the strobes at the candelas you will be running them at.
 

nhfire77

Senior Member
Location
NH
using a whole lot of guesses, if you are using system sensor devices, if you could spread the load evenly over the two circuits about 1.4A per, and if a MAX of 150' using 16/2, you would need a min of 18AH batteries.

Please note all my IF's

If you are asking these questions, I assume you don't know how to due load and battery calcs. You need to learn that or get someone competent to do if for yo. You must do them when you add anything.
 

dhalleron

Senior Member
Location
Louisville, KY
The MS9050UD panel actually has 2 circuits and a total of 2.5 amps, not 2.5 amps per circuit.

It depends on how bright you are setting the strobes, but I would guess you will need a power supply.

Most of the time it is less expensive to upgrade the panel to the MS9200UDLS with the additional XRM24B transformer. It will have 4 circuits and 6 amps of power for horns and strobes. This route would be cheaper overall because you only need one set of batteries and only need to mount and wire one piece of equipment.

Firelite has a battery calculator on their website for most all of their panels. What horn/strobes are you using? They need to be the same brand as the existing in order to synchronize them. System Sensor has a good load/voltage drop calculator on their site for their products.

As a rule of thumb when I am estimating I use 7 horn/strobes per circuit at 75 candela and 14awg wire not exceeding 400 feet on a 1.5 amp circuit. That will normally leave room to add a one device if needed. Many people will have a different number they use, but this works for me. You get more or less on a circuit depending on how bright the strobes are set.
 
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MichaelGP3

Senior Member
.....Firelite has a battery calculator on their website for most all of their panels. What horn/strobes are you using? They need to be the same brand as the existing in order to synchronize them.....
This is only sometimes true; there are older models of certain brands that just won't synchronize. In these cases old devices that need to synchronize need to be replaced. Which may or may not be all of them.
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
Circuit Quantity

Circuit Quantity

Please note that the minimum number of notfication zones will be equal to the number of floors you are convering. Reading into your post, it looks like there are three floors. If there is a basement with notification in it as well, that's at least four (4) zones. This is per NFPA 72(2007) 6.8.6.3. In addition, the 2009 IBC limits the extent of each zone to 22,500 sq ft and a maximum dimension of 300 ft in one direction.
 

DM2-Inc

Senior Member
Location
Houston, Texas
Notification Zones

Notification Zones

the minimum number of notfication zones will be equal to the number of floors you are convering
If the intent is to use "Zone" notification, than yes, the above statement is true, however nothing prohibits the design to consist of fewer zones provided they all operate simultaneously. Section 6.8.6.3 addresses "Notification Zones", section 3.3.218.2 defines "Notification Zones" as...
"an area covered by notification appliances that are activated simultaneously"


...the 2009 IBC limits the extent of each zone to 22,500 sq ft...
The term "...zone..." relates to "Initiating Device Circuits", not "Notification Appliance Circuits".
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
If the intent is to use "Zone" notification, than yes, the above statement is true, however nothing prohibits the design to consist of fewer zones provided they all operate simultaneously. Section 6.8.6.3 addresses "Notification Zones", section 3.3.218.2 defines "Notification Zones" as...
"an area covered by notification appliances that are activated simultaneously"




The term "...zone..." relates to "Initiating Device Circuits", not "Notification Appliance Circuits".
6.8.6.3.2 Clearly states that the "The boundaries of notification zones shall be coincident with building outer walls, building fire or smoke compartment boundaries, floor separations or other fire safety subdivisions." No waiver if everything goes off at once.

For the IBC, your point is at least arguable. Note however under 907.6.3 that the "Exception" talks about automatic sprinkler system zones, and the additional requirements apply to high-rise buildings only, suggesting these are only sub-classes of "zones" generally. And the definition of "Zone" is "A defined area within the protected premises. A zone can define an area from which a signal can be received, an area to which a signal can be sent or an area in which a form of control can be executed."
 
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