Fire Alarm FAQ

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JamesM

New member
Sorry to be a nuisance. I am a journeyman electrician who has recently been "thrown to the wolves". Our company recently lost our best fire alarm guy and I am stuck trying to pick up the pieces with minimal experience. I know the very basics of a looped addressable system, but I have 2 minor issues.

a. Can I run 14/4 (mc in this building) for a speaker/strobe or do I need to run 2 seperate 14/2 wires?

b. I have to incorporate a couple 24v magnetic door holders into the system. Whats the easiest way to go about this? is there a module for this? relays? which circuit does it tie into?

thank you for any help
 

nakulak

Senior Member
every FA system has an approved set of plans, and a submittal book. Some plans actually have typical connection shown for each device (landing terminal numbers). You need to check the set of plans to see if the plans are even correct, and check to see that the plans show enough conductors (sometimes the designers screw up). There might be two plans for each area - power wiring and lon loop wiring. The last couple FA speaker/strobes I did had a power and a lon loop, but I don't know if they are all like that. Same with smoke sounder bases - you might need 2 in 2 out, might not. Check the device cuts and the plans so you know what you are doing.
 

dhalleron

Senior Member
Location
Louisville, KY
I know Silent Knight and Firelite both recommend running the strobes and speakers in separate cables. This is true even though they end up in the same box. Depending on your speaker circuits, they could be non-power limited and your strobes are power limited. Also a badly filtered strobe power supply could cause a very low noise on the speakers when they are not being used.

Sometimes door holders are 120VAC powered locally with an addressable relay on the SLC controlling them. Most addressable relays can handle a low current (about .5A) at 120VAC. Sometimes the door holders are powered by a low voltage power supply and still controlled with a relay.

Always refer to the install manual for whatever brand fire alarm panel you are using. The specs can differ from one brand to another.
 

nakulak

Senior Member
one more thing - check the approved plans for red ink. A lot of times the FM adds in devices that the designer didn't think was necessary.
 

nhfire77

Senior Member
Location
NH
a. Can I run 14/4 (mc in this building) for a speaker/strobe or do I need to run 2 seperate 14/2 wires?

Typically you will find running 14/2 is easier, you will have many nonspeaker strobes that only need the strobe circuit, this will reduce the speaker circuit length, but troubleshooting in the future would be difficult.

Separate cables that just junction through when not needed does add more work, but allows for more test/troubleshooting access.

The voltage drop for each circuit should be calculated, don't overextend it just because you can, most guys do this, it's a bad habit



b. I have to incorporate a couple 24v magnetic door holders into the system. Whats the easiest way to go about this? is there a module for this? relays? which circuit doe


As said, read your manual.

As for door holders, most draw 15mA, and most FACP's have 500-1000mA of aux 24vdc. If you want to simplify it run the aux power to the door holders, with one leg through the alarm relay on the FACP. You may even be able to have the power turn off in the event of an AC power loss, so you won't have to add them into the battery calcs.

Or, you could use a constant output or aux output on a NAC booster through an addressable relay module to cut power on alarm.
 
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nhfire77

Senior Member
Location
NH
one more thing - check the approved plans for red ink. A lot of times the FM adds in devices that the designer didn't think was necessary.

That would really piss me off if that happened and they didn't tell you exactly what they added. That's a real jerk move,
 

nakulak

Senior Member
I did an itty bitty designer clothing store last year and the fm wanted a strobe in every dressing room, inked it on the plan, plans weren't on the job, you know the rest.
 

nhfire77

Senior Member
Location
NH
I did an itty bitty designer clothing store last year and the fm wanted a strobe in every dressing room, inked it on the plan, plans weren't on the job, you know the rest.

Did his apologize to you for being a jerk? (I wouldn't expect him to change his mind though)
 

nakulak

Senior Member
we were the jerks - didn't check the plans. he was cool - gave us a temp c/o so we could fix it.
 

nhfire77

Senior Member
Location
NH
Right in our fire alarm proposals.

Not included:

Additional devices and equipment required by the fire department.

IE the ol oh you need a master box/radio box/mass evac system that we don't have a written policy/code for?
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
That would really piss me off if that happened and they didn't tell you exactly what they added. That's a real jerk move,

I haven't had anyone do this to me. Any fire marshall, fire inspector, or fire sub-code official who makes this a practice is gunning for trouble. Many jurisdictions request/require signed and sealed plans. Most states consider the alteration of signed and sealed plans to be a big no-no. Additional sanctions may apply, not to mention liability.

Lawyer: So Mr. Engineer, are these your signed and sealed drawings?

Me: Nope.

Lawyer: Wha...?

Me: See those hand annotations? I didn't initial them, so I didn't approve them. Go fish.


And lest anyone attempt to get clever with a large format copier, that's what the "sealed" part is all about. In addition, I always sign my drawings in red ink so it's very easy for me to tell if I'm looking at an original or a copy.
 

iwire

Moderator
Staff member
Location
Massachusetts
I haven't had anyone do this to me. Any fire marshall, fire inspector, or fire sub-code official who makes this a practice is gunning for trouble. Many jurisdictions request/require signed and sealed plans. Most states consider the alteration of signed and sealed plans to be a big no-no. Additional sanctions may apply, not to mention liability.

Lawyer: So Mr. Engineer, are these your signed and sealed drawings?

Me: Nope.

Lawyer: Wha...?

Me: See those hand annotations? I didn't initial them, so I didn't approve them. Go fish.


And lest anyone attempt to get clever with a large format copier, that's what the "sealed" part is all about. In addition, I always sign my drawings in red ink so it's very easy for me to tell if I'm looking at an original or a copy.

Where I am the Fire Chief gets wide powers and the engineers drawings mean nothing to them. You either do what the FD asks for or you do not get a CO. Pretty straight forward. :grin:
 

nhfire77

Senior Member
Location
NH
Maybe Lowe's Framingham:grin:, I know it did get voice evac system as an extra.

It's funny how that occurs, I had Manchester nh turn down a FACP (Bosch g series not my idea/specs) after we had approval for it and it was installed. Had to change out the panel and all the devices. Chalked up to a miscommunication in the fire marshals office. Wow was I $$$ and the owner :(.
 
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gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
Where I am the Fire Chief gets wide powers and the engineers drawings mean nothing to them. You either do what the FD asks for or you do not get a CO. Pretty straight forward. :grin:

The issue, as explained to me by someone who is licensed in New Jersey for inspecting everything except elevators is that "you touched it, you own it". Once you red-line a drawing, now you are the designer of record. The errors-and-ommissions policies for municipalities don't cover anything outside the scope of employment, and designing is not the plan reviewer's job. If he has an bone to pick, he can reject the plans and send a note to the effect:

"Mr. Engineer, notification appliance coverage in Hallway H-2 does not appear to meet the minimum requirements of NFPA 72-2002 section 7.5.4.4 "Spacing in Corridors". Please review and resubmit."

I'm cool with that. I'll "A" make corrections or "B" find a code section that covers my original design. If "A", then there'll be a revised set of signed and sealed drawings with my signature and their approval on them and everyone is covered.
 
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