Class A Fire Alarm Requirement for Conduit

[rdbutler]

Situation: Job specification calls for the signalling line circuit and the notification appliance circuit to be class A. NFPA 72 states that the return circuit must be in a separate raceway. All class A job's I've been involved with in the past required 100% conduit. This new job is being designed for free air wire with stub ups only.

Question: Is there a requirement for class A circuit to be in enclosed raceway (EMT)?

It doesn't make sense to me to spec a job for class A without requiring the wire to be in conduit. Seems like the whole concept for class A circuits is survivability.

 

[tom baker]

Re: Class A Fire Alarm Requirement for Conduit

Not sure what a Class A Fire Alarm is.
NEC allows power limited FA to be run in cable. NFPA 72 has other requirements. NEC requires non power limited to be run with a chapter 3 wiring method.
There are very, very few non power limited fire alarm systems.

 

[rdbutler]

Re: Class A Fire Alarm Requirement for Conduit

Class A is a wiring method where the circuit leaves the panel, hits every device and returns to the panel on another set of terminals. This to allow for all devices to continue to work in the event of a single open on the circuit.

Class B is where there is an actual end-of-line, and only the devices up to the point of an open on the circuit would continue to function.

Class A is an added durability factor that basically provides redundancy.

I'm wondering if anyone has ever installed a class A fire alarm system without being 100% in pipe. Are there any known codes that require this type of system be installed in conduit?

All I can find in NFPA 72 (2002) is in section 6.4.2.2.2.

All styles of Class A circuits using physical conductors (e.g., metallic, optical fiber) shall be installed such that the outgoing and return conductors, exiting from and returning to the control unit, respectively, are routed separately. The outgoing and return (redundant) circuit conducots shall not be run in the same cable assembly (i.e., multi-conductor cable), enclosure, or raceway.

 

[rdbutler]

Re: Class A Fire Alarm Requirement for Conduit

conducots = conductors :roll:

 

[iwire]

Re: Class A Fire Alarm Requirement for Conduit

Depending on the specs we may or may not run raceways for class A FA systems.

We may run raceways, MC or low energy cable.

It could be argued that physical survivability is less important with class A than with Class B as class A is electrically redundant.

A break in a class A system should only result in a trouble signal but all devices should remain operational.

 

[rdbutler]

Re: Class A Fire Alarm Requirement for Conduit

I guess you are right iwire. Class A is more survivable than Class B all else being equal.

I just figured if the engineer specified Class A wiring, the intent would be to provide physical redundancy to the system. I guess installing 100% conduit would just be the next step in that effort.

Thanks

 

[peter d]

Re: Class A Fire Alarm Requirement for Conduit

The raceway requirements are dictated by local codes. For instance, both Las Vegas and Rhode Island, among others, have very specific local codes that require all FA circuits to be in a raceway, regardless of being Class A or B.


There is nothing in NFPA 72 that explicitly calls for a raceway system, except on the municipal circuit of a master box system.

Also, 72 does call for a 2 hr rating on certain systems in specific applications, but a metal raceway does not provide anything close to a 2 hr rating. In this case, a special cable called Circuit Integrity cable (which I have never seen or used) is required.

 

[ron]

Re: Class A Fire Alarm Requirement for Conduit

The national codes do not require anything more than Class B. An engineer that specifies Class A, has the option to also specify raceway or not (unless local code requires raceway, as mentioned by earlier poster).
I have been put into the position on several projects, where the rather small increase to go to Class A circuits was OK to the client, but the cost to install in Raceway was not. So we compromised and used class A without raceway above 10' AFF.
The term "routed separately" that you found in the NFPA 72 (Fire Alarm Code) is generally detailed by the specifying engineer with a particular distance or fire partition separation. Since Class A is a specification item, there is usually design professional on the project to add details such as mentioned above.

 

[ron]

Re: Class A Fire Alarm Requirement for Conduit

Peter,
I've specified and had installed some CI cable, and CIC cable (which gets installed in raceway) and other than expense and thicker jacket, seems to be a good product type.

 

[peter d]

Re: Class A Fire Alarm Requirement for Conduit

Originally posted by ron:
Peter,
I've specified and had installed some CI cable, and CIC cable (which gets installed in raceway) and other than expense and thicker jacket, seems to be a good product type.

What was the building occupancy type that caused you to spec this?

 

[ron]

Re: Class A Fire Alarm Requirement for Conduit

Two separate applications. 1st is a highrise. 2nd is what the building code calls an unlimited area building, where there is 200,000 sq ft on each floor.
I identify the separate zones, and have the installer provide CI or CIC cable from the control panels to those areas. Where a control panel is provided in the separate area, then the CI or CIC cable is run from control panel to control panel.

 

[c_picard]

FYI Peter d,
Rhode Island now allows type MC, but color codes still apply which makes lead times for delivery unpredictable.

 

[ron]

What color code is required for fire alarm cable? I guess it must be a local Rhode Island amendment, because it is not national.

 

[c_picard]

Rhode island color code is as follows;

Initiating circuit= Red+ Black-
NAC = blue+ white-
Flashing strobe= blue+ white-
Sprinkler/standpipe= red+ black-
Aux. power supply= violet+, brown-
Door holder= grey, grey
Master box trip= orange, orange
Elevatorcapture= brown, yellow
HVAC shutdown= orange, yellow
remote annunciator = violet numbered at each end
bond wires= green or bare
from master box to municipal loop= black,white
AC power=black, white, red if needed

 

[peter d]

FYI Peter d,
Rhode Island now allows type MC, but color codes still apply which makes lead times for delivery unpredictable.

I'm a little confused by your comments. Bear in mind I'm aware of most RI fire alarm issues, being a native. The way I learned to install a fire alarm is the "Rhode Island way." (re:waste of time and material, but that's another story)

I don't have any problem finding FA MC cable. Most suppliers have huge stocks of it on hand in the black/red and blue/white, both in 250's and reels. With the rush to get systems installed and running, the suppliers are doing a good job keeping it in stock.


I'm not quite sure what you mean by "RI now allows MC." I was using fire alarm MC 6 years ago (mind you, I was working for someone and didn't have clue back then). Hasn't it always been allowed? :?

 

[peter d]

What color code is required for fire alarm cable? I guess it must be a local Rhode Island amendment, because it is not national.

Yes, RI has its own code as C Picard stated. Basically, all FA systems in raceway, follow the color code, no splices, FD inspects the job and approves.

As you can guess from the list of requirements in C Picard's post, you end up keeping a lot of different colored spools of THHN on hand.


There is no national standard found in the NEC or 72.

Personally, I don't see a need for a color code, especially with modern addressable systems. It's pretty obvious what a small guage, twisted shielded red cable is for.

 

[c_picard]

"now allows..." was misleading, sorry.
The supplier we are using right now (no names) took 6 weeks to get 16/2 black/red. We got the wrong cable real quick! 16/2 black white, then black red but TSP!

 

[peter d]

The supplier we are using right now (no names) took 6 weeks to get 16/2 black/red. We got the wrong cable real quick! 16/2 black white, then black red but TSP!

Well, that explains it. Was there any reason why you needed 16/2? I believe the RI approved 16/2 blue/white MC is a special construction that must be custom made, as it's not listed in the AFC or Allflex catalogs (last time I checked a few months ago.) That's the only reason why I can guess that it took so long to get.


The 14/2 MC in blk/red and blue/white is readily available.

 

[c_picard]

Yeah,
The 14/2 did show up first, but black & red. Then I got 14 blue/white, delivered on the back of a pickup straight from AFC. To make a long story longer the total WRONG cable=13,000ft, total CORRECT cable 6 weeks later=8,170ft(recieved partial reels), NEED total of 11,000 feet.

1000' red 16AWG THHN also backordered.

And here comes the ceiling tile!!

 

[iwire]

I'm not quite sure what you mean by "RI now allows MC." I was using fire alarm MC 6 years ago (mind you, I was working for someone and didn't have clue back then). Hasn't it always been allowed? :?

Pete are you really sure of the time frame?

RI had been an all pipe fire alarm system state for a long time it has only been in the last few or more years that MC has been generally accepted.

It was possible to ask for special permission to use MC cable however than like now the color code applied.

It used to be special order to get the RI conductor colors in MC, now as you say they are available in stock.

At least that has been my experience but keep in mind I work for an unwelcome out of state contractor. :lol: :shock: :roll: