2 smoke detectors in each room?

[dds]

I am a registered Electrical apprentice wiring my house addition. The city inspector requires that I remove the two existing bedroom smoke detectors that are connected to a burglar/fire panel with back-up battery and plug in transformer. He wants 120v detectors with 14/3 wire. There must be thousands of residential burg/fire panels installed throughout the U.S.A. Would this interpretation put the Alarm industry out of business? Or does the alarm industry install a 2nd smoke detector in the same room? What is the correct interpretation of the building code?
Dave

 

[ron]

Re: 2 smoke detectors in each room?

Most building codes refer to NFPA 72 for specific items not addressed in the building code.
Depending on which code you follow, this may be helpful.
National Fire Alarm Code (NFPA 1996)
Chapter 2 - Household Warning Equipment
2-3. Power Supplies
2-3.1 General
2-3.1.2 There shall be a primary (main) and a secondary (standby) power source. For electrically powered household fire warning equipment, the primary (main) power source shall be ac; the secondary (standby) power source shall be a battery.
Exception No. 3: Detectors and alarms powered from a monitored dc circuit of a control unit where power for the control unit meets the requirements of Section 2-3 and the circuit remains operable upon loss of primary (main) ac power.

 

[ron]

Re: 2 smoke detectors in each room?

I should also share that a few years ago when doing my home, I installed a control panel (Ademco) with low voltage smoke detectors and security related stuff. The smoke detectors where located in the same locations I would install standard lighting circuit interconnected detectors in someone else's home.
The inspector wanted what he wanted, and I now have two detectors in each area of my home (it wasn't worth the argument)

 

[al hildenbrand]

Re: 2 smoke detectors in each room?

Dave,

That's exactly the way it is in my area. The line voltage, interconnected, battery backup SDs can be connected to a security system thru an interface module, but the security system's own SDs are not acceptable for the Fire Marshall required SDs. Bottom line, the smokes have to be able to work even if the security system is shut off for non-payment of monitoring fees.

Another way to think about it is, the SD is there to wake the sleeper so they can escape in the few moments after alarm caused by an aggressive fire. Security systems are about reporting to a monitoring service when nobody is there.

I would double check to verify that, after installing a 120V interconnected battery backup set of smokes, whether, in fact, the security system detection has to be removed. Where I am, it doesn't matter if the security system is there or not.

 

[dds]

Re: 2 smoke detectors in each room?

thanx for the info. I remember from the past... that the $30+ smoke detectors I curretly have are a better quality detector listed to be monitored by a central monitoring station. And that the 120V detectors are not listed to be monitored because of a greater possibility for a false alarm. I'll have to revarify that info. I havn't bought a 120V SD yet. Looks like I may buy my first set soon. I have a Napco panel and it is not monitord by a central station. I just wanted the Quality detectors. Oh, and even my neighbors can hear when my fire alarm goes off.

 

[Guest]

Re: 2 smoke detectors in each room?

My AHJ interprets it to say that low-voltage smokes don't satisfy the smoke requirements. They ask for a parallel smoke system. Additionally, a lot of alarm setups only include heat detectors.

[Edited for speeling by ieSpell]

[ November 21, 2003, 08:46 PM: Message edited by: awwt ]

 

[ryan_618]

Re: 2 smoke detectors in each room?

Section R317 of the IRC (which probably governs) simply states that they shall be wired so that when one goes off, they all go off. It says nothing about volatage, but it does reference the NFPA 72, as Ron has pointed out.

 

[ty]

Re: 2 smoke detectors in each room?

In my area, it can be either.
Fire Code does not require both and it's pointless.
The argument that if someone doesn't sign up for monitoring service or has service shut off due to non-payment doesn't hold water. The system will still alarm, it just won't be monitored by a company.
We just did a very large custom home and the homowner did all of his own security wiring including the smoke detectors. He hasn't signed up for monitoring yet, but his smokes work and alarm and so does the security system.
If there are security companies that are wiring theses systems and shutting them off from alarming for any reason, they are doing a great injustice and should be held liable for the outcome of any tradjedy associated with their action.

 

[ty]

Re: 2 smoke detectors in each room?

I re-read my post and while both systems may not be completely pointless, they definatley are not required or necessary.

 

[jrdsg]

Re: 2 smoke detectors in each room?

interesting, isn't it, that commercial fire alarm smoke detectors are all low-voltage and run on the same kind of eol resistor-supervised circuit as the residential systems mentioned above. if anything a properly wired low-voltage system is a better life-safety solution, since it operates with or without ac power. the battery back-up requirement for ac smokes is a recent change and has not yet been adopted in all jurisdictions.

 

[pierre]

Re: 2 smoke detectors in each room?

The building code requires the smoke detector system to be "HARD WIRED", "INTERCONNECTED", and to have each smoke head "SOUND" independently of each other. The older style low voltage 'systems' did not have independent sounding smoke heads, there was usually a horn or bell located somewhere in the house. That is the reason for adding the 'line voltage' smoke heads.
Hard wired does not mean it has to be line voltage.

The burgler/fire alarm system manufacturers have taken care of that situation, so now the smoke heads will independently sound. Installing two different types of smoke detectors is not necessary any more

Pierre

 

[iwire]

Re: 2 smoke detectors in each room?

Now that makes sense, I had never seen a reason for the FD not accepting a security company's smokes until now.

Now I know the reason, Thanks Pierre.

 

[ron]

Re: 2 smoke detectors in each room?

pierre,
Could you help me find where in the code it requires each head to sound individually?

 

[pierre]

Re: 2 smoke detectors in each room?

Ron

11.5.1.2 (B) Where more than one smoke or heat alarm is installed for new constuction, they shall be arranged so that the operation of any smoke or heat alarm causes the alarm in all smoke and heat alarms within the dwelling unit to sound.
(qoute from the 2002 NFPA 72)

NYS follows this document.

Pierre

 

[ron]

Re: 2 smoke detectors in each room?

Pierre,
I agree that the paragraph you quoted indicates to sound the alarm in each smoke/heat detector within the dwelling.
What I don't see is a requirement that each detector have a sounder. I agree, if there is one, it should be activated.
11.5.1.2 requires a sound that is audible in all occupiable dwelling areas, but not nessasarily a sounder in each detector.
If a single (or multiple) sounder (horn) is placed, such that the entire occupiable dwelling area is alerted, controlled by a control panel, I think that is all that is required.

 

[dds]

Re: 2 smoke detectors in each room?

Ron, that is exactly the point I raised with the inspector when applying for the permit. He didn't agree with that.
I noticed that the wording is:"causes the alarm in all smoke and heat alarms within the dwelling unit to sound."
The word "alarms" is used instead of detectors.
I still believe I have a better system already installed and the expensive upgrade to detectors that have a sounder is not needed.

 

[pierre]

Re: 2 smoke detectors in each room?

Hello Ron
I am responding to you, but I do not have the copy of the NFPA 72 at home. When I have a chance, I will qoute it and we will try to disect it, but I know the building and fire officials will tell you what I have already stated.
Why else would the fire alarm system manufacturers change the audible sounding in their units if they did not have to?

Pierre

 

[ty]

Re: 2 smoke detectors in each room?

my area adopts the International Fire Code. In the 2003 book, there is no mention that I can find in 907.2.10 that would require each smoke to sound independantly of the others.
Ron, the way that you suggest passes inspection here all of the time.