Gentex Smoke Detectors

[apostolakisl]

there is 0 supervision on any portion of the detection circuit for all of the detection technologies on these units. 

 
Per the specs listed above, these units have a form c contact.  So you can supervise them by using the NC contact for your LV loop with the final device (the last one on the HV daisy chain) powering a supervising 120vac relay.  Along with that you include an EOL resistor.  So if either your LV loop broke or shorted, or your HV power were interupted, the LV would go from eol resistor value to either open or short.

 

[Travis4710]

Depends on if the inspector is good with LV systems or requires 120vac system.  It would seem that there is no universal standard on this point.
 
If they require 120vac then I think the Gentex ones should work, except I don't see anything about them tandem sounding.  The odds are almost 100% that the inspector will require tandem sounding, and frankly, I wouldn't want ones that don't.  CO monitoring is not necessarily code and if you don't have any appliances that could make CO you may have no requirement for that at all.  The Gentex advantage would be that it offers you a simple solution for connecting to your alarm panel.
 
If the inspector accepts LV detectors, then there are quite a lot of options.  I like the GE ones I put in, but other brands are quite similar.  The LV ones tandem sound based on the fact that you set your panel up to reverse voltage during an alarm.  With a voltage reversal all detectors sound.  Their are 2 wire systems and 4 wire systems.  The 4 wire models are generically applicable to just about any security panel, the 2 wire ones will need to be brand specifically compatible.  2 wires is slightly simpler to hook up.  4 wire ones allow you to put a generic non-powered heat detector on the same loop if so desired.  The GE ones can be purchased with EOL supervising relays for simplcity of wiring.  They also can be purchased with aux relay for activating a 3rd party device during an alarm.  

 
Code requires HV interconnected smoke detectors.  According the the spec sheet I posted the GN503FF will interconnect with the S1209 smoke detector ( http://www.gentex.com/box/315?iframe=true&width=900&height=600 ).  I was thinking of putting the GN503FF smoke/co detectors outside of the bedrooms and the S1209 in the bedrooms, because I have a gas cooktop as well as gas logs on the main living floor.

 

[Del91574]

Barring a local code or building requirement, no national code specifically states the smoke detectors installed in a residence must be HV. It does state the units need to be hardwired, have suitable uninteruptable power and battery backup, as well as provide a minimum of 80 dB at pillow height (typically 3' AFF), tandem ring, as well as be installed in compliance with the NEC. Most municipalities meet the IBC or BOCA for their standards as a minimum, with the variance being those that are more stringent, but I've never heard of a locale that didn't have at least a recognized standard.
 
I'm more for the installation of LV units, their benefits, build quality and inherent design is superior than any HV unit that would be connected to a panel.
 
In the case of LV only, analog detectors, I'd go with the System Sensor I4 units and module, or intermingle I4 and I3 units on the same circuit. There's variations of the theme, but the I3/I4 install is vastly superior and requires less conductors.