I just commissioned a dormitory with these units installed...literally 750 in 150 dorm units, all connected to monitor modules on an addressable FACP.
There's a lot more than putting a supervision relay on the last smoke and saying it's monitoring the devices or the entire circuit for power and integrity because it's not going to!
Even if the detectors are wired continuous with a single 14/3 to the last detector, the only way to connect these units is to have all the detectors pigtailed to the in/out cabling with wire nuts, etc. There's no provision to connect the wiring as an in/outbound series, contrary to normal alarm system smokes. Pull the detector off the baseplate and unplug it, it'll leave the wiring intact, no change in circuit integrity and the 120VAC is going to go from the first detector to the last, so again, even if you install a RIB relay to supervise the presence of 120VAC at the last detector in a loop (end of line, right?),all that RIB is going to tell you is if there's 120VAC on the circuit,
not if the individual detector(s) themselves have power or are even connected to the circuit feeding the power to the RIB.
If the connection for the contacts to ancillary equipment is anywhere in the loop besides the last detector, the entire circuit downstream can be dead and the contacts on the unit are never going to change. The same goes for the traveler, it can be disconnected or cut anywhere and the system is never going to know it...and there's no way to supervise that 9V traveler/tandem connection because there's no voltage on it in "normal" conditions. So in actuality, what is the supervision relay going to tell you about the circuit in this case compared to a 4 wire LV fire alarm circuit? If you remove a detector or power on a LV circuit, the circuit is opened and the power is either not continuous (relay opens) or the circuit is opened, not so on a HV system unless you install a RIB at
every detector, and still, that does
nothing to supervise if the detector is removed. Even if you run a circuit along
every detector in the loop for FA and CO notification, the way the plug and pigtails are configured, it still
will not open the circuit if the detector is removed from the circuit.
REMEMBER: on a LV system any cabling installed in/under terminals
MUST be physically broken and
NOT twisted together. The better designed units actually separate the in/out pairs of the circuit. If you have a 4 wire system, you have 8 conductors under the terminals. If you have a 2 wire system, you have 4 conductors under the terminals, contrary to how HV systems are connected.
Also, keep in mind, by installing these units and their connection to the ancillary equipment, that in itself necessitates the installation of a listed box divider to separate out the dry contacts and LV cabling from the 120V feed....so now the installation is going to be further complicated to be compliant.
Have a good day