Owen,
First, per NFPA 72 a tamper switch is defined as a supervisory
signal-initiating device in chapter 17.16 [2013]. It functions when a
switch is closed, completing a circuit. In this respect it is no
different than a smoke detector as the alarm signal, in this case
supervisory, is only created when the valve is moved two or fewer
revolutions of the hand wheel of the valve or upon motion of the control
apparatus of the valve of more than 1/5th of its travel distance.
As for how many of these devices can be supplied by one pair of wires
that answer is only limited by NFPA 72, which limits the number of such
devices on a circuit. Section 23.8.5.6.2 [2013] advises that:
The number of supervisory signal–initiating devices permitted to be
connected to a single initiating device circuit shall not exceed 20.
There may be limitations established by the device manufacturer, or the
panel, or the addressable modules and the listing of those devices
should be reviewed prior to raising an alarm [no pun intended].
Further, the explanatory text in the handbook gives the following
information [all emphasis is mine]:
The Code permits up to 20 supervisory signal–initiating devices on
a_*single initiating device circuit*_ because doing so does not
degrade the reliability or operability of the fire alarm system. Site
specific needs and conditions might dictate that a circuit serves
fewer devices. For example, if a facility has 20 sprinkler control
valves each equipped with a supervisory switch, _*all the valve
supervisory switches could be connected to the same initiating
device circuit and still comply with the Code*_. However, if a
supervisory signal were received, it would require that someone
check every valve to find the one initiating the signal. Supervisory
signal–initiating devices include valve supervisory switches, air
pressure switches, building temperature switches, fire protection
water tank level and temperature switches, and other devices that
are designed to ensure that fire protection and life safety features
are in service at the time of a fire. Refer to the defined terms
supervisory signal-initiating device and supervisory signal in
3.3.132.5 and 3.3.257.9.
So, there doesn't appear to be any reason that such an arrangement as
you've described would not be in compliance with the applicable code.
You might also ask for testing to prove that the tampers on all of the
valves generate the required signal at the panel.
sincerely,
*Ken Wagoner, SET
*Parsley Consulting***
*350 West 9th Avenue, Suite 206
*Escondido, California 92025
*****Phone 760-745-6181*
Visit our website <http://www.parsleyconsulting.com/> ***
On 07/04/2017 9:38 AM, [email protected] wrote:
Here is the situation on an installation at a new hotel. The DCVA has tamper
switches. Two PIV's near by do not have tamper switches. The hotel is complete,
no wiring had been run to the PIV's. (CFC 903.4) The DCVA and PIV's sit within
the same large planter with lots of finished concrete between the valves and
the alarm panel, about 150'. So the alarm guys tapped into the wiring of the
DCVA tampers and ran it to the PIV's to install tampers. Is that legal? If a
PIV is closed will it show at the panel or monitoring company as a DCVA tamper?
I'm not knowledgeable on the wiring of devices.
Owen Evans
13D Design
Sent from my iPhone
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