Technical data

32.
2.4.4 Nitrogen Regulating Device
The Reliable Nitrogen Regulating Device is used to regulate pressure to individual or multiple preac-
tion and dry systems using Reliable Model A-2 Pressure Maintenance Devices. The nitrogen supply is
obtained from a high pressure nitrogen cylinder (or cylinders) which are sold or rented separately. The
Nitrogen Regulating Device includes a single stage pressure regulator equipped with high pressure
inlet and low pressure outlet gauges. As the nitrogen is gradually depleted and the pressure inside
the cylinder drops, the low pressure regulated output remains stable. If desired, an optional adjust-
able pressure switch is available for monitoring the nitrogen pressure between the tank regulator and
connection to the pressure maintenance device(s). The switch is installed between the Nitrogen Regu-
lating Device outlet and the Model A-2 Pressure Maintenance Device, and signals the approaching
depletion of the nitrogen supply. The Nitrogen Regulating Device is provided with a coiled ¼” copper
tube and fittings for connection to the fire protection system pneumatic supply line.
Approvals and technical data for the Nitrogen Regulating Device can be found on Reliable Automatic
Sprinkler Company Bulletin 254.
Figure 35
NS PAK
Figure 36
NITROGEN REGULATING DEVICE
2.5 Pneumatic Pressure Supervision
Pressure switches are used to monitor pneumatic pressure in dry pipe and special systems, and are neces-
sary to provide low pressure notification in the event of sprinkler damage, leaks, or failure of the compressed
gas system. In some systems, activation of the pressure switch may also serve as a condition required for
opening the main system control valve.
2.5.1 Model EPS40 Pressure Switch
The System Sensor Model EPS40 switch is designed to detect a 10 psi
(0.7bar) decrease (and in some cases, increase) from normal system
pressure in automatic fire protection systems. They are typically used
to supervise system pneumatic pressure in preaction and dry systems
using 10 psi or higher pressure. These switches can be used to initi-
ate electronic signals and/or control auxiliary fire equipment when a low
pressure condition occurs. Although factory set, the adjustment wheel
requires no special tools and can be used to adjust the nominal value of
the “window” at which the switches activate.
The EPS40-1 Series features field adjustable pressure sensitivity between
10 and 100 psi (0.7 and 6.9 bar) and is used for low pressure supervi-
sion only. It is factory set to be used in a nominal 40 psi (2.8 bar) system
with a switch transfer occurring at 30 psi (2 bar) on decreasing pressure. The EPS40-2 Series features
field adjustable pressure sensitivity between 10 and 100 psi (0.7 and 6.9 bar) and is used for low and
high pressure supervision. It is factory set to be used in a nominal 40 psi (2.8 bar) system with a switch
transfer occurring at 30 psi (2 bar) on decreasing pressure and a second switch transfer occurring at
50 psi (3.5 bar) on rising pressure.
Figure 37