4.
Hydrostatic Testing of DDX-LP Valves and DDX-
LP Systems
As required by NFPA 13, fire sprinkler systems with working
pressures up to and including 150 psi are to be hydrostatically
tested at a water pressure of 200 psi. Fire sprinkler systems with
working pressures above 150 psi are required to be hydrostati-
cally tested at 50 psi above the system working pressure. In ad-
dition to the hydrostatic tests described above, dry pipe systems
require an additional low pressure air test.
In some cases, hydrostatic testing (in accordance with the
NFPA 13 requirements noted above) will result in pressures that
exceed the working pressure of the valve and trim kit for the two-
hour test period.
The valve and applicable trim kit have been tested, approved
and listed under these conditions and as such, hydrostatic test-
ing in accordance with NFPA 13 is acceptable. In addition, the
clapper can remain in the closed position and the trim kit need
not be isolated, as each has been designed to withstand hydro-
static testing as required by NFPA 13.
Subjecting the valve and trim to pressures higher than their
rating is limited to the hydrostatic test as referenced by NFPA13.
It does not address the occurrence of a “water hammer” effect,
which may damage the valve. A “water hammer” in the water
supply piping of the valve can create pressures in excess of the
rated pressure and should be avoided by all necessary means.
This condition may be created from improper fire pump set
-
tings, underground construction work, or an improper venting
of trapped air in the water supply piping.
System Supervisory Pressure Requirements
The DDX-LP PrePaK system includes gauges indicating the
air/nitrogen and water pressures on the Model DDX-LP sys-
tem. Table A specifies the air or nitrogen pressure to be main
-
tained in the sprinkler system piping based on the water supply
pressure. The factory installed Pressure Maintenance Device
in the unit automatically regulates makeup air or nitrogen flow
to maintain pressure with normal leakage from system piping,
while restricting the flow of makeup air or nitrogen to the sys-
tem. Please note that when the optional Model B1 Accelerator
is to be utilized to expedite water-delivery time, the air or nitro-
gen pressure must be not less than 15 psi (1.0 bar).
The factory-installed system low air pressure switch may need
on-site adjustment to correspond with the air pressure values
found in Table A. Adjustment, if required, should be made ac-
cording to Potter Bulletin 5401564 included with the switch.
System Electrical Requirements
All 24 VDC electrical connections in the Reliable Model DDX-
LP PrePaK system are translated to a water tight terminal box
mounted on the inside of the enclosure. All field wiring connec
-
tions are made at this terminal box.
A separate power connection is provided for the optional air
compressor.
Note:
The air compressor must be connected to a grounded
metallic, permanent wiring system, or an equipment grounding
terminal or lead on the product. Power supply wiring must con-
form to all required safety codes and be installed by a qualified
person. Check that the supply voltage agrees with that listed on
compressor nameplate.
Maintenance
The Reliable DDX-LP PrePaK system and associated equip-
ment shall periodically be given a thorough inspection and test.
NFPA 25, Standard for Inspection, Testing and Maintenance of
Water Based Fire Protection Systems, provides minimum main-
tenance requirements. Systems should be tested, operated,
cleaned and inspected at least annually, and parts replaced as
required. Periodically open the condensate drain valve beneath
the air tank to drain any condensate accumulation. Reliable
Technical Bulletins 338 and 519 provide additional information
for maintaining the Model DDX-LP Deluge Valve.
System Setup (Refer to Figure 2)
1. Close the main valve controlling water supply to the Model
DDX-LP deluge valve. Also, close the two ¼” valves sup-
plying air or nitrogen to the system.
2. Close the pushrod chamber supply valve.
3. Open the main drain valve and drain the system.
4. Open all drain valves and vents at low points throughout
the system, closing them when flow of water has stopped.
5. Open the Manual Emergency Release valve.
Note:
The
above steps accomplish the relieving of pressure in the
pushrod chamber of the deluge valve.
6. Push in the plunger of ball drip valve to force the ball from
its seat, and drain any water in the alarm line.
7. Push in and rotate the deluge valve’s external reset knob
counter-clockwise (when facing valve) until you hear a dis-
tinct clicking noise, indicating that the clapper has reset.
Note:
The reset knob can be rotated only after pressure
in the pushrod chamber is reduced to atmospheric condi-
tions (0 psig).
Water Pressure psi (bar)
System Air or Nitrogen Pressure
psi (bar)
Maximum
Not Less Than
20 (1.4)
8 (0.6)
30 (2.1)
10 (0.7)
50 (3.4)
12 (.8)
75 (5.2)
13 (.9)
100 (6.9)
15 (1.)
125 (8.6)
16 (1.1)
150 (10.3)
17 (1.2)
175 (12.1)
18 (1.2)
200 (13.8)
19 (1.3)
225 (15.5)
21 (1.4)
250 (17.2)
22 (1.5)
275 (19.0)
23 (1.6)
300 (20.7)
24 (1.7)
Table A
Notes:
1.
Supervisory air or nitrogen pressure should not exceed 30 psi (2.1 bar).
Excess pressure may result in damage to the actuator.
2.
Fastest valve operation is achieved with supervisory air or nitrogen
pressure indicated; however, pressure must never be less than the
minimum specified in the table above.
3.
Air maintenance devices that maintain a constant pressure are
recommended; however, if a tank-less compressor is used, the
“compressor on” setting of the pressure switch must never be lower than
the minimum pressure in the table above.
Summary of Contents for N2-Blast DDX-LP PrePaK
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