UNITED Nitrogen Pac SC-W, Установка, наладка, обслуживание

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UNITED FIRE SYSTEMS - NITROGEN-
PAC™
MODEL SC-W
INSTALLATION, COMMISSIONING, AND MAINTENANCE MANUAL
REVISION 1.01 MAR 2021 - P/N 30-NPWICM-000
23
2.6.9. Are Sprinkler Systems Equipped with Quick-Opening Devices (Dry Accelerators)? Dry accelerators are used
on some sprinkler systems to ensure that water is delivered to the farthest sprinkler head in an acceptable period of
time. Dry accelerators combined with natural pipe leakage and deliberate purging to increase nitrogen
concentration can lead to unwanted dry-pipe valve trips. To avoid valve trips during purging:
(a) Ensure that the dry accelerator device is functioning properly. Consider replacing an existing dry accelerator with
a new device if the device has been in service for an extended period of time.
(b) Reduce natural leakage to as near-zero as possible. Special attention should be paid to existing systems, as
natural leakage tends to increase as systems age.
(c) If necessary, close the dry accelerator inlet valve during purging. NOTE! Closing the dry accelerator inlet valve
may lengthen the time for water to reach the furthest sprinkler head. Ensure that the system end user and the
Authority Having Jurisdiction (AHJ) are aware of the consequences of closing the valve during purging, and
consider this acceptable. (It should NOT be necessary to keep the dry accelerator inlet valve closed once the
nitrogen purity reaches 98%, and the manual PVA purge valve or the TAP device automatic purge valve is
closed.)
2.6.10. Nitrogen Receiver.
(a) The nitrogen receiver can be wall mounted if sufficient wall space exists and if the wall is capable of holding the
weight of the device. Select the Model NR-5 Nitrogen Receiver.
(b) The nitrogen receiver can be mounted on the sprinkler riser above the sprinkler valve if sufficient clear space is
available on the pipe, and the pipe bracing is capable of handling the additional weight. Select the Model NR-5
Nitrogen Receiver.
(c) The nitrogen receiver can be floor mounted if wall mounting and riser mounting are impractical. Select the Model
NR-10 Nitrogen Receiver.
2.6.11. Nitrogen / Air Maintenance Device
– Model NAMD-1.
If existing sprinkler systems have air maintenance
devices already installed, such devices may be re-used. It is recommended that each of these devices be
thoroughly inspected and tested for proper operation and absence of internal corrosion and debris before re-use.
If sprinkler systems are new, or existing devices require replacement, use qty. (1) Model NAMD-1 per sprinkler
riser.
2.6.12. Nitrogen Purging and Sensing.
(a) Purge Vent Assembly (Model PVA). Each sprinkler system requires the installation of a purge vent assembly
(PVA) to permit replacement of air within each system with nitrogen. The purge vent assembly includes a manual
shutoff valve and an automatic float valve to prevent water discharge when the sprinkler system fills with water.
Each model of PVA includes the proper orifice for purging and the proper outlet connection for the nitrogen purity
monitoring method chosen. Choose the proper model of purge vent assembly ( Model PVA) per
Table 4 .
Table 4
Purge Vent Assemblies
Model Description Outlet Connection
PVA-2 For use on systems with TRUE ADVANCED PURGE
™ (TAP)
Device Push-on tubing
PVA-4 For use on systems with Hand-Held N
2
Purity Analyzer Female quick-connect
(PVA-1)
DO NOT use Model PVA-1 Purge Vent Assembly on NITROGEN-
PAC™ Model SC-W systems.
The orifice in this assembly is intended for use with M Series systems only.
(PVA-3)
DO NOT use Model PVA-1 Purge Vent Assembly on NITROGEN-
PAC™ Model SC-W systems.
The outlet connection on this assembly is intended for use with Model SC-1 and SC-2 systems only.
(b) Hand-Held Nitrogen Purity Analyzer
– Model NA-2
. The hand-held nitrogen purity analyzer Model NA-2 is used
to manually measure nitrogen purity at each PVA-4 and at the N
2
purity analyzer connection point on the Model
SC-W assembly.