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TM 07661B-14/1
APPENDIX A
h.
Check Valves. Check valves (11, figure 1-2) are installed in the nitrogen lines downstream of the pressure
regulators. The valves prevent back-flow of chemical agents into the respective nitrogen pressure regulators.
i.
Pressure Relief Valves. A pressure relief valve (12, figure 1-2) is located downstream of the pressure regulator
and check valve in each of the nitrogen manifolds. The function of the relief valves is to guard against
overpressurization of the systems in the event of pressure regulator failure. Each of these self-resetting valves is factory
adjusted to relieve pressure at 250 psi. The valve is safety wired to prevent CARELESS tampering with the pressure
relief valve.
j.
AFFF Tank Heater. The heater (13, figure 1-2) is attached to the bottom of the AFFF tank and is used to heat
the AFFF solution when the tank temperature falls below 450 F.
k.
Hose Reels. A hose reel (14, figure 1-2) capable of storing 150 feet of twin handline hose is mounted on the
front of the fire extinguisher. Swivel joints at each reel inlet provide rotatable connections between hoses and hose reel,
while serving as bearings to allow easy rotation of the reels' storage drum. Two sprockets, chin and hand crank provide a
manual means of rewinding the hose onto the reel after use. Thus the reel provides convenient storage for hose while
keeping it connected to the chemical tanks, and readily available. A second reel (8, figure 1-3) identical to the one on the
fire extinguisher, is mounted on a two-wheeled cart, completely separate from the fire extinguisher. It provides storage
for 150 additional feet of twinned hose. The use of quick-disconnect fittings allow the hoses to be connected together
rapidly for additional coverage when required.
I.
Twinned Handline Assemblies. The twinned handline assemblies (15, figure 1-2) transmit the chemical agents
from the hose reels to the discharge nozzles. Each unit is comprised of two one inch, non-collapsible hoses, 150 feet
long and encased in a woven polyester jacket. Outlet ends-of the hoses are equipped with quick disconnect fitting for
increased flexibility. Couplings are arranged so that the remote reel and nozzle cannot be connected to improper agents.
The hoses are internally grounded.
m.
Twin Nozzle Assembly. The twin nozzle assembly (16, figure 1-2) serves two basic functions. First, it is the
operator's final control of the pressurized chemical agents. Opening either of the nozzles, which are closely coupled by a
tie bar bracket, allows the respective chemical agent to be discharged. The nozzles second function is to disperse the
A 1-11
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