SINGLE AGENT HOSE REEL.- The single agent hose reel (fig. 5-25) consists of 125 feet or 150 feet of 1 1/2-inch noncollapsible hose for

Figure ^{5-25.-Single agent hose reel.}

AFFF/water solution or water alone, The hose reel is installed near accesses to main machinery spaces for reentry purposes, and at aviation facilities such as hangar bays, flight decks, and helo decks; the hose is used as the primary attack fire-fighting hose. There are two types of single agent nozzles. One is rated at 95 gpm, is trigger operated, and is found on all machinery space reentry hoses. The other is rated at 125 gpm, is bail operated, and is found on aviation facility hoses. The nozzles are rated at a constant flow of 95 or 125 gpm with an adjustable fog pattern and a variable-stream nozzle.

AFFF GENERATING SYSTEMS

AFFF generating systems vary throughout the fleet and from one ship to the next. The complexity and variation of the system will depend on the demand for AFFF/water solution on a particular ship. You need a basic understanding of

Figure 5-26.-AFFF injection station (12 gpm). 5-22

the theory of operation for troubleshooting and maintenance procedures. The following paragraphs will discuss the theory and operation of AFFF generating systems. The discussions will make use of the AFFF equipment and components that you studied earlier in this chapter.

12-gpm Injection System

The 12-gpm injection system will pump AFFF concentrate into the distribution piping at a fixed rate of 12 gpm, combining the concentrate and the water to produce the AFFF/water solution (fig. 5-26). The system is activated by venting the hycheck valve (water control valve) through an actuation control valve. The control line for the powertrol valve is connected downstream of the hycheck valve. As water is discharged through the hycheck valve, the water flow pressurizes the distribution piping and the operating chamber of the powertrol valve, thus causing the valve to open. A limit switch is installed on the powertrol valve. It energizes the motor controller and pump assembly (fig. 5-27) (positive displacement, sliding vane).

Two-Speed Injection System

The two-speed injection system (fig. 5-28) will inject AFFF concentrate into the water stream at a rate of 27 or 65 gpm, depending on the demand for the fire-fighting agent that is placed on the system. The system is actuated by activating an SOPV, electrically or manually. The SOPV will vent the operating chamber of the hycheck valve and pressurize the operating chamber of the powercheck valve. The switch assembly of an SOPV will cause electrical activation of the pump assembly (positive displacement, sliding vane) via the motor controller. The AFFF concentrate is pumped into the distribution piping where it combines with the water flow. This in turn produces the AFFF/water solution. The two-speed injection station can be activated locally with the local controls on the motor controller.

Single-Speed Injection System

The single-speed injection system will inject AFFF concentrate into the water stream of the countermeasure washdown (CMWD) system at a rate of 60 or 80 gpm, depending on the type of pump used, thus producing AFFF/water solution. This system is currently installed onboard aircraft carriers (CVs). The system is actuated by an SOPV. The SOPV will pressurize the operating chamber of the CMWD system powertrol valve. When the activation switch for the CMWD system powertrol valve is activated, an electrical signal from the switch will activate the pump assembly (positive displacement, sliding vane) via the motor controller. On some aircraft carriers, the activation of the singlespeed injection system and countermeasure washdown system is accomplished with independent switches when the AFFF/water solution is desired.