When it comes to compressed air foam systems, nothing can match the ease of use of the ONE STEP™ CAFSystem. ONE STEP incorporates a powerful integrated midship-mounted air compressor system and revolutionary compact foam generators to provide a reproducible homogenous, micro-cellular, continuous bubble stream. A characteristic of each ONE STEP™ CAFSystem is the pre-set flow rate and pre-set pressure for water and air. The operator does not have to adjust flows and pressures.

Request More Information


Mixing Pressure Control Valve 
The ONE STEP™ CAFSystem uses an independent, patented pressure regulation, which keeps constant mixing pressure in the mixing chamber of the foam generator. This pressure regulation allows a variation of pump discharge pressure above the minimum working pressure of the ONE STEP without disrupting the function of the ONE STEP systems or changing the consistency of the extinguishing agent.

Air Compressor
GHH-Rand air end with tapered roller bearings and triple lip shaft seal, oil-flooded, rotary screw type, sized to supply 150 scfm (4.25 m3/min) at a minimum of 125 P.S.I.G ( 8.6 bar).

Pneumatic Modulating Inlet Valve
The air compressor is controlled by the pneumatic modulation inlet valve mounted on the air end. The pneumatic modulating inlet valve controls air delivery while maintaining constant pressure.

Fixed Air Pressure Operation
The compressor supplies a fixed air pressure supply to the foam generators at 116 PSI (7.8 Bar). Pressure balancing systems are not used or required.

- Fixed - Air pressure defaults to manual setting on compressor mounted control valve.
- Unload - Air pressure reduced to 40 P.S.I.G. (2.75 bar) for standby operations or when water only from the pump is required

Air Compressor Drive
The compressor is driven off the back of a standard Waterous pump transmission. The compressor drive is direct. The compressor shall be run in unload mode for pump testing and high pressure pump use. Power is transferred via a synchronous drive “toothed belt” with an adjustable tensioner. The system is designated to operate the air end at rated capacity when the fire pump is developing 130 to 140 P.S.I.G. (9 to 9.7 bar) in a “no flow” state.

Air Compressor Oil System

A spin-on, full-flow oil filter unit is part of the system to control oil flow to the cooler. All oil lines are routed in braided hose conforming to SAE 100R1 standards for hydraulic hose.

Modular Air/Oil Separator Unit
Replacement elements for the oil filter and separator are available.

Air Compressor Cooling System
The air compressor is cooled by the Waterous fire pump1, utilizing an all copper and brass shell and tube heat exchanger. When the fire pump is operating, water flows through the heat exchanger while an in-line removable strainer, on the water inlet side, prevents clogging. The system maintains oil temperature within 160° to 225°F (71° to 107° C).

Foam Concentrate Piping
All concentrate piping is stainless steel, brass or high pressure wire braid reinforced hose with stainless steel or brass fittings.

Foam Manifolds
Foam manifolds are constructed of cast iron. The manifold is a fully integrated assembly with foam injector port, flow meter mount and high-flow, low-loss, spring-assisted brass swing check valve to prevent back-flow of foam concentrate or foam solution into the pump.

Optional Advantus® 3E or 6E

A fully automatic electronic direct foam injection system is furnished and installed. The system is capable of Class A foam concentrates and most Class B foam concentrates. The system includes the following:


Digital Electronic Control Display

Located on the pump operator's panel, the electronic control display enables the operator to perform the following functions:

  • Provide push-button control of foam proportioning rates from 0.1% to 1%, in 0.1% increments; 3% and 6%
  • Show current flow-per-minute of water
  • Show total volume of water discharged during and after foam operations are completed
  • Show total amount of foam concentrate used
  • Show which foam supply tank is in use
  • Perform setup and calibrate functions for the microcontroller
  • Flash a “low concentrate” warning when the foam concentrate tank(s) run(s) low
  • Flash an “error” warning with associated code in the event of an electronic malfunction
  • Provide a manual back-up mode, controlled by the operator

12 or 24-Volt Electric Motor

A 12 or 24-volt electric motor driven Hydra-Cell positive displacement foam concentrate pump, rated at 3 GPM @ 150 psi (11.3 l/min @10 bar) or 6 GPM @ 150 psi (22.6 l/min @ 10 bar) and with operating pressures up to 450 psi (32 bar).


150-OS CAFSystem

Dimensional Drawings


Service Parts List

Specification Sheets 

Performance Sheets

Preferred Specification

PowerPoint Presentation


Sales/Application/Service Help

Industry-leading sales and support.

When you purchase Waterous equipment, not only do you get quality products, you get quality service. Our expert service technicians are the best in the business and they are always happy to answer any service questions you might have. The numbers for our service and training specialists are listed below for your convenience. If you have a general service question please call our main number and our staff will kindly direct you to the appropriate department.

Sales/Applications Assistance

Phone: 651-450-5234 (Press 3)


Service Assistance
Phone: 651-450-5200
Fax: 800-488-1228



 150-OS | CAFSystem Series