AFEX fire suppression system tanks with header Fire Suppression Systems: Side Cartridge vs Stored Pressure

You're in the market for a fire suppression system for your heavy-duty mobile equipment. So, what's the difference between a stored pressure and side cartridge operated system? This article will walk through some frequently asked questions to help you make the right decision for your application.

¿Cual es la Diferencia?

Stored pressure agent tanks have the compressed nitrogen gas that is used as the propellant for the dry chemical agent stored in the same canister as the dry chemical.

Side cartridge operated units store the químico seco in a non-pressurized container and the compressed nitrogen gas in a separate cartridge. Only at the time of actuation is the tank under pressure and then, only briefly.

Installation of AFEX fire suppression system on a Caterpillar DozerCómo se Compacta el Polvo Químico Seco A:B:C?

Settling and compaction are common to both stored pressure and side cartridge-operated vehicle fire suppression systems. This is a result of the vibration inherent to that application.

However, side cartridge units are designed to fluff the powder before discharge. The gas passes through perforations in the gas tube, breaking up, and fluffing the powder before discharge.

Doesn't a Stored Pressure Vehicle Fire System Keep the Dry Chemical in Suspension?

No. La gravedad específica del nitrógeno es 0,97 y la gravedad específica del polvo A:B:C es 1,8. En un extintor, estos materiales se asentarán según su gravedad específica, y los más pesados se asentarán en el fondo. Como el polvo A:B:C es más pesado que el gas nitrógeno, dicha mezcla no permanecerá en suspensión.

If the Powder Compacts, How Does this Affect the Discharge of the Agent?

In side cartridge operated systems, the nitrogen gas is introduced to the agent tank through a tube with gas escape ports designed to break up and fluidize the dry chemical before it is forced out to the distribution network. Stored pressure units depend upon the downward pressure of the nitrogen gas to force the compacted powder back up a siphon tube and out the distribution network.

Fire suppression system dry chemical tank installed on a CAT982 Wheel LoaderHow Important is it to Have a Gauge on the Tanks? Are They Reliable?

Pressure gauges are used on stored pressure units to indicate if they are properly charged. However, experience has shown that these gauges are not reliable indicators of the working condition of the system. These inexpensive gauges are known to have the pointer stick to the lens of the gauge and to have the bordon tube, which controls the movement of the indicator needle, take a memory set, and cause the needle not to move. The accuracy of these gauges is reflective of their cost – less than $1 each. Relying on these gauges to indicate the readiness of the system would be risky.

La condición de trabajo de un sistema de supresión de incendios no puede ser revelado simplemente por el estado de un manómetro. El estado de la manguera de actuación, el estado de los sensores y el sistema de detección, y el estado del sistema de distribución también son cuestiones clave. No hay sustituto para un examen completo del sistema sobre una base periódica regular para evaluar su preparación.

¿Qué Tan Probable es que el Nitrógeno se Escape de Cada Tipo de Unidad?

Stored pressure fire suppression systems depend upon rubber “O” rings on the valve stem and in the valve assembly to seal the compressed nitrogen gas in the tank. These “O” rings can be deformed by vibration or improper installation, allowing the pressure to leak. These units have a vent check on the control head whose purpose is to bleed off any pressure that can cause the control head to pre-maturely discharge the agent cylinder. Pressure gauges are installed on stored pressure units to monitor the rate of leakage.

Las unidades de cartucho lateral están “selladas de por vida” con un disco de bronce. Estas unidades solo necesitan pesarse para verificar que estén correctamente llenas.

¿Cómo Decido Cuál es Mejor Para Mi Aplicación?

The difference between side cartridge and stored pressure suppression systems is found in more than just their design. Each type will do well when used in the right application and in the right environment. The secret is knowing when and where to use each type.

The state-of-the-art side cartridge units are preferred industry wide in the heavy mobile equipment market for the following reasons:

  • Construcción resistente
  • El diseño simple elimina los puntos de falla
  • Servicio fácil en el sitio
  • Bajo mantenimiento
  • No se requieren herramientas especiales
  • 50 años de protección contra incendios de vehículos

Las unidades de presión almacenada comparten su nicho con las unidades operadas por cartuchos laterales como extintores de incendios portátiles y en situaciones estacionarias, como la protección de campanas extractoras de restaurantes y estaciones de conmutación eléctrica.

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