LOW EXPANSION FOAM

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 Low Expansion Foam

These systems can ONLY be an addition to the main fixed fire fighting system (CO₂, water spray or high expansion foam).

A mixture of water with foam (12:1 maximum) is led to spreaders, monitors or hydrants and it is at these points that air is entrained and the foam produced. There must be sufficient points of delivery to give a foam blanket of 150mm over the risk area.

All equipment must be located outside of the protected machinery space.

There are two main types: ‑

1) Pressurised System

Premixed foam & water is stored in a tank which is pressurised when required by CO₂

This system needs no source of power or pumps and is immediately available.

2) Ratio or Metered System

Foam compound in a tank is mixed with pumped water as required. This has the advantage of a smaller volume fixed tank that does not need to withstand extra pressure, but the system now requires pump(s) and a power supply.