Low, Medium and High Expansion

Bas moyen et Haut foisonnement Mousse BIOEX

Expansion is the ratio between the Foam Volume obtained and the Volume of Foaming Solution used to produce it.

For example: 100 litres of water + foam concentrate pre-mix give 1000 litres of foam. Expansion is therefore 1000/100 = 10.

The more air is introduced the higher the expansion. There are 3 types of expansion depending on the equipment used:

  1. Low expansion â€“ usually used on widespread hydrocarbon fires (storage tanks, holding tanks). Its higher density allows the use of long range jets using hoses or monitors. Low Expansion foam is little sensitive to atmospheric conditions, wind or rain: it is stable and provides a strong cover. Its high water content guarantees significant additional cooling.
  2. Medium Expansion â€“ used for smaller surfaces (solvent storage, cellars) as a rule in closed or partially closed areas of which the walls limit the spread. Medium Expansion foam can be sprayed up to about ten metres. Its low density makes it sensitive to wind and bad weather.
  3. High Expansion â€“ preferably used on dry product fires or on premises on which there are mixed risks (stores, warehouses). As the range is almost nil, the spreading orifice must be brought to the immediate area of the fire.

Expansion closely depends on the type of foam concentrate and the type of hose used. Thus, protein foam concentrates are usually suitable for Low and Medium expansion. Synthetic foam concentrates are suitable for Low, Medium and High Expansion.

Expansion

 

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