HOW TO TEST THE PROPORTIONING RATE OF FOAM PROPORTIONERS: WHAT YOU SHOULD KEEP IN MIND

The exact foam agent flow rate is vital for successful firefighting when foam is used. This is why the proportioning rate of a foam proportioner should be tested at least once per year. With a FireDos proportioner, this is very easy – and, compared with other technologies, it is cost-saving and eco-friendly.

The minimum extinguishing water flow rate from which a proportioner can achieve its actual nominal proportioning rate is called the start-up flow rate. A proportioning rate of 1% means that one liter of premix consists of 10 ml foam agent and 990 ml water. But how do I check that?

FireDos proportioners allow testing of the proportioning rate while no premix or extinguishing foam is produced.

• A ball valve is used to switch between actual foam agent proportioning into the extinguishing water and returning the foam agent into the foam agent tank at atmospheric pressure. 
• The foam agent flow rate is measured by a flow meter.
• A volumetric flow meter is used to determine the extinguishing water flow rate. As an alternative, the foam agent flow rate can be measured by means of a measurement container in the return line.

calculation of the proportioning rate

The ratio of returned/contained foam agent and water volume is used to calculate and check the proportioning rate.