3.7 Expansion ratio
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Statutory Documents - IMO Publications and Documents - Circulars - Maritime Safety Committee - MSC.1/Circular.1312 – Revised Guidelines for the Performance and Testing Criteria, and Surveys of Foam Concentrates for Fixed Fire-Extinguishing Systems – (10 June 2009) - Annex – Revised Guidelines for the Performance and Testing Criteria, and Surveys of Foam Concentrates for Fixed Fire-Extinguishing Systems - 3 Tests for Type Approval of Foam Concentrates - 3.7 Expansion ratio

3.7 Expansion ratio

  3.7.1 The test should be carried out according to paragraph 3.7.2 with simulated seawater at about 20șC having the characteristics stated in paragraph 3.7.3.

  3.7.2 Determination of the expansion ratio

  • .1 apparatus:

    • .1 plastic collecting vessel of volume V, known to ± 16 ml, as shown in figure 2, equipped with a bottom discharge facility;

    • .2 foam collector, as shown in figure 3; and

    • .3 foam making equipment with nozzle, as shown in figure 4, which when tested with water has a flow rate of 11.4 l/min at a nozzle pressure of 6.3 ± 0.3 bar;

  • .2 procedure:

    • .1 check that the pipe work and hose from the foam solution tank to the nozzle is completely full of solution. Set up the nozzle horizontally directly in front of the foam collector with the front of the nozzle 3 ± 0.3 m from the top edge of the collector. Wet the vessel internally and weigh it (W1 ). Set up the foam equipment and adjust the nozzle pressure to give a flow rate of 11.4 l/min. Discharge the foam and adjust the height of the nozzle so that the discharge strikes the collector centrally. Keep the nozzle horizontal. Stop the foam discharge and rinse all foam from the collector. Check that the foam solution tank is full. Start discharging the foam and after 30 ± 5 s to allow the discharge to stabilize, place the collecting vessel, with the discharge outlet closed, on the collector. As soon as the vessel is full, remove it from the collector, strike the foam surface level with the rim and start the clock. Weigh the vessel (W2 );

    • .2 calculate the expansion E from the equation:

in which it is assumed that the density of the foam solution is 1 and where:

V =

is the vessel volume in ml;
W1 =

is the mass of the empty vessel in grams;
W2 =

is the mass of the full vessel in grams; and

    • .3 open the drainage facility and collect the foam solution in the measuring cylinder to measure the 25% drainage time (see paragraph 3.8.1 below).

  3.7.3 Simulated sea water may be made up by dissolving in 0.9584 kg of potable water:

25 g Sodium chloride (NaCl);
11 g Magnesium chloride (MgCl2 6 H2O);
1.6 g Calcium chloride (CaCl2 2H2O);
4 g Sodium sulphate (Na2 SO4).
Parent topic: 3 Tests for Type Approval of Foam Concentrates
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