3.9 Fire tests
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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 - 3.9 Fire tests

3.9 Fire tests

 Fire tests should be carried out according to paragraphs 3.9.1 to 3.9.7.

  Note: The fire tests of this subsection 3.9 are more expensive and time consuming than the other tests of these Guidelines. It is recommended that fire tests should be carried out at the end of the test programme, so as to avoid the expense of unnecessary testing of foam concentrates which do not comply in other respects.

  3.9.1 Environmental conditions:

  • .1 air temperature 15 ± 5ºC;

  • .2 fuel temperature 17.5 ± 2.5ºC;

  • .3 water temperature 17.5 ± 2.5ºC;

  • .4 foam solution temperature 17.5 ± 2.5ºC; and

  • .5 maximum wind speed 3 m/s in proximity of the fire tray.

  Note: If necessary, some form of wind-screen may be used.

  3.9.2 Observations during the fire test:

 During the fire test, record the following:

  • .1 indoor or outdoor test;

  • .2 air temperature;

  • .3 fuel temperature;

  • .4 water temperature;

  • .5 foam solution temperature;

  • .6 wind speed;

  • .7 extinction time; and

  • .8 25% burnback time.

  Note: Burnback time may either be determined visually by an experienced person or may be determined from thermal radiation measurements (a suitable method is described in standard EN 1568).

  3.9.3 Foam solution:

  • .1 prepare a foam solution following the recommendations from the supplier for concentration, maximum premix time, compatibility with the test equipment, avoiding contamination by other types of foam, etc; and

  • .2 the test should be carried out with simulated sea water at about 20ºC having the characteristics stated in paragraph 3.7.3 above.

  3.9.4 Apparatus:

  • .1 fire tray: square tray with the following dimensions:

    area 4.5 m2;
    depth 200 mm;
    thickness of steel wall 2.5 mm;
    with a vertical steel backboard 1 ± 0.05 m high and 1 ± 0.05 m long;

  • .2 foam making equipment: in accordance with paragraph 3.7.2.1 for type B foam concentrates. For type A foam concentrates, the foam application rate should be as determined by the manufacturer, up to a total of three nozzles in accordance with paragraph 3.7.2.1;

  • .3 burnback pot: circular burnback pot with the following dimensions:

    diameter 300 ± 5 mm;

    height 150 ± 5 mm;

    thickness of steel wall 2.5 mm.

  3.9.5 Fuel

  3.9.5.1 For type B foams, use an aliphatic hydrocarbon mixture with physical properties according to the following specification:

distillation range 84ºC to 105ºC;
maximum difference between initial and final boiling points 10ºC;
maximum aromatic content 1%;
density at 15ºC 707.5 ± 2.5 kg/m3;
temperature about 20ºC.

  Note: Typical fuels meeting this specification are n-heptane and certain solvent fractions sometimes referred to as commercial heptane.

The Administration may require additional fire tests using an additional test fuel.

  3.9.5.2 For type A foams, acetone and isopropyl alcohol should be used as the standard test fuels. However, the Administration may require additional fire tests using different test fuels for water-miscible cargoes that require a higher foam application rate than acetone. Impurities for all type A fuels should not exceed 1%.

  3.9.6 Test procedure:

  • .1 place the tray directly on the ground and ensure that it is level. If using heptane, add approximately 90 l of simulated sea water having the characteristics stated in paragraph 3.7.3, and check that the base of the tray is completely covered. Set up the foam nozzle horizontally, about 1 m above the ground in a position where the central part of the foam discharge will strike the centre axis of the backboard, 0.35 ± 0.1 m above the rim of the tray (gentle application). Add 144 ± 5 l of fuel, to give a nominal freeboard of 150 mm. If using acetone or isopropyl alcohol, add 234 ± 5 l of fuel directly into the tray, without water, to give a nominal freeboard of 150 mm;

  • .2 ignite the tray not more than 5 min after adding the fuel and allow it to burn for a period of 60 ± 5 s after full involvement of the surface of the fuel, then start foam application; and

  • .3 apply foam for 300 ± 2 s. Stop foam application and after a further 300 ± 10 s place the burnback pot, containing 2 ± 0.1 l of fuel in the centre of the tray and ignite. Visually estimate when 25% of the tray is covered by sustained flames or by “flare up” flames (see Note below), ignoring any faint, barely visible, or transient flames.

  • Note: During the burnback test, a “flare up” may occur, in which large flames may be sustained for periods typically from 30 s to 3 min before decreasing in intensity.

  3.9.7 Permissible limits:

  • .1 extinction time: not more than 5 min; and

  • .2 burnback time: not less than 15 min for 25% of the surface.

Parent topic: 3 Tests for Type Approval of Foam Concentrates
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