3.8 Fire tests

 Fire tests should be carried out in accordance with 3.8.1 to 3.8.7 below.

• NOTE: The fire tests of section 3.8 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 expense of unnecessary testing of foam concentrates which do not comply in other respects.

  3.8.1 Environmental conditions

• .1 Air temperature: 15 ± 5°C.

• .2 Maximum wind speed: 3 m/s in proximity of the fire tray.

  3.8.2 Records

During the fire test, the following should be recorded:

• .1 indoor or outdoor test;

• .2 air temperature;

• .3 fuel temperature;

• .4 water temperature;

• .5 foam solution temperature;

• .6 wind speed; and

• .7 extinction time.

  3.8.3 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.

• .2 The test should be carried out with seawater at about 20°C. Simulated seawater with the characteristics stated in 3.6.3 maybe used.

  3.8.4 Apparatus

• .1 Fire tray:

  Circular fire tray of steel with dimensions as follows:

  	-	diameter at rim:	1,480 ± 15 mm
  	-	depth:	150 ± 10 mm
  	-	normal thickness of steel wall:	2.5 mm

• NOTE: The tray has an area of approximately 1.73m².

• .2 Foam-making equipment:

  In accordance with subparagraph 3.6.2.1.

  3.8.5 Fuel

An aliphatic hydrocarbon mixture with physical properties according to the following specification should be used:

• • NOTE: Typical fuels meeting this specification are n-hepthane and certain solvent fractions sometimes referred to as commercial hepthane

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

  3.8.6 Test procedure

  3.8.6.1 Place the tray directly on the ground and ensure that it is level. Add approximately 30l of fresh water and 55 ± 2l of fuel, to give a nominal freeboard of 100 mm.

  3.8.6.2 Not later than 5 min after adding of a fuel, ignite the fuel and allow it to burn free for a period of not less than 180 s after the full involvement. Set up the foam equipment at a height which is equal to the upper edge of the rim as it is shown at figure 1. 200 ± 5 s after full involvement of the surface into the fire, apply foam along the wall of the tray for a period of 120 ± 2 s. Record the extinction time as the period from start of foam application to extinction.

  3.8.7 Permissible limits

Extinction time % not more than 120 s.

Figure 1 Fire test arrangement of medium expansion foam