3.2 Control Measurements

 The testing laboratory should take reference specimens of all those materials whose characteristics are important to the performance of the specimen (excluding steel and equivalent material).

 The reference specimens should be used for the non-combustibility test, if appropriate, and for the determination of the thickness, the density and, where appropriate, the moisture and/or binder content.

 The reference specimens for sprayed materials should be made when the material is sprayed on the structural core and they should be sprayed in a similar manner and in the same orientation.

 The laboratory should conduct the following control tests, as appropriate to the type of material and the proposed classification, on the reference specimens after they have been conditioned as specified in section 4.

 For the determination of the thickness, the density and the moisture and/or binder content three specimens should be used, and the value quoted as the mean of the three measurements.

 When an insulation material is encapsulated within the construction and it is not possible for the laboratory to take specimens of the material prior to the test for conducting the control measurements, the applicant should be requested to provide the requisite samples of the material. In these cases it should be clearly stated in the test report that the measured properties were determined from samples of the material provided by the applicant for the test.

 Notwithstanding the above, the laboratory should attempt, wherever possible, to verify the properties by using samples which may be cut from the specimen before test or by checking against similar properties determined after test. When samples of the material are cut from the test specimen before test, the specimen should be repaired in a manner such that its performance in the fire test is not impaired.

 If necessary (see 3.1), non-combustibility tests in accordance with the test method for qualifying marine construction materials as non-combustible, developed by the Organization, should be conducted. Adhesives used in the construction of the specimen are not required to be non-combustible; however, they are recommended to have low flame-spread characteristics.

 The thickness of each material and combination of materials should be measured by using a suitable gauge or callipers.

 The thickness of a sprayed insulation material should be measured using a suitable probe at positions adjacent to each of the unexposed-face thermocouples referred to in 7.5.1.1 and 7.5.1.2.

 The density of each material should be determined from measurement of the weight and the dimensions.

 The density of mineral wool or any similar compressible material should be related to the nominal thickness.

 Specimens of each material, measuring minimum 60 mm x 60 mm x thickness of the material, should be weighed (initial conditioned weight W ₁) and then heated in a ventilated oven at a temperature of 105 ± 2°C for 24 h and reweighed when cooled (W ₂). However, gypsum-based, cementatious and similar materials should be dried at a temperature of 55 ± 5°C to constant weight (W ₂).

 The moisture content (W ₁-W ₂) of each specimen should be calculated as a percentage of the dry weight (W ₂).

 After the percentage moisture contents have been calculated as specified above, the specimens should be further heated in an oven at a temperature of 550 ± 20°C for 24 h and again weighed (W ₃). The binder content ( W ₂-W ₃) should be calculated as a percentage of the dry weight (W ₂).