Section 3 Testing procedures

3.1.1 This Section gives details of the test methods to be used for base materials and on finished plastics products such as fibre reinforced plastics (FRP) piping and any testing required in the construction of composite vessels.

3.1.2 In general, testing is to be carried out by a competent independent test house which, at the discretion of LR, may or may not require witnessing by the Surveyor.

3.1.3 Alternatively, testing may be carried out by the manufacturer subject to these tests being witnessed by the Surveyor.

3.1.4 All testing is to be carried out by competent personnel.

3.1.5 Unless specified otherwise, testing is to be carried out in accordance with a recognised ISO standard, where one exists, and all test programmes are to have written procedures.

3.1.6 Alternatively, testing may be carried out in accordance with a National Standard provided that it conforms closely to an appropriate ISO standard and subject to prior agreement with the Surveyor.

3.1.7 Mechanical properties are to be established using suitable testing machines of approved types. The machines and other test equipment are to be maintained in a satisfactory and accurate condition and are to be recalibrated at approximately annual intervals. Calibration is to be undertaken by a nationally recognised authority or other organisation of standing and is to be to the satisfaction of the Surveyor. A record of all calibrations is to be kept available in the test house. The accuracy of test machines is to be within ± one per cent.

3.2.1 Thermoplastic samples are to be prepared in accordance with the manufacturer's recommendations for moulding. For finished products, samples are to be taken from the product during production in accordance with the manufacturer's quality plan, but where this is impractical, separate test samples are to be prepared in a manner identical with that of the product.

3.2.2 Samples of thermosetting resins are to be prepared using the curing system recommended by the manufacturer and identical with that used for the finished product.

3.2.3 The post curing conditions for samples of thermosetting resins are to be as recommended by the manufacturer and identical with those used for the finished product. Where the samples are made for the general approval of a resin, the post curing conditions are to be those in which the resin is intended to be used.

3.2.4 Where curing of the product is intended to take place at room temperature, the sample is to be allowed to cure at room temperature (18 to 21°C) for 24 hours followed by a post-cure at 40°C for 16 hours.

3.2.5 Where a reinforcement is to be used, the ratio of reinforcement to resin or polymer is to be nominally the same as that of the finished product or in accordance with Table 14.2.2 Glass fraction by weight for different reinforcement types or Table 14.2.3 Content by volume for different reinforcement types.

3.2.6 Where laminates are prepared specifically for approval test purposes, the reinforcement is to be laid parallel plied.

3.3.1 The test specimen is to be prepared in accordance with the appropriate ISO standard and the requirements of this Section.

3.3.2 Precautions are to be taken during machining to ensure that the temperature rise in the specimen is kept to a minimum.

3.4.1 Strain measurement is to be made by the use of a suitable extensometer or strain gauge.

3.4.2 The rate of strain is to be in accordance with the appropriate ISO standard.

3.4.3 The number of test specimens from each sample to be tested is to be in accordance with the ISO standard. For mechanical testing this is five.

3.5.1 If a test specimen fails because of faulty preparation or incorrect operation of the testing machine, it is to be discarded and replaced by a new specimen.

3.5.2 In addition, if the deviation of one result in a group of five exceeds the mean by more than two standard deviations, that result is to be discarded and one further specimen tested, see Ch 14, 1.8 Re-test procedure 1.8.1 and Ch 14, 1.8 Re-test procedure 1.8.2.

3.6.1 All load/displacement graphs and tabulated results are to be reported, including mean values and the calculated standard deviation.

3.6.2 Additionally, full details of the sample and specimen preparation are to be provided including (where applicable):

1. Catalyst/accelerator or curing agent types and mix ratio.

2. Weights of resins, and/or reinforcements used.

3. Casting/laminate dimensions.

4. Number of layers of reinforcement used.

5. Curing/post-curing conditions.

3.7.1 The data requirements in Ch 14, 2.2 Thermoplastic polymers and Ch 14, 2.3 Thermosetting resins for thermoplastic or thermosetting resins or polymers are to be determined in accordance with suitable National or International Standards.

3.7.2 Recognised Standards to which specimens of unreinforced thermoplastic resins are to be tested are listed in Table 14.3.1 Tests for unreinforced thermoplastic resins.

Table 14.3.1 Tests for unreinforced thermoplastic resins

Test	Standard
Tensile properties	ISO 527-2	Test speed = 5 mm/min Specimen 1A or 1B
Flexural properties	ISO 178	Test speed = mm/min
Water absorption	ISO 62	Method 1
Temperature of deflection under load	ISO 75-2	Method A
Compressive properties	ISO 604	Test speed - as for ductile materials
Note 1. Water absorption - result to be expressed as milligrams. Note 2. Tensile modulus values are to be determined using an extensometer which may be removed for strain to failure.

3.7.3 Test standards for unreinforced cast thermosetting resins are given in Table 14.3.2 Tests on unreinforced cast thermoset resin specimens.

Table 14.3.2 Tests on unreinforced cast thermoset resin specimens

Test	Standard
Tensile properties	ISO 527-2	Test speed = 5 mm/min Specimen 1A or 1B
Flexural properties	ISO 178	Test speed = mm/min
Water absorption	ISO 62	Method 1
Temperature of deflection under load	ISO 75-2	Method A
Compressive properties	ISO 604	Test speed = 1 mm/min
Note 1. ISO 62 - where resins are intended for use under ambient conditions to avoid additional post-curing, the requirement in ISO 62 for pre-drying the test specimen at 50°C is to be omitted. The test result is to be expressed as mg of water. Note 2. ISO 527-2 - tensile properties are to be measured using extensometry.

3.7.4 The Standards to which laminate specimens of any type are to be tested are listed in Table 14.3.3 Tests on laminate specimens.

Table 14.3.3 Tests on laminate specimens

Test	Standard
Tensile properties	ISO 527-4	Test speed = 2 mm/min Specimen types II or III
Flexural properties	ISO 14125	Test speed = mm/min
		Method A
Compressive properties	ISO 604	Test speed = 1 mm/min
Interlaminar shear	ISO 14130
Water absorption	ISO 62	Method 1
Glass content	ISO 1172
Note 1. ISO 62 - where resins are intended for use under ambient conditions to avoid additional post-curing, the requirement in ISO 62:2008 for pre-drying the test specimen at 50°C is to be omitted. The test result is to be expressed as mg of water. Note 2. ISO 527-4 - tensile properties are to be measured using extensometry. Note 3. Tensile modulus values are to be determined using an extensometer which may be removed for strain to failure.

3.8.1 Initially, the core shear strength and modulus are to be determined by ISO 1922 or ASTM C273/C273M. Test sandwich panels are then to be prepared and subjected to four-point flexural tests to determine the apparent shear properties according to ASTM C393/C393M (short beam) at two representative thicknesses (i.e. 15 mm and 30 mm). Testing is to be carried out at ambient temperature and at 70°C. The following requirements are to be observed:

1. Each skin is to be identical and have a thickness not greater than 21 per cent of the nominal core thickness. For hand laid constructions, each skin is to comprise a lightweight chopped strand mat reinforcement (300 g/m²) consolidated at a glass content, by weight, of 0,3 against the core, plus the required number of woven reinforcements consolidated, using an isophthalic polyester resin, to give a minimum glass content, by weight, of 0,5.

2. The method of construction of the sandwich laminate is to reflect the core material manufacturer's instructions for use, i.e. application of bonding paste, surface primer or any other recommended system.

3. Where vacuum bagging techniques or equivalent systems are used, these will be subject to individual consideration.

4. All resins and reinforcements are to hold current LR approval.

5. Curing conditions are to be in accordance with Ch 14, 3.2 Preparation of test samples 3.2.3 and Ch 14, 3.2 Preparation of test samples 3.2.4.

6. The dimensions of the test samples should be based on the requirements of ASTM C393 Paragraph 5.1, and the ratio parameters as indicated in ASTM C393 Paragraph 5.2, using a proportional limit stress (F) for the woven roving skins of 130 N/mm² and a span (a ₂) of not less than 400 mm.

3.8.2 For each type of test sample, the following data are to be reported, together with the submission of a representative test sample showing the mode of failure for each density of core material:

1. Skin and core thickness, and core type and density.

2. Resin/catalyst/accelerator ratio.

3. Skin construction, including types and weight of reinforcements, resin(s), etc.

4. Details of production method and curing conditions (temperature and times).

5. Where additional preparation of the foam is involved, for example the use of primers or bonding pastes, full details are to be provided.

6. Actual span between base supports for each type of test sample.

3.8.3 The following requirements apply to end-grain balsa:

1. The data requirements of Ch 14, 2.7 Core materials 2.7.1 are to be provided, where applicable, according to suitable National or International Standards.

2. The balsa is to be tested according to the requirements of Ch 14, 3.8 Structural core materials 3.8.1.

3. The test methods for balsa are given in Table 14.3.4 Tests on end-grain balsa.

Table 14.3.4 Tests on end-grain balsa

Test	Standard
Density	ISO 845
Tensile properties	ASTM C297/C297M
	Test speed = mm/min
Compressive properties	ISO 844
	Test speed = mm/min
Shear properties	ISO 1922 Test speed = 1 mm/min

3.8.4 The following requirements apply to rigid foams:

1. The data requirements of Ch 14, 2.7 Core materials 2.7.1 are to be provided in accordance with a suitable National or International Standard.

2. The foam is to be tested according to the requirements of Ch 14, 3.8 Structural core materials 3.8.1.

3. The test methods for rigid foams are to be in accordance with Table 14.3.4 Tests on end-grain balsa.

3.8.5 The following requirements apply to synthetic felt type materials:

1. The data requirements of Ch 14, 2.10 Synthetic felt type materials with or without microspheres 2.10.1 are to be provided according to suitable National or International Standards.

2. The material is to be tested according to the requirements of Ch 14, 3.8 Structural core materials 3.8.1, with the following modifications:

   1. The core of the laminate test sandwich panel is to be prepared with a fibre content as recommended by the manufacturer.

   2. The felt fibre/resin ratio is to be stated.

   3. The required test thicknesses of the cores are to be changed from 30 mm and 15 mm to 12 mm and 6 mm respectively.

3. The prepared laminate of the base material is to be of minimum thickness 3,5 mm with a minimum of three layers.

4. The specified tests on the laminate (see Ch 14, 2.10 Synthetic felt type materials with or without microspheres 2.10.3) are to be conducted according to the requirements of Table 14.3.3 Tests on laminate specimens.

3.9.1 Test samples of the cured chock resin are to be prepared under ambient conditions and then post-cured at the exotherm temperature as determined in Ch 14, 2.11 Machinery chocking compounds (resin chocks) 2.11.3.

3.9.2 The specified properties are to be determined as required by Table 14.3.5 Tests for machinery chocking components.

3.9.3 The percentage linear shrinkage of cured material is to be measured.

3.9.4 Creep is to be measured according to the following method:

1. A 25 mm x 20 mm diameter parallel faced cylinder is to be pre-loaded against a steel base at 2,5 N/mm² or 3,5 N/mm², or at the specified higher loading condition, at ambient temperature for 16 hours.

2. The temperature is to be increased at the rate of 8°C per hour until the service temperature (60°C or 80°C) is reached.

3. During this time, the creep of the cylinder is to be measured at 15 minute intervals.

4. The temperature and loading are to be maintained for a minimum of 1000 hours (or until stabilised), measuring the creep at intervals of 24 hours.

5. A plot of creep in mm (linear scale) against time (log scale), together with full experimental details, is to be provided for review by LR.

3.9.5 Where a manufacturer requests a chocking resin to be reapproved and provided that there has been no change in formulation, the following properties are to be determined on samples of chocking resin that have been subject to the cure/post-cure conditions of the initial certification :

1. Creep to be measured at specified loading as per initial approval over a period of 200 hours as per Ch 14, 3.9 Machinery chocking compounds 3.9.4.
2. Peak exotherm temperature on cured/post-cured chocking resin.
3. Barcol hardness.
4. Temperature of deflection under load.

3.10.1 All mechanical properties as required by Ch 14, 2.12 Rudder and pintle bearings are to be measured according to suitable National or International Standards.

3.10.2 Frictional properties are to be determined according to a method agreed with LR.

3.11.1 The requirements for sterntube bearings are as defined in Ch 14, 2.13 Sterntube bearings.