Section 5 Control of material quality for composite construction

5.1.1 This Section gives the general requirements for control of material quality when used in the construction of composite craft.

5.1.2 For composite craft built under the Rules, the survey of materials is to be conducted in accordance with the requirements of Ch 14, 1 General requirements to Ch 14, 3 Testing procedures and this Section.

5.2.1 The requirements for design submission are detailed in the appropriate Part of the Rules which includes full information on composite materials.

5.3.1 All constructions are to be carried out using materials approved or accepted by LR.

5.3.2 All materials are to be in accordance with the approved construction documentation.

5.3.3 All batches of materials are to be provided with unique identifications by their manufacturers. Components are to be similarly identified.

5.3.4 No batch of material is to be used later than its date of expiry.

5.3.5 The Builder is to ensure that all batches of materials are used systematically and sequentially.

5.3.6 The Builder is to maintain, on a continuous basis, records of the amounts of resin and reinforcement used, in order to ensure that the proportions remain within the limits set in the construction documentation.

5.3.7 Records are to be kept of the sequence and orientation of the reinforcements.

5.3.8 The Builder is to ensure that each section of the construction is traceable to the batch or batches of material used. The unique identifications required under Ch 14, 1.11 Identification of products and base materials 1.11.1 are to be included on all relevant quality control documentation.

5.3.9 Any curing system used is to be demonstrated as suitable for the intended purpose and all pyrometric equipment is to be calibrated at least annually and adequate records maintained.

5.3.10 The post-curing temperature is to be controlled and recorded by the attachment of suitably placed thermocouples.

5.4.1 Where the Builder has a quality assurance system, this is to include the requirements of this Section.

5.5.1 Dimensions and tolerances are to conform to the approved construction documentation.

5.5.2 The thicknesses of the laminates are, in general, to be measured at not less than ten points, evenly distributed across the surface. In the case of large sections, at least ten evenly distributed measurements are to be taken in bands across the width at maximum spacing of two metres along the length.

5.5.3 The responsibility for maintaining the required tolerances and making the necessary measurements rests with the Builder. Monitoring and random checking by the Surveyor does not absolve the Builder from this responsibility.

5.5.4 Where ultrasonic thickness gauges are used, these are to be calibrated against an identical laminate (of measured thickness) to that on which the thickness measurement is to be carried out. If suitable pieces are not available from the construction, then a small sample of identical lay-up is to be prepared.

5.6.1 The materials, prefabricated sections or components used are to be in accordance with the approved construction documentation.

5.6.2 Where alternative materials are used, these are to be of approved or accepted types and the manufacturer is to demonstrate to the Surveyor's satisfaction, prior to their introduction, their suitability with respect to performance, otherwise full testing as appropriate will be required.

5.7.1 Where so required, the material manufacturer is to provide the purchaser with certificates of conformity for each batch of material supplied, indicating the relevant values specified in Ch 14, 5.7 Material testing 5.7.4 to Ch 14, 5.7 Material testing 5.7.8. These values are to comply with those specified by the approved construction documentation.

5.7.2 Where the Builders do not conduct verification testing of the information indicated in Ch 14, 5.7 Material testing 5.7.4 to Ch 14, 5.7 Material testing 5.7.8, they are to ensure that copies of all certificates of conformity (which must indicate the actual tested values) are obtained for all batches of materials received, and maintain accurate records. The Surveyor may at any time select a sample of a material for testing by an independent, where applicable, source and should such tests result in the material failing to meet the specification, then that batch will be rejected.

5.7.3 The following tests are to be carried out, where applicable, on receipt of any material:

1. The consignment is to be divided into its respective batches and each batch is to be labelled accordingly.

2. Each batch is to be visually examined for conformity with the batch number, visual quality and date of expiry.

3. Each batch is to be separately labelled and stored separately.

4. Each unit, within the batch, is to be labelled with the batch number.

5. Records are to be maintained of the above and these are to be cross-referenced with the certificate of conformity for the material and/or the Builder's own test results.

5.7.4 For thermosetting resins, reinforced or otherwise, the resin manufacturer is to have determined, on samples taken from each batch, at least the following:

1. All resins:

   1. Viscosity.

   2. Gel time.

   3. Filler content, where applicable.

2. Polyester and vinylester resins:

   1. Type (orthophthalic, isophthalic, etc.).

   2. Volatiles content.

   3. Acid value.

3. Epoxide resins:

   1. Free epoxide content.

4. Phenolic resins:

   1. Free phenol content.

   2. Free formaldehyde content.

5.7.5 For thermoplastics, the polymer manufacturer is to have made the following measurements on samples taken from each batch:

1. Melting point.

2. Melt flow index.

3. Density.

4. Filler/pigment content, where applicable.

5. Tensile stress at yield and break.

6. Tensile strain at yield and break.

5.7.6 Where the resin or polymer manufacturer mixes batches, both the original batches and the mixed batch are to be tested in accordance with Ch 14, 5.7 Material testing 5.7.4 or Ch 14, 5.7 Material testing 5.7.5 as appropriate. The mixed batch is then to be given a unique batch number.

5.7.7 For reinforcements, the material manufacturer is to have recorded, where applicable, the following for each batch of material:

1. Tex of yarn(s) or roving(s).

2. Ends per 100 mm in all reinforcement orientations.

3. Weight per square metre.

4. Binder/size content.

5. Stitch type and count.

6. Type of fibre used.

7. Surface treatment and/or finish.

5.7.8 For core materials, the following properties are to be recorded by the manufacturer for each batch:

1. Type of material.

2. Density.

3. Description (block, scrim mounted, grooved).

4. Thickness and tolerance.

5. Sheet/block dimensions.

6. Surface treatment.

Together with the following mechanical properties:

In the case of rigid foams:

1. Compressive strength (stress at maximum load) and modulus of elasticity.

2. Core shear strength.

In the case of end-grain balsa:

1. Tensile strength (stress at maximum load).

2. Compressive strength (stress at maximum load) and modulus of elasticity.

5.7.9 During construction, tests are to be carried out on the constituents and final product in accordance with Table 14.5.1 Tests during construction.

5.7.10 The standards of acceptance for testing are those listed in the material manufacturer's specification, approved construction documentation or agreed quality control procedures as applicable.

5.7.11 Laminate fibre content is to be determined at the request of the Surveyor, in particular where the thickness measured does not correlate with the specified fibre content, by weight. This will, in general, result in additional reinforcement being required.

5.7.12 If the batch of resin or polymer, or the curing agent, or their ratio is changed, at least two additional measurements of the gel time are to be carried out during each shift.

5.8.1 All constructional mouldings and any components are to be visually examined and are to be free from surface defects and blemishes.

5.9.1 Repairs of minor cosmetic blemishes are permitted providing that these are brought to the attention of the Surveyor.

5.9.2 A repair procedure for these minor blemishes is to be included in the agreed quality control procedures.

5.9.3 Structural repairs are subject to individual consideration and full written details must be approved by the plan approval office prior to introduction.

5.10.1 Records of the construction are to be kept in such a manner that traceability of all the component materials used is ensured. The Surveyor is to be given full facilities for tracing the material's origin when required.

5.10.2 Small representative samples of each batch of material are to be retained, these being suitably labelled to ensure tracebility.

5.10.3 When so requested by the Surveyor, the Builder is to provide copies of all test data and/or manufacturers' certificates of conformity appertaining to any material used.

5.11.1 This Section provides the minimum property values required of a material for approval or acceptance by LR and are applicable to materials cured under ambient conditions.

5.11.2  Gel coat resins. When the cast resin is tested according to the requirements of Ch 14, 2.3 Thermosetting resins, Table 14.5.2 Gel coat resins, minimum property values gives the minimum values for the respective properties.

5.11.3  Laminating resins. When tested according to the requirements of Ch 14, 2.3 Thermosetting resins and Ch 14, 2.4 Reinforcements, Table 14.5.3 Laminating resins, minimum property values and Table 14.5.4 Laminating resins, minimum values for properties for CSM laminate at 0,3 glass fraction by weight give the minimum properties for the cast resin and chopped strand mat laminate respectively.

5.11.4 When tested to the requirements of Ch 14, 2.4 Reinforcements for reinforcements, Table 14.5.5 Laminates, minimum property requirements gives the minimum properties for laminates.

5.11.5 Alternatively, materials may be approved by use of the actual tested values whereby the approval value shall equal the mean of the tested values minus twice the standard deviation of a minimum of five tested values.

5.12.1  Table 14.5.6 Minimum characteristics and mechanical properties of rigid expanded foams at 20°C gives minimum values for closed cell forms for core construction based on PVC or polyurethane.

5.12.2 Other types of foam will be subjected to individual consideration. A minimum core shear strength of 0,5 N/mm² is to be achieved.

5.13.1  Table 14.5.7 Minimum characteristics and mechanical properties of end-grain balsa gives the minimum property requirement for end-grain balsa.

5.14.1 After 1000 hours the chocking resin must be stabilised and maximum creep is to be less than or equal to 0,2 per cent.

5.14.2 Compliance with Ch 14, 5.14 Synthetic chocking compounds 5.14.1 is to be demonstrated at the time of chocking compound approval for a specified cure/post cure schedule. The Izod, barcol, compression, and water and oil absorption are additionally to be determined for the creep tested cure/post cure schedule.

5.14.3 Confirmation of creep, barcol and compression will be required for cure/post cure conditions which differ from those shown on the product approval certificate.

5.15.1 All other materials will be subject to special consideration.