Section 1 Non-Metallic Materials

1.1 General

1.1.1 The guidance given in this Appendix is in addition to the requirements of Pt 11, Ch 4, 5.1 Materials where applicable to non-metallic materials.

The manufacture, testing, inspection and documentation of non-metallic materials shall in general comply with recognised Standards, and with the specific requirements of this Part as applicable.

When selecting a non-metallic material, the designer must ensure it has properties appropriate to the analysis and specification of the system requirements.

A material can be selected to fulfil one or more requirements.A wide range of non-metallic materials may be considered. Therefore the section below on material selection criteria cannot cover every eventuality and must be considered as guidance.

1.2 Material selection criteria

1.2.1 Non-metallic materials may be selected for use in various parts of liquefied gas carrier cargo systems based on consideration of the following basic properties:

Insulation – the ability to limit heat flow
Load bearing – the ability to contribute to the strength of the containment system
Tightness – the ability to provide liquid and vapour tight barriers
Joining – the ability to be joined (for example by bonding, welding or fastening).

Additional considerations may apply, depending on the specific system design.

1.3 Properties of materials

1.3.1 Flexibility of insulating material

The ability of an insulating material to be bent or shaped easily without damage or breakage.

1.3.2 Loose fill material

A homogeneous solid, generally in the form of fine particles, such as a powder or beads, normally used to fill the voids in an inaccessible space to provide an effective insulation.

1.3.3 Nanomaterial

A material with properties derived from its specific microscopic structure.

1.3.4 Cellular material

A material type containing cells that are either open, closed or both and which are dispersed throughout its mass.

1.3.5 Adhesive material

A product that joins or bonds two adjacent surfaces together by an adhesive process.

1.3.6 Other materials

Materials that are not characterised in this section of the Part shall be identified and listed. The relevant tests used to evaluate the suitability of material for use in the cargo system shall be identified and documented.

1.4 Material selection and testing requirements

1.4.1 Material specification

When the initial selection of a material has been made, tests are to be conducted to validate the suitability of this material for the use intended.

The material used shall clearly be identified and the relevant tests shall be fully documented.

Materials shall be selected according to their intended use. They shall:

be compatible with all the products that may be carried
not be contaminated by any cargo nor react with it
not have any characteristics or properties affected by the cargo and
be capable to withstand thermal shocks within the operating temperature range.

1.4.2 Material testing

The tests required for a particular material depend on the design analysis, specification and intended duty. The list of tests below is for illustration. Any additional tests required, for example in respect of sliding, damping and galvanic insulation, shall be identified clearly and documented.

Materials selected according to Pt 11, Ch 21, 1.4 Material selection and testing requirements 1.4.1 of this Appendix shall be tested further according to Table 21.1.1 Material testing.

Thermal shock testing should submit the material and/or assembly to the most extreme thermal gradient it will experience when in service.

Material testing

Table 21.1.1 Material testing

Mechanical tests		X		X
Tightness tests			X
Thermal tests	X
Physical tests (see 6.9.2.5)

Inherent properties of materials
Tests shall be carried out to ensure that the inherent properties of the material selected will not have any negative impact in respect of the use intended.
For all selected materials, the following properties shall be evaluated:
- Density; example Standard ISO 845
- Linear coefficient of thermal expansion (LCTE); example Standard ISO 11359 across the widest specified operating temperature range. However, for loose fill material, the volumetric coefficient of thermal expansion (VCTE) shall be evaluated as this is more relevant.
Irrespective of their inherent properties and intended duty, all materials selected shall be tested for the design service temperature range down to 5°C below the minimum cargo design temperature, but not lower than –196°C.

Each property evaluation test shall be performed in accordance with recognised Standards. Where there are no such standards, the test procedure proposed shall be fully detailed and submitted to the Administration for acceptance. Sampling shall be sufficient to ensure a true representation of the properties of the material selected.

Mechanical tests

The mechanical tests shall be performed in accordance with Table 21.1.2 Mechanical tests.

Table 21.1.2 Mechanical tests

Mechanical tests	Load bearing structural
Tensile	ISO 527 ISO 1421 ISO 3346 ISO 1926
Shearing	ISO 4587 ISO 3347 ISO 1922 ISO 6237
Compressive	ISO 604 ISO 844 ISO 3132
Bending	ISO 3133 ISO 14679
Creep	ISO 7850

If the chosen function for a material relies on particular properties such as tensile, compressive and shear strength, yield stress, modulus or elongation, these properties shall be tested to a recognised Standard. If the properties required are assessed by numerical simulation according to a high order behaviour law, the testing shall be performed to the satisfaction of the Administration.

Creep may be caused by sustained loads, for example cargo pressure or structural loads. Creep testing shall be conducted based on the loads expected to be encountered during the design life of the containment system.

Tightness tests

The tightness requirement for the material shall relate to its operational functionality.

Tightness tests shall be conducted to give a measurement of the material’s permeability in the configuration corresponding to the application envisaged (e.g. thickness and stress conditions) using the fluid to be retained (e.g. cargo, water vapour or trace gas).

The tightness tests shall be based on the tests indicated as examples in Table 21.1.3 Tightness tests.

Table 21.1.3 Tightness tests

Tightness tests

Tightness

Porosity/Permeability

ISO 15106

ISO 2528

ISO 2782

Thermal conductivity tests

Thermal conductivity tests shall be representative of the lifecycle of the insulation material so its properties over the design life of the cargo system can be assessed. If these properties are likely to deteriorate over time, the material shall be aged as best as possible in an environment corresponding to its lifecycle, for example, operating temperature, light, vapour and installation (e.g. packaging, bags, boxes, etc).

Requirements for the absolute value and acceptable range of thermal conductivity and heat capacity shall be chosen taking into account the effect on the operational efficiency of the cargo containment system. Particular attention should also be paid to the sizing of the associated cargo handling system and components such as safety relief valves plus vapour return and handling equipment.

Thermal tests shall be based on the tests indicated as examples in Table 21.1.4 Thermal conductivity tests or their equivalents.

Table 21.1.4 Thermal conductivity tests

Thermal tests

Insulting

Thermal conductivity

ISO 8301

ISO 8302

Heat capacity

Physical tests

In addition to the requirements of Pt 11, Ch 4, 5.1 Materials 5.1.3 (c) and Pt 11, Ch 4, 5.1 Materials 5.1.4 (b), Table 21.1.5 Physical tests provides guidance and information on some of the additional physical tests that may be considered.

Table 21.1.5 Physical tests

Physical tests	Flexible insulating	Loose fill	Nanomaterial	Cellular	Adhesive
Particle size		x
Closed cells content				ISO 4590
Absorption/desorption	ISO 12571	x		ISO 2896
Absorption/desorption			x
Viscosity					ISO 2555 ISO 2431
Open time					ISO 10364
Thixotropic properties					x
Hardness					ISO 868

Requirements for loose fill material segregation shall be chosen considering its potential adverse effect on the material properties (density, thermal conductivity) when subjected to environmental variations such as thermal cycling and vibration. Requirements for a materials with closed cell structures shall be based on its eventual impact on gas flow and buffering capacity during transient thermal phases.

Similarly, adsorption and absorption requirements shall take into account the potential adverse effect an uncontrolled buffering of liquid or gas may have on the system.

1.5 Quality control and quality assurance (QA/QC)

1.5.1 General

Once a material has been selected, after testing as outlined in Pt 11, Ch 21, 1.4 Material selection and testing requirements of this Appendix, a detailed quality assurance/quality control (QA/QC) programme shall be applied to ensure the continued conformity of the material during installation and service. This programme shall consider the material starting from the manufacturer’s quality manual (QM) and then follow it throughout the construction of the cargo system.

The QA/QC programme shall include the procedure for fabrication, storage, handling and preventive actions to guard against exposure of a material to harmful effects. These may include, for example, the effect of sunlight on some insulation materials or the contamination of material surfaces by contact with personal products such as hand creams.

The proposed procedure is to be submitted to LR for consideration. All other materials in the containment system are also to be considered and included in the aforementioned procedure.

The sampling methods and the frequency of testing in the QA/QC programme shall be specified to ensure the continued conformity of the material selected throughout its production and installation.

Where powder or granulated insulation is produced, arrangements should be made to prevent compacting of the material due to vibrations.

1.5.2 QA/QC during component manufacture

The QA/QC program in respect of component manufacture must include, as a minimum but not limited to, the following items:

Component identification
For each material, the manufacturer shall implement a marking system to clearly identify the production batch. The marking system shall not interfere in any way with the properties of the product.
This marking system shall ensure complete traceability of the component and shall include:
- Date of production and potential expiration date
- Manufacturer’s references
- Reference specification
- Reference order
- When necessary, any potential environmental parameters to be maintained during transportation and storage.
Production sampling and audit method
Regular sampling is required during production to ensure the quality level and continued conformity of a selected material. The frequency, the method and the tests to be performed shall be defined in QA/QC program; for example, these tests will usually cover, inter alia, raw materials, process parameters and component checks.

Process parameters and results of the production QC tests shall be in strict accordance with those detailed in the QM for the material selected.

The objective of the audit method as described in the QM is to control the repeatability of the process and the efficacy of the QA/QC program.

During auditing, Auditors shall be provided with free access to all production and QC areas. Audit results must be in accordance with the values and tolerances as stated in the relevant QM.

1.6 Bonding and joining process requirement and testing

1.6.1 Bonding procedure qualification

The Bonding Procedure Specification and Qualification Test should be defined in accordance with an appropriate recognised Standard.

The bonding procedures shall be fully documented before work commences to ensure the properties of the bond are acceptable.

The following parameters are to be considered when developing a specification:

surface preparation
materials storage and handling prior to installation
covering time
open time
mixing ratio, deposited quantity
environmental parameters (temperature, humidity)
curing pressure, temperature and time.

Additional requirements are to be included if necessary to ensure acceptable results.

The bonding procedures specification shall be validated by an appropriate procedure qualification testing programme.

1.6.2 Personnel qualifications

Personnel involved in bonding processes shall be trained and qualified to recognised Standards. Regular tests shall be made to ensure the continued performance of people carrying out bonding operations to ensure a consistent quality of bonding.

1.7 Production bonding tests and controls

1.7.1 Destructive testing

During production, representative samples shall be taken and tested to check they correspond to the required level of strength as required for the design.

1.7.2 Non-destructive testing

During production, tests which are not detrimental to bond integrity shall be performed using an appropriate technique such as:

visual examination
internal defects detection (for example acoustic, ultrasonic or shear test
local tightness testing.

If the bonds have to provide tightness as part of their design function, a global tightness test of the cargo containment system shall be completed after the end of the erection in accordance with the designer’s and QA/QC programme.

The QA/QC standards shall include acceptance standards for the tightness of the bonded components when built and during the lifecycle of the containment system.