Overview
ISO 22975-5:2019 - "Solar energy - Collector components and materials - Part 5: Insulation material durability and performance" sets out requirements and test methods for insulation materials used in solar collectors. The standard applies to common insulation types used in solar thermal systems, including rigid polyurethane foam (PU), phenolic foam (PF), mineral wool (MW) and mineral fibre. It defines how to assess durability and performance properties that affect long-term thermal efficiency and safety of flat-plate and evacuated-tube collectors.
Key topics and technical requirements
ISO 22975-5 specifies standardized test procedures and reporting for insulation material properties, including:
- Material scope: Rigid PU, PF, mineral wool and mineral fibre for solar collectors.
- Physical properties: Apparent density, bulk density, dimensions, apparent open-cell percentage (PU/PF).
- Mechanical durability: Dimensional stability, compression properties and compression behaviour.
- Moisture behaviour: Water absorption, hygroscopic sorption, moisture content and water vapour transmission/permeance/resistance.
- Thermal performance: Thermal resistance and thermal conductivity testing (steady-state heat flow).
- Ageing and durability: Accelerated aged value of thermal resistance for closed-cell plastics, and procedures for retention of performance over time.
- Safety and reaction to fire: Flammability tests and non-combustibility evaluation where applicable.
- Other performance issues: Maximum use temperature for mineral wool/mineral fibre and outgassing tests for flat-plate collector applications.
- Sampling and reporting: Defined sampling methods, acceptance procedures and a normative test-report structure; Annex B provides recommended performance levels for specific applications when agreed by purchaser and seller.
The standard references established ISO test methods (for example ISO 291, ISO 845, ISO 8301, ISO 11925-2, ISO 11561 and others) to ensure consistent, reproducible results.
Practical applications and users
ISO 22975-5 is intended for professionals involved in the lifecycle of solar thermal collectors:
- Manufacturer and material suppliers: specifying, testing and certifying insulation products for collectors.
- Test laboratories and QA teams: performing standardized durability and performance tests.
- Designers and system integrators: selecting insulation with reliable thermal and moisture performance for flat-plate and evacuated-tube collectors.
- Procurement and certification bodies: defining acceptance criteria and contractual requirements.
- Researchers and product developers: assessing new insulation formulations for collector use.
Adoption of ISO 22975-5 supports reliable insulation selection, improved collector performance, longer service life and conformity with industry best practice.
Related standards
Notable referenced standards include ISO 291, ISO 845, ISO 8301, ISO 11925-2, ISO 11561, ISO 12571 and others cited in ISO 22975-5. See the ISO 22975 series for related parts covering other collector components.