Overview
ISO 18959:2025 - Thermal insulation products - Rigid nano‑microporous insulation for industrial applications - Specification defines factory-made rigid nano‑microporous insulation for industrial surfaces operating from 100 °C to 1 150 °C. It covers product form (boards and pipe sections), material description (nano‑microporous composite of inorganic powder, fibres and opacifiers), required product characteristics, test procedures, conformity evaluation, and marking and labelling. The standard does not prescribe fitness‑for‑purpose levels for specific installations; those are set by regulations or application‑specific standards.
Key topics and requirements
- Product scope: Rigid nano‑microporous insulation (RMI) supplied as boards or pipe sections for high‑temperature industrial insulation.
- Temperature classification: Products are classified by classification temperature (Type950, Type1050, Type1150) determined by permanent linear change testing.
- Thermal performance:
- Manufacturer must declare thermal conductivity (λ) and provide a conductivity vs. temperature curve (typically 200–800 °C) per ISO 13787.
- Measured by ISO 8302 (boards) or ISO 8497 (pipe sections). At a test mean temperature of 500 °C, λD ≤ 0.036 W/(m·K) for Type950 and ≤ 0.045 W/(m·K) for other types.
- Dimensional and geometric tolerances:
- Length/width tolerances vary by size (e.g., ±5 mm to ±10 mm depending on dimensions).
- Squareness, flatness and linearity limits (boards: squareness ≤ 6 mm/m; thickness squareness ≤ 2 mm; flatness ≤ 3 mm; pipe section linearity ≤ 3 mm or 0.6%).
- Mechanical and physical properties:
- Permanent linear change on heating ≤ 3.0 % at the classification temperature.
- Apparent density tolerance ±10 % from nominal (ISO 29470).
- Compressive stress at 10 % deformation (ISO 29469) must meet declared levels (e.g., CS(10\Y) 200–500 kPa).
- Chemical considerations:
- Trace water‑soluble chloride levels must be declared and not exceeded (ISO 12624) - important for corrosion-sensitive substrates like stainless steel.
- Conformity & quality:
- Sampling, conditioning, testing procedures and factory production control (Annex A) are specified.
- Requirements for marking and labelling to support traceability and specification compliance.
Applications and users
Practical applications include high‑temperature industrial insulation for furnaces, petrochemical plants, power generation, process vessels and piping where low thermal conductivity and compact insulation thickness are required. Typical users:
- Insulation manufacturers (product specification and FPC)
- Design engineers and thermal insulation specifiers
- Procurement teams and project managers selecting insulation materials
- Test laboratories and conformity assessors
- Regulatory authorities and plant safety engineers
Related standards
ISO 18959:2025 references several test and vocabulary standards, including:
Keywords: ISO 18959:2025, rigid nano‑microporous insulation, thermal insulation, industrial applications, thermal conductivity, high‑temperature insulation, product specification, testing and conformity.