ISO 21239:2026

Thermal insulation products for buildings — Reflective insulating products — Specification ISO 21239:2026

Publication date:   Jan 27, 2026

Scope

This document specifies the requirements for factory-made thermal insulating products containing one or more reflective or low-emissivity surface components, and designed to be used in conjunction with an incorporated air space, for the thermal insulation of buildings.
This document specifies products manufactured in the form of rolls, boards and sheets, and also covers products that are used in prefabricated thermal insulation systems and composite panels. Such prefabricated systems and composite panels are not within the scope of this document. The products specified in this document are not intended for use in load-bearing applications.
This document does not specify the required level of a given property to be achieved by a product to demonstrate fitness for purpose in an application. The levels of performance required for a given application are to be found in project specifications.