ISO 21844:2018

Cellular plastic - Cellulose foam thermal insulation - Material specification

ISO 21844:2018 specifies material requirements and identifies the test methods to be used to determine these requirements for cellulose foam for thermal insulation for buildings and other applications. There are four categories of material characterized by the density of the material.

Plastiques alvéolaires — Matériau d'isolation à base de mousse de cellulose — Spécifications

General Information

• Status: Published
• Publication Date: 24-Apr-2018
• ICS: 83.100 - Cellular materials
• Technical Committee: ISO/TC 61/SC 10 - Cellular plastics
• Drafting Committee: ISO/TC 61/SC 10/WG 10 - Plastic insulation
• Current Stage: 9093 - International Standard confirmed
• Start Date: 25-Sep-2023
• Completion Date: 13-Dec-2025

Overview

ISO 21844:2018 - Cellular plastic - Cellulose foam - Material specification defines material requirements and test methods for cellulose-based foam used as thermal insulation in buildings and other applications. The standard covers four material categories differentiated by density, and sets limits for mechanical, thermal and emission properties, plus manufacturing, sampling, conformity and labelling requirements.

Key topics and technical requirements

• Material composition & manufacture
  • Cellulose foam contains at least 50% paper by weight, expanded with a starch mixture.
  • Restrictions on dyes (only water‑soluble, non‑harmful dyes allowed) and prohibition of fluorescent whitening agents.
  • Removal of foreign matter (films, laminates) during pulping; control of hazardous discharges, odour, noise and water pollution.
  • Mandatory retention of Safety Data Sheets (SDS) for chemical inputs.
• Performance limits (representative values from the standard)
  • Four density categories with minimum densities: 20, 25, 30, 35 kg/m³.
  • Minimum compressive strength (at 10% deformation): 7–13 kPa depending on category.
  • Maximum initial thermal conductivity: 32–38 mW/(m·K) depending on category.
  • Long‑term thermal resistance and dimensional stability requirements (tested per ISO 11561 and ISO 2796).
  • Water vapour permeability, water absorption (max 5% by volume), bending load at break and emission limits for formaldehyde and VOCs (measured after 7 days per ISO 16000 series).
• Testing, sampling and conditioning
  • Test methods referenced: ISO 844, 845, 1209‑1, 1663, 2796, 2896, 8301, 11561, 16000‑4 and 16000‑9.
  • Specimen conditioning at 23 ±2 °C and specified relative humidity; laboratory environment requirements also defined.
• Conformity, marking and reporting
  • Manufacturer declares conformity control system per ISO 12576‑1.
  • Labelling must include product name, dimensions, manufacturer, lot or batch ID and ISO 21844 reference.
  • Detailed test reporting requirements and recommendation for ISO/IEC 17025 accreditation of testing labs.

Applications and users

• Who uses ISO 21844:2018
  • Insulation manufacturers (product specification and quality control).
  • Testing laboratories (methodology and reporting).
  • Architects, specifiers and contractors selecting cellulose foam insulation for building envelopes.
  • Product certifiers and regulators verifying safety, emissions and performance.
• Practical uses
  • Specifying compliant cellulose foam products for energy‑efficient buildings.
  • Establishing production quality control, sampling procedures and acceptance criteria.
  • Ensuring low emissions (formaldehyde/VOCs) and documented test evidence for procurement and certification.

Related standards

• ISO 844, 845, 1209‑1, 1663, 2796, 2896, 8301, 11561, 12576‑1, ISO 16000‑4, ISO 16000‑9 and ISO/IEC 17025 (testing accreditation).

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 21844
First edition
2018-04
Cellular plastic — Cellulose foam
thermal insulation — Material
specification
Plastiques alvéolaires — Matériau d'isolation à base de mousse de
cellulose — Spécifications
Reference number
©
ISO 2018
© ISO 2018
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
ii © ISO 2018 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General requirements . 2
4.1 Dyes and fluorescent whitening agent . 2
4.2 Foreign matters . 2
4.3 Manufacturing process. 2
4.4 Toxic substance . 2
4.5 Appearance . 2
4.6 Performance . 2
4.7 Dimension . 3
5 Test methods . 3
5.1 Sampling . 3
5.2 Specimen preparation . 3
5.3 Appearance . 3
5.4 Conditioning of specimens . 3
5.5 Laboratory conditions when testing is conducted . 4
6 Conformity control . 4
7 Marking and labelling . 4
8 Report . 4
Bibliography . 6
Foreword
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electrotechnical standardization.
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described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
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URL: www .iso .org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 10, Cellular
plastics.
iv © ISO 2018 – All rights reserved

Introduction
The cellulose foam contains at least 50 % of paper by weight as the raw material, which is expanded
with a starch mixture.
INTERNATIONAL STANDARD ISO 21844:2018(E)
Cellular plastic — Cellulose foam thermal insulation —
Material specification
1 Scope
This document specifies material requirements and identifies the test methods to be used to determine
these require
...