ISO 21925-1-2018 PDF

Full title and description

Fire resistance tests — Fire dampers for air distribution systems — Part 1: Mechanical dampers. This International Standard specifies a standardised furnace test method and requirements for mechanical fire dampers used in air distribution systems to assess their resistance to heat and their ability to prevent the spread of fire and smoke between compartments.

Abstract

ISO 21925-1:2018 defines the test procedure for determining the fire resistance performance of mechanical fire dampers installed in air distribution systems. The standard focuses on heat exposure, integrity and insulation properties under standard fire conditions, and notes exclusions such as dampers used solely for smoke control and certain suspended‑ceiling installations where separate evaluation is required.

General information

• Status: Published (International Standard).
• Publication date: 28 November 2018 (ISO edition: 2018-11).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 13.220.50 — Fire‑resistance of building materials and elements.
• Edition / version: Edition 1 (2018).
• Number of pages: 39 pages (official ISO document page count).

Scope

This part of ISO 21925 specifies a furnace test method for mechanical fire dampers in air distribution systems to evaluate their ability to limit the passage of fire and hot gases between fire compartments. It applies to mechanical dampers intended to provide fire resistance performance (integrity and insulation) and, where applicable, smoke leakage characteristics. It is not intended for dampers used only for smoke control, for air‑transfer devices outside ductwork, or for dampers in suspended ceilings where the damper/duct installation may affect ceiling performance and require different evaluation.

Key topics and requirements

• Standardised furnace test procedure for assessing damper resistance to heat (based on ISO/ISO 834 fire curve principles).
• Assessment criteria for integrity (E) and insulation (I) performance; guidance on evaluating smoke leakage where applicable (S classification considerations).
• Requirements and preparation of test specimens, installation details and mounting configurations to reflect intended field installation.
• Procedures for evaluating mechanical components such as thermal release mechanisms (e.g., fusible links) and their influence on damper performance.
• Exclusions and special considerations: smoke‑only systems, air‑transfer low‑pressure applications, and suspended‑ceiling installations.

Typical use and users

Manufacturers of fire dampers and HVAC components, independent fire testing laboratories, certification bodies, fire safety engineers, building code and compliance authorities, consulting engineers and specifiers use ISO 21925-1:2018 to design, test, classify and document mechanical fire dampers for building projects and product certification. It is also used where international (non‑regional) test methods are required or accepted.

Related standards

ISO 21925-1:2018 is part of the ISO 21925 series; ISO 21925-2:2021 covers intumescent dampers (Part 2). Earlier ISO documents in the ISO 10294 series (Parts 1–4) were withdrawn and replaced by parts of ISO 21925. In practice, regional standards such as EN 1366-2 (fire resistance tests for fire dampers) and classification standards (for example EN 13501-3 in Europe) are often referenced alongside or instead of ISO 21925 depending on regulatory and market requirements—ISO and EN test results are not automatically interchangeable and regulatory acceptance should be confirmed for each jurisdiction.

Keywords

fire dampers, fire resistance tests, mechanical dampers, air distribution systems, integrity (E), insulation (I), smoke leakage (S), ISO 21925, HVAC fire protection, furnace test method.

FAQ

Q: What is this standard?

A: ISO 21925-1:2018 is an International Standard that specifies a furnace test method and requirements for mechanical fire dampers in air distribution systems to determine fire resistance performance.

Q: What does it cover?

A: It covers test procedures, specimen installation, evaluation criteria for integrity and insulation (and where applicable smoke leakage considerations), and specific requirements for mechanical dampers — while excluding dampers used solely for smoke control and certain suspended‑ceiling situations.

Q: Who typically uses it?

A: Product manufacturers, test laboratories, certification bodies, fire safety engineers, building designers and regulatory authorities use this standard to evaluate, classify and document the fire performance of mechanical dampers.

Q: Is it current or superseded?

A: ISO 21925-1:2018 is the published, current Part 1 edition (published November 2018) and replaces earlier ISO 10294-series documents for mechanical dampers. Users should verify national adoption or any newer revisions issued after 2018 before relying on the standard for regulatory compliance.

Q: Is it part of a series?

A: Yes — ISO 21925 is a multi‑part series. Part 1 covers mechanical dampers (2018) and Part 2 covers intumescent dampers (published 2021). Other parts or related guidance may exist or be developed by ISO/TC 92/SC 2.

Q: What are the key keywords?

A: Fire dampers, mechanical dampers, fire resistance, air distribution systems, E/I/S classification, furnace test, HVAC fire protection.