Overview
ISO 6944-1:2024 - Fire containment - Elements of building construction - Part 1: Ventilation ducts specifies a standardized laboratory method to determine the fire resistance of vertical and horizontal ventilation ducts. The test evaluates duct behaviour under standardized fire conditions when exposed to fire from outside the duct (duct A) and fire inside the duct (duct B). ISO 6944-1:2024 is intended to be used in conjunction with ISO 834-1 and replaces the 2008 edition (minor revision). Annex A provides general guidance and background.
Key topics and technical requirements
- Scope and exclusions: Applies to representative ducts and assemblies but is not applicable to ducts whose fire resistance depends on a ceiling, ducts with fire dampers at fire separations, inspection door leaves unless included in the tested duct, two- or three-sided ducts, suspension-device fixings to floors/walls, or kitchen extract ducts (see ISO 6944-2).
- Test apparatus and conditions: Detailed requirements for furnace, instrumentation and control to reproduce standardized fire curves.
- Test specimen specifications: Size, length, cross-section, number, joints, openings, compensators and support arrangements for both horizontal and vertical ducts.
- Instrumentation: Placement and use of thermocouples (furnace and unexposed surfaces), pressure measurement and data collection protocols.
- Test procedure and measurements: Criteria and methods for assessing integrity, insulation, smoke leakage, restraint forces, and thermal elongation/shortening during test exposure.
- Performance criteria and reporting: Defined pass/fail criteria for integrity and insulation, procedures for terminating tests, and required contents of the test report.
- Field of direct application: Guidance on extrapolating test results to different duct sizes, pressure differences, vertical heights, suspension devices and supporting constructions.
Practical applications - who uses ISO 6944-1:2024
- Fire safety engineers and consultants assessing or specifying duct fire performance for building designs.
- HVAC and mechanical designers selecting or detailing duct systems in fire-rated constructions.
- Manufacturers of ductwork, fire-resistant linings and firestopping systems validating products and claiming fire resistance ratings.
- Test laboratories and certification bodies performing standardized resistance tests and issuing reports.
- Building regulators and code officials referencing test methods and evidence for compliance.
Typical applications include evaluating duct assemblies for compartmentation, specifying passive fire protection for ventilation systems, and producing test evidence for product certification.
Related standards
- ISO 834-1 (standard fire-resistance furnace/time–temperature curve) - normative companion for fire exposure.
- ISO 6944-2 - covers kitchen extract ducts (excluded from Part 1).
- ISO 5167-2 / ISO 5167-3 - referenced flow measurement standards updated in this edition.
Keywords: ISO 6944-1:2024, fire containment, ventilation ducts, fire resistance test, duct A, duct B, HVAC fire safety, ISO 834-1, smoke leakage, integrity, insulation.