ISO 834-13:2019

Overview

ISO 834-13:2019 specifies test and assessment methods for determining how applied fire protection contributes to the fire resistance of steel beams (I- and H-sections) that have web openings. The standard addresses beams exposed to fire on three or four sides and is focused on cellular beams and beams with openings that can affect structural performance. ISO 834-13:2019 uses measured temperature ratios around web openings and solid web areas to derive a limiting steel temperature for structural analysis, and it relies on product data from ISO 834-10 and ISO 834-11 to determine required fire protection thickness.

Key topics and requirements

• Scope and applicability: Applies to fire protection systems (passive and reactive) already assessed to ISO 834-10 / ISO 834-11 and to beams with circular, rectangular or elongated openings; single small openings may need engineering judgement.
• Test methods and equipment: Defines furnace conditions, specimen construction (cellular beam test sections), installation, conditioning and instrumentation (thermocouples, furnace temperature, pressure).
• Thermal measurement & ratios: Establishes the principle of temperature ratios between web posts, points around openings and a web reference area (≥250 mm from hole edge) to characterise thermal response.
• Assessment procedure: Prescribes how to calculate web-post and web-reference temperatures, locate limiting temperatures, apply additional thermal modification factors and produce an assessment report.
• Multi-temperature analysis (MTA / EMTA): Uses elemental multi-temperature analysis as a basis for determining product thickness for beams with web openings.
• Failure modes: Recognises specific fire failure mechanisms for beams with openings - web-post buckling, shear at openings and Vierendeel bending - and requires the structural model to consider the critical mode.
• Limits: Includes guidance on limits to applicability and conservative approaches for non-standard opening shapes.

Practical applications and users

ISO 834-13:2019 is valuable for:

• Structural and fire safety engineers assessing fire resistance of cellular beams and beams with web openings.
• Fire test laboratories conducting temperature and thermal-response testing on protected steel sections.
• Manufacturers and specifiers of fire protection materials who need to determine product thickness for beams with openings.
• Building designers, code authorities and consultants preparing compliance documentation and assessment reports.

Practical outcomes include validated temperature data for structural models, derived limiting temperatures for use in fire limit state calculations, and a route to specify appropriate fire protection thicknesses for beams with web openings.

Related standards

• ISO 834-10 and ISO 834-11 - provide product test data and elemental re-analysis used together with ISO 834-13 to determine required fire protection thickness.