ISO TS 16733-2-2026 PDF

Full title and description

St ISO TS 16733-2-2026 — Fire safety engineering — Selection of design fire scenarios and design fires — Part 2: Design fires. This Technical Specification gives guidance for specifying quantitative design fires to be used as input in fire safety engineering analyses of buildings and other structures.

Abstract

This document provides guidance for the specification of design fires for use in fire safety engineering (FSE) analyses of the built environment. It describes how to define credible but suitably severe design fires (for example heat release rate profiles and other characterising parameters) to determine consequences in deterministic engineering assessments and performance-based designs.

General information

• Status: Published
• Publication date: January 2026 (published 9 January 2026 — edition 2).
• Publisher: International Organization for Standardization (ISO)
• ICS / categories: 13.220.01 (Protection against fire in general)
• Edition / version: Edition 2 (2026)
• Number of pages: 48

Key bibliographic and lifecycle details as published by ISO and international standards distributors.

Scope

The scope covers guidance for the selection and specification of design fires used in fire safety engineering analyses for buildings, structures and similar assets. It is intended to support performance-based design by providing procedures and examples for defining design-fire inputs (such as heat release rate curves, limiting conditions and assumptions about compartmentation and ventilation) so that consequences can be evaluated quantitatively. The document supplements other parts of the ISO 16733 series and replaces the previous 2021 edition of Part 2.

Key topics and requirements

• Guidance on preparing quantitative design fires (heat release rate time-histories and characteristic parameters).
• Procedures for selecting representative and sufficiently severe design fire scenarios for deterministic FSE analyses.
• Consideration of fuel load, fire growth behaviour, ventilation effects and compartment geometry when specifying design fires.
• Recommended assumptions and documentation to ensure traceability of design-fire inputs and sensitivity considerations.
• Relationship to other methods (qualitative scenario selection in Part 1; links to quantitative risk approaches).

Topics above are summarised from the published Technical Specification and companion / preceding parts of the ISO 16733 series.

Typical use and users

Used by fire safety engineers, building designers, consultants performing performance-based fire safety assessments, code and regulatory bodies evaluating alternative designs, researchers and educators, and insurers assessing risk exposure. Typical applications include design of active and passive fire protection measures, evacuation and egress analyses, and verification of structural/fire resistance requirements under specified design-fire exposures.

Related standards

Part of the ISO 16733 series. Closely related documents include ISO 16733-1 (selection of design fire scenarios) and other ISO/TC 92/SC 4 outputs; the 2026 Part 2 replaces ISO/TS 16733-2:2021. For full quantitative risk approaches see related standards such as ISO 16732‑1 and other fire engineering guidance documents.

Keywords

design fire; design-fire scenario; fire safety engineering; heat release rate; performance-based design; fire scenario selection; fire growth; ventilation; ISO 16733.

FAQ

Q: What is this standard?

A: ISO/TS 16733-2:2026 is a Technical Specification providing guidance on specifying quantitative design fires for use in fire safety engineering analyses.

Q: What does it cover?

A: It covers methods and guidance for defining credible and suitably severe design-fire inputs (for example heat release rate curves and associated assumptions) that are used in deterministic FSE consequence analyses and performance-based design evaluations.

Q: Who typically uses it?

A: Fire safety engineers, consultants, designers, regulators, researchers and insurers who perform or review performance-based fire safety assessments.

Q: Is it current or superseded?

A: Current — this is Edition 2 published in January 2026 and it supersedes the 2021 edition of ISO/TS 16733-2.

Q: Is it part of a series?

A: Yes — it is Part 2 of the ISO 16733 series (Part 1 addresses selection of design fire scenarios); the series is maintained by ISO/TC 92/SC 4 (Fire safety engineering).

Q: What are the key keywords?

A: design fire, heat release rate, design-fire scenario, fire safety engineering, performance-based design, fire scenario selection, ISO 16733.