ISO 21927-4:2019

Smoke and heat control systems — Part 4: Natural smoke and heat exhaust ventilators — Design, requirements and installation

This document applies to the design and installation of natural smoke and heat exhaust ventilators (NSHEVs) for spaces from which smoke is extracted vertically by thermal buoyancy via the roof in the case of single-storey buildings and via the uppermost storey in the case of multi-storey buildings. It also applies to spaces in which NSHEVs are installed in external walls. This document includes tables and calculation methods for the design of clear layers in order to comply with the requirements of various protection objectives. This document includes information and provisions to be taken into account when applying the design rules set out herein and when installing NSHEVs.

Systèmes pour le contrôle des fumées et de la chaleur — Partie 4: Exutoires de fumées et de chaleur naturels — Dimensionnement, exigences et mise en place

General Information

• Status: Published
• Publication Date: 01-Apr-2019
• ICS: 13.220.20 - Fire protection
• Technical Committee: ISO/TC 21/SC 11 - Smoke and heat control systems and components
• Drafting Committee: ISO/TC 21/SC 11 - Smoke and heat control systems and components
• Current Stage: 9020 - International Standard under periodical review
• Start Date: 15-Apr-2024
• Completion Date: 15-Apr-2024

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 21927-4
First edition
2019-04
Smoke and heat control systems —
Part 4:
Natural smoke and heat exhaust
ventilators — Design, requirements
and installation
Systèmes pour le contrôle des fumées et de la chaleur —
Partie 4: Exutoires de fumées et de chaleur naturels —
Dimensionnement, exigences et mise en place
Reference number
ISO 21927-4:2019(E)
©
ISO 2019

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ISO 21927-4:2019(E)

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ii © ISO 2019 – All rights reserved

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ISO 21927-4:2019(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 2
5 Design principles . 2
5.1 General . 2
5.2 Height of space . 3
5.3 Target height of the clear layer, height of smoke barrier . 3
5.4 Area of smoke reservoir . 4
5.5 Air inlets . 4
5.6 Duration of fire growth . 5
5.7 Theoretical fire area, design groups . 5
5.8 Aerodynamic effectiveness of NSHEVs . 6
6 Design . 6
6.1 General . 6
6.2 Smoke exhaust openings in roofs . 6
6.3 Smoke exhaust ope
...