ISO 21927-5:2018
(Main)Smoke and heat control systems — Part 5: Powered smoke exhaust systems — Requirements and design
Smoke and heat control systems — Part 5: Powered smoke exhaust systems — Requirements and design
This document applies to powered smoke exhaust systems in spaces with a large area and with a ceiling height of minimum 3 m, in which smoke protection is required. It includes tables and calculation methods for the design of clear layers in order to comply, inter alia, with the requirements of various protection objectives. This document includes information and provisions concerning the requirements for powered smoke exhaust systems, their design and rules for their installation. NOTE The requirements for testing the ventilators are dealt with in ISO 21927‑3. Other parts of the ISO 21927 series of standards deal with the power supply (ISO 21927‑10), control equipment (ISO 21927‑9) and smoke control ducts and smoke control dampers (ISO 21927‑7 and ISO 21927-8 respectively). Design, as specified in this document, does not apply to: — spaces with fixed gas extinguishing systems; — storage facilities for hazardous materials; — spaces in which there is a risk of explosions; — corridors; — stairwells.
Installations pour l'extraction de fumée et de chaleur — Partie 5: Systèmes d'extraction de fumée mécaniques — Exigences et planification
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INTERNATIONAL ISO
STANDARD 21927-5
First edition
2018-11
Smoke and heat control systems —
Part 5:
Powered smoke exhaust systems —
Requirements and design
Installations pour l'extraction de fumée et de chaleur —
Partie 5: Systèmes d'extraction de fumée mécaniques — Exigences et
planification
Reference number
©
ISO 2018
© ISO 2018
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Design principles . 2
4.1 General . 2
4.2 Height of space . 4
4.3 Target height of the clear layer, d, in a smoke reservoir, A . 4
R
4.4 Area of smoke reservoir, A . 4
R
4.5 Air supply . 4
4.5.1 General. 4
4.5.2 Natural air replacement. 5
4.5.3 Powered air replacement . 5
4.6 Duration of fire growth to be assumed in the design . 5
4.7 Design group . 5
5 Calculating the volume flow of the smoke gases to be exhausted . 6
5.1 Basis of the calculation . 6
5.2 Using the tables . 6
6 Component temperature classes . 8
7 Rules for installation . 9
8 Energy supply for powered smoke exhaust ventilators.13
9 Controlling powered smoke exhaust ventilators .13
10 Marking .13
Bibliography .14
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso
.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 21, Equipment for fire protection and fire
fighting, Subcommittee SC 11, Smoke and heat control systems and components.
A list of all parts in the ISO 21927 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2018 – All rights reserved
Introduction
Smoke and heat control systems (SHCS) create and maintain smoke free areas in construction works by
controlling smoke flow, and thus improving the conditions for the safe escape and/or rescue of people
and animals and the protection of property, and permit the fire to be fought while still in its early
stages. The use of smoke and heat exhaust ventilation systems (SHEVS) to create smoke-free areas
beneath a buoyant smoke layer has become widespread. Their value in assisting in the evacuation of
people from construction works, reducing fire damage and financial loss by preventing smoke logging,
facilitating firefighting, reducing roof temperatures and retarding the lateral spread of fire is firmly
established. For these benefits to be obtained, it is essential that smoke and heat exhaust ventilators
operate fully and reliably whenever called upon to do so during their installed life. A heat and smoke
exhaust ventilation system is a scheme of safety equipment intended to play a positive role in a fire
emergency.
Components for any smoke and heat control system are installed as part of a properly designed system.
Smoke and heat control systems help to:
— keep escape and access routes free from smoke;
— facilitate firefighting operations;
— delay and/or prevent flashover and thus full development of a fire;
— protect equipment and furnishings;
— reduce thermal effects on structural components during a fire;
— reduce damage due to thermal decomposition products and hot gases.
Pressure differential systems are used either to positively pressurize spaces separated from the fire or
to depressurize the space containing the fire in order to limit or prevent the flow of smoke and heat into
adjacent spaces. A typical use would be to pressurize an escape stair well in order to protect vertical
means of escape.
Depending on the design of the system, natural or powered smoke and heat ventilators can be used in a
smoke and heat control system.
Control equipment is needed to control all components in a SHCS, such as:
— natural ventilators;
— powered ventilators;
— smoke barriers;
— smoke dampers;
— air inlets;
— duct sections;
— dampers.
SHCS control equipment can also provide control for day-to-day ventilation and signals to other fire
safety equipment under fire conditions.
SHCS control equipment can be for extra-low–voltage or low-voltage electrical systems or pneumatic
systems or any combination thereof.
INTERNATIONAL STANDARD ISO 21927-5:2018(E)
Smoke and heat control systems —
Part 5:
Powered smoke exhaust systems — Requirements and
design
1 Scope
This document applies to powered smoke exhaust systems in spaces with a large area and with a
ceiling height of minimum 3 m, in which smoke protection is required. It includes tables and calculation
methods for the design of clear layers in order to comply, inter alia, with the requirements of various
protection objectives.
This document includes information and provisions concerning the requirements for powered smoke
exhaust systems, their design and rules for their installation.
NOTE The requirements for testing the ventilators are dealt with in ISO 21927-3. Other parts of the
ISO 21927 series of standards deal with the power supply (ISO 21927-10), control equipment (ISO 21927-9) and
smoke control ducts and smoke control dampers (ISO 21927-7 and ISO 21927-8 respectively).
Design, as specified in this document, does not apply to:
— spaces with fixed gas extinguishing systems;
— storage facilities for hazardous materials;
— spaces in which there is a risk of explosions;
— corridors;
— stairwells.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 21927-3, Smoke and heat control systems — Part 3: Specification for powered smoke and heat exhaust
ventilators
ISO 21927-8, Smoke and heat control systems — Part 8: Smoke control dampers
ISO 21927-9, Smoke and heat control systems — Part 9: Specification for control equipment
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 21927-3 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at https: //www .electropedia .org/
— ISO Online browsing platform: available at https: //www .iso .org/obp
3.1
roof-mounted ventilator
smoke exhaust ventilator designed to be mounted on a roof above a smoke reservoir and having exterior
weather protection
3.2
wall-mounted ventilator
smoke exhaust ventilator designed to be mounted in the upper part of an external wall
3.3
centrally installed ventilator
smoke exhaust ventilator to which smoke control ducts (3.7) from several smoke reservoirs can be
connected
3.5
area of smoke reservoir
A
a
area within a large space enclosed or bounded by smoke barriers or wall elements
3.6
design group
auxiliary design value that is used in the design of powered smoke exhaust systems and takes account
of the assumed duration of fire growth and the fire propagation rate
3.7
smoke control duct
duct through which smoke and heat are exhausted
3.8
single compartment smoke control damper
smoke control damper that is designed for use in a single smoke reservoir and can be connected to
single compartment smoke control ducts (3.7)
3.9
multi-compartment smoke control damper
fire-resistant smoke control damper designed for use in or on smoke control ducts (3.7) connecting
several smoke reservoirs, or in separating structural elements
4 Design principles
4.1 General
The design of powered smoke exhaust systems (see example in Figure 1) depends, inter alia, on the heat
release rate, the theoretical fire area of a building or the resulting design group, the target height of the
clear layer and the height of the sp
...
INTERNATIONAL ISO
STANDARD 21927-5
First edition
2018-11
Smoke and heat control systems —
Part 5:
Powered smoke exhaust systems —
Requirements and design
Installations pour l'extraction de fumée et de chaleur —
Partie 5: Systèmes d'extraction de fumée mécaniques — Exigences et
planification
Reference number
©
ISO 2018
© ISO 2018
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Design principles . 2
4.1 General . 2
4.2 Height of space . 4
4.3 Target height of the clear layer, d, in a smoke reservoir, A . 4
R
4.4 Area of smoke reservoir, A . 4
R
4.5 Air supply . 4
4.5.1 General. 4
4.5.2 Natural air replacement. 5
4.5.3 Powered air replacement . 5
4.6 Duration of fire growth to be assumed in the design . 5
4.7 Design group . 5
5 Calculating the volume flow of the smoke gases to be exhausted . 6
5.1 Basis of the calculation . 6
5.2 Using the tables . 6
6 Component temperature classes . 8
7 Rules for installation . 9
8 Energy supply for powered smoke exhaust ventilators.13
9 Controlling powered smoke exhaust ventilators .13
10 Marking .13
Bibliography .14
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso
.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 21, Equipment for fire protection and fire
fighting, Subcommittee SC 11, Smoke and heat control systems and components.
A list of all parts in the ISO 21927 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2018 – All rights reserved
Introduction
Smoke and heat control systems (SHCS) create and maintain smoke free areas in construction works by
controlling smoke flow, and thus improving the conditions for the safe escape and/or rescue of people
and animals and the protection of property, and permit the fire to be fought while still in its early
stages. The use of smoke and heat exhaust ventilation systems (SHEVS) to create smoke-free areas
beneath a buoyant smoke layer has become widespread. Their value in assisting in the evacuation of
people from construction works, reducing fire damage and financial loss by preventing smoke logging,
facilitating firefighting, reducing roof temperatures and retarding the lateral spread of fire is firmly
established. For these benefits to be obtained, it is essential that smoke and heat exhaust ventilators
operate fully and reliably whenever called upon to do so during their installed life. A heat and smoke
exhaust ventilation system is a scheme of safety equipment intended to play a positive role in a fire
emergency.
Components for any smoke and heat control system are installed as part of a properly designed system.
Smoke and heat control systems help to:
— keep escape and access routes free from smoke;
— facilitate firefighting operations;
— delay and/or prevent flashover and thus full development of a fire;
— protect equipment and furnishings;
— reduce thermal effects on structural components during a fire;
— reduce damage due to thermal decomposition products and hot gases.
Pressure differential systems are used either to positively pressurize spaces separated from the fire or
to depressurize the space containing the fire in order to limit or prevent the flow of smoke and heat into
adjacent spaces. A typical use would be to pressurize an escape stair well in order to protect vertical
means of escape.
Depending on the design of the system, natural or powered smoke and heat ventilators can be used in a
smoke and heat control system.
Control equipment is needed to control all components in a SHCS, such as:
— natural ventilators;
— powered ventilators;
— smoke barriers;
— smoke dampers;
— air inlets;
— duct sections;
— dampers.
SHCS control equipment can also provide control for day-to-day ventilation and signals to other fire
safety equipment under fire conditions.
SHCS control equipment can be for extra-low–voltage or low-voltage electrical systems or pneumatic
systems or any combination thereof.
INTERNATIONAL STANDARD ISO 21927-5:2018(E)
Smoke and heat control systems —
Part 5:
Powered smoke exhaust systems — Requirements and
design
1 Scope
This document applies to powered smoke exhaust systems in spaces with a large area and with a
ceiling height of minimum 3 m, in which smoke protection is required. It includes tables and calculation
methods for the design of clear layers in order to comply, inter alia, with the requirements of various
protection objectives.
This document includes information and provisions concerning the requirements for powered smoke
exhaust systems, their design and rules for their installation.
NOTE The requirements for testing the ventilators are dealt with in ISO 21927-3. Other parts of the
ISO 21927 series of standards deal with the power supply (ISO 21927-10), control equipment (ISO 21927-9) and
smoke control ducts and smoke control dampers (ISO 21927-7 and ISO 21927-8 respectively).
Design, as specified in this document, does not apply to:
— spaces with fixed gas extinguishing systems;
— storage facilities for hazardous materials;
— spaces in which there is a risk of explosions;
— corridors;
— stairwells.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 21927-3, Smoke and heat control systems — Part 3: Specification for powered smoke and heat exhaust
ventilators
ISO 21927-8, Smoke and heat control systems — Part 8: Smoke control dampers
ISO 21927-9, Smoke and heat control systems — Part 9: Specification for control equipment
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 21927-3 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at https: //www .electropedia .org/
— ISO Online browsing platform: available at https: //www .iso .org/obp
3.1
roof-mounted ventilator
smoke exhaust ventilator designed to be mounted on a roof above a smoke reservoir and having exterior
weather protection
3.2
wall-mounted ventilator
smoke exhaust ventilator designed to be mounted in the upper part of an external wall
3.3
centrally installed ventilator
smoke exhaust ventilator to which smoke control ducts (3.7) from several smoke reservoirs can be
connected
3.5
area of smoke reservoir
A
a
area within a large space enclosed or bounded by smoke barriers or wall elements
3.6
design group
auxiliary design value that is used in the design of powered smoke exhaust systems and takes account
of the assumed duration of fire growth and the fire propagation rate
3.7
smoke control duct
duct through which smoke and heat are exhausted
3.8
single compartment smoke control damper
smoke control damper that is designed for use in a single smoke reservoir and can be connected to
single compartment smoke control ducts (3.7)
3.9
multi-compartment smoke control damper
fire-resistant smoke control damper designed for use in or on smoke control ducts (3.7) connecting
several smoke reservoirs, or in separating structural elements
4 Design principles
4.1 General
The design of powered smoke exhaust systems (see example in Figure 1) depends, inter alia, on the heat
release rate, the theoretical fire area of a building or the resulting design group, the target height of the
clear layer and the height of the sp
...
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