Fire tests -- Smoke-control door and shutter assemblies

ISO/TR 5925-2:2006 provides a commentary that explains the general philosophy and factors on which the test specified in Part 1 of ISO 5925 has been designed, to describe the limitations of its application and to provide some general guidance for those who use the result of the test. Smoke control-door and shutter assemblies can be used as part of a smoke containment strategy for the purposes of life safety or property protection.

Essais au feu -- Assemblages porte et volet pare-fumée

Požarni preskusi - Dimna vrata z opremo - 2. del: Komentar k preskusni metodi in uporabi preskusnih pogojev ter rezultatov preskusa v strategiji obvladovanja dimnih plinov

To tehnično poročilo vsebuje komentar, ki pojasnjuje splošna načela in dejavnike, na podlagi katerih je bil načrtovan preskus, opredeljen v 1. delu standarda ISO 5925, ter opisuje omejitve njegove uporabe in podaja nekaj splošnih navodil za osebe, ki uporabljajo rezultate preskusa. Dimna vrata z opremo je mogoče uporabiti kot del strategije obvladovanja dimnih plinov za namene zaščite življenja ali lastnine.

General Information

Status
Published
Publication Date
05-Jul-2006
Current Stage
6060 - International Standard published
Start Date
20-Jun-2006
Completion Date
06-Jul-2006

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TECHNICAL ISO/TR
REPORT 5925-2
Second edition
2006-07-15
Fire tests — Smoke-control door
and shutter assemblies —
Part 2:
Commentary on test method and the
applicability of test conditions and the
use of test data in a smoke containment
strategy
Essais au feu — Assemblages porte et volet pare-fumée —
Partie 2: Commentaires sur la méthode d'essai et applicabilité des
conditions d'essai et emploi des données d'essai dans une stratégie de
confinement de la fumée
Reference number
ISO/TR 5925-2:2006(E)
ISO 2006
---------------------- Page: 1 ----------------------
ISO/TR 5925-2:2006(E)
PDF disclaimer

This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but

shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In

downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat

accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.

Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation

parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In

the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

© ISO 2006

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2006 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/TR 5925-2:2006(E)
Contents Page

Foreword............................................................................................................................................................ iv

Introduction ........................................................................................................................................................ v

1 Scope ..................................................................................................................................................... 1

2 Terms and definitions........................................................................................................................... 1

3 General principles................................................................................................................................. 2

4 Smoke control....................................................................................................................................... 3

5 Appropriateness of the test conditions and the selection of sealing system.............................. 10

6 Use of test outputs ............................................................................................................................. 11

Bibliography ..................................................................................................................................................... 12

© ISO 2006 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/TR 5925-2:2006(E)
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.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

In exceptional circumstances, when a technical committee has collected data of a different kind from that

which is normally published as an International Standard (“state of the art”, for example), it may decide by a

simple majority vote of its participating members to publish a Technical Report. A Technical Report is entirely

informative in nature and does not have to be reviewed until the data it provides are considered to be no

longer valid or useful.

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.

ISO/TR 5925-2 was prepared by Technical Committee ISO/TC 92, Fire safety, Subcommittee SC 2, Fire

containment.

This second edition cancels and replaces the first edition (ISO/TR 5925-2:1997), which has been technically

revised.

ISO/TR 5925 consists of the following parts, under the general title Fire tests — Smoke-control door and

shutter assemblies:
⎯ Part 1 : Ambient and medium temperature leakage test procedure

⎯ Part 2: Commentary on test method and the applicability of test conditions and the use of test data in a

smoke containment strategy
1) To be published. (Revision of ISO 5925-1:1981)
iv © ISO 2006 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/TR 5925-2:2006(E)
Introduction

Technical Committee ISO/TC92, Fire Safety, has prepared ISO 5925-1, a test specification for smoke control

doors.

In a fire, the decomposition of materials results in the production of heat and fire gases containing smoke

particles. The associated expansion of gases can lead to the creation of a pressure differential across door

faces often influenced by wind pressures, mechanical or natural smoke extract systems, stack effect or a

combination of these. This pressure differential induces the movement of smoke or air past any openings or

gaps, including those in a door assembly. Schemes to keep areas within buildings free of smoke use various

techniques, including barriers to its movement, exhausting, dilution, pressurization, either singly or in some

suitable combination of all of these. Where the pressure differential across the door is positive, i.e. gases are

being driven through any gap; standard tests have been developed to measure the leakage of smoke when

such conditions exist. The test method does not deal generally with doors installed in conjunction with active

smoke control methods, such as pressurization or exhaust, and this part of ISO/TR 5925 has been prepared

to assist designers to specify doors that have the appropriate smoke control characteristics for the situation in

which they are being used.

In addition to identifying when the door is likely to have a passive smoke control function, this part of

ISO/TR 5925 tries to make it clear as to when ambient or medium temperature smoke control is appropriate,

and when the threshold gap is significant.
© ISO 2006 – All rights reserved v
---------------------- Page: 5 ----------------------
TECHNICAL REPORT ISO/TR 5925-2:2006(E)
Fire tests — Smoke-control door and shutter assemblies —
Part 2:
Commentary on test method and the applicability of test
conditions and the use of test data in a smoke containment
strategy
1 Scope

This Technical Report provides a commentary that explains the general philosophy and factors on which the

test specified in Part 1 of ISO 5925 has been designed, to describe the limitations of its application and to

provide some general guidance for those who use the result of the test. Smoke control-door and shutter

assemblies can be used as part of a smoke containment strategy for the purposes of life safety or property

protection.
2 Terms and definitions

For the purposes of this document, the terms and definitions given in Part 1 of ISO 5925 and the following

apply.
2.1
door assembly

assembly comprising a fixed part (the door frame), one or more movable parts (the door leaves) and its

hardware

NOTE The purpose of the door assembly is to allow or prevent access of persons and/or goods. The term hardware

includes such items as hinges, latches, door handles, locks, keyholes (excluding keys), letter plates, sliding gear, closing

devices, electrical wiring and any other items that can influence the performance of the assembly being tested.

2.2
shutter assembly

assembly comprising fixed parts, e.g. a barrel housing and vertical guides and one or more moveable parts,

normally in the form of a curtain constructed from linked metal laths, or other flexible material and a barrel on

which the curtain is wound together with any powered mechanism, e.g. an electric motor and its associate

power supply

NOTE The shutter assembly is to allow the passage of goods, vehicles or persons, albeit where the shutter is

normally closed in use, a personnel door should be provided for the passage of persons.

2.3
fire door

door or shutter assembly capable of maintaining for a specified period some, or all of the fire resistance

criteria defined in ISO 3008, as appropriate for the door in use
2.4
smoke control door

door or shutter assembly whose primary function is to restrict the passage of smoke as determined by a test in

accordance with Part 1 of ISO 5925
© ISO 2006 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO/TR 5925-2:2006(E)
2.5
fire and smoke control door

door or shutter assembly meeting some, or all of the criteria for fire and smoke control as appropriate for the

door in use
2.6
ambient temperature

for the purpose of this Technical Report, ambient temperature is an air temperature of (20 ± 10) °C

2.7
medium temperature

for the purpose of this Technical Report, medium temperature is an air temperature of (200 ± 20) °C

2.8
high temperature

temperature representative of a standardized fully developed fire which is as specified in ISO 834-1

NOTE For ease of use, doors are identified by a code letter/number and these are shown in Figure 1.

2.9
make-up air

air that is made available to dilute the fire gases in order to reduce their temperature

3 General principles
3.1 Smoke and its influence

Smoke is the term used to describe the airborne products of combustion generated by the fire, together with

large volumes of air that become entrained into them due to their motion. These combustion products can

contain solid and liquid particulates within a gaseous mass.

Almost all fires produce smoke, which, when enclosed by a building, has the potential to become extremely

hazardous to its occupants and damaging to property. Most deaths in fires are due to smoke inhalation, rather

than to the victim having been burned.

The gaseous combustion products, chiefly carbon dioxide and water vapour, usually include toxic gases, the

most common being carbon monoxide, although hydrogen cyanide and other minor species can be present to

some extent. Amongst these, irritant gases such as acrolein can have a significant effect on people attempting

to escape fire.

The solid and liquid fractions of the products of combustion are also responsible for the poor visibility through

smoke. This adds to the problems presented by the smoke. Not only is it physiologically hazardous in its own

right, but escape through it is made more difficult by it obscuring escape routes. These fractions can

themselves be irritants and can be particularly dangerous to people who are subject to asthma or other

respiratory problems.

Smoke can also cause damage to property. Most fires produce soot and many generate corrosive gases such

as hydrogen chloride. The effect of these on sensitive equipment can be responsible for large monetary

losses due to equipment damage, the need for system clean-up and subsequent business interruption.

3.2 Smoke dynamics

All fires start from an ignition and grow at a rate generally determined by the environment in which the fire

starts and the nature of the materials involved in the event. Sometimes the fire can smoulder for a

considerable period, especially if the materials that have been ignited have a low rate of heat release or the

environment does not readily sustain combustion. Smoke produced during such a fire has very little buoyancy

and whatever buoyancy it has due to gas density differentials as a result of increased temperature is soon lost.

2 © ISO 2006 – All rights reserved
---------------------- Page: 7 ----------------------
ISO/TR 5925-2:2006(E)

Smoke produced under these low temperature conditions is, therefore, subject to the movement dominated by

the ambient air current, particularly any that is induced by mechanical means, such as ventilation and air

conditioning. In the absence of ambient currents, these cool gases generally mix with the environment and do

not stratify as is expected from hot buoyant gases.

Once the heat release increases, the smoke’s buoyancy increases and it soon begins to dominate air currents

in the enclosure. When the fire reaches a sufficient size, the smoke rises in a plume towards the ceiling. As it

does so, it entrains large volumes of air, greatly increasing smoke volume but reducing its temperature and

the concentration of chemical constituents.

The total entrained volume of air increases substantially with increasing height of the plume. With sufficient

buoyancy, the smoke impinges the ceiling, spreading out radially to reach any side walls and then forms a

layer that deepens as more smoke is produced.

Smoke flows out of the enclosure of origin through any upper openings that exist or develop. This outflow is

balanced by an inflow of air usually at a lower level. The openings can exist by design or occur as a result of

failure of one of the boundary elements.

An opening can be part of a smoke ventilation or extract system, where either vents open to allow smoke out

or a fan-assisted ducting system exhausts the hot gases and smoke. In such cases, make-up air is required to

come into the enclosure at a lower level, normally from designated sources, but also, possibly, from around

doors. Doors designed to provide make-up air do not require smoke sealing around their perimeter.

Similarly, one of the boundary elements most likely to fail as a result of the exposure to hot gases is windows

in the external façade, where high temperature differentials on the surface of the glass can lead to shattering.

Under ideal environmental conditions, this exhausts the smoke, making the need for enclosure sealing

unnecessary. However, unlike a designed-in vent that is designed to work in conjunction with winds from most

directions, the failure of an external window on a façade with a wind imposed on it can have the opposite

effect. Any wind-induced pressure in the enclosure can impose demands on the walls separating other parts

of the building with respect to their ability to prevent smoke leakage through gaps.

Similarly, if the enclosure is unfenestrated or where the windows do not break as a result of the thermal

exposure, then the pressure increases and the smoke layer deepens.

A normal door is the one element in the boundary of a structure that is naturally leaky, having a gap all around

the moving leaf, unless a seal is introduced to restrict it. A smoke-control door is provided to restrict the flow of

smoke, whether it is wind-induced or the result of natural buoyancy.

It should be recognized, however, that any smoke transferring through door gaps is likely to lose much of its

heat energy in the process and, as a consequence, the temperature and buoyancy are also reduced.

Experimental work has demonstrated that smoke leaving an enclosure via narrow gaps, such as those around

a door leaf perimeter, soon become fully mixed with the air.

Within the enclosure, as new flammable material becomes involved as a result of increasing heat transfer to it,

more air is required for the fuel volatiles to burn. If this is not available, either the fire does not grow any further

or the fuel volatiles burn instead outside the enclosure of origin, i.e. after moving via windows to the open air

or to an adjacent ventilated space, if it is available.

Without engineering intervention, it would be natural for the space containing the fire to contain hot buoyant

gases and for the immediately adjacent, protected spaces to fill with clean air without any buoyancy.

4 Smoke control
4.1 Design objectives

Since smoke can have a major impact on the overall design of the building, it needs to be considered at the

earliest possible stage of the design process. Normal escape provisions in buildings, e.g. restrictions on travel

distances and emergency lighting provisions, do not assume significant levels of smoke management. Where

© ISO 2006 – All rights reserved 3
---------------------- Page: 8 ----------------------
ISO/TR 5925-2:2006(E)

good smoke management is introduced, either by exhaust, ventilation, pressurization or by containment, then

these provisions may be relaxed. Any such relaxation has a profound influence on the building design/layout

and, therefore, it is important that the method of smoke control to be used be nominated early in the design

process.

Smoke-control systems for life safety are designed to maintain a tenable environment for occupants to

facilitate their safe escape from the building to a place of relative safety or a refuge, preferably separated

structurally from the area being evacuated. Smoke-control systems for property protection are generally

designed to reduce the level of contamination in a space by keeping smoke logging down to acceptable levels.

There are a number of ways that smoke control can be achieved:
⎯ natural ventilation;
⎯ mechanical smoke exhaust;
⎯ pressurization;
⎯ smoke containment.

NOTE An alternative to pressurizing a space is to depressurize the adjacent spaces(s), but this is difficult to achieve

in a fire, as the depressurization fans are generally overwhelmed by the fire gases.

The choice of system may be dictated by the area in which the smoke is to be controlled. With such “active”

measures, then, natural or powered exhaust is more appropriate then “passive” smoke containment has a

limited function, and can possibly make the situation worse by lack of the make-up air, and hence reduced

entrainment and higher gas temperatures, as discussed in 4.2, unless separate provision is made for

“make-up” air.

If, however, it is an adjacent space that is to be protected, then a method that has been used historically to

keep such an area free of smoke has been pressurization of the space, especially staircases. Actively

exhausting smoke from the area on fire also provides some protection to the adjacent spaces. This protection

can be compromised if the smoke temperature in the space exceeds the operating temperature of the fan,

causing it to cease operating. At such times, the space becomes vulnerable to smoke logging.

A simple-to-introduce alternative to exhaust or pressurization is the use of smoke containment, initially

between the enclosure on fire and the space being protected or between adjacent protected areas.

4.2 Protection of adjacent and remote/removed spaces by smoke containment

For smoke containment to work, it is important that the elements bounding the enclosure of fire origin and the

adjacent enclosures remain impermeable to the flow of smoke and hot gases for as long as is necessary to

maintain tenable conditions for life safety or an adequately pollution-free environment for property protection.

There are several fairly distinct stages in this scenario that it is important to address individually for each

space in which smoke is contained.
4.2.1 Scenario within the room of fire origin

In the period immediately following a small ignition, assuming that the materials initially involved in the fire

have a high thermal inertia and a relatively low rate of heat release, the smoke cools and mixes readily with

the surrounding atmosphere. As such, the barrier formed by the bounding structure can initially experience

exposure to cool, ambient smoke. As such, any seals designed to restrict that smoke, including seals around

door edges or the sealing systems used to retain glass within the door leaf, are required to be effective at only

ambient conditions. If the fire continues to grow in intensity and size, with a corresponding increase in the rate

of heat release, then the plume becomes buoyant, increasing in both temperature and volume. The

temperature of this plume becomes elevated and any ambient temperature test method for evaluating smoke

containment can be inappropriate. It is possible by reference to the appropriate scenario in 4.2.2 to 4.2.4 to

produce an estimate of the smoke temperature and hence identify the most suitable test regime to reproduce

those conditions.
4 © ISO 2006 – All rights reserved
---------------------- Page: 9 ----------------------
ISO/TR 5925-2:2006(E)

In addition to the heat release from the fire, there are many other features that influence these temperatures:

⎯ height of the room;
⎯ thermal losses to, or through, the boundary structure;
⎯ availability of make-up air (dilution);
⎯ presence of a suppression system.

In a single-storey enclosure, initially these elevated temperatures are imposed only on seals in the upper part

of the enclosure and can be applied to linear-gap seals, glazing seals or service penetration seals for which

no smoke-leakage tests c
...

SLOVENSKI STANDARD
SIST-TP ISO/TR 5925-2:2018
01-september-2018
1DGRPHãþD
SIST ISO/TR 5925-2:1998
Požarni preskusi - Dimna vrata z opremo - 2. del: Komentar k preskusni metodi in
uporabi preskusnih pogojev ter rezultatov preskusa v strategiji obvladovanja
dimnih plinov

Fire tests -- Smoke-control door and shutter assemblies -- Part 2: Commentary on test

method and the applicability of test conditions and the use of test data in a smoke

containment strategy

Essais au feu -- Assemblages porte et volet pare-fumée -- Partie 2: Commentaires sur la

méthode d'essai et applicabilité des conditions d'essai et emploi des données d'essai

dans une stratégie de confinement de la fumée
Ta slovenski standard je istoveten z: ISO/TR 5925-2:2006
ICS:
13.220.50 Požarna odpornost Fire-resistance of building
gradbenih materialov in materials and elements
elementov
91.060.50 Vrata in okna Doors and windows
SIST-TP ISO/TR 5925-2:2018 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST-TP ISO/TR 5925-2:2018
---------------------- Page: 2 ----------------------
SIST-TP ISO/TR 5925-2:2018
TECHNICAL ISO/TR
REPORT 5925-2
Second edition
2006-07-15
Fire tests — Smoke-control door
and shutter assemblies —
Part 2:
Commentary on test method and the
applicability of test conditions and the
use of test data in a smoke containment
strategy
Essais au feu — Assemblages porte et volet pare-fumée —
Partie 2: Commentaires sur la méthode d'essai et applicabilité des
conditions d'essai et emploi des données d'essai dans une stratégie de
confinement de la fumée
Reference number
ISO/TR 5925-2:2006(E)
ISO 2006
---------------------- Page: 3 ----------------------
SIST-TP ISO/TR 5925-2:2018
ISO/TR 5925-2:2006(E)
PDF disclaimer

This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but

shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In

downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat

accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.

Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation

parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In

the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

© ISO 2006

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2006 – All rights reserved
---------------------- Page: 4 ----------------------
SIST-TP ISO/TR 5925-2:2018
ISO/TR 5925-2:2006(E)
Contents Page

Foreword............................................................................................................................................................ iv

Introduction ........................................................................................................................................................ v

1 Scope ..................................................................................................................................................... 1

2 Terms and definitions........................................................................................................................... 1

3 General principles................................................................................................................................. 2

4 Smoke control....................................................................................................................................... 3

5 Appropriateness of the test conditions and the selection of sealing system.............................. 10

6 Use of test outputs ............................................................................................................................. 11

Bibliography ..................................................................................................................................................... 12

© ISO 2006 – All rights reserved iii
---------------------- Page: 5 ----------------------
SIST-TP ISO/TR 5925-2:2018
ISO/TR 5925-2:2006(E)
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.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

In exceptional circumstances, when a technical committee has collected data of a different kind from that

which is normally published as an International Standard (“state of the art”, for example), it may decide by a

simple majority vote of its participating members to publish a Technical Report. A Technical Report is entirely

informative in nature and does not have to be reviewed until the data it provides are considered to be no

longer valid or useful.

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.

ISO/TR 5925-2 was prepared by Technical Committee ISO/TC 92, Fire safety, Subcommittee SC 2, Fire

containment.

This second edition cancels and replaces the first edition (ISO/TR 5925-2:1997), which has been technically

revised.

ISO/TR 5925 consists of the following parts, under the general title Fire tests — Smoke-control door and

shutter assemblies:
⎯ Part 1 : Ambient and medium temperature leakage test procedure

⎯ Part 2: Commentary on test method and the applicability of test conditions and the use of test data in a

smoke containment strategy
1) To be published. (Revision of ISO 5925-1:1981)
iv © ISO 2006 – All rights reserved
---------------------- Page: 6 ----------------------
SIST-TP ISO/TR 5925-2:2018
ISO/TR 5925-2:2006(E)
Introduction

Technical Committee ISO/TC92, Fire Safety, has prepared ISO 5925-1, a test specification for smoke control

doors.

In a fire, the decomposition of materials results in the production of heat and fire gases containing smoke

particles. The associated expansion of gases can lead to the creation of a pressure differential across door

faces often influenced by wind pressures, mechanical or natural smoke extract systems, stack effect or a

combination of these. This pressure differential induces the movement of smoke or air past any openings or

gaps, including those in a door assembly. Schemes to keep areas within buildings free of smoke use various

techniques, including barriers to its movement, exhausting, dilution, pressurization, either singly or in some

suitable combination of all of these. Where the pressure differential across the door is positive, i.e. gases are

being driven through any gap; standard tests have been developed to measure the leakage of smoke when

such conditions exist. The test method does not deal generally with doors installed in conjunction with active

smoke control methods, such as pressurization or exhaust, and this part of ISO/TR 5925 has been prepared

to assist designers to specify doors that have the appropriate smoke control characteristics for the situation in

which they are being used.

In addition to identifying when the door is likely to have a passive smoke control function, this part of

ISO/TR 5925 tries to make it clear as to when ambient or medium temperature smoke control is appropriate,

and when the threshold gap is significant.
© ISO 2006 – All rights reserved v
---------------------- Page: 7 ----------------------
SIST-TP ISO/TR 5925-2:2018
---------------------- Page: 8 ----------------------
SIST-TP ISO/TR 5925-2:2018
TECHNICAL REPORT ISO/TR 5925-2:2006(E)
Fire tests — Smoke-control door and shutter assemblies —
Part 2:
Commentary on test method and the applicability of test
conditions and the use of test data in a smoke containment
strategy
1 Scope

This Technical Report provides a commentary that explains the general philosophy and factors on which the

test specified in Part 1 of ISO 5925 has been designed, to describe the limitations of its application and to

provide some general guidance for those who use the result of the test. Smoke control-door and shutter

assemblies can be used as part of a smoke containment strategy for the purposes of life safety or property

protection.
2 Terms and definitions

For the purposes of this document, the terms and definitions given in Part 1 of ISO 5925 and the following

apply.
2.1
door assembly

assembly comprising a fixed part (the door frame), one or more movable parts (the door leaves) and its

hardware

NOTE The purpose of the door assembly is to allow or prevent access of persons and/or goods. The term hardware

includes such items as hinges, latches, door handles, locks, keyholes (excluding keys), letter plates, sliding gear, closing

devices, electrical wiring and any other items that can influence the performance of the assembly being tested.

2.2
shutter assembly

assembly comprising fixed parts, e.g. a barrel housing and vertical guides and one or more moveable parts,

normally in the form of a curtain constructed from linked metal laths, or other flexible material and a barrel on

which the curtain is wound together with any powered mechanism, e.g. an electric motor and its associate

power supply

NOTE The shutter assembly is to allow the passage of goods, vehicles or persons, albeit where the shutter is

normally closed in use, a personnel door should be provided for the passage of persons.

2.3
fire door

door or shutter assembly capable of maintaining for a specified period some, or all of the fire resistance

criteria defined in ISO 3008, as appropriate for the door in use
2.4
smoke control door

door or shutter assembly whose primary function is to restrict the passage of smoke as determined by a test in

accordance with Part 1 of ISO 5925
© ISO 2006 – All rights reserved 1
---------------------- Page: 9 ----------------------
SIST-TP ISO/TR 5925-2:2018
ISO/TR 5925-2:2006(E)
2.5
fire and smoke control door

door or shutter assembly meeting some, or all of the criteria for fire and smoke control as appropriate for the

door in use
2.6
ambient temperature

for the purpose of this Technical Report, ambient temperature is an air temperature of (20 ± 10) °C

2.7
medium temperature

for the purpose of this Technical Report, medium temperature is an air temperature of (200 ± 20) °C

2.8
high temperature

temperature representative of a standardized fully developed fire which is as specified in ISO 834-1

NOTE For ease of use, doors are identified by a code letter/number and these are shown in Figure 1.

2.9
make-up air

air that is made available to dilute the fire gases in order to reduce their temperature

3 General principles
3.1 Smoke and its influence

Smoke is the term used to describe the airborne products of combustion generated by the fire, together with

large volumes of air that become entrained into them due to their motion. These combustion products can

contain solid and liquid particulates within a gaseous mass.

Almost all fires produce smoke, which, when enclosed by a building, has the potential to become extremely

hazardous to its occupants and damaging to property. Most deaths in fires are due to smoke inhalation, rather

than to the victim having been burned.

The gaseous combustion products, chiefly carbon dioxide and water vapour, usually include toxic gases, the

most common being carbon monoxide, although hydrogen cyanide and other minor species can be present to

some extent. Amongst these, irritant gases such as acrolein can have a significant effect on people attempting

to escape fire.

The solid and liquid fractions of the products of combustion are also responsible for the poor visibility through

smoke. This adds to the problems presented by the smoke. Not only is it physiologically hazardous in its own

right, but escape through it is made more difficult by it obscuring escape routes. These fractions can

themselves be irritants and can be particularly dangerous to people who are subject to asthma or other

respiratory problems.

Smoke can also cause damage to property. Most fires produce soot and many generate corrosive gases such

as hydrogen chloride. The effect of these on sensitive equipment can be responsible for large monetary

losses due to equipment damage, the need for system clean-up and subsequent business interruption.

3.2 Smoke dynamics

All fires start from an ignition and grow at a rate generally determined by the environment in which the fire

starts and the nature of the materials involved in the event. Sometimes the fire can smoulder for a

considerable period, especially if the materials that have been ignited have a low rate of heat release or the

environment does not readily sustain combustion. Smoke produced during such a fire has very little buoyancy

and whatever buoyancy it has due to gas density differentials as a result of increased temperature is soon lost.

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Smoke produced under these low temperature conditions is, therefore, subject to the movement dominated by

the ambient air current, particularly any that is induced by mechanical means, such as ventilation and air

conditioning. In the absence of ambient currents, these cool gases generally mix with the environment and do

not stratify as is expected from hot buoyant gases.

Once the heat release increases, the smoke’s buoyancy increases and it soon begins to dominate air currents

in the enclosure. When the fire reaches a sufficient size, the smoke rises in a plume towards the ceiling. As it

does so, it entrains large volumes of air, greatly increasing smoke volume but reducing its temperature and

the concentration of chemical constituents.

The total entrained volume of air increases substantially with increasing height of the plume. With sufficient

buoyancy, the smoke impinges the ceiling, spreading out radially to reach any side walls and then forms a

layer that deepens as more smoke is produced.

Smoke flows out of the enclosure of origin through any upper openings that exist or develop. This outflow is

balanced by an inflow of air usually at a lower level. The openings can exist by design or occur as a result of

failure of one of the boundary elements.

An opening can be part of a smoke ventilation or extract system, where either vents open to allow smoke out

or a fan-assisted ducting system exhausts the hot gases and smoke. In such cases, make-up air is required to

come into the enclosure at a lower level, normally from designated sources, but also, possibly, from around

doors. Doors designed to provide make-up air do not require smoke sealing around their perimeter.

Similarly, one of the boundary elements most likely to fail as a result of the exposure to hot gases is windows

in the external façade, where high temperature differentials on the surface of the glass can lead to shattering.

Under ideal environmental conditions, this exhausts the smoke, making the need for enclosure sealing

unnecessary. However, unlike a designed-in vent that is designed to work in conjunction with winds from most

directions, the failure of an external window on a façade with a wind imposed on it can have the opposite

effect. Any wind-induced pressure in the enclosure can impose demands on the walls separating other parts

of the building with respect to their ability to prevent smoke leakage through gaps.

Similarly, if the enclosure is unfenestrated or where the windows do not break as a result of the thermal

exposure, then the pressure increases and the smoke layer deepens.

A normal door is the one element in the boundary of a structure that is naturally leaky, having a gap all around

the moving leaf, unless a seal is introduced to restrict it. A smoke-control door is provided to restrict the flow of

smoke, whether it is wind-induced or the result of natural buoyancy.

It should be recognized, however, that any smoke transferring through door gaps is likely to lose much of its

heat energy in the process and, as a consequence, the temperature and buoyancy are also reduced.

Experimental work has demonstrated that smoke leaving an enclosure via narrow gaps, such as those around

a door leaf perimeter, soon become fully mixed with the air.

Within the enclosure, as new flammable material becomes involved as a result of increasing heat transfer to it,

more air is required for the fuel volatiles to burn. If this is not available, either the fire does not grow any further

or the fuel volatiles burn instead outside the enclosure of origin, i.e. after moving via windows to the open air

or to an adjacent ventilated space, if it is available.

Without engineering intervention, it would be natural for the space containing the fire to contain hot buoyant

gases and for the immediately adjacent, protected spaces to fill with clean air without any buoyancy.

4 Smoke control
4.1 Design objectives

Since smoke can have a major impact on the overall design of the building, it needs to be considered at the

earliest possible stage of the design process. Normal escape provisions in buildings, e.g. restrictions on travel

distances and emergency lighting provisions, do not assume significant levels of smoke management. Where

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good smoke management is introduced, either by exhaust, ventilation, pressurization or by containment, then

these provisions may be relaxed. Any such relaxation has a profound influence on the building design/layout

and, therefore, it is important that the method of smoke control to be used be nominated early in the design

process.

Smoke-control systems for life safety are designed to maintain a tenable environment for occupants to

facilitate their safe escape from the building to a place of relative safety or a refuge, preferably separated

structurally from the area being evacuated. Smoke-control systems for property protection are generally

designed to reduce the level of contamination in a space by keeping smoke logging down to acceptable levels.

There are a number of ways that smoke control can be achieved:
⎯ natural ventilation;
⎯ mechanical smoke exhaust;
⎯ pressurization;
⎯ smoke containment.

NOTE An alternative to pressurizing a space is to depressurize the adjacent spaces(s), but this is difficult to achieve

in a fire, as the depressurization fans are generally overwhelmed by the fire gases.

The choice of system may be dictated by the area in which the smoke is to be controlled. With such “active”

measures, then, natural or powered exhaust is more appropriate then “passive” smoke containment has a

limited function, and can possibly make the situation worse by lack of the make-up air, and hence reduced

entrainment and higher gas temperatures, as discussed in 4.2, unless separate provision is made for

“make-up” air.

If, however, it is an adjacent space that is to be protected, then a method that has been used historically to

keep such an area free of smoke has been pressurization of the space, especially staircases. Actively

exhausting smoke from the area on fire also provides some protection to the adjacent spaces. This protection

can be compromised if the smoke temperature in the space exceeds the operating temperature of the fan,

causing it to cease operating. At such times, the space becomes vulnerable to smoke logging.

A simple-to-introduce alternative to exhaust or pressurization is the use of smoke containment, initially

between the enclosure on fire and the space being protected or between adjacent protected areas.

4.2 Protection of adjacent and remote/removed spaces by smoke containment

For smoke containment to work, it is important that the elements bounding the enclosure of fire origin and the

adjacent enclosures remain impermeable to the flow of smoke and hot gases for as long as is necessary to

maintain tenable conditions for life safety or an adequately pollution-free environment for property protection.

There are several fairly distinct stages in this scenario that it is important to address individually for each

space in which smoke is contained.
4.2.1 Scenario within the room of fire origin

In the period immediately following a small ignition, assuming that the materials initially involved in the fire

have a high thermal inertia and a relatively low rate of heat release, the smoke cools and mixes readily with

the surrounding atmosphere. As such, the barrier formed by the bounding structure can initially experience

exposure to cool, ambient smoke. As such, any seals designed to restrict that smoke, including seals around

door edges or the sealing systems used to retain glass within the door leaf, are required to be effective at only

ambient conditions. If the fire continues to grow in intensity and size, with a corresponding increase in the rate

of heat release, then the plume becomes buoyant, increasing in both temperature and volume. The

temperature of this plume becomes elevated and any ambient temperature test method for evaluating smoke

containment can be inappropriate. It is possible by reference to the appropriate scenario in 4.2.2 to 4.2.4 to

produce an estimate of the smoke temperature and hence identify the most suitable test regime to reproduce

those conditions.
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In addition to the heat release from the fire, there are many other features that influence these temperatures:

⎯ height of the room;
⎯ thermal losses to, or through, the boundary structure;
⎯ availability of make-up air (dilution);
⎯ presence of a suppression system.

In a single-storey enclosure, initially these elevated temperatures are imposed only on seals in the upper part

of the enclosure and can be applied to linear-gap seals, glazing seals or service penetration seals for which

no smoke-leakage tests currently exist, neither at ambient, nor elevated temperatures. Seals fitted around the

perimeter of door assemblies are not exposed to smoke at these temperatures until the smoke layer has

deepened to below door head height, although there are a number of gas temperature/buoyancy conditions as

the smoke goes through the transition from smouldering to fully buoyant.

Once the gas layer descends below 2,7 m, especially if it has a temperature of around 200 °C, the

temperature currently recommended in Part 1 of ISO 5925, the conditions are life threatening to the occupants

of the space. If there is a risk of the smoke extending down to this height, then smoke management by

exhaust and/or dilution is normally introduced to ensure that these temperatures and smoke layer heights do

not develop or are not exceeded. It is only in a single-storey environment without smoke management that

doors installed at ground-floor level are subjected to smoke at such temperatures and, even then, probably

only over the upper part of the leaf.

However, doors can be installed at a higher level in such a space, e.g. off a gallery, balcony, a mezzanine or

large unprotected accommodation stair, in which case the doors are subjected to smoke/gas temperatures

greater than this, even before a flashover or full fire development has occurred in the enclosure. Doors in such

locations can experience medium temperature conditions over their full height, including the threshold, at an

early stage in a fire.

Following the full development of the fire, either following flashover or as a result of the free burning of the

adjacent contents in an enclosure that is too large to flashover, a door can be expected to experience

exposure to smoke and hot gases at, or near, fire temperatures. Within Part 1 of ISO 5925, there are no such

conditions specified. In practice, there is no recognized method of quantifying leakage in the fully developed

fire but experimental evidence indicates that intumescent seals, fitted to the leaf perimeter of a doorset, can

be expected to restrict the flow of “hot” smoke.

Whilst fire-resisting, smoke-control doorsets do not play a constructive role in a natural, or powered smoke-

exhaust system, vertical-drop steel rolling steel doors/roller shutters can play a useful function in such

applications. As part of a smoke exhaust system, it is important that the buoyant smoke that collects at a high

level in an enclosure is not allowed to traverse too far because the gases would be further diluted and lose

their buoyancy as a result of a loss of their temperature differential compared to the ambient conditions

outside the building. The egress velocity of the gases through vents is governed by the differential

temperature and so this is important. To prevent this dilution and cooling, smoke screens or curtains are used

to create a smoke reservoir, which aids the extraction. Partly dropped roller shutters can be used to act as

smoke curtains or reservoir screens and may be used partially closed, thereby providing a source of input air

for the smoke exhaust system at the bottom, but at the same time providing a barrier to reduce smoke spread

nearer the top.The egress velocity of the gases through vents is governed by the differential temperature and

so this is important.

From the above, it can be seen that doors in the boundary of an enclosure of fire origin are exposed to various

smoke temperatures and over/under pressures, depending upon the level at which they are installed, the

stage in the fire and the smoke-management measures that are incorporated.

Table 1 identifies, for doors in the space of fire origin, the appropriate exposure conditions to consider when

determining the smoke-tightness requirements for the doors in these applications.

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Table 1 — Summary of smoke exposure conditions for doors in the boundary
of the space of fire origin
Door configuration
Smoke
temperature
b c d e
A B C D

Ambient Briefly at the beginning Very briefly over the full Briefly at the beginning No exposure

and possibly over full height of the door and possibly over full
height of door height of the door

Medium For an extended period For an extended period No exposure Extended periods over

up to the onset of up to the onset of full height
flashover over the upper flashover over the full
2/3rds of the door height of door, including
the threshold
g g
High For the period following For the duration No exposure No exposure
flashover and over the between flashover and
majority of the door extinguishment over full
height height
See Figure 1.

A: Door assemblies at ground-floor level within the boundary of an enclosure (GF1) without an “active” smoke-control system operating in

the enclosure.

B: Door assemblies at elevated positions within the boundary of an enclosure (E1) without an “active” smoke-control system operating in

the enclosure.

C: Door assemblies at ground-floor level within the boundary of an enclosure (GF1) with a properly designed “active” smoke-control

system operating in the enclosure.

D: Door assemblies at elevated positions within the boundary of the enclosure (E1) with a properly designed smoke-control system

operating in the enclosure.

The amount of the door subjected to medium temperature smoke depends upon position of neutral pressure axis within the space.

Can experience these conditions if smoke control system is overwhelmed or fails.

4.2.2 Scenario within a ground-floor space adjacent to the enclosure of fire origin with no active

smoke control in the enclosure

Whilst the boundary to the enclosure of fire origin remains imperforate, the adjacent, protected spaces are not

likely to experience any smoke logging. However, if the door(s
...

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