ISO 22185-1:2021
(Main)Diagnosing moisture damage in buildings and implementing countermeasures — Part 1: Principles, nomenclature and moisture transport mechanisms
Diagnosing moisture damage in buildings and implementing countermeasures — Part 1: Principles, nomenclature and moisture transport mechanisms
This document defines moisture damage and it specifies the moisture sources and the moisture transport mechanisms in buildings. It includes a method for classification of moisture damage based on the relation of: — materials and constituent materials, — phenomena, and — functionalities that can be affected. This document deals with: 1) building damage that is induced by (gaseous/liquid/solid) water, and 2) damage to building components, human health, and property contained in the enclosure. This document makes no mention of warranties for building damage.
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INTERNATIONAL ISO
STANDARD 22185-1
First edition
2021-02
Diagnosing moisture damage
in buildings and implementing
countermeasures —
Part 1:
Principles, nomenclature and
moisture transport mechanisms
Reference number
ISO 22185-1:2021(E)
©
ISO 2021
---------------------- Page: 1 ----------------------
ISO 22185-1:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 22185-1:2021(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Moisture transport mechanism . 2
5 Moisture sources . 3
6 Moisture damage . 3
7 Phenomena resulting from moisture . 4
7.1 Algae/bryophyte . 4
7.2 Aesthetic changes . 4
7.3 Condensation . 4
7.4 Corrosion . 4
7.5 Crack . 4
7.6 Creaking . 5
7.7 Deformation . 5
7.8 Dissolved destructive elements . 5
7.9 Dissolution . 5
7.10 Expansion . 5
7.11 Floating . 5
7.12 Floor squeak/floor squeaking . 5
7.13 Freezing . 6
7.14 Frost heave . 6
7.15 Wood decay . 6
7.16 Gap . 6
7.17 Hardening . 6
7.18 High humidity . 6
7.19 Low humidity . 6
7.20 Mite . 7
7.21 Mould . 7
7.22 Peeling/exfoliation/delamination/adhesion loss/spall . 7
7.23 Rust . 7
7.24 Shrinkage . 7
7.25 Softening . 7
7.26 Thrust up/creeping up . 7
7.27 Unplanned bulk water entry . 8
7.28 Water-leakage . 8
7.29 Warpage . 8
7.30 Wetting . 8
7.31 Wrinkle . 8
8 Performance affected by moisture . 8
8.1 Envelope or enclosure — Risk of water penetration, deterioration of components
and systems — Important for designing for durability . 8
8.1.1 Ability to support bonded materials . 8
8.1.2 Airtightness . 9
8.1.3 Capillary breaking layer. 9
8.1.4 Durability . 9
8.1.5 Electrical insulation performance . 9
8.1.6 Environmental separation . 9
8.1.7 Function of components . 9
8.1.8 Functionality . 9
© ISO 2021 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 22185-1:2021(E)
8.1.9 Moisture-proof performance/damp-proof performance . 9
8.1.10 Thermal insulation performance . 9
8.1.11 Waterproofing performance .10
8.2 Occupant comfort and owner value — Aesthetics, satisfaction of users .10
8.2.1 Acoustic separation .10
8.2.2 Building aesthetics .10
8.2.3 Opening performance of windows and doors .10
8.2.4 Occupant comfort .10
8.2.5 Property value .10
8.2.6 Visibility (performance of transparent material).10
8.2.7 Walkability of floor .10
8.3 Structure — Risk of collapse .11
8.3.1 Structural capacity and deflection .11
8.3.2 Structural support .11
9 Building components affected by moisture .11
9.1 Building equipment .11
9.2 Exterior finishing material.11
9.3 Joint .11
9.4 Hardware .12
9.5 Interior finishing material .12
9.6 Opening .12
9.7 Piping .12
9.8 Space .13
9.9 Storage item .13
9.10 Structure/body structure .13
9.11 Substrate/underlayment/sheathing .13
9.12 Thermal insulation material .13
9.13 Waterproofing membrane .14
9.14 Wiring .14
10 Classifications of moisture damage .14
10.1 General .14
10.2 Constituent materials (sub-classification of materials) .14
10.3 Functionalities that can be affected .15
10.4 Materials .15
10.5 Phenomena.15
Bibliography .19
iv © ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 22185-1:2021(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.
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 205, Building environment design, in
collaboration with the Technical Committee ISO/TC 163, Thermal performance and energy use in the
built environment.
A list of all parts in the ISO 22185 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.
© ISO 2021 – All rights reserved v
---------------------- Page: 5 ----------------------
ISO 22185-1:2021(E)
Introduction
The term “moisture damage” is interpreted in many ways. Cognisance of moisture damage is not always
consistent between specialists (engineers, researchers, etc.) residents and building users, leading to
confusion. For example, residents and building users would consider the occurrence of condensation
on window glass or on the surface of a metal sash to be a prime example of moisture damage, but
considering the durability of glass and metal materials, it is not always appropriate to call that
“moisture damage”. Then again, supposing the condensation that occurs on the glass becomes the cause
of an outbreak of moulds on the curtains, that would be called moisture damage. It is imperative to
resolve the confusion by defining “moisture damage” and by demonstrating the criteria for diagnosing
whether an occurring phenomenon in a building is moisture damage or not.
This document defines moisture damage in buildings and demonstrates criteria for diagnosing
whether phenomena that occurs in a building is moisture damage or not, for a common understanding
between residents, building users and specialists. It also demonstrates methods for the classification
of moisture damage.
This document is the first part of a series of standards on moisture damage. In the following parts,
a framework for investigating and taking countermeasures against moisture damage, and design
methods of building for reducing moisture damage will be shown.
The basic ideas of this document are derived from Reference [6].
vi © ISO 2021 – All rights reserved
---------------------- Page: 6 ----------------------
INTERNATIONAL STANDARD ISO 22185-1:2021(E)
Diagnosing moisture damage in buildings and
implementing countermeasures —
Part 1:
Principles, nomenclature and moisture transport
mechanisms
1 Scope
This document defines moisture damage and it specifies the moisture sources and the moisture
transport mechanisms in buildings.
It includes a method for classification of moisture damage based on the relation of:
— materials and constituent materials,
— phenomena, and
— functionalities that can be affected.
This document deals with:
1) building damage that is induced by (gaseous/liquid/solid) water, and
2) damage to building components, human health, and property contained in the enclosure. This
document makes no mention of warranties for building damage.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
condensation damage
damage (3.3) caused by water vapour condensing on a material resulting in the material's deterioration
and reduced performance which then affect human health
3.2
critical relative humidity
limit for a material to maintain acceptable function throughout the time the material is exposed to the
moisture state
Note 1 to entry: Temperature, exposure time, dirt, combination with other materials and varying moisture
conditions also affect, in a complicated manner.
© ISO 2021 – All rights reserved 1
---------------------- Page: 7 ----------------------
ISO 22185-1:2021(E)
Note 2 to entry: The critical moisture condition can be expressed either as a critical relative humidity (RH ) or
crit
as critical moisture content (w ).
crit
3.3
damage
phenomena that affect the function/performance of the building (structural resistance/architectural/
functional depression of components, functional depression and malfunction of building equipment,
decrease in value of property), aesthetics and that cause a deterioration in the living environment of
the building, including human health
3.4
frost damage
damage (3.3) including surface cracks, peeling/exfoliation/delamination caused by the repeated
freezing/thawing of moisture inside the materials or on a surface between a material and freezing water
3.5
moisture content
moisture mass per unit mass of dry materials, or moisture mass or volume per unit volume of materials
Note 1 to entry: Depending on the standard physical quantity, either moisture content (mass by mass) u [kg/kg],
3 3 3
moisture content (mass by volume) w [kg/m ], or moisture content (volume by volume) Ψ [m /m ] is used.
3.6
moisture damage
damage (3.3) in the building originating in (gaseous/liquid/solid) water
3.7
salt damage
damage (3.3) due to salt, including corrosion of metal materials caused by touching with salt in the air,
cracks in the concrete from the corrosion/expansion of reinforcing steel rod due to salt adhesion, and
detachment, etc., caused by crystallized/deposited salt in ceramic materials
Note 1 to entry: Visible salt deposition on surfaces can cause aesthetic problems.
4 Moisture transport mechanism
To make moisture planning meaningful, the critical moisture levels shall be well defined. However,
these boundaries are always more or less uncertain. The solution may be to introduce some degree of
safety margin. The size of the safety margin that should be introduced depends on the severity of the
impact of a moisture state above the critical one. In cases where the degradation rate can be controlled,
it is sometimes even possible to allow moisture levels above the critical, if this does not affect the indoor
climate, health or the expected lifespan of the material or the structure.
Moisture in building porous materials transfers as vapour or liquid.
Vapour transfers as diffusion and effusion caused by vapour pressure gradients, and as the diffusion
caused by temperature gradient.
Liquid transfers as capillary flow caused by the gravity in capillary suction. For vertical direction,
liquid transfers also by gravitation.
In the presence of gradient in total air pressure, liquid and vapour transfer due to the gradient in total air
pressure in addition to the mechanisms described above. This is classified as a transfer by convection.
Wind pressure and difference in air pressure caused by difference between indoor and outdoor air
temperatures are typical examples that cause convective transfer of vapour and liquid through cracks
in or between building materials and also through permeable porous material. Mechanical ventilation
will also influence the gradient in total air pressure.
2 © ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
ISO 22185-1:2021(E)
5 Moisture sources
Moisture sources in building can be classified by the time of generation as follows:
a) generated before construction;
b) generated during construction;
c) generated after construction.
Table 1 presents examples of moisture sources. The letters in the bracket (a, b, or c) denote that the
moisture source can generate at the time categorised above.
Table 1 — Moisture sources' examples
Moisture sources (a) (b) (c)
Generated before Generated during Generated after
construction construction construction
Precipitation (a) (b) (c)
Vapour outside the build- (a) (b) (c)
ing
Vapour inside the building (a) (b) (c)
Water in soil (liquid and (a) (b) (c)
vapour)
Built-in moisture (initially (a) (b) (c)
contained in the material)
Leakage (b) (c)
Water from adhesive (b) (c)
Post occupancy water (c)
use, e.g. shower, baths,
dishwasher, wet cleaning
of floor
6 Moisture damage
In order to refer to moisture damage, a phenomenon shall satisfy both of the following two conditions.
(1) A phenomenon which causes damage.
(2) A phenomenon is directly related to (gaseous/liquid/solid) water.
This is the definition of moisture damage, which is described in Figure 1.
© ISO 2021 – All rights reserved 3
---------------------- Page: 9 ----------------------
ISO 22185-1:2021(E)
Figure 1 — Definition of moisture damage
7 Phenomena resulting from moisture
7.1 Algae/bryophyte
"Algae" is the generic term for a living being that performs photosynthesis on the earth other than
bryophyte, fern plants, and seed plants, and includes blue algae (cyanobacteria) and green algae, etc.
Bryophyte includes moss, liverwort and hornwort. When the materials are placed under the outside
weather conditions, moisture content on the surface or the water droplets adhere to the surface may
breed algae or bryophyte and may cause aesthetic problems. If the humid conditions are prolonged, it is
more likely that algae and bryophyte are observed.
Related terms: condensation, high humidity.
7.2 Aesthetic changes
Wetting of a material that results in changes to pigments or accelerates other processes that result in
staining or discolouration.
Related terms: wetting, condensation, colour fading, stain.
7.3 Condensation
Condensation is the change of the physical state of water from gas phase into liquid phase. Condensation
occurs on a surface that is at or below the ‘dew point’ temperature.
Related terms: wetting, high humidity.
7.4 Corrosion
Corrosion means that a metal is altered or is consumed from the surface due to the rust by oxidization,
or electrolytically by the differences of ionization tendencies. In some metals, when it rusts on the
surface, it works as a protective film, and it does
...
INTERNATIONAL ISO
STANDARD 22185-1
First edition
Diagnosing moisture damage
in buildings and implementing
countermeasures —
Part 1:
Principles, nomenclature and
moisture transport mechanisms
Member bodies are requested to consult relevant national interests in ISO/TC
163 before casting their ballot to the e-Balloting application.
PROOF/ÉPREUVE
Reference number
ISO 22185-1:2020(E)
©
ISO 2020
---------------------- Page: 1 ----------------------
ISO 22185-1:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii PROOF/ÉPREUVE © ISO 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 22185-1:2020(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Moisture transport mechanism . 2
5 Moisture sources . 3
6 Moisture damage . 3
7 Phenomena resulting from moisture . 4
7.1 Algae/bryophyte . 4
7.2 Aesthetic changes . 4
7.3 Condensation . 4
7.4 Corrosion . 4
7.5 Crack . 4
7.6 Creaking . 5
7.7 Deformation . 5
7.8 Dissolved destructive elements . 5
7.9 Dissolution . 5
7.10 Expansion . 5
7.11 Floating . 5
7.12 Floor squeak/floor squeaking . 5
7.13 Freezing . 6
7.14 Frost heave . 6
7.15 Wood decay . 6
7.16 Gap . 6
7.17 Hardening . 6
7.18 High humidity . 6
7.19 Low humidity . 6
7.20 Mite . 7
7.21 Mould . 7
7.22 Peeling/exfoliation/delamination/adhesion loss/spall . 7
7.23 Rust . 7
7.24 Shrinkage . 7
7.25 Softening . 7
7.26 Thrust up/creeping up . 7
7.27 Unplanned bulk water entry . 8
7.28 Water-leakage . 8
7.29 Warpage . 8
7.30 Wetting . 8
7.31 Wrinkle . 8
8 Performance affected by moisture . 8
8.1 Envelope or enclosure — Risk of water penetration, deterioration of components
and systems — Important for designing for durability . 8
8.1.1 Ability to support bonded materials . 8
8.1.2 Airtightness . 9
8.1.3 Capillary breaking layer. 9
8.1.4 Durability . 9
8.1.5 Electrical insulation performance . 9
8.1.6 Environmental separation . 9
8.1.7 Function of components . 9
8.1.8 Functionality . 9
© ISO 2020 – All rights reserved PROOF/ÉPREUVE iii
---------------------- Page: 3 ----------------------
ISO 22185-1:2020(E)
8.1.9 Moisture-proof performance/damp-proof performance . 9
8.1.10 Thermal insulation performance . 9
8.1.11 Waterproofing performance .10
8.2 Occupant comfort and owner value — Aesthetics, satisfaction of users .10
8.2.1 Acoustic separation .10
8.2.2 Building aesthetics .10
8.2.3 Opening performance of windows and doors .10
8.2.4 Occupant comfort .10
8.2.5 Property value .10
8.2.6 Visibility (performance of transparent material).10
8.2.7 Walkability of floor .10
8.3 Structure — Risk of collapse .11
8.3.1 Structural capacity and deflection .11
8.3.2 Structural support .11
9 Building components affected by moisture .11
9.1 Building equipment .11
9.2 Exterior finishing material.11
9.3 Joint .11
9.4 Hardware .12
9.5 Interior finishing material .12
9.6 Opening .12
9.7 Piping .12
9.8 Space .13
9.9 Storage item .13
9.10 Structure/body structure .13
9.11 Substrate/underlayment/sheathing .13
9.12 Thermal insulation material .13
9.13 Waterproofing membrane .14
9.14 Wiring .14
10 Classifications of moisture damage .14
10.1 General .14
10.2 Constituent materials (sub-classification of materials) .14
10.3 Functionalities that can be affected .15
10.4 Materials .15
10.5 Phenomena.15
Bibliography .19
iv PROOF/ÉPREUVE © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 22185-1:2020(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.
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 205, Building environment design, in
collaboration with the Technical Committee ISO/TC 163, Thermal performance and energy use in the
built environment.
A list of all parts in the ISO 22185 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.
© ISO 2020 – All rights reserved PROOF/ÉPREUVE v
---------------------- Page: 5 ----------------------
ISO 22185-1:2020(E)
Introduction
The term “moisture damage” is interpreted in many ways. Cognisance of moisture damage is not always
consistent between specialists (engineers, researchers, etc.) residents and building users, leading to
confusion. For example, residents and building users would consider the occurrence of condensation
on window glass or on the surface of a metal sash to be a prime example of moisture damage, but
considering the durability of glass and metal materials, it is not always appropriate to call that
“moisture damage.” Then again, supposing the condensation that occurs on the glass becomes the cause
of an outbreak of moulds on the curtains, that would be called moisture damage. It is imperative to
resolve the confusion by defining “moisture damage” and by demonstrating the criteria for diagnosing
whether an occurring phenomenon in a building is moisture damage or not.
This document defines moisture damage in buildings and demonstrates criteria for diagnosing
whether phenomena that occurs in a building is moisture damage or not, for a common understanding
between residents, building users and specialists. It also demonstrates methods for the classification
of moisture damage.
This document is the first part of a series of standards on moisture damage. In the following parts,
a framework for investigating and taking countermeasures against moisture damage, and design
methods of building for reducing moisture damage will be shown.
The basic ideas of this document are derived from Reference [6].
vi PROOF/ÉPREUVE © ISO 2020 – All rights reserved
---------------------- Page: 6 ----------------------
INTERNATIONAL STANDARD ISO 22185-1:2020(E)
Diagnosing moisture damage in buildings and
implementing countermeasures —
Part 1:
Principles, nomenclature and moisture transport
mechanisms
1 Scope
This document defines moisture damage and it specifies the moisture sources and the moisture
transport mechanisms in buildings.
It includes a method for classification of moisture damage based on the relation of:
— materials and constituent materials,
— phenomena, and
— functionalities that can be affected.
This document deals with:
1) building damage that is induced by (gaseous/liquid/solid) water, and
2) damage to building components, human health, and property contained in the enclosure. This
document makes no mention of warranties for building damage.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
condensation damage
damage (3.3) caused by water vapour condensing on a material resulting in the material's deterioration
and reduced performance which then affect human health
3.2
critical relative humidity
limit for a material to maintain acceptable function throughout the time the material is exposed to the
moisture state
Note 1 to entry: Temperature, exposure time, dirt, combination with other materials and varying moisture
conditions also affect, in a complicated manner.
© ISO 2020 – All rights reserved PROOF/ÉPREUVE 1
---------------------- Page: 7 ----------------------
ISO 22185-1:2020(E)
Note 2 to entry: The critical moisture condition can be expressed either as a critical relative humidity (RH ) or
crit
as critical moisture content (w ).
crit
3.3
damage
phenomena that affect the function/performance of the building (structural resistance/architectural/
functional depression of components, functional depression and malfunction of building equipment,
decrease in value of property), aesthetics and that cause a deterioration in the living environment of
the building, including human health
3.4
frost damage
damage (3.3) including surface cracks, peeling/exfoliation/delamination caused by the repeated
freezing/thawing of moisture inside the materials or on a surface between a material and freezing water
3.5
moisture content
moisture mass per unit mass of dry materials, or moisture mass or volume per unit volume of materials
Note 1 to entry: Depending on the standard physical quantity, either moisture content (mass by mass) u [kg/kg],
3 3 3
moisture content (mass by volume) w [kg/m ], or moisture content (volume by volume) Ψ [m /m ] is used.
3.6
moisture damage
damage (3.3) in the building originating in (gaseous/liquid/solid) water
3.7
salt damage
damage (3.3) due to salt, including corrosion of metal materials caused by touching with salt in the air,
cracks in the concrete from the corrosion/expansion of reinforcing steel rod due to salt adhesion, and
detachment, etc., caused by crystallized/deposited salt in ceramic materials
Note 1 to entry: Visible salt deposition on surfaces can cause aesthetic problems.
4 Moisture transport mechanism
To make moisture planning meaningful, the critical moisture levels shall be well defined. However,
these boundaries are always more or less uncertain. The solution may be to introduce some degree of
safety margin. The size of the safety margin that should be introduced depends on the severity of the
impact of a moisture state above the critical one. In cases where the degradation rate can be controlled,
it is sometimes even possible to allow moisture levels above the critical, if this does not affect the indoor
climate, health or the expected lifespan of the material or the structure.
Moisture in building porous materials transfers as vapour or liquid.
Vapour transfers as diffusion and effusion caused by vapour pressure gradients, and as the diffusion
caused by temperature gradient.
Liquid transfers as capillary flow caused by the gravity in capillary suction. For vertical direction,
liquid transfers also by gravitation.
In the presence of gradient in total air pressure, liquid and vapour transfer due to the gradient in total air
pressure in addition to the mechanisms described above. This is classified as a transfer by convection.
Wind pressure and difference in air pressure caused by difference between indoor and outdoor air
temperatures are typical examples that cause convective transfer of vapour and liquid through cracks
in or between building materials and also through permeable porous material. Mechanical ventilation
will also influence the gradient in total air pressure.
2 PROOF/ÉPREUVE © ISO 2020 – All rights reserved
---------------------- Page: 8 ----------------------
ISO 22185-1:2020(E)
5 Moisture sources
Moisture sources in building can be classified by the time of generation as follows:
a) generated before construction;
b) generated during construction;
c) generated after construction.
Table 1 presents examples of moisture sources. The letters in the bracket (a, b, or c) denote that the
moisture source can generate at the time categorised above.
Table 1 — Moisture sources' examples
Moisture sources (a) (b) (c)
Generated before con- Generated during con- Generated after construc-
struction struction tion
Precipitation (a) (b) (c)
Vapour outside the build- (a) (b) (c)
ing
Vapour inside the building (a) (b) (c)
Water in soil (liquid and (a) (b) (c)
vapour)
Built-in moisture (initially (a) (b) (c)
contained in the material)
Leakage (b) (c)
Water from adhesive (b) (c)
Post occupancy water (c)
use, e.g. shower, baths,
dishwasher, wet cleaning
of floor
6 Moisture damage
In order to refer to moisture damage, a phenomenon shall satisfy both of the following two conditions.
(1) A phenomenon which causes damage.
(2) A phenomenon is directly related to (gaseous/liquid/solid) water.
This is the definition of moisture damage, which is described in Figure 1.
© ISO 2020 – All rights reserved PROOF/ÉPREUVE 3
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ISO 22185-1:2020(E)
Figure 1 — Definition of moisture damage
7 Phenomena resulting from moisture
7.1 Algae/bryophyte
"Algae" is the generic term for a living being that performs photosynthesis on the earth other than
bryophyte, fern plants, and seed plants, and includes blue algae (cyanobacteria) and green algae, etc.
Bryophyte includes moss, liverwort and hornwort. When the materials are placed under the outside
weather conditions, moisture content on the surface or the water droplets adhere to the surface may
breed algae or bryophyte and may cause aesthetic problems. If the humid conditions are prolonged, it is
more likely that algae and bryophyte are observed.
Related terms: condensation, high humidity.
7.2 Aesthetic changes
Wetting of a material that results in changes to pigments or accelerates other processes that result in
staining or discolouration.
Related terms: wetting, condensation, colour fading, stain.
7.3 Condensation
Condensation is the change of the physical state of water from gas phase into liquid phase. Condensation
occurs on a surface that is at or below the ‘dew point’ temperature.
Related terms: wetting, high humidity.
7.4 Corrosion
Corros
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