ISO/TR 52019-2:2017
(Main)Energy performance of buildings — Hygrothermal performance of building components and building elements — Part 2: Explanation and justification
Energy performance of buildings — Hygrothermal performance of building components and building elements — Part 2: Explanation and justification
ISO/TR 52019-2:2017 contains information to support the correct understanding and use of ISO 6946, ISO 10211, ISO 13370, ISO 13786, ISO 13789 and ISO 14683. ISO/TR 52019-2:2017 does not contain any normative provision.
Performance énergétique des bâtiments — Performances hygrothermiques des composants et parois de bâtiments — Partie 2: Explication et justification
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Standards Content (Sample)
TECHNICAL ISO/TR
REPORT 52019-2
First edition
2017-06
Energy performance of buildings —
Hygrothermal performance of
building components and building
elements —
Part 2:
Explanation and justification
Performance énergétique des bâtiments — Performances
hygrothermiques des composants et parois de bâtiments —
Partie 2: Explication et justification
Reference number
ISO/TR 52019-2:2017(E)
©
ISO 2017
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ISO/TR 52019-2:2017(E)
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ISO/TR 52019-2:2017(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and subscripts . 2
5 Description of the methods . 2
5.1 Outputs . 2
5.2 General description . 2
6 ISO 6946 . 3
7 ISO 10211 . 4
8 ISO 13370 . 4
8.1 General . 4
8.2 Thermal properties of the ground . 4
8.3 The influence of flowing ground water . 4
8.4 Application to dynamic simulation programmes . 4
8.5 Embedded heating or cooling systems . 4
8.6 Cold stores . 4
9 ISO 13786 . 4
10 ISO 13789 . 5
11 ISO 14683 . 5
Annex A (informative) ISO 13370: Thermal properties of the ground . 6
Annex B (informative) ISO 13370: The influence of flowing ground water .8
Annex C (informative) ISO 13370: Application to dynamic simulation programmes .10
Annex D (informative) ISO 13370: Slab-on-ground floor with an embedded heating or
cooling system .18
Annex E (informative) ISO 13370: Cold stores .19
Annex F (informative) ISO 13370: Worked examples .20
Annex G (informative) ISO 13786: Principle of the method and examples of applications .29
Annex H (informative) ISO 13786: Information for computer programming .33
Annex I (informative) ISO 13786: Examples .35
Annex J (informative) ISO 13789: Information on type of dimensions .38
Annex K (informative) ISO 13789: Ventilation airflow rates .40
Annex L (informative) ISO 14683: Example of the use of default values of linear thermal
transmittance in calculating the heat transfer coefficient .45
Annex M (informative) Detailed worked examples for ISO 6946, ISO 13370 and ISO 13789 .49
Bibliography .58
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ISO/TR 52019-2:2017(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 on 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 the following
URL: w w w . i s o .org/ iso/ foreword .html.
ISO/TR 52019-2 was prepared by ISO Technical Committee ISO/TC 163, Thermal performance and
energy use in the built environment, Subcommittee SC 2, Calculation methods, in collaboration with the
European Committee for Standardization (CEN) Technical Committee CEN/TC 89, Thermal performance
of buildings and building components, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
A list of all parts in the ISO 52019 series can be found on the ISO website.
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ISO/TR 52019-2:2017(E)
Introduction
The set of EPB standards, technical reports and supporting tools
In order to facilitate the necessary overall consistency and coherence, in terminology, approach,
input/output relations and formats, for the whole set of EPB-standards, the following documents and
tools are available:
a) a document with basic principles to be followed in drafting EPB-standards:
[8]
CEN/TS 16628:2014, Energy Performance of Buildings - Basic Principles for the set of EPB standards ;
b) a document with detailed technical rules to be followed in drafting EPB-standards;
CEN/TS 16629:2014, Energy Performance of Buildings - Detailed Technical Rules for the set of EPB-
[9]
standards .
The detailed technical rules are the basis for the following tools:
1) a common template for each EPB-standard, including specific drafting instructions for the relevant
clauses;
2) a common template for each technical report that accompanies an EPB standard or a cluster of EPB
standards, including specific drafting instructions for the relevant clauses;
3) a common template for the spreadsheet that accompanies each EPB standard, to demonstrate the
correctness of the EPB calculation procedures.
Each EPB-standards follows the basic principles and the detailed technical rules and relates to the
[5]
overarching EPB-standard, ISO 52000-1 .
One of the main purposes of the revision of the EPB-standards is to enable that laws and regulations
directly refer to the EPB-standards and make compliance with them compulsory. This requires that
the set of EPB-standards consists of a systematic, clear, comprehensive and unambiguous set of energy
performance procedures. The number of options provided is kept as low as possible, taking into account
national and regional differences in climate, culture and building tradition, policy and legal frameworks
(subsidiarity principle). For each option, an informative default option is provided (Annex B).
Rationale behind the EPB technical reports
There is a risk that the purpose and limitations of the EPB standards will be misunderstood, unless
the background and context to their contents – and the thinking behind them – is explained in some
detail to readers of the standards. Consequently, various types of informative contents are recorded
and made available for users to properly understand, apply and nationally or regionally implement the
EPB standards.
If this explanation would have been attempted in the standards themselves, the result is likely to be
confusing and cumbersome, especially if the standards are implemented or referenced in national or
regional building codes.
Therefore each EPB standard is accompanied by an informative technical report, like this one, where
all informative content is collected, to ensure a clear separation between normative and informative
[9]
contents (see CEN/TS 16629 ):
— to avoid flooding and confusing the actual normative part with informative content,
— to reduce the page count of the actual standard, and
— to facilitate understanding of the set of EPB standards.
[5]
This was also one of the main recommendations from the European CENSE project that laid the
foundation for the preparation of the set of EPB standards.
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ISO/TR 52019-2:2017(E)
This document
This technical report accompanies the suite of EPB standards on thermal transmission properties
of building elements. It relates to ISO 6946, ISO 10211, ISO 13370, ISO 13786, ISO 13789 and
ISO 14683, which form part of a set of standards related to the evaluation of the energy performance
of buildings (EPB).
The role and the positioning of the accompanied standards in the set of EPB standards is defined in the
introductions to ISO 6946, ISO 10211, ISO 13370, ISO 13786 and ISO 14683.
Accompanying spreadsheets
Concerning ISO 6946, ISO 10211, ISO 13370, ISO 13786 and ISO 14683, spreadsheets were produced for:
— ISO 6946;
— ISO 13370;
— ISO 13789.
These spreadsheets are available at www .epb .center.
In this document, examples of each of these calculation sheets are included in Annex M.
No accompanying calculation spreadsheets were prepared on:
— ISO 10211: this document does not provide a calculation procedure; it provides test cases and
performance criteria for calculation procedures.
— ISO 13786: this document provides complex matrix calculation procedures. Instead of a spreadsheet,
Annex I contains examples of calculation results obtained by a computer program.
— ISO 14683: this document does not provide a calculation procedure; it provides choices between
procedures provided elsewhere and default tabulated values. Instead, Annex L contains examples
of the use of default values.
The first series of standards on thermal and hygrothermal properties of building components and
elements were prepared by ISO Technical Committee TC 163 in the 1980s, as a result of growing global
concern on future fuel shortages and inadequate health and comfort levels in buildings. During the
following decades these first standards were revised and new standards were added, to cope with
new developments and additional needs. From the 1990s on, these standards were developed in close
collaboration with CEN.
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TECHNICAL REPORT ISO/TR 52019-2:2017(E)
Energy performance of buildings — Hygrothermal
performance of building components and building
elements —
Part 2:
Explanation and justification
1 Scope
This document contains information to support the correct understanding and use of ISO 6946,
ISO 10211, ISO 13370, ISO 13786, ISO 13789 and ISO 14683.
This document does not contain any normative provision.
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 6946:2017, Building components and building elements — Thermal resistance and thermal
transmittance — Calculation methods
ISO 7345, Thermal insulation — Physical quantities and definitions
ISO 10211, Thermal bridges in building construction — Heat flows and surface temperatures — Detailed
calculations
ISO 13370:2017, Thermal performance of buildings — Heat transfer via the ground — Calculation methods
ISO 13786, Thermal performance of building components — Dynamic thermal characteristics —
Calculation methods
ISO 13789, Thermal performance of buildings — Transmission and ventilation heat transfer coefficients —
Calculation method
ISO 14683, Thermal bridges in building construction — Linear thermal transmittance — Simplified
methods and default values
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 6946, ISO 7345, ISO 10211,
ISO 13370, ISO 13786, ISO 13789 and ISO 14683 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
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ISO/TR 52019-2:2017(E)
4 Symbols and subscripts
For the purposes of this document, the symbols and subscripts given in ISO 6946, ISO 7345, ISO 10211,
ISO 13370, ISO 13786, ISO 13789 and ISO 14683 apply.
5 Description of the methods
5.1 Outputs
The main outputs of ISO 6946, ISO 7345, ISO 10211, ISO 13370, ISO 13786, ISO 13789 and ISO 14683 are:
— thermal transmission properties of building elements (thermal resistance, thermal transmittance
or dynamic thermal characteristics of a wall, floor or roof);
— heat transfer coefficient for the whole building (or part of a building).
5.2 General description
Together with ISO 10456, ISO 10077-1, ISO 10077-2 and ISO 12631, these documents (ISO 6946,
ISO 7345, ISO 10211, ISO 13370, ISO 13786, ISO 13789 and ISO 14683) provide the methodology to
obtain heat transfer coefficients for a building starting from the properties of materials used for its
construction and the size and geometry of the building.
[7]
The results provide input for calculation of energy needs for heating and cooling by ISO 52016-1
when one of the simplified (monthly or hourly) calculation methods is being used in ISO 52016-1. In the
case of detailed dynamic simulations, the component (or subcomponent) properties are used directly
as inputs for the building simulation.
In applications where individual component properties are needed, these documents provide:
— in the case of minimum component requirements, the U-value or R-value of the construction;
— for multi-zone calculations with assumed thermal interaction between the zones, the thermal
transmission properties of the separating construction;
Figure 1 illustrates the linkages between these documents.
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ISO/TR 52019-2:2017(E)
Figure 1 — Linkage between documents
[20] [21]
More information can be found in and .
6 ISO 6946
ISO 6946 provides a calculation method that is valid for most building components (walls and roofs).
It is based on calculating the upper limit of thermal resistance of the component (which would apply if
the heat flow were unidirectional from warm side to cold side) and the lower limit (in which the plane
separating each layer is isothermal). Except for components consisting entirely of homogeneous layers
(for which the upper and lower limits are equal) the true thermal resistance of a component is between
these two limits. ISO 6946 specifies use of the arithmetic mean of the two limits provided that their
ratio does not exceed 1,5.
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ISO/TR 52019-2:2017(E)
7 ISO 10211
ISO 10211 specifies the method for detailed calculation of thermal bridges. It can be applied to a whole
building or part of it, and also to the calculation of linear and point thermal transmittances which are
used in ISO 13789.
8 ISO 13370
8.1 General
ISO 13370 is used for calculation of heat transfer via the ground, taking account of its contribution to
the total thermal resistance in the case of U-value calculations and of its thermal inertia in the case of
time-dependent calculations.
The following sub-clauses provide information in addition to that given in ISO 13370.
[12] [19]
More background information can be found in references – .
8.2 Thermal properties of the ground
ISO 13370 specifies thermal properties for three representative types of ground. Particular values can
be provided in ISO 13370:2017, Annex A.
Annex A provides background information on the properties of the ground.
8.3 The influence of flowing ground water
In most cases it is not necessary to take account of ground water since its flow rate is usually sufficiently
small that it has a negligible effect on heat transfer rates. Further information and a method of allowing
for the effect of ground water when its flow rate is known are given in Annex B.
8.4 Application to dynamic simulation programmes
ISO 13370:2017, Annex F contains a procedure for the application to dynamic simulation programmes.
Annex C provides background information and validation of this procedure.
8.5 Embedded heating or cooling systems
Annex D describes a modification of the methodology in ISO 13370 for floors with an embedded heating
or cooling system.
8.6 Cold stores
Annex E provides a method to calculate the heat gain to a cold store from heating elements in the
ground (included to avoid frost heave).
9 ISO 13786
ISO 13786 defines a method of calculation of the dynamic thermal characteristics of a building
component. Annex G gives background to the matrix method given in ISO 13786.
Annex H provides information on computer programming for complex numbers and Annex I gives the
results of some sample calculations.
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ISO/TR 52019-2:2017(E)
10 ISO 13789
ISO 13789 defines the calculation of the transmission heat transfer coefficient of a building, using the
heat transmission properties of the building elements and thermal bridge used in its construction.
A decision is needed on the system of dimensions to be used – internal, overall internal or external.
Annex J illustrates the three systems and the effect of the systems on the linear thermal transmittance
of junctions between elements. Annex J is relevant also to ISO 10211 and ISO 14683.
For the ventilation heat transfer coefficient the air flow rate through conditioned spaces is needed.
Annex K provides a possible method, with associated data.
11 ISO 14683
ISO 14683 defines the methodology for determination of linear thermal transmittances and provides
default values for when specific information is not available. Annex L provides examples of the influence
of thermal bridges on the transmission heat loss coefficient.
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ISO/TR 52019-2:2017(E)
Annex A
(informative)
ISO 13370: Thermal properties of the ground
For the purposes of this annex, the symbols and subscripts given in ISO 13370 apply.
The thermal properties of the ground depend on several factors, including density, degree of water
saturation, particle size, type of mineral constituting the particles, and whether frozen or unfrozen. As
a result, the thermal properties vary considerably from one location to another, and at different depths
at a given location, and also may vary with time due to changes in moisture content or due to freezing
and thawing.
Values of the properties of the ground used for heat transfer calculations, including measured values,
should be representative of the ground in the vicinity of the building and over the period of time to
which the calculation refers (e.g., the heating season).
Table A.1 indicates the range of thermal conductivity for various types of unfrozen ground, and shows
the representative values specified in ISO 13370.
Table A.1 — Thermal conductivity of ground
Moisture Thermal
Dry density Degree Representative
content conductivity
Ground type ρ of saturation value of λ
u λ
g
3
kg/m % W/(m·K)
kg/kg W/(m·K)
silt 1 400 to 1 800 0,10 to 0,30 70 to 100 1,0 to 2,0 1,5
clay 1 200 to 1 600 0,20 to 0,40 80 to 100 0,9 to 1,4 1,5
peat 400 to 1 100 0,05 to 2,00 0 to 100 0,2 to 0,5 —
dry sand 1 700 to 2 000 0,04 to 0,12 20 to 60 1,1 to 2,2 2,0
wet sand 1 700 to 2 100 0,10 to 0,18 85 to 100 1,5 to 2,7 2,0
a a
rock 2 000 to 3 000 2,5 to 4,5 3,5
a
Usually very small (moisture content < 0,03 mass), except for porous rocks.
The heat capacity per volume, ρ · c, can be obtained from Formula (A.1).
ρρ⋅=cc⋅+cu⋅ (A.1)
()
sw
where
c is the specific heat capacity of the ground, in J/(kg·K);
3
ρ is the dry density, in kg/m ;
c is the specific heat capacity of minerals, in J/(kg·K);
s
c is the specific heat capacity of water, in J/(kg·K);
w
u is the moisture content mass by mass referred to the dry state, in kg/kg.
For most minerals, c approximately 1 000 J/(kg·K), and c = 4 180 J/(kg·K) at 10 °C.
s w
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ISO/TR 52019-2:2017(E)
The representative values of ρ · c specified in ISO 13370 are obtained from Formula (A.1), as follows
(rounding to one significant figure):
6 6
— clay/silt: ρ · c = 1 600 × (1 000 + 4 180 × 0,20) = 2,94 × 10 → 3 × 10
6 6
— sand: ρ · c = 1 800 × (1 000 + 4 180 × 0,05) = 2,18 × 10 → 2 × 10
6 6
— rock: ρ · c = 2 500 × 800 = 2,00 × 10 → 2 × 10
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ISO/TR 52019-2:2017(E)
Annex B
(informative)
ISO 13370: The influence of flowing ground water
For the purposes of this annex, the symbols and subscripts given in ISO 13370 apply.
The effect of flowing ground water can be assessed by multiplying the steady-state heat flow rate by a
factor, G . To determine the factor, knowledge is required of the depth of the water table and the rate
w
of ground water flow. For slab-on-ground floors and basements, G multiplies the steady-state ground
w
heat transfer coefficient, H . For suspended floors, G multiplies the ground thermal transmittance, U .
g w g
The factor should not be applied to the periodic heat transfer coefficients, H and H .
pi pe
z l d
w c f
Values of G are given in Table B.1 as a function of the dimensionless ratios , and , where
w
B B B
z is the depth of the water table below ground level, in m;
w
l is a calculation length which relates the heat flow by conduction to the heat flow due to
c
ground water, in m;
B Is the characteristic dimension of floor, in m;
d Is the total equivalent thickness of the slab on ground floor, in m.
f
The length l is given by Formula (B.1).
c
λ
l = (B.1)
c
ρ cq
ww w
where
q is the mean drift velocity of the ground water, in m/s;
w
ρ is the density of water, in kg/m ;
w 3
c is the specific heat capacity of water, in J/(kg·K).
w
NOTE 1 ρ · c = 4,18 × 10 , in J/(m ·K) at 10 °C.
w w 6 3
NOTE 2 If l >> B, the conduction heat flow predominates. If l << B, the ground water heat flow predominates.
c c
Table B.1 — Values of G
w
G
w
z /B l /B
w c
d /B = 0,1 d /B = 0,5 d /B = 1,0
f f f
0,0 1,0 1,01 1,01 1,00
0,0 0,2 1,16 1,11 1,07
0,0 0,1 1,33 1,20 1,13
0,0 0,0 — 1,74 1,39
0,5 1,0 1,00 1,00 1,00
0,5 0,1 1,06 1,04 1,02
0,5 0,02 1,11 1,07 1,05
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ISO/TR 52019-2:2017(E)
Table B.1 (continued)
G
w
z /B l /B
w c
d /B = 0,1 d /B = 0,5 d /B = 1,0
f f f
0,5 0,0 1,20 1,12 1,08
1,0 0,1 1,05 1,03 1,02
2,0 0,0 1,02 1,01 1,00
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ISO/TR 52019-2:2017(E)
Annex C
(informative)
ISO 13370: Application to dynamic simulation programmes
C.1 General
For the purposes of this annex, the symbols and subscripts given in ISO 13370 apply.
ISO 13370:2017, Annex F provides a method of treating heat transfers via the ground in connection with
transient methods for the calculation of heat flows or temperatures in buildings, using a time interval
of one hour or less.
The method involves modelling the floor construction together with the ground as a single component,
consisting of each layer in the floor construction plus 0,5 m depth of ground plus a virtual layer.
The virtual layer has a thermal resistance R and has negligible thermal capacity. R is calculated from
vi vi
Formula (C.1).
1
R = −−RR −R (C.1)
vi si fg
U
The boundary condition at the bottom of the virtual layer is a virtual temperature, θ , which is
vi
calculated for each time interval being applied in the numerical model using Formula (C.2).
Φ
t
θθ= − (C.2)
vi,ittnt,
AU
where Φ is calculated at time t, using the numerical model.
t
Using this method, the virtual layer represents the ground in the n
...
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