SIST EN ISO 15927-5:2005

Hygrothermal performance of buildings - Calculation and presentation of climatic data - Part 5: Data for design heat load for space heating (ISO 15927-5:2004)

ISO 15927-5:2004 specifies the definition, method of calculation and method of presentation of the climatic data to be used in determining the design heat load for space heating in buildings. These include the winter external design air temperatures and the relevant wind speed and direction, where appropriate.
Heat loss through the ground, which also contributes to the heat load for buildings, depends on longer-term temperature changes; methods for calculating ground heat loss are given in ISO 13370.

Wärme- und feuchteschutztechnisches Verhalten von Gebäuden - Berechnung und Darstellung von Klimadaten - Teil 5: Daten zur Bestimmung der Norm-Heizlast für die Raumheizung (ISO 15927-5:2004)

Performance hygrothermique des bâtiments - Calcul et présentation des données climatiques - Partie 5: Données pour la charge calorifique de conception pour le chauffage des locaux (ISO 15927-5:2004)

L'ISO 15927-5:2004 spécifie la définition ainsi que les méthodes de calcul et de présentation des données climatiques nécessaires à la détermination de la charge thermique nominale pour le chauffage des locaux dans les bâtiments. Ces données comprennent la température extérieure hivernale de dimensionnement thermique et la vitesse et la direction appropriées du vent, selon le cas.
La perte calorifique par le sol qui contribue également à la charge thermique des bâtiments dépend des changements de température à plus long terme. Les méthodes de calcul de la perte calorifique par le sol sont données dans l'ISO 13370.

Higrotermalne značilnosti stavb - Izračun in predstavitev podnebnih podatkov - 5. del: Podatki za določitev računske potrebne toplote za ogrevanje prostorov (ISO 15927-5:2004)

Ta standard določa definicijo, metodo za izračun in metodo za predstavitev zimskih zunanjih projektnih temperatur, ki se uporabljajo za določanje največjih toplotnih zahtev za ogrevanje v stavbah. To je povezano z merjenjem hitrosti vetra na lokacijah, kjer veter spremljajo nizke temperature.

General Information

• Status: Published
• Publication Date: 31-Jan-2005
• ICS: 91.120.10 - Thermal insulation of buildings
• ICS: 91.120.30 - Waterproofing
• Technical Committee: TOP - Thermal insulation
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Feb-2005
• Due Date: 01-Feb-2005
• Completion Date: 01-Feb-2005
• Directive: 305/2011 - Regulation (eu) No 305/2011 of the European Parliament and of the Council of 9 march 2011 laying down harmonised conditions for the marketing of construction products and repealing council directive 89/106/eec
• Directive: 89/106/EEC - Construction products
• Directive: TRRTP129 - Tehnična smernica TSG-12640-001:2008 Zdravstveni objekti
• Ref Project: EN ISO 15927-5:2004 - Hygrothermal performance of buildings - Calculation and presentation of climatic data - Part 5: Data for design heat load for space heating (ISO 15927-5:2004)

Relations

• Amended By: SIST EN ISO 15927-5:2005/A1:2012 - Hygrothermal performance of buildings - Calculation and presentation of climatic data - Part 5: Data for design heat load for space heating - Amendment 1 (ISO 15927-5:2004/A1:2011)
• Effective Date: 01-Mar-2011
• Parent: SIST EN ISO 15927-1:2004 - Hygrothermal performance of buildings - Calculation and presentation of climatic data - Part 1: Monthly means of single meteorological elements (ISO 15927-1:2003)
• Effective Date: 22-Dec-2008

Overview

EN ISO 15927-5:2004 - "Hygrothermal performance of buildings - Calculation and presentation of climatic data - Part 5: Data for design heat load for space heating" specifies how to define, calculate and present climatic input data used to determine the design heat load for space heating. It defines winter external design temperatures, coincident wind speed and dominant wind direction for the conditions that control peak heating demand. The standard also sets data-quality expectations (e.g., use of WMO-observed measurements and long-term records) and shows how to present results for individual locations or areas.

Key topics and technical requirements

• Design temperature types
  • n‑day mean design temperature (n = 1, 2, 3 or 4 days) calculated with an average return period of 1 year.
  • Hourly mean design temperature defined as the hourly temperature exceeded on average in 99% of hours during the coldest month.
• Calculation methods
  • Priority of input data: hourly → three‑hourly → specified daily observations → daily max/min (least accurate).
  • Procedures for averaging across n consecutive days and for interpolating from coarser time resolution.
• Wind considerations
  • Coincident wind speed: average wind speed over the period used to define the design temperature.
  • Dominant wind direction: range of directions relevant to the design condition.
• Data quality and period
  • Preferably use continuous measurement records of at least 20 years; document the period used.
  • Measurements should follow WMO Guide No. 8 methods.
• Presentation and geographical representation
  • Prescribed formats for presenting data for a specific site, region or zone and for indicating reference altitude.
• Notes
  • Ground heat loss depends on longer-term temperatures; ISO 13370 gives methods for ground heat transfer.

Practical applications and users

Who uses EN ISO 15927-5:

• HVAC and heating system designers for sizing boilers, heat pumps and distribution systems
• Building services engineers and energy modelers providing peak-load inputs
• Architects assessing thermal performance and heating strategy
• National/regional standards bodies and consultants producing climate design datasets
• Researchers and meteorologists preparing design-weather files

Practical uses:

• Determining peak heating capacity (design heat load) for residential, commercial and institutional buildings
• Creating site-specific or regional climate input data for dynamic thermal simulation and compliance reporting
• Combining temperature and wind data to estimate infiltration-related heat loss during design conditions

Related standards

• ISO 6243 - Climatic data symbols and terminology
• ISO 13370 - Heat transfer via the ground (ground heat loss methods)
• WMO Guide No. 8 - Guide to meteorological instruments and observation methods
• Other parts of ISO 15927 (e.g., Part 1: monthly means; other parts under development)

Keywords: EN ISO 15927-5:2004, design heat load, winter external design temperature, coincident wind speed, climatic data, space heating, building heat loss, ISO 13370.

Standards Content (Sample)

SLOVENSKI STANDARD
01-februar-2005
+LJURWHUPLþQH]QDþLOQRVWLVWDYE±,]UDþXQLQSUHGVWDYLWHYNOLPDWVNLKSRGDWNRY±
GHO3RGDWNL]DGRORþLWHYUDþXQVNHSRWUHEQHWRSORWH]DRJUHYDQMHSURVWRURY,62

Hygrothermal performance of buildings - Calculation and presentation of climatic data -
Part 5: Data for design heat load for space heating (ISO 15927-5:2004)
Wärme- und feuchteschutztechnisches Verhalten von Gebäuden - Berechnung und
Darstellung von Klimadaten - Teil 5: Daten zur Bestimmung der Norm-Heizlast für die
Raumheizung (ISO 15927-5:2004)
Performance hygrothermique des bâtiments - Calcul et présentation des données
climatiques - Partie 5: Données pour la charge calorifique de conception pour le
chauffage des locaux (ISO 15927-5:2004)
Ta slovenski standard je istoveten z: EN ISO 15927-5:2004
ICS:
91.120.10 Toplotna izolacija stavb Thermal insulation
91.120.30 =DãþLWDSUHGYODJR Waterproofing
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 15927-5
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2004
ICS 07.060; 91.120.10
English version
Hygrothermal performance of buildings - Calculation and
presentation of climatic data - Part 5: Data for design heat load
for space heating (ISO 15927-5:2004)
Performance hygrothermique des bâtiments - Calcul et Wärme- und feuchteschutztechnisches Verhalten von
présentation des données climatiques - Partie 5: Données Gebäuden - Berechnung und Darstellung von Klimadaten -
pour la charge calorifique de conception pour le chauffage Teil 5: Bemessungstemperaturen der Außenluft im Winter
des locaux (ISO 15927-5:2004) und zugehörige Winddaten (ISO 15927-5:2004)
This European Standard was approved by CEN on 27 October 2004.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Central Secretariat or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2004 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 15927-5:2004: E
worldwide for CEN national Members.

Foreword
This document (EN ISO 15927-5:2004) has been prepared by Technical Committee ISO/TC 163
"Thermal insulation" in collaboration with Technical Committee CEN/TC 89 “Thermal
performance of buildings and building components”, the secretariat of which is held by SIS.

This European Standard shall be given the status of a national standard, either by publication of
an identical text or by endorsement, at the latest by May 2005, and conflicting national standards
shall be withdrawn at the latest by May 2005.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

Endorsement notice
The text of ISO 15927-5:2004 has been approved by CEN as EN ISO 15927-5:2004 without any
modifications.
INTERNATIONAL ISO
STANDARD 15927-5
First edition
2004-11-15
Hygrothermal performance of
buildings — Calculation and presentation
of climatic data —
Part 5:
Data for design heat load for space
heating
Performance hygrothermique des bâtiments — Calcul et présentation
des données climatiques —
Partie 5: Données pour la charge calorifique de conception pour le
chauffage des locaux
Reference number
ISO 15927-5:2004(E)
©
ISO 2004
ISO 15927-5:2004(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 2004
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 [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2004 – All rights reserved

ISO 15927-5:2004(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references . 1
3 Terms, definitions, symbols and units . 1
4 Methods of calculation . 2
5 Coincident wind speed. 4
6 Dominant wind direction . 4
7 Reference altitude. 4
8 Presentation of data. 5
9 Data representing a geographical area, region or zone. 6

ISO 15927-5:2004(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.
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 15927 was prepared by the European Committee for Standardization (CEN) in collaboration with
Technical Committee ISO/TC 163, Thermal performance and energy use in the built environment,
Subcommittee SC 2, Calculation methods, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
ISO 15927 consists of the following parts, under the general title Hygrothermal performance of buildings —
Calculation and presentation of climatic data:
 Part 1: Monthly means of single meteorological elements
 Part 5: Data for design heat load for space heating
The following parts are under preparation:
 Part 4: Data for assessing the annual energy for cooling and heating systems
 Part 6: Accumulated temperature differences (degree days)

iv © ISO 2004 – All rights reserved

ISO 15927-5:2004(E)
Introduction
The choice of design heat load for space heating is a matter of balancing user needs against cost. On the one
hand, users expect a heating system to maintain the internal temperatures needed for health and comfort; on
the other hand, very high heating demand arises from time to time, when a meteorological extreme occurs. It
may be uneconomic to design heating systems for rare extremes, as this can lead to high capital (initial) cost
and to lower operational efficiency of the system.
The practical solution is to choose an infrequent, but not extreme, climatological value as the basis for the
design load. This means that from time to time heat demand will exceed the system capacity, with the result
that internal temperatures will be lower than desired, or that supplementary heating will be needed (e.g. from
local heaters). The methods of calculation in this part of ISO 15927 include a standard return period or
frequency, which is judged to give an acceptable balance between risk of inadequate performance and cost.
The definition of winter external design temperatures also needs to reflect the interaction between buildings
and their external environment. Buildings possess thermal inertia and do not respond instantly to changes in
weather conditions. The time delay (or lag) before internal conditions are significantly affected varies among
different types of construction and heating methods. To allow for this, winter external design temperatures,
calculated according to this part of ISO 15927, can be defined over a range of periods from as short as 1 h to
as long as 4 days.
The influence of wind is important, as infiltration can cause a large proportion of heat loss from buildings that
are not airtight; this is especially true in climates where infrequent, low temperatures are associated with high
wind speeds. This part of ISO 15927 specifies that average coincident wind speed and range of directions are
determined for the conditions of the winter external design temperature.

INTERNATIONAL STANDARD ISO 15927-5:2004(E)

Hygrothermal performance of buildings — Calculation and
presentation of climatic data —
Part 5:
Data for design heat load for space heating
1 Scope
This part of ISO 15927 specifies the definition, method of calculation and method of presentation of the
climatic data to be used in determining the design
...

SLOVENSKI STANDARD
01-februar-2005
Higrotermalne značilnosti stavb - Izračun in predstavitev podnebnih podatkov - 5.
del: Podatki za določitev računske potrebne toplote za ogrevanje prostorov (ISO
15927-5:2004)
Hygrothermal performance of buildings - Calculation and presentation of climatic data -
Part 5: Data for design heat load for space heating (ISO 15927-5:2004)
Wärme- und feuchteschutztechnisches Verhalten von Gebäuden - Berechnung und
Darstellung von Klimadaten - Teil 5: Daten zur Bestimmung der Norm-Heizlast für die
Raumheizung (ISO 15927-5:2004)
Performance hygrothermique des bâtiments - Calcul et présentation des données
climatiques - Partie 5: Données pour la charge calorifique de conception pour le
chauffage des locaux (ISO 15927-5:2004)
Ta slovenski standard je istoveten z: EN ISO 15927-5:2004
ICS:
91.120.10 Toplotna izolacija stavb Thermal insulation of
buildings
91.120.30 Zaščita pred vlago Waterproofing
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 15927-5
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2004
ICS 07.060; 91.120.10
English version
Hygrothermal performance of buildings - Calculation and
presentation of climatic data - Part 5: Data for design heat load
for space heating (ISO 15927-5:2004)
Performance hygrothermique des bâtiments - Calcul et Wärme- und feuchteschutztechnisches Verhalten von
présentation des données climatiques - Partie 5: Données Gebäuden - Berechnung und Darstellung von Klimadaten -
pour la charge calorifique de conception pour le chauffage Teil 5: Bemessungstemperaturen der Außenluft im Winter
des locaux (ISO 15927-5:2004) und zugehörige Winddaten (ISO 15927-5:2004)
This European Standard was approved by CEN on 27 October 2004.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Central Secretariat or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2004 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 15927-5:2004: E
worldwide for CEN national Members.

Foreword
This document (EN ISO 15927-5:2004) has been prepared by Technical Committee ISO/TC 163
"Thermal insulation" in collaboration with Technical Committee CEN/TC 89 “Thermal
performance of buildings and building components”, the secretariat of which is held by SIS.

This European Standard shall be given the status of a national standard, either by publication of
an identical text or by endorsement, at the latest by May 2005, and conflicting national standards
shall be withdrawn at the latest by May 2005.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

Endorsement notice
The text of ISO 15927-5:2004 has been approved by CEN as EN ISO 15927-5:2004 without any
modifications.
INTERNATIONAL ISO
STANDARD 15927-5
First edition
2004-11-15
Hygrothermal performance of
buildings — Calculation and presentation
of climatic data —
Part 5:
Data for design heat load for space
heating
Performance hygrothermique des bâtiments — Calcul et présentation
des données climatiques —
Partie 5: Données pour la charge calorifique de conception pour le
chauffage des locaux
Reference number
ISO 15927-5:2004(E)
©
ISO 2004
ISO 15927-5:2004(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 2004
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 [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2004 – All rights reserved

ISO 15927-5:2004(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references . 1
3 Terms, definitions, symbols and units . 1
4 Methods of calculation . 2
5 Coincident wind speed. 4
6 Dominant wind direction . 4
7 Reference altitude. 4
8 Presentation of data. 5
9 Data representing a geographical area, region or zone. 6

ISO 15927-5:2004(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.
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 15927 was prepared by the European Committee for Standardization (CEN) in collaboration with
Technical Committee ISO/TC 163, Thermal performance and energy use in the built environment,
Subcommittee SC 2, Calculation methods, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
ISO 15927 consists of the following parts, under the general title Hygrothermal performance of buildings —
Calculation and presentation of climatic data:
 Part 1: Monthly means of single meteorological elements
 Part 5: Data for design heat load for space heating
The following parts are under preparation:
 Part 4: Data for assessing the annual energy for cooling and heating systems
 Part 6: Accumulated temperature differences (degree days)

iv © ISO 2004 – All rights reserved

ISO 15927-5:2004(E)
Introduction
The choice of design heat load for space heating is a matter of balancing user needs against cost. On the one
hand, users expect a heating system to maintain the internal temperatures needed for health and comfort; on
the other hand, very high heating demand arises from time to time, when a meteorological extreme occurs. It
may be uneconomic to design heating systems for rare extremes, as this can lead to high capital (initial) cost
and to lower operational efficiency of the system.
The practical solution is to choose an infrequent, but not extreme, climatological value as the basis for the
design load. This means that from time to time heat demand will exceed the system capacity, with the result
that internal temperatures will be lower than desired, or that supplementary heating will be needed (e.g. from
local heaters). The methods of calculation in this part of ISO 15927 include a standard return period or
frequency, which is judged to give an acceptable balance between risk of inadequate performance and cost.
The definition of winter external design temperatures also needs to reflect the interaction between buildings
and their external environment. Buildings possess thermal inertia and do not respond instantly to changes in
weather conditions. The time delay (or lag) before internal conditions are significantly affected varies among
different types of construction and heating methods. To allow for this, winter external design temperatures,
calculated according to this part of ISO 15927, can be defined over a range of periods from as short as 1 h to
as long as 4 days.
The influence of wind is important, as infiltration can cause a large proportion of heat loss from buildings that
are not airtight; this is especially true in climates where infrequent, low temperatures are associated with high
wind speeds. This part of ISO 15927 specifies that average coincident wind speed and range of directions are
determined for the conditions of the winter external design temperature.

INTERNATIONAL STANDARD ISO 15927-5:2004(E)

Hygrothermal performance of buildings — Calculation and
presentation of climatic data —
Part 5:
Data for design heat load for space heating
1 Scope
This part of ISO 15927 specifies the definition, method of calculation and method of presentation of the
climatic data to be used in determining the des
...