SIST EN ISO 11855-4:2021/A1:2023
(Amendment)Building environment design - Embedded radiant heating and cooling systems - Part 4: Dimensioning and calculation of the dynamic heating and cooling capacity of Thermo Active Building Systems (TABS) - Amendment 1 (ISO 11855-4:2021/Amd 1:2023)
Building environment design - Embedded radiant heating and cooling systems - Part 4: Dimensioning and calculation of the dynamic heating and cooling capacity of Thermo Active Building Systems (TABS) - Amendment 1 (ISO 11855-4:2021/Amd 1:2023)
Umweltgerechte Gebäudeplanung - Flächenintegrierte Strahlungsheiz- und -kühlsysteme - Teil 4: Auslegung und Berechnung der dynamischen Heiz- und Kühlleistung für thermoaktive Bauteilsysteme (TABS) - Änderung 1 (ISO 11855-4:2021/Amd 1:2023)
Dieses Dokument ermöglicht die Berechnung der Spitzenkühlleistung thermoaktiver Bauteil-systeme (TABS) – Typ V nach ISO 11855 1 auf der Grundlage von Wärmeeinträgen, wie solaren Wärmeinträgen, internen Wärmeeinträgen und Lüftung, sowie in Hinblick auf Kühlergröße, Flüssigkeitsstrom usw. die Berechnung des wasserseitigen Bedarfs an Kühlleistung, die für das System vorgesehen ist.
Conception de l'environnement des bâtiments - Systèmes intégrés de chauffage et de refroidissement par rayonnement - Partie 4: Dimensionnement et calculs relatifs au chauffage adiabatique et à la puissance frigorifique pour systèmes d'éléments de construction thermoactifs (TABS) - Amendement 1 (ISO 11855-4:2021/Amd 1:2023)
Načrtovanje notranjega okolja v stavbah - Vgrajeni sevalni ogrevalni in hladilni sistemi - 4. del: Dimenzioniranje in izračun zmogljivosti dinamičnega ogrevanja in hlajenja toplotnoaktivnih delov stavbe (TABS) - Dopolnilo A1 (ISO 11855-4:2021/Amd 1:2023)
General Information
Relations
Overview
EN ISO 11855-4:2021/A1:2023 is Amendment 1 to ISO 11855‑4 (published as a CEN/ISO European Standard). It focuses on the dimensioning and calculation of the dynamic heating and cooling capacity of Thermo Active Building Systems (TABS) - Type V. The amendment updates the introduction, key clauses and figures, and clarifies methods for calculating peak cooling capacity and the water‑side cooling power required to size cooling plant and fluid circuits.
Key keywords: EN ISO 11855-4:2021/A1:2023, Thermo Active Building Systems, TABS, embedded radiant heating and cooling systems, dynamic heating and cooling capacity, dimensioning, peak cooling capacity.
Key topics and technical requirements
- Scope for Type V TABS: Methods to calculate peak cooling capacity based on heat gains (solar, internal, ventilation) and to determine cooling power demand on the water side for equipment sizing (e.g., chiller capacity, flow rate).
- Dynamic calculation approach: Emphasis on time‑dependent (dynamic) performance rather than only steady‑state results, enabling peak‑shaving and system interaction assessment.
- Equivalent resistances for simulation: Clause 8 was revised to provide methods for deriving equivalent thermal resistances between the pipe level (heat conduction layer) and upward/downward surfaces to support dynamic building simulations.
- Calculation clarification: For certain system types, equivalent inward and outward resistances are calculated directly; for others they are derived from inward/outward specific heat flux and total surface heat transfer coefficient (convection + radiation).
- Included formula: The amendment retains the equivalent resistance relationship in the form: R = Δθ / q_t − 1 / h where Δθ is the medium temperature difference, q_t the specific heat flux, and h the total heat transfer coefficient (convection + radiation).
- Updated figures and diagrams: Figures showing pipe positions, simple TABS schematics, peak‑shaving examples and temperature/PMV profiles were revised for clarity.
Practical applications and target users
- Who uses this standard
- HVAC and MEP engineers designing slab‑integrated radiant systems (TABS)
- Building energy modelers and simulation specialists
- System integrators sizing chillers, pumps and control loops
- Architects and consultants specifying low‑energy building services
- Manufacturers of radiant piping and hydronic equipment
- Where it applies
- Sizing of TABS for commercial, institutional and residential buildings
- Dynamic simulation workflows for energy‑efficient designs and peak load reduction
- Determining water‑side cooling requirements and chiller selection
- Integrating renewable low‑temperature heat/cold sources with building mass
Related standards
- ISO 11855‑1 (comfort criteria, system types)
- ISO 11855‑2, ‑3, ‑5, ‑6, ‑7 (steady‑state methods, design/dimensioning, installation, control, input parameters for ISO 52031)
This amendment ensures clearer, harmonized calculation and simulation inputs for designers implementing energy‑efficient TABS solutions.
Standards Content (Sample)
SLOVENSKI STANDARD
01-december-2023
Načrtovanje notranjega okolja v stavbah - Vgrajeni sevalni ogrevalni in hladilni
sistemi - 4. del: Dimenzioniranje in izračun zmogljivosti dinamičnega ogrevanja in
hlajenja toplotnoaktivnih delov stavbe (TABS) - Dopolnilo A1 (ISO 11855-
4:2021/Amd 1:2023)
Building environment design - Embedded radiant heating and cooling systems - Part 4:
Dimensioning and calculation of the dynamic heating and cooling capacity of Thermo
Active Building Systems (TABS) - Amendment 1 (ISO 11855-4:2021/Amd 1:2023)
Umweltgerechte Gebäudeplanung - Flächenintegrierte Strahlungsheiz- und -
kühlsysteme - Teil 4: Auslegung und Berechnung der dynamischen Heiz- und
Kühlleistung für thermoaktive Bauteilsysteme (TABS) - Änderung 1 (ISO 11855-
4:2021/Amd 1:2023)
Conception de l'environnement des bâtiments - Systèmes intégrés de chauffage et de
refroidissement par rayonnement - Partie 4: Dimensionnement et calculs relatifs au
chauffage adiabatique et à la puissance frigorifique pour systèmes d'éléments de
construction thermoactifs (TABS) - Amendement 1 (ISO 11855-4:2021/Amd 1:2023)
Ta slovenski standard je istoveten z: EN ISO 11855-4:2021/A1:2023
ICS:
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
91.140.30 Prezračevalni in klimatski Ventilation and air-
sistemi conditioning systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 11855-4:2021/A1
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2023
EUROPÄISCHE NORM
ICS 91.040.01
English Version
Building environment design - Embedded radiant heating
and cooling systems - Part 4: Dimensioning and calculation
of the dynamic heating and cooling capacity of Thermo
Active Building Systems (TABS) - Amendment 1 (ISO
11855-4:2021/Amd 1:2023)
Conception de l'environnement des bâtiments - Umweltgerechte Gebäudeplanung - Flächenintegrierte
Systèmes intégrés de chauffage et de refroidissement Strahlungsheiz- und -kühlsysteme - Teil 4: Auslegung
par rayonnement - Partie 4: Dimensionnement et und Berechnung der dynamischen Heiz- und
calculs relatifs au chauffage adiabatique et à la Kühlleistung für thermoaktive Bauteilsysteme (TABS) -
puissance frigorifique pour systèmes d'éléments de Änderung 1 (ISO 11855-4:2021/Amd 1:2023)
construction thermoactifs (TABS) - Amendement 1
(ISO 11855-4:2021/Amd 1:2023)
This amendment A1 modifies the European Standard EN ISO 11855-4:2021; it was approved by CEN on 14 May 2023.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for inclusion of
this amendment into the relevant national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This amendment 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 CEN-CENELEC Management Centre has the
same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11855-4:2021/A1:2023 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO 11855-4:2021/A1:2023) has been prepared by Technical Committee ISO/TC
205 "Building environment design" in collaboration with Technical Committee CEN/TC 228 “Heating
systems and water based cooling systems in buildings” the secretariat of which is held by DIN.
This Amendment to the European Standard EN ISO 11855-4:2021 shall be given the status of a national
standard, either by publication of an identical text or by endorsement, at the latest by April 2024, and
conflicting national standards shall be withdrawn at the latest by April 2024.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 11855-4:2021/Amd 1:2023 has been approved by CEN as EN ISO 11855-
4:2021/A1:2023 without any modification.
INTERNATIONAL ISO
STANDARD 11855-4
Second edition
2021-08
AMENDMENT 1
2023-10
Building environment design —
Embedded radiant heating and cooling
systems —
Part 4:
Dimensioning and calculation of the
dynamic heating and cooling capacity
of Thermo Active Building Systems
(TABS)
AMENDMENT 1
Conception de l'environnement des bâtiments — Systèmes intégrés de
chauffage et de refroidissement par rayonnement —
Partie 4: Dimensionnement et calculs relatifs au chauffage
adiabatique et à la puissance frigorifique pour systèmes d'éléments de
construction thermoactifs (TABS)
AMENDEMENT 1
Reference number
ISO 11855-4:2021/Amd.1:2023(E)
ISO 11855-4:2021/Amd.1:2023(E)
© ISO 2023
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 copyrig
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Frequently Asked Questions
SIST EN ISO 11855-4:2021/A1:2023 is a amendment published by the Slovenian Institute for Standardization (SIST). Its full title is "Building environment design - Embedded radiant heating and cooling systems - Part 4: Dimensioning and calculation of the dynamic heating and cooling capacity of Thermo Active Building Systems (TABS) - Amendment 1 (ISO 11855-4:2021/Amd 1:2023)". This standard covers: Dieses Dokument ermöglicht die Berechnung der Spitzenkühlleistung thermoaktiver Bauteil-systeme (TABS) – Typ V nach ISO 11855 1 auf der Grundlage von Wärmeeinträgen, wie solaren Wärmeinträgen, internen Wärmeeinträgen und Lüftung, sowie in Hinblick auf Kühlergröße, Flüssigkeitsstrom usw. die Berechnung des wasserseitigen Bedarfs an Kühlleistung, die für das System vorgesehen ist.
Dieses Dokument ermöglicht die Berechnung der Spitzenkühlleistung thermoaktiver Bauteil-systeme (TABS) – Typ V nach ISO 11855 1 auf der Grundlage von Wärmeeinträgen, wie solaren Wärmeinträgen, internen Wärmeeinträgen und Lüftung, sowie in Hinblick auf Kühlergröße, Flüssigkeitsstrom usw. die Berechnung des wasserseitigen Bedarfs an Kühlleistung, die für das System vorgesehen ist.
SIST EN ISO 11855-4:2021/A1:2023 is classified under the following ICS (International Classification for Standards) categories: 91.140.10 - Central heating systems; 91.140.30 - Ventilation and air-conditioning systems. The ICS classification helps identify the subject area and facilitates finding related standards.
SIST EN ISO 11855-4:2021/A1:2023 has the following relationships with other standards: It is inter standard links to SIST EN ISO 11855-4:2021. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
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