EN 772-22:2018
(Main)Methods of test for masonry units - Part 22: Determination of freeze/thaw resistance of clay masonry units
Methods of test for masonry units - Part 22: Determination of freeze/thaw resistance of clay masonry units
This document specifies a method for determining the freeze/thaw resistance of clay masonry units in one of two categories F1 or F2.
Prüfverfahren für Mauersteine - Teil 22: Bestimmung des Frost-Tau-Widerstandes von Mauerziegeln
Dieses Dokument legt ein Verfahren zur Bestimmung des Frost-Tau-Widerstands von Mauerziegeln in den Kategorien F1 oder F2 fest.
Méthodes d'essai des éléments de maçonnerie - Partie 22: Détermination de la résistance au gel/dégel des éléments de maçonnerie en terre cuite
Le présent document spécifie une méthode permettant de déterminer la résistance au gel/dégel des éléments de maçonnerie en terre cuite dans l’une des deux catégories F1 ou F2.
Metode preskušanja zidakov - 22. del: Ugotavljanje odpornosti proti zmrzovanju/tajanju opečnih zidakov
Ta dokument določa metodo za ugotavljanje odpornosti proti zmrzovanju/tajanju opečnih zidakov v eni od kategorij F1 ali F2.
General Information
Relations
Overview
EN 772-22:2018 - Methods of test for masonry units, Part 22 specifies a laboratory method to determine the freeze/thaw resistance of clay masonry units. The procedure classifies units into two performance categories (F1 or F2) by assembling a test panel, partially saturating it, subjecting one face to repeated freeze–thaw cycles and assessing damage. The standard is intended for manufacturers, test laboratories and quality/approval bodies concerned with the frost durability of clay bricks and terracotta building products.
Key topics and technical requirements
- Scope & classification: Defines classification into F1 or F2 based on assessed damage after testing (criteria and percentage limits are specified in the standard).
- Specimen preparation: Sampling per EN 771-1; panels sized between 0.25 m² and 0.5 m², panel height limited to 0.75 m; units may be characterized for water absorption per EN 772-21.
- Mortar and jointing: Use of rapid-setting high-alumina cement mortar; joints finished flush. Guidance on mortar mix and optional use of neoprene joints for production-control testing is included.
- Partial saturation methods: Two options:
- Cold water immersion: full immersion at room temperature for 7 days ± 8 h.
- Hot-water procedure (80 °C): controlled heating to (80 ± 3) °C, maintained and then cooled to achieve a total immersion time between ~44 and 56 hours (detailed timing specified).
- Freeze/thaw cycling: Panels are insulated on all faces except the exposed face, preconditioned by a flood spray, then subjected to up to 100 freeze/thaw cycles. Freezing and thawing periods (including the first extended freeze) and heat-transfer/temperature distribution requirements are defined.
- Apparatus: A unidirectional freeze–thaw machine with controlled air circulation, a heat flow meter for calibration/heat extraction measurements, and calibrated spray-water delivery (Annexes A–C describe meter and calibration).
- Evaluation: Damage assessment categories and the pass/fail/classification rules are set out; test report content is prescribed.
Practical applications & users
- Brick and terracotta manufacturers: product development, factory production control, and compliance verification.
- Independent testing laboratories: standardized procedure for generating reproducible freeze–thaw data.
- Specifiers, architects and engineers: selecting masonry units suitable for cold-climate exposure.
- Certification bodies and regulators: demonstrating conformity with European masonry durability requirements.
Related standards
- EN 771-1 - Specification for clay masonry units
- EN 772-21 - Water absorption test for clay masonry units
- EN 197-1 - Cement specifications (high-alumina cement referenced)
- EN 13139 - Aggregates for mortar
Keywords: EN 772-22:2018, freeze/thaw resistance, clay masonry units, masonry testing standards, freeze–thaw cycles, test panel construction, heat flow meter.
Standards Content (Sample)
SLOVENSKI STANDARD
01-februar-2019
1DGRPHãþD
SIST-TS CEN/TS 772-22:2006
0HWRGHSUHVNXãDQMD]LGDNRYGHO 8JRWDYOMDQMHRGSRUQRVWLSURWL
]PU]RYDQMXWDMDQMXRSHþQLK]LGDNRY
Methods of test for masonry units - Part 22: Determination of freeze/thaw resistance of
clay masonry units
Prüfverfahren für Mauersteine - Teil 22: Bestimmung des Frost-Tau-Widerstandes von
Mauerziegeln
Méthodes d'essai des éléments de maçonnerie - Partie 22: Détermination de la
résistance au gel/dégel des éléments de maçonnerie en terre cuite
Ta slovenski standard je istoveten z: EN 772-22:2018
ICS:
91.100.25 Gradbeni izdelki iz terakote Terracotta building products
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN 772-22
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2018
EUROPÄISCHE NORM
ICS 91.100.25 Supersedes CEN/TS 772-22:2006
English Version
Methods of test for masonry units - Part 22: Determination
of freeze/thaw resistance of clay masonry units
Méthodes d'essai des éléments de maçonnerie - Partie Prüfverfahren für Mauersteine - Teil 22: Bestimmung
22: Détermination de la résistance au gel/dégel des des Frost-Tau-Widerstandes von Mauerziegeln
éléments de maçonnerie en terre cuite
This European Standard was approved by CEN on 26 October 2018.
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 CEN-CENELEC Management Centre 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 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey 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
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 772-22:2018 E
worldwide for CEN national Members.
Contents Page
European Foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Principle . 4
5 Apparatus . 4
6 Materials . 5
7 Preparation of specimens . 5
7.1 Sampling . 5
7.2 Water absorption . 5
7.3 Conditioning and preparation of specimens . 5
8 Construction of a test panel . 6
8.1 General . 6
8.2 Conditioning of a test panel . 8
8.2.1 General . 8
8.2.2 Partial saturation by cold water immersion . 8
8.2.3 Partial saturation by immersion in water at 80°C . 8
9 Procedure of freezing and thawing . 8
9.1 General . 8
9.2 Freeze/thaw cycling . 8
9.2.1 General . 8
9.2.2 Freezing period . 9
9.2.3 Thawing period . 9
9.2.4 Reconditioning after an interruption . 9
9.3 Examination of test panel and units . 9
10 Evaluation of results . 9
10.1 Assessment of damage . 9
10.2 Assessment of freeze/thaw resistance . 10
11 Test report . 12
Annex A (informative) Heat flow meter . 14
Annex B (normative) Calibration — Measurement of rate of spray water . 16
Annex C (normative) Calibration — Measurement of heat transfer rate . 17
European Foreword
This document (EN 772-22:2018) has been prepared by Technical Committee CEN/TC 125 “Masonry”, the
secretariat of which is held by BSI.
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 June 2019, and conflicting national standards shall be withdrawn at
the latest by June 2019.
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.
This document supersedes CEN/TS 772-22:2006.
The most significant changes compared to the previous edition include:
— definition for sand grading for mortar has been tightened;
— rubber joints between units are only permitted for product development and factory production control
testing;
— a clause for partial saturation at 80 °C is added;
— only flush finish joints are permitted;
— monitoring of temperature is taken from 30 mm from the face not 40 mm;
— classification as F2 is given if not more than 10% of units exhibit damage of Type 4 or above, rather than
no units of type 4 or above;
— classifications of F1(n) and F2(80°C) are added;
— a detailed description of a heat flow meter is provided.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
1 Scope
This document specifies a method for determining the freeze/thaw resistance of clay masonry units in one of
two categories F1 or F2.
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.
EN 771-1, Specification for masonry units — Part 1: Clay masonry units
EN 772-21, Methods of test for masonry units — Part 21: Determination of water absorption of clay and calcium
silicate masonry units by cold water absorption
EN 197-1, Cement — Part 1: Composition, specifications and conformity criteria for common cements
EN 13139, Aggregates for mortar
3 Terms and definitions
No terms and definitions are listed in this document.
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
4 Principle
A panel of clay masonry units is assembled from units and rapid hardening mortar which when sufficiently
hardened is immersed in water for a prescribed period of time. The panel is subsequently cooled for a specified
period and the water in the units near to one face is repeatedly thawed and refrozen while the rear of the panel
remains permanently frozen (achieving a so called pinch effect). Damage caused by the freezing and thawing
action is assessed and used to determine the freeze/thaw resistance of the bricks.
5 Apparatus
An appropriate testing machine capable of generating the freeze–thaw cycles specified in 9.2 and ensuring
unidirectional freezing and thawing through one face of the units.
Several different designs of testing machines are suitable all of which use a fan to circulate air in the machine.
It is important that the machine circulates the air such that the flow is essentially parallel to the face of the
panel under test.
A water tank for soaking, made of plastic or steel.
A heat flow meter. The heat flow meter is an insulated device for extracting heat over the central area of the
surface of what during a test would be the exposed face of the panel. The area is matt black and shall be capable
of extracting heat such that when the air temperature is recorded as −15°C as in 9.2.2 and the centre of the
plate is maintained at 0°C the average rate of heat extraction can be measured. A typical example is described
in Annex A and a suitable calibration procedure in Annex C.
6 Materials
High alumina cement shall conform to EN 197-1.
Sand shall conform to EN 13139 with a grain size distribution between the limits shown in Figure 1.
Mesh width in mm
Figure 1 — Grain size distribution
7 Preparation of specimens
7.1 Sampling
The method of sampling shall be in accordance with EN 771-1. Sufficient units shall be sampled in order to
2 2
construct a panel with a face which has a surface area in between 0,25 m and 0,5 m . Each unit shall be
numbered.
7.2 Water absorption
All units selected to construct the panel may be characterized for their water absorption following the
procedure described in EN 772-21.
7.3 Conditioning and preparation of specimens
If the water absorption has been determined, all of the units shall be left to dry individually for at least one day
under laboratory conditions. Units, the headers of which are exposed in the panel, shall be cut and, if necessary,
shortened in order to prevent part of the cut unit from protruding at the rear of the panel. Both half units shall
be renumbered with the original unit number and e.g. the addition a and b.
Percentage by weight passing
8 Construction of a test panel
8.1 General
Test panels shall be constructed from units with the identifying marks visible on the face of the panel to be
exposed and a rapid setting high alumina cement mortar.
NOTE The mortar needs to be strong enough and provide adequate adhesion such that panels can be handled safely
but which is not so strong as to make dismantling the panel after testing difficult. This has been achieved in different
laboratories by using a cement:sand mix of 1:4 or 1:6 by volume depending on the characteristics of the sand used. For
product development or factory production control some laboratories find it more convenient to form the joints of
neoprene rubber or similar. Wherever testing is carried out to test the validity of a manufacturer’s declaration, mortar
joints should be used in accordance with this clause.
If the initial rate of water absorption needs to be adjusted before laying, the bricks should be wetted.
A typical panel is shown in Figure 2. Cut units at the end of courses shall be turned so that the header of the
unit forms part of the face of the panel to be exposed to the freeze/thaw cycles. The depth of these header faced
units should be equal to the width of the full units in order to create such a plane that in the freeze/thaw test
the panel can be fitted closely to the insulation at the rear. A layer of foam rubber should be used at the rear
face such that the flow of air in any gap is eliminated.
The panel height should be limited to 0,75 m.
The mortar joints shall be finished with a steel tool to give a flush finish on the front and back faces of the
panels as shown in Figure 3. Sufficient units shall be used to construct a panel measuring between 0,25 m and
0,5 m .
Dimensions in millimetres
Key
1 Header
2 Stretcher
3 Mortar joint
4 Foam rubber
5 Insulation
6 Foam rubber
Figure 2 — Typical test panel
Key
1 Masonry unit
2 Flush finish to mortar joint
Figure 3 — Joint finish
8.2 Conditioning of a test panel
8.2.1 General
The test panel shall be allowed to cure in ambient laboratory conditions for at least 3 days. Each unit in the
panel shall than be examined. Any existing defects shall be noted with a water proof marker. The situation
(with or without markings) shall be captured by means of a high resolution photograph.
The panel will then be partially saturated by one of the two methods given below.
8.2.2 Partial saturation by cold water immersion
The panel will be completely immersed in a tank of water at room temperature for 7 days ± 8 h.
8.2.3 Partial saturation by immersion in water at 80°C
The panel is immersed in an insulated tank filled with tap water at room temperature. The tank is closed and
the water temperature is raised to (80 ± 3)°C within a period of 2 to 5 hours. The temperature is maintained
for a total of (24 ± 1) hours including a 2 to 5 hours temperature rise. The temperature is then decreased to
room temperature within a period of 2 to 5 hours. This is done by gradually putting tap water at room
temperature into the tank. In this condition the panel remains until the total immersion time from the start of
the process is at least 44 hours and not more than 56 hours.
9 Procedure of freezing and thawing
9.1 General
All faces of the panel except tha
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Frequently Asked Questions
EN 772-22:2018 is a standard published by the European Committee for Standardization (CEN). Its full title is "Methods of test for masonry units - Part 22: Determination of freeze/thaw resistance of clay masonry units". This standard covers: This document specifies a method for determining the freeze/thaw resistance of clay masonry units in one of two categories F1 or F2.
This document specifies a method for determining the freeze/thaw resistance of clay masonry units in one of two categories F1 or F2.
EN 772-22:2018 is classified under the following ICS (International Classification for Standards) categories: 91.100.25 - Terracotta building products. The ICS classification helps identify the subject area and facilitates finding related standards.
EN 772-22:2018 has the following relationships with other standards: It is inter standard links to CEN/TS 772-22:2006. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
EN 772-22:2018 is associated with the following European legislation: EU Directives/Regulations: 305/2011; Standardization Mandates: M/116. When a standard is cited in the Official Journal of the European Union, products manufactured in conformity with it benefit from a presumption of conformity with the essential requirements of the corresponding EU directive or regulation.
You can purchase EN 772-22:2018 directly from iTeh Standards. The document is available in PDF format and is delivered instantly after payment. Add the standard to your cart and complete the secure checkout process. iTeh Standards is an authorized distributor of CEN standards.
The standard EN 772-22:2018 provides a comprehensive method for evaluating the freeze/thaw resistance of clay masonry units, classified into two distinct categories: F1 or F2. Its primary scope is crucial for anyone involved in the production or use of clay masonry units, as it addresses the durability of these materials in regions subject to freezing conditions. One of the significant strengths of EN 772-22:2018 is its clear and systematic approach to testing. By delineating specific procedures for assessing freeze/thaw resistance, the standard ensures consistency and reliability in testing results. The categorization into F1 and F2 allows for a targeted evaluation based on anticipated service conditions, which is highly relevant for designers and architects aiming for long-lasting masonry solutions. Moreover, the relevance of EN 772-22:2018 extends beyond mere compliance; it plays a critical role in safeguarding structural integrity and longevity. In climates prone to freeze and thaw cycles, the insights gained from adhering to this standard can effectively mitigate the risks of material degradation, ultimately resulting in cost savings over the lifecycle of masonry constructions. The document also encourages best practices in the manufacturing and selection of clay masonry units, promoting quality assurance across the industry. By adhering to the methodologies outlined in EN 772-22:2018, manufacturers can better position their products in the marketplace, as these standards reflect a commitment to durability and performance. In summary, the EN 772-22:2018 standard is an essential reference for producers and users of clay masonry units, highlighting its scope, strengths, and relevance in assessing freeze/thaw resistance. Its implementation can lead to improved product quality, ensuring that structures built with these materials stand the test of time in varying climates.
표준 EN 772-22:2018은 클레이 조적체의 동결/융해 저항성을 평가하기 위한 시험 방법을 명확히 규명하고 있습니다. 이 문서는 F1 또는 F2의 두 가지 범주 중 하나에 해당하는 클레이 조적체의 동결과 융해 저항성을 결정하는 방법을 상세히 기술하여, 사용자들이 이 표준에 따라 일관된 결과를 얻을 수 있도록 돕습니다. 이 표준의 강점은 무엇보다도 체계적이고 과학적인 접근 방식을 채택하고 있다는 점입니다. 시험 방법은 철저하게 검증된 절차를 기반으로 하여, 조적체의 내구성을 평가하는 데 유용한 신뢰할 수 있는 데이터 제공을 목표로 합니다. 이러한 세부적인 접근은 건축 및 건설 분야에서 품질 보증과 관련된 중요한 역할을 수행하는데 기여합니다. 또한, EN 772-22:2018의 적절한 범위는 클레이 조적체의 사용이 증가하고 있는 현대 건축 환경에서 더욱 중요해지고 있습니다. 특히, 극심한 기후 변화와 관련하여 조적체의 내구성 및 안전성을 평가하는 것이 필수적이기 때문에, 이 표준은 건축업계에 있어 필수적인 지침서로 자리 잡고 있습니다. 결론적으로, SIST EN 772-22:2019은 클레이 조적체의 동결/융해 저항성을 평가하는 데 유용한 표준으로, 그 명확한 범위와 신뢰성 있는 시험 방법은 업계 전문가들에게 큰 가치를 제공하는 중요한 문서입니다.
La norme SIST EN 772-22:2019, qui fait partie des méthodes d'essai pour les éléments de maçonnerie, se concentre spécifiquement sur la détermination de la résistance au gel/dégel des unités de maçonnerie en argile. Cette norme est cruciale pour garantir la durabilité et la performance à long terme des matériaux de construction. Le champ d'application de cette norme est particulièrement pertinent dans les régions sujettes à de fortes variations de températures, où le gel et le dégel peuvent affecter la structure des éléments en maçonnerie. En spécifiant un moyen précis de mesurer la résistance au gel/dégel pour les unités en argile, cette norme offre une clarté essentielle pour les fabricants, les architectes, et les ingénieurs en construction. Parmi les forces évidentes de la norme EN 772-22:2018, on note sa capacité à classer les matériaux en deux catégories, F1 et F2. Cette classification permet d’identifier rapidement l'aptitude d'une unité de maçonnerie à résister aux cycles de gel et de dégel, facilitant ainsi le choix des matériaux appropriés en fonction des conditions climatiques auxquelles ils seront exposés. Ce niveau de détail aide à préserver l'intégrité des constructions en maçonnerie, contribuant à des bâtiments plus sûrs et plus durables. En outre, la norme répond à un besoin croissant dans l'industrie de la construction d'implémenter des protocoles d'essai standardisés. La mise en œuvre d'une telle norme assure une comparaison uniforme entre différents produits et fabricants, renforçant ainsi la confiance dans la qualité des matériaux de maçonnerie utilisés. Cela est d'autant plus pertinent dans un contexte où la performance face aux conditions climatiques extrêmes devient de plus en plus cruciale. Enfin, la norme EN 772-22:2018 reste d’une grande pertinence dans le développement durable des matériaux de construction, car elle encourage l'utilisation de produits qui peuvent résister à des conditions climatiques sévères, minimisant ainsi le besoin de réparations fréquentes et de remplacements coûteux. En conclusion, cette norme constitue un outil indispensable pour l'évaluation de la qualité et de la durabilité des unités de maçonnerie en argile, jouant un rôle clé dans l'amélioration des pratiques de construction.
EN 772-22:2018は、クレイメイソンリユニットの凍結/融解抵抗を測定するための標準化された方法を提供しています。この文書は、F1またはF2の2つのカテゴリーのいずれかに分類されたクレイメイソンリユニットの性能評価に特化しており、特に気候条件の変化に対する耐性を評価するための重要な基準となっています。 この標準の強みは、凍結/融解抵抗の測定に関する明確で具体的な手順を示すことにより、実施者に対して一貫性のあるテスト結果を保証する点です。さらに、この標準によって、製造者や施工者は、使用するクレイメイソンリユニットの適切な選択が可能となり、長期的な耐久性を確保するための信頼できる指標を得ることができます。 また、EN 772-22:2018の関連性は、気候変動が進行する中で、建材の耐久性に対する要求が高まっていることにあります。この標準は、クレイメイソンリユニットの耐性を評価するための国際的なリファレンスとして機能し、様々な地域での適用性に寄与します。業界全体がこの標準を採用することで、建設業界の技術基準の向上が期待され、消費者に対してもより高品質な製品が提供されることとなるでしょう。 クレイメイソンリユニットの選定や評価において、EN 772-22:2018は地盤を固める重要な役割を果たし、建築物の耐久性と安全性の確保に寄与します。
Die Norm EN 772-22:2018 beschreibt ein Verfahren zur Bestimmung der Frost-/Tauwechselbeständigkeit von Tonmauerziegeln, die in zwei Kategorien F1 oder F2 eingeteilt sind. Der Umfang dieser Norm ist von zentraler Bedeutung für die Bauindustrie, da sie die Zuverlässigkeit und Langlebigkeit von Mauerwerk unter extremen klimatischen Bedingungen gewährleistet. Ein herausragendes Merkmal der Norm EN 772-22:2018 ist die klare und präzise Methodik, die es Fachleuten ermöglicht, die Frostbeständigkeit von Mauerziegeln systematisch zu bewerten. Dieser Aspekt ist insbesondere relevant für Bauprojekte in Regionen mit kaltem Klima, wo die Gefahr von Frostschäden erheblich ist. Die Festlegung von zwei Kategorien, F1 und F2, ermöglicht eine differenzierte Beurteilung und Auswahl der geeigneten Materialien basierend auf den spezifischen Anforderungen. Die Anwendung dieser Norm unterstützt nicht nur die Qualitätssicherung im Bauwesen, sondern trägt auch zu einem nachhaltigen Bauen bei. Durch die Gewährleistung, dass nur geeignete Materialien verwendet werden, können Bauherren langfristige Schäden und die damit verbundenen Kosten vermeiden. Darüber hinaus fördert die Norm die Einhaltung von Sicherheitsstandards und die Vertrauensbildung zwischen Herstellern, Architekten und Bauherren. Zusammenfassend lässt sich sagen, dass die Norm EN 772-22:2018 einen wesentlichen Beitrag zur Qualitätssicherung im Mauerwerksbau leistet, indem sie eine verlässliche Methode zur Bestimmung der Frost-/Tauwechselbeständigkeit bereitstellt. Ihre Relevanz im Kontext moderner Baupraktiken ist unbestreitbar und stellt sicher, dass die langlebigen Eigenschaften von Tonmauerziegeln auch unter herausfordernden klimatischen Bedingungen erhalten bleiben.
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