International Rosenheim Window & Facade Conference - Conclusion

Date: 17.10.2013 | ID: PI131096 | Download: International Rosenheim Window & Facade Conference - Conclusion PI131096 (PDF) | Author(s): Jürgen Benitz-Wildenburg

Modern windows improve the quality of life and provide efficiency, safety and security, and a future

The smart fox in our programme would also have been pleased with the outcome "Modern windows improve the quality of life". The almost 1,000 experts from 18 countries who attended the largest European key industry event, the International Rosenheim Window & Facade Conference on 10 and 11 October, also appreciated the large volume of information and practical tips pertaining to technology, research and standardisation. The visitors took significant stimuli and incentives for putting into practice from the 26 lectures and four workshops that were held. Those who could not be present at the Conference can find much of the information in the conference proceedings comprising 170 pages and 600 lecture slides on CD Rom – both are available online.


In his status assessment, the director of the institute, Professor Ulrich Sieberath, pointed out in the plenary session that the Energiewende will remain the driving force in the construction market. In the context of building materials, building components and building services engineering, the solar energy gained from windows must be taken increasingly into consideration in legislation and standards. The introduction of an energy label by the EU Commission promises an improvement and hence, it is being prepared by a European R&D project in which ift Rosenheim is playing the lead role. "The European Energy Label will come and be implemented in the EnEV 2016 and thus, continue to promote the use of energy-efficient windows" explained Professor Sieberath. Moreover, the demographic development, too, must be given greater consideration during product development. More specifically: barrier-free, safe and user-friendly designs. Products in future must also withstand the dangers and concrete effects of climatic change, for example, those resulting from tornados and flooding.


The EU Commission's new requirements such as safety for children, prevention of condensation, burglar resistance and sustainability will affect the development of products significantly as well. The Commission explains "safety for children" for example by the use of windows that prevent falling down or injuries caused by crushing and shearing, having splinter protection and prevent misuse (protection against tampering). In the 8 sets of topics, new aspects of technology, legislation, standardisation, research and marketing have been presented and discussed.


In the set of topics "Energy Turnaround" the informal estimates of André Hempel (BMVBS – Senior Government Council) were pursued eagerly, since at that time there was no official news regarding the EnEV. In the meantime, the EnEV including the amendments of the Federal Council (Bundesrat) has come into force and the estimates of Hempel have been confirmed to a large extent, for example, the fact that the energy passes are checked for plausibility nationwide and re-calculated in case of any inconsistencies and monitored locally, and that initially, there will be no new stringencies and that the standard of new constructions in the future shall be guided by KfW40 houses. The law amending the Tenancy Act (Mietrechtsänderungsgesetz) discussed for improved depreciation of energy-related refurbishments for tax purposes is desirable but can barely be enforced politically. However, Hempel has pointed out that the Energiewende will remain right at the top of the political agenda, and that the building industry may reckon with the introduction of the EnEV with effect from 1 June 2014.

Solar shading is still highly neglected by many windows manufacturers, although the requirements have already been defined clearly in the EnEV 2009 and builders, too, have been increasingly sensitised with respect to this aspect. The "Solar protection standard" DIN°4108-2 has also been made more stringent and must be complied with.
Dr. Martin H. Spitzner (ift Rosenheim) has clearly demonstrated that in modern architecture deploying large amounts of glazing, almost every house requires solar shading and he explained the handling and the limitations of the simplified verification procedure in accordance with DIN 4108-2. ift Rosenheim has worked out simple diagrams for this purpose, with the help of which the necessary level of shading can be read off depending on the window surface area, the type of building and the climatic region. These diagrams will be available until the end of the year in the form of expert information. 


In the set of topics covering Refurbishment, the statement of Christian Wetzel (University of Stuttgart) "The replacement of windows is always worth it if there are occasions to do so in any case". "Occasions in any case" mean the refurbishment or coating of facades or windows where costs for scaffolding, paint and installation work are incurred "in any case". Wetzel also demonstrated the bandwidth of the influencing parameters such as interest on capital, service life, energy price increases and duration of use, and how considerably these affect the calculation of the economy or efficiency. The crux of energy-related refurbishment, however, is and remains the necessary building renovation in case of construction damages, new and different usage, inheritance or sale. What needs to be done is to steer the discussion to the pure additional costs and this is where it can be demonstrated that modern energy-efficient building components and construction materials are worth it in most cases.


Martin Heßler (ift Rosenheim) too, announced a happy message with the statement that "Condensate and mould can be prevented". Efficiently insulating window frames in conjunction with triple-layer glazing units and a warm edge can be called the standard and they jointly prevent the formation of condensation if … Yes, if the ventilation and heating behaviour is compatible with the room atmospheric humidity. This is exactly the subject matter of most legal disputes subsequently. This is why Heßler differentiated between various cases based on the practical experience of the experts at ift as well as the root causes of damage. This can be used as an aid of argumentation in case of complaints.


The set of topics Glazing treated the results of two highly exciting research projects as well as the amendments to DIN 18008 "Glass in construction". Norbert Sack (ift Rosenheim) explained the construction principles with the help of which the surface weight of insulating glass units can be reduced and the problems that may arise in the process. While the use of thinner, toughened glass does not basically imply any change in the construction, the edge seal must also be changed with the use of lighter sheets and plastic plates. In general, however, such constructions are also feasible. Potentially lower glass thicknesses are also of interest for the load case of wind load, if non-linear calculation methods are used. The related details are furnished in the Research report (ISBN: 978-3-86791-337-3).

Karin Lieb (ift Rosenheim) cited a journey in the past, specifically in the year 1985, in which the first larger facade was built in Germany at ift Rosenheim with Structural Sealant Glazing (SSG). In 2012, the SSG facade had to deviate from an energy-efficient glass construction and was thus available as a reference object for new detailed research work regarding the durability. The investigations of the old facade and the analysis of the monitoring conducted since years, resulted in excellent conformity of the short test procedure in accordance with ETAG 002-1. The experience and results obtained can be used today in an outstanding way for innovative facades, which need no "belt and suspenders to fight the fear" and so far could be built only with approval on a "case-to-case" basis. ift Rosenheim can accompany such projects assisted by monitoring concepts, to simplify and accelerate the approval process.

Professor Dr Geralt Siebert (University of the German Federal Armed Forces in Munich) concluded with his explanations regarding the dimensioning and verifications of the load-bearing capacity for glass constructions in accordance with DIN 18008 "Glass in construction – Design and construction rules", which is based on the dimensioning concept of the Eurocodes. The lecture could provide only an initial overview of the structure of this multi-layered topic to support the participants in planning further measures, such as an update or the deployment of the appropriate software as well as advanced training. After the introduction of DIN 18008 by the building authorities, ift Rosenheim plans to prepare diagrams for common practical cases with the help of which simple verification is possible.

In the set of topics Market and Trends the common thread regarding the diverse arguments in favour of modernising old windows has linked very different viewpoints. Professor Dr. Runa Hellwig (University of Augsburg, energy-efficient design) stressed the great impact of windows on the room climate. The key words here are ventilation, daylight and thermal comfort. However, it was not the technology in the foreground, but instead what the users would like to have, what they need and actually do. Human beings have a completely different "sense of climate", and, in fact, culturally as well as individually. Accordingly, those in warm or tropical regions want a continuous draft -- something that is almost scorned here in Germany. This fact is often disregarded and the impact on the planned energy saving effect is highly underestimated as a result. Professor Hellwig emphasised that this is why user expectations need to be analysed in greater detail. This is where the findings of software development can be transferred to the control and operation of automatically operated and controlled windows.

Ulrich Tschorn (Verband Fenster + Fassade, VFF, Association Windows & Facades) demonstrated with several examples how differently you can consider the perspective of efficiency or economy, and thus, confront the issue of amortisation period. By considering "costs incurred in any case" also makes the financial outcome far more favourable. Tschorn also showed ways of escaping the price discussion and demonstrated that new windows are fun and offer benefits, for example, greater sound insulation, safety, security and comfort. This is where comparisons with other purchasing incentives help when the purchasing decisions are not taken on the basis of economical considerations, be it a new motor car, new shoes or a new bathroom, which do not save any costs at all – something, in contrast, that every new window achieves. Tschorn provided the slogan "New windows are fun, and they save money and do something good for the climate and the environment".


Professor Dr. Ulrich Bogenstätter (University of Applied Sciences Mainz, technical building management) who held the concluding lecture on this set of topics, provided many insider tips, such as how the potential and appropriate point in time for the sale of windows to landlords can be established – often, merely a glance into the financial statement of accounts of a housing society is adequate. In the process, he presented current figures, which enable market segmentation as well as an analysis of the various motives for a purchase and thus, to identify the proper decision-making criteria. He differentiated roughly between the portfolio manager, the dealer and the manager, all of whom have different motives for investments. Professor Bogenstätter got to the heart of the matter regarding the motive for all decision-makers "The main thing is to avoid any disputes with the tenants". If you also consider the most significant complaints regarding old windows such as noise, condensation and draught, then this paves the way for quality manufacturers and member companies of the RAL-Gütegemeinschaft (RAL Quality Assurance Association).


The set of topics on Research then led to the near and distant future. Ministerial Councillor Hans-Dieter Hegner (BMVBS, Federal Ministry of Transport, Building and Urban Affairs) guided the audience into the year 2020, when all new windows and increasingly older refurbished buildings too, shall be designed as plus energy houses. This means that one house generates more energy than what it consumes for heating, hot water and the overall domestic electricity for the household. What is important is that only a small portion of the electricity generated by PV systems is used for heating and hot water and thus, it can be used for the household, the necessary system equipment and electric mobility (Electromobility). The technology is already available today, based on the building concept of the KfW 55 and KfW 40 houses respectively and is being offered even today as commercial standard of manufacturers of prefabricated houses – incidentally, with moderate additional costs of around 15%. What is still missing is intelligent energy management to be able to use as much energy as possible in a decentralised way, which means in your own house. More specifically: using as much energy as possible at midday while the sun is shining, for example, using the washing machine, the deep freezer, the dishwasher or the battery of the E-mobile.  Above all, what was also of interest was the presentation of exemplary energy plus houses with modern glass facades for the use of solar energy, which sparked the desire in all participants to copy this construction. Apart from the technical aspects, Hegner stressed primarily on the high living quality of these houses and got to the heart of the matter with the typical charm of a resident of Berlin: "Plus energy houses sell efficiency, safety and security, and the future; the glass surface fetch plenty of daylight and act as an anti-depressant." Detailed information on the projects and the topic are available at

The lecture of Dr. Jan Wurm (Arup Germany) led to Hamburg to the area of the International Building Exhibition IBA and demonstrated the technical and organisational backgrounds of a "green facade" which maybe in 20 years will set a new standard for construction. Behind the "green facade", which is being covered by all the media at present, is an insulating glazing, inside which tiny microalgae are growing and forming biomass, which can be "harvested" in the evening during the summer. The algae facade works like a vertical greenhouse in which biomass grows and, at the same time, provides shade, cooling and even generates biomass. It is definitely interesting that the "algae harvest" is already part of a circle of utilisation, to which pharmaceutical, cosmetic and foodstuff manufacturers have access. Even if the system technology is still elaborate and complex, and the energy efficiency is less than that of PV modules, this is a refreshingly new approach for sustainable and environment-friendly building technology, which, for this reason, has been supported by the research initiative "Zukunft Bau" and which will be showcased in March of 2014 at the fensterbau/frontale on the occasion of the ift special exhibition "vibrant research for vibrant lives".

In the set of topics Block Safety and Security the focus was shifted towards burglar resistance and fire safety, which, at present, are especially covered in public discussions. Jens Pickelmann (ift Rosenheim) substantiated the enhanced level of interest in improved burglar resistance with the strongly increasing number of burglaries and the high rate of aborted burglary attempts with burglary-resistant windows and doors. These successful measures also call politicians to action, which has already led to the definition of minimum requirements in the Netherlands, but is still being discussed in Germany. All the same, today, the resistance class RC 2 or RC 2N is already being demanded for public buildings in tenders for building elements. Furthermore, Pickelmann explained with the help of drawings, pictures and practical examples, how the testing of new windows and retrofit products is planned and organised effectively; how "old" test reports can be used and what needs to be followed during construction, retrofitting and installation.

In the second lecture, Dr Gerhard Wackerbauer (ift Rosenheim) discussed the fire behaviour of materials in windows and facades, since the public building law specifies at least "normal flammability" for all building components and this is applicable accordingly all over Europe. With the help of excerpts from the building laws, standards and practical cases, Dr Wackerbauer illustrated where more stringent rules apply, how the verifications need to be performed, and how they may be achieved for flammable materials such as sealants for joints and sealing profiles. The possible simplifications for planning, tenders and verifications of fire-resistant building components and building materials provided an insight into the existing classification standard EN 13501-1 and an outlook to the future European Product Standard EN 16034 for windows and doors with fire protection characteristics.


The set of topics on Construction dealt with wood preservatives in window construction, quality-related strategies for plastic windows and with EN 1090 for the "design of steel and aluminium structures". The first lecture was conducted by Dr. Odette Moarcas (ift Rosenheim), whose aim was dealing intelligently with the new standard on wood preservation, DIN 68800. In practice, the issue is often of whether and how a chemical wood preservative needs to be used. The goal of the standard and of most builders is to dispense with chemical preservatives, even if less resistant types of softwoods such as spruce and pine are used. This is absolutely possible if the purpose of use and the structural boundary conditions are suitable – A label by the architect "Wood preservation in accordance with DIN 68800" is not adequate under any circumstances; more specific description is necessary. The results of a research project were also interesting, in which 2,119 opaque-coated windows made of spruce or pine were analysed. It was a clear statement that the tightness of the joints in the frame joint area is essential and that primarily only the windows in exposed conditions on the 10th to 12th floor suffered greater damage. Moreover, practical, constructive recommendations were furnished for the execution and specifications in tenders in practice. This also included the finding that protection against blueing is not chemical wood preservative and hence, it may be used with the class 0 as well – is absolutely reasonable for frames made out of softwood with bright glaze finish and wood-metal windows.


Jörn Peter Lass (ift Rosenheim) made a digression into the secrets of quality assurance, with which primarily manufacturers of the RAL-Gütegemeinschaften (Quality Associations) have enhanced the quality of plastic window profiles and plastic windows substantially. The Quality Association for PVC Windows (Gütegemeinschaft Kunststoff-Fensterprofilsysteme e.V.) in Bonn has established a change of paradigm with the new quality and test provisions of RAL GZ-176, since now not only are the material properties of the profiles themselves tested, but those of the entire system including the seals, components, fittings and insulating glass as well as the procedures for bonding and lamination. In this way, even interactions are acquired and it is ensured that in the end, a window system that is suitable for use is available to the fabricator, i.e. the window manufacturer. The entire test system is built in a modular fashion and thanks to its specific rules of interchangeability it supports expeditious advanced development of window systems. The individual test procedures and monitoring rules have been synchronised with the RAL system GZ-695 of the windows manufacturer and thus relieve both partners, i.e. system providers and window manufacturers of unnecessary duplicate tests. In this way, the entire system of quality assurance has been simplified and optimised so that consumers can now get even better window systems.


The set of topics on Building Laws dealt with the revisions of the Model Building Code (Musterbauordnung, MBO) and the amended requirements for sound insulation as well as barrier-free building, the topic of the future. Klaus Diether Wathling (General Building Supervisory Authority in Berlin) explained the rules and regulations of the revised MBO relevant for windows and facades with respect to their fire safety (§ 26 - § 45) as well as other regulations. In principle, all building materials that are permanently incorporated into building structures must  have at least a low fire resistance rating ("normally flammable") in accordance with § 28, section 2 of the MBO. Non-load-bearing external walls or parts must consist of fire-resistant building materials in accordance with § 28, section 3 of the MBO. What is new now is that there is an exemption clause applicable for the characteristic "normally flammable" materials only for entire windows and doors (including profiles and glazing) as well as for joint sealants (of windows or in the joints of exterior walls), provided that they are not window walls or facades. Naturally, more stringent requirements are applicable to special constructions, especially in high-rise buildings (OK FFB > 22 m, High-rise Special Construction Model Regulations, MHHR). Here, all components of external walls must consist of non-combustible building materials in accordance with section 3.4 of the MHHR. This also applies to substructures, blinds, window frames, Venetian blinds, and solar shading. However, it is not applicable to insulating materials in non-combustible, closed profiles of fixed glazing, sealant materials for joints (sealing of window panes, between profiles) or to small parts that are not load-bearing. Normally flammable materials are permitted here. What is new is the regulation for concepts for escape routes (§ 33 MBO) in building class 3-5 (buildings higher than 7 m or with more than two utilisation units with a total of more than 400 m²), which requires that in interior staircase areas there must be an opening of > 1 m² for smoke discharge with opening devices on the ground floor and at the topmost point of the staircase. This requirement is often applicable to windows as well. In the model list of the Technical Building Regulations (Musterliste der Technischen Baubestimmung, M-LTB) there are additional requirements for windows and facades: In section 2.6: Rear-ventilated surfacing of exterior walls, appendix 2.6/4, special fire safety-related precautions are defined for cavities spanning various floors, and horizontal fire barriers as well as door and window reveals made of steel sheets (d > 1.5 mm must be provided). Overall, the mapping to the German and European classes is possible, for example in accordance with DIN EN 13 501-1. The current version of the MBO and all special building legislation can be found in German free of charge at


Robert Kolacny (ift Rosenheim) discussed the relevance of freedom from barriers and its implementation according to the building law. In § 2, section 9 and in § 50, the MBO requires that buildings (cultural, educational and health-related facilities as well as assembly halls, restaurants and hotels) open to the public as well as residential buildings with more than three dwelling units must be accessible to the disabled without any specific difficulty and basically without any external aids or assistance (barrier-free). The Federal Study "Housing for the Elderly" establishes the need for 2.5 million residential units suitable for the elderly and thus demonstrates the great significance and the market potential for barrier-free products. The standardised specifications are laid down in DIN 18040 Parts 1 and 2. Robert Kolacny analysed the regulations relevant for windows and doors as well as the constructional implementation with the help of numerous practical examples. In particular, the zero millimetre threshold height is being discussed intensively, since there are constructional difficulties regarding watertightness and thermal bridges.  Kolacny demonstrated approaches for solutions and showed that there are constructional principles for French doors up to 9A, which offer watertightness and that low coefficients of thermal bridges can be achieved. However, apart from this, operating comfort is also relevant. Large and heavy elements primarily lead to increased operating forces here. Here, too, technical /constructional solutions are available as described in the course of the lecture.

Bernd Saß (ift Rosenheim) explained the amendments of the Standard for Sound Insulation DIN 4109, which has been completely and comprehensively revised in 2013. The level of requirements has remained the same, but the calculation and verification procedures have changed. No tolerance is deducted, which means that the measured value R´wP can be compared directly with the calculated value R´wR and may be used. The planners must consider different correction factors for the uncertainty "u" when determining the required sound insulation, in which the impact of measurement uncertainty, the real conditions of construction and the product dispersion are taken into consideration. The required value R´wR is no longer determined by the subtraction of a flat value of tolerance. The extended catalogues of building components for windows and doors as well as newly added tables for glazing, interior doors and joints are a big plus. ift Rosenheim will create a catalogue of building components for facades as well within the scope of a research project, which will then include data for the longitudinal wave propagation as well. In this way, tenders and the technical documentation will get simplified for the manufacturers. Overall, the changes for practical use in the window and facade industry are very positive. Of course, manufacturers of windows, doors and facade manufacturers also need to deal with the details.


In the final plenary session, Professor Christian Niemöller reported on the current status of the Construction Products Regulation. He was satisfied with the professional preparation and implementation by large manufacturers with respect to the creation of documents and the obligation for declaration, but he also expressed his concern regarding the smaller handcraft industries, which may run into trouble with the market surveillance authorities in the future. This would be justified, since the officials of the market surveillance met in September for an initial exchange of experiences where they discussed opinions regarding the procedure. Hence, intensified activities may have to be reckoned with in 2014. These will be in the form of random and event-driven and they will focus on the formal correctness of the documents. During the next discussion, various specific issues were presented that were addressed and answered competently by Professor Niemöller and Professor Sieberath. These shall be available shortly at the ift website under the "CE mark" tab.


The workshops covering Saving on Energy Costs, Easy Installation, Construction Products Regulation and Ventilation Concept have been well attended this year, which was probably on account of the practical tips, with which a considerable sum of money can be saved directly, for example, in the case of energy management. These slides and calculation samples have been included in the conference proceedings of the International Rosenheim Window & Facade Conference.

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