Ist Elektrosmog eine Herausforderung für die Bautechnik?

Is Electric Smog a new challenge for the construction technology? Today electric energy is being applied extensively to every sphere of our life. Despite the measures for the peoples protection, that are been developed therefore, experts and ecologically aware citizens worry about the influence this increase could have on our healthiness. Not least because of its economic relevance the problem of electric smog is discussed controversial and with more and more polemic. Therefore this article provides specialized information for the impartial reader to support him in forming an opinion. Thereby the article concentrates on measures that determine the protection level of the human health – according to endangerments caused by electromagnetic fields – during the design and realization phase of building construction.     

Robustheit von Tragwerken – ein vergessenes Entwurfsziel?

Robustness of structures – a forgotten design target? Engineering structures may react on high or unplanned load scenarios in considerably different manner: Some remain nearly free of damage, others are affected by loss of their load‐bearing capacity. The property of structural survival with rather limited damage is called structural robustness, defined with respect to a specific action. However and in opposition to classical structural properties, like redundancy or ductility, for robustness neither exists an exact definition nor any quantification, up to now. The present contribution attempts both in engineering‐like manner; it explains the gained derivations by example of several structural responses, and draws attention to catalogues and procedures for enhancement of structural robustness.     

Phenolindex – ein sinnvoller Parameter für die Altlastenbewertung?

Der Phenolindex reagiert unterschiedlich empfindlich auf verschiedene Phenolhomologe. Insbesondere die in Verkokungsprozessen entstehenden Alkylphenole lassen sich mit diesem Summenparameter schlecht quantifizieren. Daher wurde ein toxischer Bestandteil von Teeren und Schwelereirestprodukten bisher in seiner Bedeutung über den Phenolindex nicht richtig eingesch?tzt und aus umweltgeologischer Sicht wenig betrachtet. Darüber hinaus existiert keine standardisierte chemische Targetanalytik, weil die Alkylphenole mit einer Ausnahme nicht zu den EPA-Phenolen geh?ren. In diesem Artikel wird die Empfindlichkeit des Phenolindex für Alkylphenole charakterisiert und quantifiziert. Die individuellen Alkylphenole tragen mit 0 bis 76% relativer Empfindlichkeit gegenüber Phenol zum Phenolindex bei. Die so gefundenen Laborergebnisse wurden mit realen Feldproben verglichen. Es zeigte sich, dass neben den Phenolen weitere Verbindungen zum Phenolindex beitragen. Damit k?nnen bei einem derzeitigen Orientierungswert von 50 μg/l tats?chlich Konzentrationen zwischen der Nachweisgrenze und 250 μg/l vorliegen. Es wird deutlich, dass eine alleinige Anwendung des Phenolindex zu einer Fehleinsch?tzung der Phenolbelastung führt.     

Phenolindex – ein sinnvoller Parameter für die Altlastenbewertung?

Alkyl phenols are toxic, water soluble organic compounds with a possible low biodegradation potential under reducing conditions. They are by-products of coking processes and main components of tars and creosote. However, they have been widely neglected to be a problem. The alkyl phenols do not belong to the EPA-phenols, except for 2,4-Dimethyl phenol. This means, that no standard analytical procedures are currently available. The often applied sum parameter “Phenolindex” does not fully account for those compounds. For a typical contamination case only a fraction of the total phenols are recovered by this parameter. On the other hand the index is positive for other coexisting organic compounds. The threshold level of phenolindex is 50 μg/l, which means that the actual concentration of phenols can range from the detection limit up to 250 μg/l. As a consequence, the use of the parameter as the only indicator for a plume will lead to a wrong estimation of the contamination problem.     

Stahl im Hochbau – ein nachhaltiger Werkstoff?

Steel for building constructions – a sustainable material? Since the Brundtland Report [12] “Our Common Future” 1985 and the Earth Summit of Rio 1992 “Sustainable Development” is omnipresent in our society: “Sustainable development is a development that meets the needs of the present without compromising the ability of future generations to meet their own needs“. The transmission of this concept into the building sector is called “Sustainable Construction“. Sustainable construction means to design and construct buildings with a holistic approach considering ecological, economical and sociocultural aspects ‐ a paradigm shift for the entire building sector. The “Austrian Steel Association” has commissioned the first mentioned author to point out in a pre‐feasibility study a SWOT‐analysis (strengths, weaknesses, opportunities and threats) of steel for constructions as well as to identify a future call for action for the steel construction industry. Three office buildings with load bearings systems made of steel, timber and reinforced concrete were compared. For the ecological assessment a life cycle analysis (LCA) on the basis of the ÖNORM EN ISO 14040 [25] was undertaken. Recycling or dismantling can not be depicted by life cycle assessments based on recent ISO draft standards. Within this work the ecological datasets for EAF‐steel (electric arc furnace) could be substantially improved.     

ThermoShield – ein Beitrag zur Wärmedämmung?

ThermoShield – a contribution to thermal insulation? For some time now, so called thermal coatings are being introduced onto the market. Advertisement to these products announce that these coatings reduce heating energy requirement in buildings considerably. These coatings are facade paintings, e.g the product “ThermoShield”, to which microscopic small ceramic bubbles are added. In the product data to these coatings, a heating energy saving up to 30% are mentioned. The manufacturer impute these saving to different effects of the “ThermoShield” coating. To check the upper mentioned promising product properties, the thermal behaviour of test specimens coated with “ThermoShield – Exterieur” are being studied within the scope of a research work at the University of Hannover. The evaluation of the measurement results showed, that the specimens coated with “ThermoShield” did not have the thermal properties expected and that this coating do not show any of the promised thermal insulating properties.