Temperatureinfluss auf Dachschneelasten von Gewächshäusern - Abtauen von Schnee über wärmedurchlässigen Dacheindeckungen

Temperature influence on roof snow loads of greenhouses - Melting of snow over heat-permeable claddings.

Snow loads often govern the design of lightweight structures. Therefore, for heated greenhouses, the melting of snow over transparent heat-permeable claddings has traditionally always been considered. The consequent reduction of snow loads allows adequate glazing sizes for optimal plant growth. Constant roof snow loads of 0,25 kN/m² or 0,75 kN/m² in the German greenhouse standard DIN 11535 have stood the test of time over many years. However, the greenhouse standard had to be adapted to the European design concept of the Eurocodes. Therefore, in March 2014 two new technical specifications have been published: DIN SPEC 18071 for commercial production greenhouses and DIN SPEC 18072 for sales greenhouses. Within German standards, this allows for a new possibility for calculating snow load reduction due to melting of snow, using the thermal coefficient. This approach is made possible by a normative reference in the Eurocode DIN EN 1991-1-3 to the international snow load standard ISO 4355. Background and use of the thermal coefficient in greenhouse design is presented in this article.