Optimising greenhouse designs for local conditions

Hans 't Hart wants to see the standard, EN 13031-1, which specifies the principles and requirements for a structure's mechanical resistance and stability, serviceability and durability irrespective of the material used, to become the norm for greenhouse projects around the world

European standard

Speaking at GreenTech's online conference in October 2020, he said NEN 3859, the first Dutch construction code for greenhouses - and probably the first in the world - was published more than 40 years ago, after storms at the end of the 1970s resulted in huge insurance claims. Four further versions were written as structures evolved and became more sophisticated. In the meantime, some European countries developed their own standards.

Hans 't Hart, a structural engineer at the independent Dutch research organisation TNO says: "As [Dutch] exports grew and the industry invested and expanded, a uniform European standard was the logical next step."

The first European edition appeared in 2001 but, for various reasons, was not widely accepted. A second was published in 2014 and, after results from the new research were released and incorporated, the final version, EN 13031-1, was completed in 2019 and NEN 3859 withdrawn. The code is being implemented in the 34 countries which are members of CEN, the European Committee for Standardization.

New wind coefficients for multispan roofs

The standard now addresses, for instance, the lack of information on the action of wind on multispan greenhouse structures, especially those of the height and area being built today.

't Hart notes, "We did some wind-tunnel tests on scale models of greenhouses of different sizes to figure out the behaviour of the wind on the roof. That resulted in new wind coefficients for multispan roofs; much better definition of roof edge zones; and [calculations for] wind friction in the middle sections, which is not described in building codes."

Click here to read more.

Photo Courtesy of AIPH

Source: AIPH