HARPO EXTENSIVE PERENNIAL SYSTEM FEATURES

The Harpo verdepensile perennial extensive system adheres to the UNI 11235:2015 standard, ensuring and exceeding the minimum characteristics for both all individual elements and system performance. The main characteristics of the system are as follows:

• Versatile and lightweight: usually the thickness of the system varies from 15 to 17 cm for the BAS line and from 16 to 20 cm for the RIC line. In both cases, the maximum retention weight of the lower thickness system starts from 160 kg/sqm.
• Aesthetic value: perennials and evergreens are used in these systems; those resistant to frost and drought, with limited height development, should be chosen, and which still provide an aesthetically pleasing and quality yield.
• Management costs: maintenance is very low, with two or three operations per year, mainly to remove weeds and replace some deadfall. Pruning is generally not necessary.
• Irrigation: it is mainly for emergencies, usually by dripline.
• Implementation costs: this solution is particularly economical in terms of the system. The choice of plants, transplanted from pots, is the factor that most affects the total cost. It proves cost-effective in roofs of limited size.
• Thermal resistance: the system contributes to energy savings with a thermal resistance that varies according to water content but is not less than 0.48 (m2 * K)/W, with substrate thickness 12 cm, according to CNR report for the BAS system.
• Runoff coefficient: variable depending on substrate thickness, specific values can be provided upon request based on studies conducted with the University of Genoa.