CUSTOMER REQUEST:

We are often asked why we are so particular about knowing theexact installation address even at the request/offer stage.

OUR ANSWER:

Providing the precise installation address is essential for calculating wind and snow loads, in compliance with the Technical Construction Standards (NTC2018).

The wind load is a function of:
– Geographical position
– Altitude
– Return period
– Ground clearance
– Distance from the coast
– Geometry (pressure coefficient Cp)
– Roughness

From the NTC it can be deduced that the wind load is, among other things, a function of the roughness class.
From the table it can be seen that it cannot be excluded that class A or B may be applied in the same street depending on the city topography.

For example, in Rome in Via Ostiense at the civic number 975 we consider the applicable Class A while at the civic number 849 it is more appropriate to use the class B. Let's suppose we need to install a 3kW system consisting of 2 rows of 3 horizontal panels fixed on the short side with a 5° inclination with respect to the flat roof. 

Well the wind load resulting from the NTC is respectively 52,20kg/m2 (civic 975) e 63,72kg/m2 (civic 849). It follows that in order to satisfy the NTC 2018 and the related safety coefficients, the system at number 849 will be, all other conditions being equal, the 24% heavier compared to the same plant at number 975.