Methodology and accuracy: what Solispec computes and by which standards

What the result is, and what it is not

Solispec turns a site, a layout and a choice of profiles into design loads, member and fixing checks, a bill of materials, drawings and a report. It is meant to take an installer from the address to a defensible estimate fast.

It is not a stamped structural design. Every result is preliminary and must be verified by a qualified engineer who knows the site, the soil or the roof, and the local building rules. The disclaimer page says the same.

Loads and standards

The loads follow the country of the site. Combinations and partial factors depend on it:

• Ukraine: DBN V.1.2-2:2006 with Changes No. 1 and No. 2 for snow and wind, with the region found from the address.
• Poland, Germany, Spain: the characteristic snow load and basic wind pressure of the national annex (PN-EN 1991 with its annex, DIN EN 1991-1-3/NA and -1-4/NA, CTE DB SE-AE) at the nearest main city, offered as a guide the user confirms.
• Combinations abroad: EN 1990 with the factors 1.5 on snow and wind, 1.35 on unfavourable and 1.0 on favourable permanent load, and the accompanying-action factors of the annex tables.
• Snow on a canopy by EN 1991-1-3 (shape coefficient 0.8 up to 30 degrees, falling to 0 at 60); wind on a canopy by the coefficients of EN 1991-1-4 Table 7.6, with the exposure factor of the terrain category.
• Any other country: the user enters the characteristic snow load and the basic wind pressure.

Member, fixing and foundation checks

From the loads the engine checks the parts that are built:

• Steel C profiles and rails by EN 1993-1-3 with the effective-width rules of EN 1993-1-5 and the buckling curves of EN 1993-1-1; tubes by EN 1993-1-1 abroad and ДБН В.2.6-198 in Ukraine.
• The rail as a continuous beam over the supports, the truss members by a frame analysis, deflection against a limit that is an assumption of the tool.
• Bolts at nodes, M10 through factory slots, with the length chosen from the clamped stack.
• Ballast against uplift and sliding, with the resultant of the wind placed as EN 1991-1-4 7.3(6) prescribes.
• Post embedment below a frost depth taken from the country’s practice (a guide), and the load a flat roof must carry against its stated allowance.

Inputs, assumptions and limits

The result is only as good as the inputs: the site and its terrain category, the building height, the profile and panel data, the roof or soil capacity you enter. Check each one.

Known limits, stated plainly:

• The national annex of EN 1993-1-3 is not applied; the recommended partial factors of the EN are used and marked as such.
• The annex values for Poland, Germany and Spain are taken at the nearest main city. A site in the mountains or at a different height than that city needs the exact zone value from the authority.
• Seismic, fatigue, corrosion, soil investigation and roof structure are not computed. Frost depth is a guide, not a geotechnical report.
• Yield uses PVGIS by month and an hourly balance; shading is simplified. It is not an hourly module simulation like PVsyst.
• A maker’s tested system and its statics approval are outside the tool. Use the maker’s own configurator where that approval is required.

Who builds it and how to reach us

Solispec is built by a solar installer and engineer from Ukraine. The engine has automated tests, and the standards it follows, with their versions, are listed on the norms pages.

Found an error or a case the tool gets wrong? Write to [email protected] and include the project link.