User documentation

This calculation is presented in three layouts – Full, Standard and Brief

Dialogue

National annex selector


Combobox "National Annex" is used for selecting proper annex for calculation of the snow load.
Snow load requires selecion the national annex, because in Standard EN are not defined characteristic values of snow load on the ground.
For explanation of the National annex parameters related to snow load select national annex from the list below.

BS National Annex

ČSN National Annex

DIN National Annex

ELOT National Annex

IS National Annex

LU National Annex

NBN National Annex

NEN National Annex

NF National Annex

ÖNORM National Annex

PN National Annex

SFS National Annex

SIST National Annex

SR National Annex

STN National Annex

General properties


General properties are similar to all snow load forms.
Checkbox "Print headline" represent official name for calculation. User can change it by uncheck "Print headline" and check "Print userdefined headline" and write his own headline into appropriate string line.
Checkbox "Print the calculation of the shape coefficients" show/hide roof geometry and calculation of the shape coefficients.

Geometry of the roof


This groupbox is visible only if checkbox for calculation of the shape coefficients is checked.
Checkbox "Snow fences or other obstruction or parapet" define, if obstruction exist. If True, coefficient μ1 = 0,8. If False, coefficient μ1 is calculated.
Roof slope α is defined in degrees and visible only if there are not obstructions.

Parameters of the snow load

These parameters are depended on selected National annex.

Exposure coefficient

These parameters are depended on selected National annex.

Thermal coefficient

These parameters are depended on selected National annex.

Calculation

Roof geometry

Roof slope

Roof slope is defined in the dialogue in degrees and used for calculation of the shape coefficients.

Shape coefficients

Snow shape coefficients are calcualted according roof slope.

Angle of pitch of roof α 0° ≤ α ≤ 30° 30° ≤ α ≤ 60° α ≥ 60°
μ1 0,8 0,8•(60 - α)/30 0,0
μ2 0,8 + 0,8•α/30 1,6 --

Characteristic value of snow load on the ground

This value depend on the selected national annex, Clause 4.1(1). More information can be found on the National annex page.

Coefficients

Exposure coefficient

This value depend on the selected national annex, Clause 5.2(7). More information can be found on the National annex page.
Table 5.1 Recommended standard values of Ce for different tophographies
Topography Ce
Windswepta 0,8
Normalb 1,0
Shelteredc 1,2
a Windswept topography: flat unobstructed areas exposed on all sides
without, or little shelter afforded by terrain, higher construction works or
trees.
b Normal topography: areas where there is no significant removal of snow
by wind on construction work, because of terrain, other construction works
or trees.
c Sheltered topography: areas in which the construction work being
considered is considerably lower than the surrounding terrain or
surrounded by high trees and/or surrounded by higher construction works.

Thermal coefficient

This value depend on the selected national annex, Clause 5.2(8). More information can be found on the National annex page.
Recommended value: Ct = 1.0

Explanation of symbols

Ce - Exposure coefficient
Cesl - Exceptional load coefficient
Ct - Thermal coefficient
sk - Characteristic value of snow load on the ground [kN/m2]
α - Roof slope [°]
μ1 - Shape coefficient
μ2 - Shape coefficient