Documentation
This document contains all National annex values, which are used in SDF - Basic package
Clause 4.1 Characteristic values, paragraph (1)
The characteristic values of snow load on the ground sk in the Czech Republic are given in Snow Load Map of the Czech Republic.
Clause 4.3 Treatment of exceptional snow loads on the ground, paragraph (1)
Exceptional snow load is not considered in the Czech Republic.
Clause 5.2 Load arrangements, paragraph (7)
Standard values are used
Clause 5.2 Load arrangements, paragraph (8)
0,8 ≤ Ct ≤ 1,0
Clause 5.3.3 Pitched roofs, paragraph (4)
Standard drifted load arrangement is used.
Clause 5.3.4 Multi-span roofs, paragraph (3)
Standard drifted snow load is used.
Clause 5.3.4 Multi-span roofs, paragraph (4)
If α ≥ 60°, the coefficient μ2 = 1,6
Clause 5.3.5 Cylindrical roofs, paragraph (1)
μ3,max = 2,0
Clause 5.3.5 Cylindrical roofs, paragraph (3)
Special drifted load arrangement is considered.
| h/b |
1/8 |
1/6 |
≥1/5 |
| μ3 |
1,45 |
1,8 |
2,0 |
For intermediate values of h/b, linear interpolation is applied for μ3.
Clause 5.3.6 Roof abutting and close to taller construction works, paragraph (1)
From the upper roof 50% of the maximum total snow load slides (for roofs where α > 15° and neglecting the effects of wind and heat transmission) which corresponds to the snow amount of s = 0,5 • 0,8 • b 1,s • sk. Corresponding value of coefficient μs = 0,8 • b1,s / ls. (It is valid also for roofs with α > 60°). See Figure NA.1a. If the lower roof is pitched, the value h1 instead of h is used in formulas.
Figure NA.1a - Snow load on the lower roof
Maximum values of coefficient μw are different for snow zones according to Table NA.1. The lower limit of coefficient μw = 0,8 for all snow zones.
Table NA.1 - Maximum values of coefficient μw
| Snow region |
I - IV |
V - VI |
VII - VIII |
| Max μw |
2,0 |
3,0 |
4,0 |
Clause 5.3.6 Roof abutting and close to taller construction works, paragraph (3)
Annex B is not applied in the Czech Republic.
Clause 6.2 Drifting at projections and obstructions, paragraph (2)
Annex B is not applied in the Czech Republic.
Clause 6.3 Snow overhanging the edge of a roof, paragraph (1)
For calculation of snow load due to overhang, Clause 6.3 is used for the snow zones V to VIII in the Czech Republic.
Clause 6.3 Snow overhanging the edge of a roof, paragraph (2)
The coefficient k remains unchanged in the Czech Republic. The bulk weight density of snow γ = 2 kN/m3 should be used for the assessment of the depth of the snow cover.