244 STRUCTURAL ELEMENTS AND BUILDING METHODS STEPS
100%
21/21 cellar stairs (+ 3 cm undercut)
90º
st ep lad d
er s
ladders
foot irons
20/23 steepest domestic stairs (+ 3 cm undercut)
58%
17/29 comfortable domestic stairs
15/33 standard outdoor dimensions
75º
irs sta 45º
14/37 shallowest rise for stairs in and by buildings 12/39 shallow stairs with r = 12 cm according to stride formula 12/46 shallow stairs with r = 12 cm according to Seifert
rs stai ide outs
30º
18% ramps and stepped paths
10º
10/55 comfortable stairs with shallow rise 12% upper limit for pedestrian ramps 6% barrier-free ramps
0%
Fig. 3.3.4: Rises for stairs, ramps and ladders
according to stride formula for stairs in buildings
according to Alwin Seifert for s 17
s
tread t t = 63 – 2r
stride length 2h + r
tread t r = 94 – 4s
stride length 2h + r
9
45
63
58
76
10
43
63
54
74
11
41
63
50
72
12
39
63
46
70
13
37
63
42
68
14
35
63
38
66
15
33
63
34
64
16
31
63
30
62
steep and uncomfortable to climb in the open air. Shallower rises are more appropriate here. > Fig. 3.3.4 But the lower the rise, the greater the length of stride, so that the above-mentioned formula no longer produces satisfactory results for small rises, as studies by Mielke, Seifert or Mader have shown. Alwin Seifert arrived at step dimensions for “relaxed walking” with considerably longer stride length (Niesel 2003, p. 291). These values can be consulted when designing stairs with a rise of less than 17 cm. > Tab. 3.3.1 Stairs at the entrance to buildings should not rise less than 14 cm, however (rises under 14 cm are not permissible under DIN 18065-1 in and by buildings). Landings are placed between the flights of steps for structuring, changes of direction, or to make walking easier. A landing should be provided after 18 steps at the latest (cf. DIN 18065). The length of the landing is derived
from the tread and the multiple of the of the assumed stride length of 63 cm (l = r + n . 63 cm). > Fig. 3.3.3
Handrails A handrail must be provided for flights with more than 3 steps. If steps are more than 3 m wide, additional handrails are required in public places. If there is a risk of falling sideways, the handrails must be appropriately braced. > Chapter 3.5 Railings and fences If there is no risk of falling, handrails can also be placed centrally if the steps are wide enough.
Anti-slip precautions and protection against standing water Specific demands are made on outdoor stairs because of the effects of the weather. To increase safety, appropriate covering materials should be selected to prevent slipperiness. Measure should also be taken to
Tab. 3.3.1: Comparison of outdoor stair calculations with r 17 according to stride formula (stride length = 63 cm) and according to Seifert (variable stride length)