路燈 隧道燈安裝在桅桿(立柱)懸臂上和立桿頂部的燈具或外部部件的靜態(tài)載荷試驗。
安裝燈具或外部部件時,使其最嚴酷表面承受載荷。
計算CdxS的最大值來確定最嚴酷表面。
其中:
Cd----拖動系數(shù);
S----承受載荷的面積(m2)
Static load test for mast-arm or post-top mounted luminaires or external parts The luminaire or external part is mounted in such a way that the most critical surface is loaded. The most critical surface is determined by calculating the highest value of Cd × S
where
Cd is the drag coefficient;
S is the area of the surface to be loaded (m2).
The drag coefficient depends on the shape of the surface. For luminaires or external parts for which the Cd is not measured, the value of 1,2 shall be taken.
NOTE 1 See Annex A for measurement of Cd.
The means of attachment shall be secured in accordance with the manufacturer’s instructions.
A constant evenly distributed load is applied for 10 min on the most critical surface.
NOTE 2 See Figure 1 for methods of equal distribution of the load. In cases where bags are used, these can be filled with sand, lead shot or small balls.
The load shall be equal to
F = 1/2 Rh × S × Cd × V2 (N)
where
Rh is equal to 1,225 kg/m3 (air volumic mass);
V is the wind speed (m/s).
The wind speeds relevant to the mounting heights of luminaires or external parts shall be
V = 45 m/s (163 km/h) for heights up to 8 m;
V = 52 m/s (188 km/h) for heights between 8 m and 15 m;
V = 57 m/s (205 km/h) for heights of more than 15 m.
NOTE 3 In some countries, the wind speed is determined by national rules (for example, Japan).
The drag coefficient is 1,2 (or the exact value measured in Annex A).
After the test, there shall be no visible failure impairing the safety, no permanent deformation from the attachment which exceeds a slope of more than 2 cm/m, and no rotation around the point of attachment.