.1 Shifting boards shall have a thickness of not
less than 50 mm and shall be fitted grain-tight and where necessary
supported by uprights.
.2 The maximum unsupported span for shifting boards
of various thicknesses shall be as follows:
Thickness
|
Maximum unsupported span
|
50 mm
|
2.5 m
|
60 mm
|
3.0 m
|
70 mm
|
3.5 m
|
80 mm
|
4.0 m
|
If thicknesses greater than these are provided the maximum
unsupported span will vary directly with the increase in thickness.
.3 The ends of all shifting boards shall be securely
housed with 75 mm minimum bearing length.