Working platforms should be fitted with guard rails along the outside and at the ends, at a height of 3 feet 6 inches from the platform. They may be temporarily removed for the landing of the workmen and material, although it is not always necessary to do so in the latter case.
Fig. 141
If a well is left in the working platform through which to hoist material, the opening should be guarded with rails as for the outside and ends.
A well hole, if likely to be of permanent use, should be fitted with a hinged flap door, that can be shut down as required.
Boards on edge should be fitted on the outside and ends of working platforms, and should rise above the platform at least 7 inches. This will allow of a 9-inch board being used standing on the putlogs. They should not be fixed near ladders where the workmen land. Additional boards should be placed at the back of any stack of bricks or other material in order to prevent it falling off the scaffold.
Fig. 142
Edge boards are usually nailed to the standards. On exposed situations it is better to tie them, as the wind, continually acting on their surface, will in time draw the nails.
Platform boards, when lapping, frequently lose their place, being kicked by the workmen during their progress about the scaffold. When this happens the boards assume the position shown on [fig. 141], and what is known as a trap is formed. The danger of a trap is shown on [fig. 142].