This section is from the book "Modern Buildings, Their Planning, Construction And Equipment Vol6", by G. A. T. Middleton. Also available from Amazon: Modern Buildings.
To enable the student to fully grasp the subject of scaffolding he should, before proceeding to read the following chapters, refer to Volume I. Part III. Chapter XIII (The Decoration Of Domestic Buildings). for a preliminary and general description of the plant in ordinary use. There he will find some particulars relating to - Standards, Ledgers, Putlogs, Scaffold-Boards, Guard-Rails, Poles, Scaffolding for Repairing Purposes, Masons' Scaffold, Communication to Scaffold, Gantries, Fixed Gantries, Travelling Gantries, Tower Gantries or Derrick Towers. In these chapters some further detailed information is afforded which, it is hoped, will be both acceptable and useful.
In the construction of scaffolding special regard should be given to the suggestions contained in the circular issued by the Home Office relating to the prevention of scaffold accidents. Up to the present there does not appear to be any legal definition of a scaffold, but a reasonable or common-sense definition - from cases which have been tried under the Workmen's Compensation Act - would appear to be that it is a temporary arrangement of poles and timber to form platforms raised from the ground for the safe approach of workmen to their work, and for the purposes of the lifting, carriage, and transfer of materials during the building operations. The nature and character of the building will determine the method of scaffolding, and to what extent the uses of braces, shores, struts, etc., may be required.
It is well to give special attention to the Home Office suggestion as to Working Platforms 10 feet or over above the ground level. Before employment takes place thereon they should be provided throughout their entire length on the outside and at the ends - (1) with a guard fixed at the height of 3 feet 6 inches above the scaffold boards, openings being left if necessary for workmen to land from the ladders, and for the landing of material; and (2) with boards fixed so that their bottom edges are resting on or abutting against the scaffold boards. Boards so fixed should rise above the scaffold not less than 7 inches. It is also suggested that all Runs or similar means of communication between different portions of the scaffold or building should not be less than 18 inches (two boards) wide. If composed of two or more boards, they should be fastened to either in such a manner as to prevent unequal sagging, by screwing or nailing pieces of 6 by 1-inch batten across their under sides every 4 feet. When nails are used they should be of wrought iron, and long enough to go through the boards and be clinched on the top side.
Reference is also made to the necessity for removable guard-rails to close the openings referred to in the manner shown in Fig. 265, a piece of 5/8-inch iron bar being bent into a hook at one end and an open ring at the other, so that it may be slipped over the end of the scaffold pole, the ring being closed or opened as required, and a pair of such ring hooks carrying a length of 4 by 2 1/2-inch rail.