fold is at a high level should be coiled upon the platform rather than allowed to hang down where it may be interfered with by curious or meddlesome persons or be fouled in some other manner. The ladder which forms the base of the painters' scaffold platform has its side-bars parallel and slightly farther apart than usual. It may be strengthened by extending a small wire rope, about 5/16′′ in diameter, along the under surface of the side-bars, from end to end. All painters' scaffolds should be equipped with guard-rails and foot-boards similar to those already described. SCAFFOLDING MATERIAL Great care should be exercised in the selection of material for scaffolds. Newness is not a sufficient test of strength. All wood should be straight grained and free from knots, injurious ringshakes or other defects. Green wood should be avoided in constructing scaffolds. Wet wood is even less resistant than green. All woods gain in strength and stiffness when thoroughly air seasoned or kiln dried. Air seasoned wood is about twice as strong and kiln dried wood three times as strong as green wood. Not only is wet wood to be avoided but also that which is alternately wet and dry often. The latter rots very quickly and planks so treated soon become unsafe. Lime also cats into wood and weakens it. Spruce is probably the most suitable of the woods that are available for use in scaffolds, though long-leaf yellow pine is acceptable if it is of first-class quality. Hemlock is not good as it is too brittle. Selected cut nails or bolts are best for fastening the parts of scaffolds together. These should be of sufficient size for the particular purpose they are expected to serve. Wire nails are not suitable for use in scaffolds. Ropes should be long fiber manilla and frequently tested for strength. Acid weakens rope but the effect is not noticeable immediately. This fact should be taken into account in making tests. Cables should be made of steel wire and must be flexible as well as strong. If they do not possess a considerable degree of flexi bility they may be damaged in winding upon the drums. Some scaffold builders galvanize their cables since this process makes the cables better able to resist the action of the weather. Where they are not galvanized some approved preservative preparation should be applied. CONSTRUCTION OF SCAFFOLDS All scaffolds should be constructed by men who understand the strength of the materials used and who know the load the scaffold they are building is expected to support. A special foreman should be in charge of and be held responsible for this work. Likewise all alterations should be made under his direction. The common practice of using inferior or insufficient material should be corrected. Care should be taken also to see that all parts of the scaffold are entirely completed. Occasionally a workman engaged in constructing a scaffold is interrupted in his work. In such cases he may forget where he left off work and leave some part of the scaffold in an unfinished and hence in a hazardous condition. Boards and planks, especially those that are not fastened, should not project far over the putlogs or beams. All projecting nails and splinters should be removed. Scaffolds should not be used until they are entirely completed including bracing, hand-rails, and foot-boards. After they are completed they should not be interfered with in any manner by other parties than the erectors. As soon as scaffolds have served the purpose for which they are constructed they should be dismantled. Dismantling should proceed from the top downward (in pole scaffolds, especially). The safer plan is to lower the parts rather than to throw them down. This is also the more economical plan since a smaller amount of material is broken up in this manner. LOADING OF SCAFFOLDS Suspended scaffolds, while yet close to the ground, should be thoroughly tested before they are used. Double the weight to be suspended, when measured in dead load, is not a sufficient test of the strength of the scaffold. There should be a safety factor of at least four because of the strain caused by the live load in moving about on the scaffold. All ropes should be tested by at least four times the weight they are expected to support. Having determined the load a scaffold is expected to sustain and having found by test that the scaffold is able to carry such load, it should not be overloaded at any time. It should not be used as a place of storage for objects that are either bulky or heavy. Material should not be piled upon the scaffold platform faster than the needs of the workmen require. It should be distributed in a reasonable manner and not concentrated at a few points. Hod-carriers should not be permitted to throw brick, mortar, or other material from their shoulders to the scaffold platform since the shock caused by such practices may result in serious accidents. In like manner workmen should not be permitted to jump upon the platform from a higher level. INSPECTION OF SCAFFOLDS Every scaffold should be inspected by a competent man each time it is completed but before it is used. This is essential even when it is to be used for only a few hours for then it is perhaps most likely to be poorly constructed. The inspection should be especially thorough when an accident may endanger a large number of persons, whether workmen or otherwise. Inspection should cover all parts of the scaffold, including handrails, foot-boards, and screens and should extend also to the part of the building above the scaffold and near the plane of the wall that is being erected. In addition to the regular inspection, every foreman should examine the scaffold and satisfy himself of its safety before allowing his men to use it. All scaffolds should be thoroughly inspected and repaired after every storm or high wind. Because the position of scaffolds is constantly changing there should be an inspection every day. A more thorough inspection should be made once a week. The inspector should be required to make a written and signed report of every inspection, covering every important element of the scaffold. Every man who works about the scaffold should be encouraged to report defects which he finds and suggest remedies for them. Ladders The side bars of ladders should be of straight-grained spruce and free from defects. The rungs should be of oak, hickory or ash and should be split and shaved to size and not turned. A ladder used for the transport of materials should not be over 30' or 35′ in height. It should project above the landing to which it extends at least 5'. If it is too short to permit this, stout strips should be nailed to the side bars. One rung should be flush with the platform to which the ladder leads. If this is not practicable the rung nearest the platform should be above and not below the platform. Generally speaking, it is better to use single length ladders with intervening platforms than to use extension ladders in building construction. Ladders up which material is carried should not be located over each other or over an unprotected area where men are at work or pass frequently. Wherever possible, material should be raised or lowered with ropes and not carried on ladders. Men should go up or down ladders one at a time so that they cannot drop material upon each other. Wherever possible, twoladder ways should be constructed: one for the use of men going and the other for the use of men going down. up Both the foot and the top of the ladder should be secured. Tho side bars should rest evenly upon a firm and level foundation. The ladder should be rigid and should not spring when in use. If it is not already sufficiently stiff it should be stayed at the middle by a brace. Ladders with missing or broken rungs or defective side bars should not be used until they are repaired. Defective side bars should not be spliced but should be replaced. Ladders should not be used when the rungs are loose enough to roll. Rungs or steps of ladders should always be notched-in or housed. All ladders should be made and repaired in a workmanlike manner and should not be hastily constructed of scraps, some of which are unsuitable for such use. Temporary Floors Not much need be said concerning the remedy for the hazards involved in leaving out the flooring from the steel framework of buildings. The absence of the flooring constitutes the hazard. The remedy is simply to supply the flooring. At least a temporary floor should be laid within two stories of the highest point at which iron workers are at work. With but little added labor and expense the lives of the workers could be much better safeguarded by putting in a temporary floor within one story of the workers. In laying temporary floors "traps" should be avoided. Because of the peculiar hazards of their work structural iron workers should be temperate, cool-headed, strong, active and healthy. They should not be permitted to work in exposed places during high winds nor at times when the beams are slippery from rain or frost. They should never be permitted to work in exposed places long enough to become unduly fatigued. Neither should they be permitted to engage in spectacular performances nor to expose themselves to unnecessary risks. Hoistways Like the absence of floors, the hazard of unguarded floor openings is apparent and the remedy is simple. The hazard exists because the openings are unguarded; the remedy is an effective guard around all floor openings. All hoistways and elevator shaft openings in each floor should be enclosed or fenced in on all sides by a barrier at least 8' in height, except on two sides where materials are taken off or put on the elevator or hoist. These two sides should be provided with an adjustable barrier not less than 2' from the edge of the shaft. Likewise all other floor openings should be guarded by enclosure walls and adjustable barriers. The Human Factor Undoubtedly many accidents in building and construction work, as in other industries, are traceable to the ignorance, carelessness or indifference of the workmen rather than to defects in materials. or construction. Workmen, like other people, are bundles of habits. These habits are formed very largely through suggestions received directly or indirectly from their environment and through imitation of other people. By constantly repeating the same actions day after day they come to be more or less involuntary and do not require the conscious judgment of the worker. Hence some accidents that are charged to carelessness should be charged to ignorance and incor |