Conductors. In the case of the inside conductors above re ferred to, cast iron soil pipes may be used; and these, if carried down in a brick wall, should, if possible, be run in interior walls, and at any rate with not less than eight inches of wall between them and the outside air.
The recess is often paekeq with xonte nonconducting material. Outside metal conductors ,ire made of tin, ziie, galvanized iron, or copper, the latter being the most desirable and also most ex pensive. Metal conductors should be made in some form which will permit expansion in ease they should become frozen solid. A corrugated round pipe or an octagonal or square pipe is to be pre ferred. Conductors are usually given an ornamental lop of large: or small proportions according to situation.
The connection between the conductor and the gutter is usually made by a bent piece of pipe, sometimes a coutiuuation of the con ductor, and often a piece of lead pipe, shown in Fig. 162, called a gooseneck. The opening from the gutter to the conductor should be protected by a strainer to prevent leaves, chips. or other substances from choking up the pipe, and the lower end, if connected with a drain, should be properly trapped.
The superintendence Of glitters and conductors should cover the con struction of the trough, if of wood to be lined, to see that it pitches in the right direction and to the required points. The weight of the metal should be examined, and the manner of securing both gutters and conductors be carefully noted. 'fin or iron surfaces which are concealed should be well painted, and all soldering well and faithfully done. The ends and backs of metal gutters must be examined to see that there is a sufficient width of metal to turn up against the wall, or to lie up on the roof, eight to ten inches being as little as it will be safe to allow. All rubbish ill the gutters must be removed, and all connections left tight and free from obstructions.
Galvanized Iron Work, The use of galvanized iron for ex terior moulded work and bay windows has of late years become an important factor in building construction. Especially is this true of modern fireproof buildings where it is desirable to use no wood in the exterior finish. Belts, cornices, pilasters, door and window finish,
and, in fact, all the trimmings of a building, which in former tines would have been made of stone or wood, are now, to a great extent, made of galvanized iron or, if not too costly, of copper. The structural treatment of galvanized iron and per being about the same, it will be necessary to our purpose only to treat of the former, remembering that for large surfaces galvanized iron is the stouter material.
Bay Windows. Perhaps the greatest use of galvanized iron at pres ent is found in the construction of bay windows. in this construction the es sentials are lightness and strength, so that it is usual to construct a light framework of steel, upon which the metal finish is secured, as in Fig. 163. Cornices are run on steel or iron brack ets secured to the brick wall or the steel frame, as may be found most available. These brackets are shaped to conform roughly to the outline of the cornice, and it is allowable to insert a reasonable amount of boarding to fora} a base for any broad washes of metal, as boarding thus placed, outside of the walls, and completely encased by metal, is not in any danger from fire. For heavy projecting cornices, the brackets should be made of steel angle irons securely built into the wall, or lathed to it, or to the steel skeleton.
Tinned Doors and Shutters. Another use to which tin is frequently put. is the making of metal-covered doors for the fire tection of exposed windows and other openings. Many city laws and insurance rules require that all windows within thirty feet of a source of danger from fire shall be protected by metal-covered shut ters of some kind, and a wooden shutter completelv encased in till has been found to he an effective protection. For protecting openings in party or division walls, the same kind of doors arc used, one on each side of the wall, leaving an air space between of about the thick ness of the wall, as in Fig. 164, and these doors are usually required to he set in rebated frames, and hung by various automatic devices of weights and fusible members, so that they will close at once if attacked by fire.