The making of intelligent working diagrams for gas or water fitting, is not difficult. Though important, comparatively few have given it due attention. When plans are accurate, the usual work of making figures to show what length the pipes are, may be dispensed with by employing self measuring ruled sheets in conjunction with the method of diagramming here de scribed. Diagramming sys tematically and with all lines approximately proportional in length, saves time in distributing the pipe. There is no wondering whether a piece runs down or up, or as to which room a bracket light looks into, or whether a piece of pipe belongs in a horizontal or in a vertical position. A properly made diagram indicates these points clearly, and also what pieces belong in the same plane. There should never be any confusion as to which pieces have been cut and which not, when getting out the pipe. Symbols can be made to show what pieces have been cut and what size they are. The symbols found by practice to answer this purpose best, are as follows: When a }-inch piece is cut, a common check mark is put beside the line on the diagram, show ing that it is } inch and has been cut. For a j-inch piece, a short, straight mark like the letter I, placed across the line, is used. For a i-inch piece, two connected marks like V are made across the line. For i-inch pieces, three connected marks, like the capital N, are made across the line. For 1-inch pieces, four connected marks, like the capital letter M, are used across the line. For 1}-inch pieces, five connected marks, like the capital W with one extra leg, are used. Each short, straight mark represents a quarter-inch in the diameter of the pipe, except in the case of I-inch pipe. For nipples that are too short to put the symbols on, draw a waved arrow from the nipple, and put the symbol upon it. Fig. 101 shows the symbols described, with corresponding sizes of pipe marked beneath them.
In reading plans of buildings, it is usual to have the front of the building, as represented by the plans, next to the person. Plans represent horizontal sections at the elevations designated; while elevations show the altitude of one floor above the other, etc. The plans of the different floors of a building are usually drawn side by side, with the outside face of the front wall on a line. By this means, a straight edge laid across the plans from side to side, will show which partitions are in line with one another. One can judge with the eye, on the cross-partitions, accurately enough to give a good idea of the relative position of the rooms on different floors, one way; but to locate the partitions running from front to back, it is necessary to measure from the wall on the plans of the different floors. House plans are almost always drawn to }-inch scale. In gasfitting diagrams, all sizes of pipe are represented by single or skeleton lines, because the pipes are small.
Now, assuming the plans to be marked for gas, center the rooms, and chalk all wall openings. Then proceed to diagram the lines
representing the pipe, making them as nearly proportional to the length of pipe as can easily be done with pocket-rule and pencil, say to k-inch scale.
Represent all vertical pipes by diagonal lines parallel to one another, whether they be bracket pipes, risers, or offsets in the line. Never represent a horizontal pipe by a diagonal line. Every vertical pipe which falls below the horizontal pipe to which it is connected, should be drawn toward the front of the plan at an angle of 45 degrees to the left. Every vertical pipe which rises above the horizontal pipe to which it is connected, should be drawn away from the front of the plan, at an angle of 45 degrees to the right. Represent all horizontal pipes by parallel lines perpendicular either to front or to side wall. When the run of pipe is from front to back, the parallel lines should be perpendicular to the front wall of the building. When the run is from side to side, the parallel lines should be perpendicular to the side wall of the building. Any line in the diagram that is perpendicular to any other line of the diagram may then be taken to represent a horizontal pipe. Any number of lines representing horizontal pipe and all joined together, are thus indicated to be in the same horizontal plane. Any single line or system of lines representing horizontal pipe, but separated from the others by a diagonal line, is therefore in a different horizontal plane. For in stance, the second floor riser, 10 feet 3 inches long, shown in the dia gram, Fig. 102, con nects the horizontal pipe under the sec ond floor with that under the third floor. These pipes are in different planes, one set be ing 10 feet 3 inches above the other.
There is one ex ception to the rule concerningdiagonal lines. Several feet of pipe can often be saved by cutting across, instead of making an angle with, the pipe. To do this without danger of confusing one as to whether the diagonal piece is intended for vertical pipe or for a di agonal piece in the horizontal plane, make such lines dotted instead of solid, as shown at C, Fig. 102.
To indicate the direction in which bracket openings look, by the way in which they are drawn, eight skeleton diagrams of bracket pipes, showing how the direction of bracket openings would be indicated for the four walls of a square room, are shown in Fig. 103. A, B, C, and D show that the pipes are vertical and run up from the floor below, A looking into the room from the front wall, B from the rear, C from the left side wall, and D from the right side wall. In accordance with plan drawing, the short lines representing the ears and nozzle of the drop-ells are made in plan position with dots at the ends to represent caps. The ears of the fitting, drawn in front of the out let, show that the fitting looks to the rear; ears behind the outlet show that it looks to the front; at the left of it, that it looks to the right; and to the right of it, that the fitting looks to the left.