In scaling the cast-iron soil pipe shown on plans, no deduction is made for fittings unless the fittings are massed together in such a bunch that little or no pipe will be used, in which case the careful estimator will determine just how much pipe he will need after deducting the fittings. The reason for counting the fittings as so much pipe is to compensate for the pipe which is cut to waste, proves defective or is broken in cutting or calking. If the estimator scaled his pipe down to the utmost limit he would be sure to run short on the installation.

Fig. 2

In order to illustrate the manner of taking off quantities from a cast-iron pipe drainage system the drawing, Fig. 2, is incorporated. In determining the amount of pipe used in the horizontal piping shown in the plan a rule would be laid on the main run, from the end of the house drain where it will join the house sewer outside the building, and the distance measured to the end of the clean-out screw at the opposite end. This drawing has been reduced so that it is not now drawn to scale, although the plan was originally. But assuming that the extreme length on the original plan was 10 inches, then, as the plan was drawn to a scale of 1/4-inch to the foot, there would be 40 feet of pipe in this run.

Having the main drain, the branches may be scaled in the same way and the various lengths of the several sizes of pipe jotted down. Having the amount of pipe that will be required the next step is to count and classify the fittings. The first fitting on the line is a 4 x 4 Y branch. This is put down as a 4-inch Y The next fitting is a 4-inch running trap with two vent hubs; next comes a 4-inch T branch, then a 4x3 branch, which is listed as a 4-inch Y.

The reason that the 4 x 4 Y, the 4 x 3 Y, also the 4 x 2 Y, are all classed as 4-inch Y fittings is because the list price and discount on branch fittings are the same for straight fittings as for those with reducing branches, and, as the object at this time is only to ascertain the cost, not to order the fittings for the work, the various branch fittings are jotted down as though of uniform size at all the outlets.

Assuming that the pipe as scaled shows 85 feet of 4-inch pipe, 22 feet of 3-inch pipe and 7 feet of 2-inch pipe; and that the pipe is to be of extra heavy quality, tar coated both inside and outside, then the list of items so far as we have gone would contain the following materials and quantities: