It will be noticed that only the sizes and lengths of pipes and the sizes and kinds of fittings can be had from the plans and the quality, such as extra heavy tar coated, and the description of the cleanout screws must be obtained from the specifications.

Having the length of pipe and the number of fittings the next requirement is to find the amount of lead and oakum that will be required. To learn this the number of joints of different size must be counted. The plan shows that there are thirty-one 4-inch joints, five 3-inch joints and five 2-inch joints, and the lead and oakum required for these joints can be found by means of the following rules:

Rule I

To find the quantity of lead required to calk a joint in iron pipe, allow one pound of lead for each inch in diameter of the pipe.

Example

What weight of lead will be required to calk twenty 6-inch pipe joints?

Solution - According to the rule, 6 pounds of lead will be required for one 6-inch pipe joint, consequently, 20 joints will require 20x6=120 pounds of lead.

In like manner the amount of oakum can be found by the following rule:

Rule

To find the oakum required to pack soil-pipe joints allow two ounces of oakum for each inch in the diameter of the pipe.

Example

What weight of oakum will be required to pack twenty 6-inch pipe joints?

Solution

According to the rule, 12 ounces of oakum will be required for one 6-inch pipe joint, therefore 12x20=220 ounces, or 15 pounds, of oakum will be required for twenty 6-inch joints.

Applying the two foregoing rules to the example of estimating under consideration, we find that it will require 149 pounds of lead and about 18 pounds of oakum for making the joints.

The labor of installing the pipe is the only item which cannot be definitely determined. This is so much a matter of the personal ability of the journeyman plumber that no definite length of time can be stated which would not be too short for some workmen and much longer than would be required by others. Assuming, however, that the trenching is done, the points of the various rising lines all marked so that the plumber has nothing to do but proceed with the installation of the pipes a good swift workman and his helper would install the pipe shown in the illustration in two days. That would be too short an allowance to make, however, as the average workman could not do it in less than three days. The estimator must know his men and be familiar with their capabilities and limitations. The personnel of the workmen in different shops varies to such an extent that the workmen of some shops require on an average 50 per cent. more time to do a given amount of work than would be required by the workmen of other shops.

The work shown in the illustration is supposed to be run in shallow trenches under the level of the cellar floor. If run in deep trenches an extra allowance of at least 10 per cent. should be made to offset the extra work and difficulties encountered. If on the other hand, the work is to be suspended under the ceiling beams, an extra allowance of 50 per cent. should be made.

The cost of labor having been determined, nothing remains to calculate but the cost of fuel for melting the lead. This can be arrived at by the number of days the man is employed on the work. One gallon of gasoline will last about one day, so that if the workman spends three days on the work it would require three gallons of gasoline to supply him. The various items of pipe, fittings, lead, oakum, fuel, labor, having now been ascertained, there remains nothing further to be taken from this plan and the task of taking off quantities may be considered as completed, although by no means has the entire work of making up an estimate been finished, for items of freight, drayage, profit, operating and other expenses which will be explained later must be taken into account, and the costs of the various items ascertained. The weight of standard and extra heavy soil pipe may be found in Table V, and from these weights the freight and drayage charges can be calculated.

Table V. Sizes And Weights Of Cast-Iron Soil Pipe