The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California
Plumbing Heating And Piping
Refer to the sample table, Table 7.44, for the labor factors to be used for installing galvanized steel or wrought-iron water piping with galvanized malleable-iron fittings. In this table the pipe sizes are given in the first column. The efficiency factors E are listed across the top of the table beginning at 0.6 and going up to 1.5. In the body of the table will be found, in man-hours, the labor required to install one fitting of the size given in the lefthand column based on the job efficiency factor established by the estimator and selected along the top of the table. As an example, assume a water line size 2-in. which requires 20 fittings including valves and couplings. In this particular case, after consideration of the job conditions, the labor situation at the location, and other factors as previously described, it is decided that the job is a little easier than normal and can probably be done on an efficiency factor of 0.9. We enter the table on the left at size 2 in. and go across the table to the column headed 0.9. At this point it is found that it will require 1.26 man-hr per fitting for this installation. Multiplying the number of fittings by the labor factor found in the table will give the man-hours required:
20 @ 1.26 = 25.2 man-hr
All labor tables of this book are essentially based on this same method of usage. Estimating is not, and probably never will be, considered an exact science. An estimate of the cost for any project can only be a figure involving many different types of operations and individual elements of cost. At best it represents the considered judgment of the estimator based on his knowledge of the work involved and his past experience on similar projects.
The material requirements for the average job are generally well established in the plans and specifications. This makes it possible to put these requirements down on paper and by quotation or otherwise set a precise value on each piece; the summation of the cost of all the pieces naturally will be the total cost of the material required for the project.
Determination of labor requirements is another matter entirely. Here we are dealing with an element of cost that can vary from job to job and actually from day to day. From a practical standpoint, it is impossible to secure exact cost data upon which to base a comprehensive analysis.
In the preparation of this book and of the tables of labor factors, we have approached the problem in a somewhat different manner. By use of all the data available and such information as could be found pertaining to the subject, we developed what we considered to be logical averages for the various operations. These were prepared in the form of tables and used for the preparation of the estimate.
