Page 8 - Industrial Process Plant Construction Estimating and Man Hour Analysis

Introduction

Introduction
This section provides methods for collecting, organizing, summarizing, present-
ing, and analyzing historical man-hour data. Labor productivity is one of the most
important items in a construction estimate. To estimate the productivity for work,
there is a dependence on the value of historical man-hours collected in field con-
struction. This section, for the most part, provides methods to determine produc-
tivity measurement of construction labor. Detailed methods of estimating are
based on historical data that have been collected, structured, and verified by math-
ematical and statistical analysis. Craft man-hour estimates are developed by using
detailed construction-work estimates that apply to any complexity of design and
use historical and quantitative data that lead to a cost driver easily understood.
The purpose of this section is to provide the reader the basic understanding to
set up cost codes, methods for collecting, organizing, summarizing, presenting,
and analyzing historical man-hour data using graphic and regression analysis
to verify historical data. Labor, productivity measurement, tracking systems, esti-
mating methods, and factors for labor productivity and impacts of overtime are
given to enable the estimator to prepare detailed accurate estimates. The historical
man-hour data in this book have been verified by measurement, project cost
reports from field erection, foremen’s report, and one-cycle time studies, and
the data are revised continuously due to construction design, engineering, labor
skill, material, equipment, and procedures. Information for man-hour analysis is
obtained from the foreman’s report and is used to find the number of man-hours
for a task and time control. The cost engineer and welding quality control in the
field monitor and verify the work. These reports are collected for field construc-
tion work. From the reports and review of the specifications, codes and drawings
the cost engineer and the estimator will examine the data for consistency, com-
pleteness, and accuracy. Reports are collected for similar work, and the data are
entered into a spreadsheet. The spreadsheet prepares the data for mathematical
analysis. The engineer and estimator determine the productivity rates. The rate
is used for future cost analysis and estimating similar scopes of work. The esti-
mate data are based on “standard,” which is defined as “forming a basis for com-
parison.” The standard unit man-hour involves these considerations: The work is
being performed by a contractor who is familiar with all conditions at the job site;
the project has the proper supervision; the workers are familiar with and skilled in
the performance of the work task; and there is an adequate supply of labor. There
are clarifications and exceptions stated for the application of the data.

xxiii