BETHESDA, Md. -- The National Electrical Contractors Association has revamped six studies that address the effects of adverse working conditions on the productivity of electrical workers. NECA says the studies provide benchmarks by which contractors can assess work in progress or establish guidelines for new electrical construction projects.

Originally produced in the 1970s and '80s, the studies have now been rewritten to cover many of the troublesome elements such as overtime, multi-story building construction and temperature and humidity typically encountered by contractors on today's construction projects. A new report that explores the cumulative impact of multiple adverse factors, such as shift work, owner-furnished items and the stacking of trades, also is included.

While the studies focus on electrical construction, they are applicable and useful to the entire construction industry, said Dr. Awad S. Hanna, P.E, well known for his research studies for the Electrical Contracting Foundation. Hanna, a professor of construction engineering and management at the University of Wisconsin-Madison, also has conducted a number of seminars for NECA's Management Education Institute.

The productivity studies include:

Normal project duration

A "normal" project is defined as a project that is managed properly and proceeds as expected. In this publication, benchmark indicators for normal project duration are established. A relationship between project size in work hours and normal project duration is developed and presented in a series of tables and charts.

Project peak workforce

The baseline for project peak workforce is established in this study. A relationship between project size in work hours and peak workforce is developed and presented in a series of tables and charts. This publication also identifies the recommended number of workers for different project sizes.

Manpower loading: rate of manpower consumption

The rate of manpower consumption is identified for the electrical contracting industry and is displayed graphically through a manpower-loading curve. Also, a powerful method for integrating multiple management and control tools in order to assess actual project status is identified. This method, called the trapezoidal technique, combines estimating methods for normal project duration, peak workforce level and rate of manpower consumption into one easy-to-use formula.

Overtime and productivity in electrical construction

This study includes a recently developed overtime model designed to estimate productivity losses resulting not only from the sporadic use of overtime, but also from the extended use of overtime. The data in this book is intended to assist contractors in recognizing the problems associated with scheduled overtime. This study also explains how to use the data to estimate the impact of overtime on construction contracts.

Effect of multi-story buildings on productivity

Buildings with 13 stories or more require additional labor costs that are unique to tall buildings. These increased costs are associated with increased quantities of material; additional time required to move workers, tools and material vertically; and a subsequent loss of productivity. This publication identifies unique tall-building costs such as type of occupancy, quantity of floor area and number of change orders. Worksheets and graphs are provided to assist the contractor with the development of an accurate estimate of costs, or work hours, for a multi-story building.

Effect of temperature on productivity

The report identifies the effect of extreme combinations of temperature and humidity on labor productivity. The results are presented in a series of tables and charts, which provide a powerful tool that can be used by contractors to adjust their bids during the bidding process and to support requests for time extensions and compensation during the construction process.

Factors affecting labor productivity for electrical contractors

The study seeks to quantify elements that decrease the productivity of work site labor. These elements, commonly referred to as factors affecting labor productivity, include overtime, shift work, over manning, over-furnished items, beneficial occupancy, stacking of trades and cumulative impacts of factors affecting labor productivity.

Benchmarks provided by the studies include normal project duration, peak workforce level and the rate of manpower consumption. Guidelines for using these benchmark tools are provided within each report.

Individual publications can be purchased for $60. Or, the entire set of seven studies can be had at a discounted price of $345. This includes the seven studies, an introductory summary of each study and a storage case. The books can be purchased from the NECA Order desk by calling 301-215-4504.

The National Electrical Contractors Association represents about 70,000 electrical contracting firms. The industry employs about 650,000 electrical workers and produces an annual volume of approximately $95 billion. NECA includes 120 U.S. chapters in addition to others in countries around the