Worrying about scheduling when preparing the estimate may seem superfluous. But a bid price based on a hypothetical rule of thumb can be dangerous.

With current computer estimating systems, scheduling functions should be easily available. Scheduling is also important for gauging personnel, financial, and physical resources necessary to commit to the project.

Perhaps of equal concern is the possibility that the schedule could avoid disputes arising from problems on the project. The schedule built for the estimate must be realistic and tie into the number of workdays allowed for the project in the specifications. The number of calendar days allowed must be adjusted for weekends and holidays when work is usually not scheduled. This reduces a 30-day month to only 21 workdays if there are no holidays in the month. In final consideration, the general contractor will dictate the schedule and an electrical contractor's estimate schedule can be used to negotiate a reasonable compromise.

In the past, when electrical portions of projects were not as large nor as complicated, it was fairly simple to take the number of labor hours, split them into various labor categories, and assume the number of persons needed. Modern projects are not only more complex; they are also more time intensive. Construction time has shortened, especially since the days of high interest rates where an owner's investment could rise dramatically if a project lingered too long in the construction phase. Schedules on most projects have been compressed, and many use the dreaded fast-track method. "Fast track" means work progresses as plans for the job are being drawn--a sure cause for ulcers.

The schedule for a project is important when the estimator begins to consider the workforce required. As the number of workers increase on the job, it is not uncommon for productivity to drop. This phenomenon can be readily understood when considering the time required to coordinate more workers, as well as the effect on tooling and supplies. Many of these factors are included in some of the labor units being used in the estimate. Financial considerations also hinge on the projected schedule, as the schedule may indicate when the peak workforce is at the site and the maximum materials are required. Most firms need to have some idea of such cash- draining periods so they can make arrangements for interim financing. Including the financing cost as a direct job cost is most often neglected, yet it does affect the bottom line.

Building a schedule from an estimate can be accomplished efficiently in a number of ways. It is best to decide, or know, the available tools or methods that may be used for the schedule construction. This is where computerized estimating can be invaluable. These programs should also accommodate the vagaries of late addenda. An estimating system that can link to one of the many schedule programs such as MS Schedule and Primavera will provide management tools that can be updated and verified as needed, or as reports come in from the field.

To make a reliable schedule, the project must be estimated in an organized fashion. In an earlier column we talked about divisions of a project, but for estimating purposes those divisions must be broken down further. If a numerical system is used, the schedule-making task will work right into the type of information used by scheduling programs, and can at the same time be used for manual schedule-building. If the company reports labor time by a number that could also be used thereby combining schedule building and job tracking into the estimating document. For smaller projects, perhaps a few subheadings will suffice, and while a schedule may not be of paramount importance, the project costs and functional project management a breakdown is certainly necessary for tracking.

A typical number system is that used for various segments as listed in the Manual of Labor Units. The manual is divided into 11 sections: Conduit and Raceways; Wire and Cable; Powers Distribution; Lighting Fixtures; Wiring Devices; Hazardous Systems; Special Systems; Grounding Systems; Equipment Connections; Temporary Power; and Outdoor Systems.

Within each of these classifications, subdivisions should be established to consider installation elements such as ceiling heights and type of construction. It's obvious that such a system may not meet the flow of an actual project. The numbering system of a computer estimating system suggests a number of numerical divisions, which when applied can be used as a sort code to segregate the labor for scheduling purposes. Numbers typically run from 100 through 800 for various systems, with room for further divisions to total 65,000--far exceeding most needs. These sort codes are then transferred to a scheduling program, from within the estimating system, and the estimator then follows that up by fitting the various operations to the schedule limits. The type of schedule selected depends largely on the talents and tools available to the estimator. A simple bar graph is better than no graph at all. A bar graph can be built with a minimum of effort and skill, but it has its shortcomings. At the other end of the spectrum is the Critical Path Schedule (CPM), a favorite of MBA schools that allows for showing multiple paths to better indicate when a crew may have to be split to accomplish more than one task level at a time.

The Program Evaluation Review Technique (PERT) chart is a graph that is done after a project is completed. It looks similar to a CPM, which is used at the start of a project. Both PERT and CPM schedules are considered network schedules. Whichever type of graph is used, the important factor is that the estimator use a reasonable approach to scheduling based on a normally expected construction routine that can build the project within the allotted time frame. It would also be helpful for the estimator to learn the scheduling process in a formal setting.

Scheduling is critical in today's markets because of the overall effect of resources the firm will have to commit to the project. Scheduling also helps safeguard the basis of the estimate. A schedule, however, will not prevent improbable demands from being made on the electrical subcontractor, such as staffing the project with more people than needed or accelerating the project. In both cases, the estimators' realistic assumptions with a logical schedule can be a strong line of defense when accusations begin to fly.

DAVID is a professor of electrical technology at Long Beach City College, Calif., a consultant and an expert witness. He can be reached at (562) 597-1877or by e-mail at edavid@lbcc.cc.ca.us.