Webster's defines estimate as: “A statement of the cost of work to be done.” For those of us in the electrical world, what this really means is: “How much is it going to cost to do the electrical work for this project?” What the electrical work will sell for is another matter. That would be bidding, which is a whole different approach, and a topic for future discussion.
Types of estimates include conceptual, budgetary, design development, and unit price. The unit price estimate is the most accurate — and best suited for construction bidding. The unit price estimate is also a method of estimating. In the unit price estimate, you assign a price and a labor quantity to each item of material for a given set of installation conditions. These are called standard conditions, which form the benchmark for an estimate. For conditions outside the benchmark, such as increased height or restricted access, you must adjust labor accordingly. The unit price estimate, which requires a detailed set of plans and specifications with all of the design decisions made, can be broken into three parts: takeoff, extension, and summary. Let's take a look at the basics involved in each stage of the estimating process.
Takeoff. Takeoff is the science of quantifying the materials necessary to complete a job, as shown on the plans and as specified. At the heart of every good estimate is a good takeoff. The word “takeoff” comes from the action of “removing” the material from a set of plans, by marking with colored pencils or highlighters, until all of the materials are taken off. The takeoff is colored to identify various sections of the estimate, such as lighting, distribution, or feeders. Takeoff is finished when all the materials have been “taken off” the plan sheets, and listed on takeoff forms (or entered into the computer). The takeoff process also includes quantifying sheet notes and indistinct items, such as rigging or testing. Most electrical takeoffs consist of eight basic sections: lighting, distribution, devices, branch circuits, equipment circuits, feeder circuits, site work, and special systems. Although other sections on a project may include emergency generators, cable trays, or fiber-optic systems, the procedure stays the same.
All good estimators follow an orderly process and a consistent routine when completing the takeoff, which minimizes errors and omissions. Count the simplest or most common items first, the more complex ones next, and the sophisticated elements last. Following this sequence of takeoff can yield additional benefits as well. For example, by counting light fixtures first, you can get a complete “walk through” of the job — and in the process become familiar with the building construction, elevations, and room layouts. This will be very helpful as you progress through the other sections of the job. After counts, move on to length measurements, such as branch and equipment circuits. Because feeder circuits are the most expensive, routing can have a significant impact on total cost. Accordingly, feeders are typically saved until the end so that you can use maximum building data to figure the best route for takeoff. Lastly, move on to calculated measurements, such as site work excavation and concrete work.
As you prepare for the takeoff, you should understand the “standard conditions” for the work your team will be performing. Only when you're thoroughly familiar with the standard conditions can the labor and materials properly be adjusted for the actual job conditions. For example, let's say your company's standard installation conditions for a 1-foot by 4-foot fluorescent lighting strip fixture include a mounting height up to 15 feet. However, the project you're estimating indicates these fixtures must be mounted at a height of 25 feet. Therefore, you must adjust the labor unit for the increase in height (labor units are a decimal expression of manhours). See Fig. 1 for typical labor unit components.
Before you actually start the takeoff process, you must review the project specifications to determine the scope and quality of materials specified for the project. You should also make note of special job expenses required, such as permits or seismic calculations. And don't forget to review the specifications for scope of vendor quotes. Take summary notes of these three areas for easy reference and to avoid overloading your memory with a mound of technical information. Once you've completed this prep work, you're ready to perform the takeoff for the basic sections noted earlier, as follows:
Lighting (includes indoor fixtures, outdoor fixtures, and site lighting):
Takeoff procedure — Count light fixtures by type, according to the Lighting Fixture Schedule. Fixture takeoff assemblies should include lamps and mounting hardware.
Standard conditions — New construction; all fixtures UL listed and purchased by the electrical contractor; up to 15-foot mounting height; use of rolling staging (ground-level location with good access); material staging within 100 feet of the work area.
Distribution (includes switchboards, panelboards, transformers, MCCs, and related equipment):
Takeoff procedure — List switchboards by size (amperage), voltage, type, and number of sections. List panelboards by size (amperage), voltage, and type. List transformers by size (KVA), voltage (primary and secondary), enclosure rating, and type. List MCCs by size (amperage), voltage, type, and number of sections. Distribution takeoff should include all wire terminations, mounting hardware, and accessories. • Standard conditions — New construction; all equipment purchased by the electrical contractor; all switchboards and MCCs included with interwiring and control circuitry; up to 10-foot mounting height; use of rigging for lifting and hoisting; ground-level location with good access; material staging within 100 feet of the work area.
Devices (includes receptacles, switches, and related equipment):
Takeoff procedure — Count devices by size, type, rating, and location (indoor/outdoor). This includes boxes, plates or covers, and fastening hardware.
Standard conditions — New construction; less than 10-foot mounting height; use of rolling staging (ground-level location with good access); material staging within 100 feet of the work area.
Branch circuits (lighting and switching circuits, and receptacle power):
Takeoff procedure — List branch circuits by size and type, wire fill, and length. Branch circuits are most often tallied by length and count, such as 350/12. Total length equals 350 feet with 12 segments (a segment has a connection on each end). Branch-circuit takeoff should include supports and any required junction boxes.
Standard conditions — New construction; up to 15-foot mounting height; use of rolling staging (ground-level location with good access); material staging within 100 feet of work area.
Equipment circuits (HVAC, motors, and other utilization equipment):
Takeoff procedure — List equipment circuits by size and type, wire fill, and length. Equipment circuit takeoff should include fittings, pull boxes, flex whips, and supports. Additionally, equipment circuit takeoff should include any disconnects, motor starters, or control stations.
Standard conditions — New construction; equipment completely assembled with only a single point connection; up to 15-foot mounting height; use of rolling staging (ground-level location with good access); material staging within 100 feet of the work area.
Feeders (includes single line diagram and all distribution circuits):
Takeoff procedure — List feeder circuits by size and type, wire fill, and length. Feeder circuit takeoff should include field bends, fittings, pull boxes, and supports. Additionally, feeder takeoff should list any core drill, wall/floor penetrations, sleeves, or fire stopping.
Standard conditions — New construction; up to 15-foot mounting height; use of rolling staging (ground-level location with good access); material staging within 100 feet of the work area.
Site work (includes power and communications service, site distribution, and site lighting circuits):
Takeoff procedure — List circuits by size and type, wire or cable fill, and length. List excavation and backfill by trench section and length, and concrete by cubic yard. List transformer pads, manholes, and handholes by size and type. Site work takeoff should include concrete reinforcing as required, grounding, and utility-specific requirements, such as special raceways and risers.
Standard conditions — New construction; good soil/digging with no import or dewatering; precast concrete substructures; standard backhoe and compaction equipment; level location with good access; material staged within 100 feet of the work area.
Special systems (includes fire alarm, tele/data, and security):
Takeoff procedure — List control panels and special equipment by system, size, and function. Count special system devices by size, type, and function. List special system circuits by size and type, wire or cable fill, and length. Special systems takeoff should include panel terminations, device boxes, mounting and supporting hardware, and ancillary items shown on the system riser diagrams.
Standard conditions — New construction; complete system purchased/installed by electrical contractor; up to 15 feet in height; use of rolling staging (ground-level location with good access); material staged within 100 feet of jobsite.
Extension. Once the takeoff is finished and all the right quantities of all the right materials have been accounted for, you can move on to the extension phase of the estimate. Extension activities consist of:
Extending the assemblies to component items.
Extending the item material prices.
Extending the item labor units, as adjusted during the takeoff.
Calculating labor rates, crew makeup, and composite labor rate.
Carrying the extended totals to the summary.
Takeoff usually is done by assemblies, which must be extended to items for pricing and laboring. This can be done manually with pricing forms and an adding machine or by computer. The manual method is time consuming and prone to error, but is very basic. Using a computer will speed the process and yield greater accuracy. The benefits of a good software program cannot be overemphasized and will typically pay for itself many times over.
The same concept applies to extending item material prices and item labor units. Pricing forms for extending material and labor are easily obtainable. However, computer templates save time and help eliminate math errors. Obtain material prices from the purchasing department or from current supplier quotes. Base labor units on company historical data. Companies that do not maintain historical data and productivity rates are destined to lose jobs by submitting bids that are too high — or too low.
When calculating labor rates, include all applicable labor costs, such as fringe benefits, taxes, insurances, and expenses. Fringe benefits should include all required costs for health and welfare, pension, training, and vacation. Taxes include social security (FICA), federal and state unemployment tax (FUTA and SUTA), and any local taxes. Insurance costs include workman's compensation, general liability (labor portion), and builders' risk or umbrella insurance. Labor-driven expenses include small tools, trucks, and “other” expenses calculated as a direct function of labor.
Labor rates are calculated for each field classification such as foreman, journeyman, and apprentice (see Table). Determine the crew makeup from consulting with the superintendent and then spread out the total manhours over the project schedule (Fig. 2). Applying the crew makeup to the labor rates, you can compute the project composite rate.
Now it's time to carry these totals (materials, labor units, and composite rate) to the summary step.
Summary. As the extended totals are carried forward to the summary, it's now time for you to add job expenses. Man lift, boom lift, crane, and other equipment should be included, whether owned or rented. Other job expense items may include permits, office trailers, electric and phone service, dumpsters, seismic calculations, and engraving.
Finally, you'll need to add in supplier and subcontractor quotes. Make sure you review all vendor quotes for proper scope and compliance with the plans and specifications. Solicit multiple quotes to ensure you receive the best prices.
With these steps behind you, it's time to total all the job costs: materials, labor, expenses, suppliers, and subcontractors. This summary yields the prime cost of the job. Prime cost is the grand total of all the direct job costs. At this point, the process of estimating is complete. Management will determine the markup and set the bid price based on your estimate. If you've done your job well, then you've created a good estimate — with all the right amounts of all the right stuff. More importantly, you've presented management with an accurate picture of the expected cost to do the job.
Hughes is an estimating manager with Bergelectric Corp., Escondido, Calif.