Cost database

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A cost database is a computerized database of cost estimating information, which is normally used with construction estimating software to support the formation of cost estimates. A cost database may also simply be an electronic reference of cost data.

Overview[edit]

A cost database includes the electronic equivalent of a cost book, or cost reference book, a tool used by estimators for many years. Cost books may be internal records at a particular company or agency,[1] or they may be commercially published books on the open market. Well known publishers include RSMeans (Reed Construction Data), Craftsman Book Company, Gulf Publishing Company, Cost Data Online (Richardson Estimating Standards), Frank R. Walker Company, BNI Building News, and Design & Construction Resources. The RSMeans Building Construction Cost Data book has a unit price section and a reference section.[2] The unit price section contains numerous items with unit prices for material, labor, and equipment, as well as the total unit price and the total unit price including overhead and profit. Additional information for items includes crew, daily output, labor hours, and the unit of measure. The items in RSMeans are organized by using the Construction Specifications Institute MasterFormat.[3] Some of the other books also organize data in this way, even if they may not use the MasterFormat numbering. The reference section includes additional data such as crew listings, cost indexes, location factors, reference tables, and square foot costs.[4] A cost database typically includes such data as well as unit price data.

The cost database may be stored in a relational database management system, which may be in either an open or proprietary format, serving the data to the cost estimating software. The cost database may be hosted in the cloud. Estimators use a cost database to store data in structured way which is easy to manage and retrieve.[5]

Details[edit]

Costing data[edit]

The most basic element of a cost estimate and therefore the cost database is the estimate line item or work item.[6] An example is "Concrete, 4000 psi (30 MPa)," which is the description of the item. In the cost database, an item is a row or record in a table (of items) and the description is a column or field for that record. Concrete may also be considered to be a material resource. In some systems, estimate line items and resources are the same, in other systems, various resources may be included with a line item. Other examples of resources are labor resources, such as carpenters, and equipment resources, such as cranes. Labor and equipment resources can be combined into a crew, which is then the assumed crew which will install the item or perform the work. Resources and crews can be stored as data in the cost database and can also be related to work items.

Examples of cost database line items:

Identifier Description Unit of Measure Crew Production Rate Material Price
1 Concrete, 4000 psi (30 mpa) cy CP-01 3.00 cy/hr 112.00
4023 Water closet, wall hung ea PB 2.50 hr/ea 620.00
6119 Motor starter, magnetic, FVNR, 10 hp size 1 ea EL 3.50 hr/ea 262.00

Examples of cost database labor resources:

Identifier Description Unit of Measure Base Price Benefits Insurances Payroll Taxes
CA Carpenter hour 37.32 12.95 5.01 4.56
CM Cement Mason hour 32.51 8.23 2.11 3.90
LA Laborer hour 26.46 5.16 5.72 3.89

Examples of cost database equipment resources:

Identifier Description Unit of Measure Base Price Fuel Filters, Oil, Grease
cv1 Concrete vibrator hour 0.72 0.21 0.02
ex2 Excavator, track-mounted, 1-1/2 cy (1.1 m3) hour 42.00 48.25 6.12
cr100 Crane, track-mounted, lattice boom, 100 ton (90 t) hour 82.50 59.16 8.27

Examples of cost database crews:

Identifier Description Unit of Measure Resource 1 Quantity 1 Resource 2 Quantity 2 Resource 3 Quantity 3
CP-01 Concrete placement hour CA 1 LA 3 cv1 1
EX-01 General excavation hour OP 1 LA 2 ex2 1

Factor and adjustment data[edit]

Various factors and adjustments may be useful in the estimating process. Some examples include:

  • Factors to adjust costs from one location to another
  • Factors to adjust costs from one time to another
  • Currency conversion factors
  • Sales and use tax rates
  • Other tax, insurance, and bond rates
  • Overhead factors

Organizational data[edit]

Data which may be used to organize a cost estimate into groups and levels, and to summarize the cost details can also be part of a cost database. A popular coding system which can be applied to construction cost estimates is MasterFormat.[7] Another coding method is Uniformat.[8] Also, various types of work breakdown structures or WBS may be used. It may also be useful to assign the costs to a chart of accounts or COA (a.k.a. Code of Accounts). Other organizational needs include:

  • Grouping by job cost account
  • Grouping by subcontractor or vendor
  • Grouping by material class or type
  • Grouping by facility, floor, level, location, area, etc.
  • Grouping by system
  • Grouping by project phase or stage
  • Grouping by inside or outside battery limits

All of these represent organizational data which can be stored in the cost database and used to support the cost estimate.

Calculational data[edit]

Data which can be used to calculate quantities and costs can also be part of a cost database. For example, there are various formulas for calculating the area of shapes, the volume of solids or spaces, and the weight of materials. There are defined unit properties of materials also. Materials each have certain densities or unit weights. Reinforcing bars are produced in certain sizes, with certain unit weights. Additionally, data which helps calculate the selection or specification of estimate contents can be included.

See also[edit]

References[edit]

  1. ^ J. David Nardon, Bridge and Structure Estimating, McGraw-Hill Book Company, 1995, Page 5
  2. ^ "RSMeans Building Construction Cost Data 2012, 70th annual edition" 2012 Reed Construction Data, Page v
  3. ^ "RSMeans Building Construction Cost Data 2012, 70th annual edition" 2012 Reed Construction Data, Pages 4, 5
  4. ^ "RSMeans Building Construction Cost Data 2012, 70th annual edition" 2012 Reed Construction Data, Page v
  5. ^ "A Visual Approach to Construction Cost Estimating", Phuwadol Samphaongoen, Marquette University, e-Publications@Marquette, Page 47
  6. ^ "A Visual Approach to Construction Cost Estimating", Phuwadol Samphaongoen, e-Publications@Marquette, Page 7
  7. ^ MasterFormat Numbers & Titles, April 2012, The Construction Specifications Institute and Construction Specifications Canada
  8. ^ "Uniformat," Construction Specifications Institute, http://www.csinet.org/uniformat

External links[edit]