WSP03710

• File Number: 8446
• Description: Cache La Poudre Platte Project
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 9/28/1982
• Author: AACE
• Title: Expected Accuracy of Cost Estimate
• Water Supply Pro - Doc Type: Report/Study

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Table 9,2

EXPECTED ACCUHACY OF COST ESTIMATES

TYPE OF ESTIMATE

O/'der of Magnitude Estimate - This is an
approximate estimate made without detailed
engineering data. Some examples woule! be:
an estimate from cost-capacity curves, <In
estimate using scaleLlp or scaledown factors,
and an approximate ratio estimate. It is
normally expected that an estimate of this
type would be accurate within +50% or -30%, *

Budget Estimate - Budget in this case applies
to the owner's budget, and not to the budget as
a project-control document. A budget estimate
is prepared with the use of flowsheets, layouts
and equipment details. It is normally e>,pected
that an estimate of this type would be accurate
within +30% or -15%. *

_c_'.

Definitive Estimate - As the name implies
this is an estimate prepared from very defined
engineering data. As a minimum, the data must
include: fairly complete plot plans and elevations,
piping and instrument diagrams, one-line electrical
diagrams, equipment data sheets and quotations,
structura I sketches, soi I data and sketches of major
foundations, bui Iding sketches and a complete set
of specifications. The "maximum" definitive
estimate would be made from "Approved for
Construction" drawings and speci,ficatiol1s.

It is expected that a definitive estimate would
be accurate within +15% and -5%. *

*Prepared by the American Assn, of Cost Engineers.

9~8

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TYPE OF
ENGINEERING
STUDY

COMPRHIENSIVE STUDY

PREDESIGN STUDY

ENGINEEH'S ESTIMAIE
AT TIME OF CONTRACT
BIDDING

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