Activity / Estimate Type

Conceptual

Preliminary

Detailed

Definitive

Purpose

Ranking/Rejection

Economic Feasibility

Project Approval

Project Control

Basis of Estimate

Site

  Location

Assumed

Preliminary

Optimised

Final

  Geotechnical

Assumed

Preliminary

Final

Final

Process

  Plant Capacity

Assumed

Preliminary

Final

Final

  Process Testwork

If available

Advanced

Complete

Complete

  Energy & Material Balance

Assumed

Advanced

Optimised

Frozen

  Process Flow Diagram

Assumed

Decided

Optimised

Frozen

  Equipment List

Assumed

Preliminary

Optimised

Final

Design

  Status of Design

Conceptual

Probable

Actual

Actual

  Equipment Selection

Assumed

Preliminary

Optimised

Final

  General Arrangement

  - Mechanical / Layout

None / Basic

Minimal

Fair Detail

Complete

  - Structural

None

Outline

Fair Detail

Complete

  Piping Drawings

None

Basic Layout

Some Detail

Advanced

  Electrical Drawings

None

Single Line

Some Detail

Advanced

  Detail Design Drawings

None

None

Some

Advanced

  Specifications

None

Standard

Preliminary

Contract Status

Project Delivery

  Procurement Plan

None

Preliminary

Final

Frozen

  Program

Simple Bar Chart

Bar Chart with Critical Path

Critical Path Network

Critical Path Network

Cost Estimate Method

General Approach

Data Base Rates

Single Quote

Multiple Quotes

Contract Value

Civil Work

Sketch Quantities

Basic Drawing Quantities

Detailed Take-Off

Contract Value

Structural

Sketch Quantities

Basic Drawing Quantities

Detailed Take-Off

Contract Value

Major Equipment Costs

Data Base

Single Quote

Multiple Quote

Contract Value

Mechanical Work

% of Equip

% of Equip

Manhrs/Tonne

Contract negotiations

Piping Work

Rough Quantities

Prelim. Take-off

Take-off

Detailed Take-Off

Instrumentation

% of Equipment

% of Equipment

Take-Off

Detailed Take-Off

Electrical Work

$ per kW

$ per kW

Take-Off

Detailed Take-Off

Indirect Costs

% of Total

% of Total

Calculated

Calculated

Economic Analysis (DCF)

Not Meaningful

Reliable Results

Final Decision Tool

n/a

Contingency for Undefined Items

Up to 30%

15% - 25%

10% - 15%

5% - 10%

Typical Accuracy

  ± 25% to 30%

  ± 15% to 25%

  ± 10% to 15%

  ± 7% to 10%