International Approach to Predicting Construction Labour Hours Speaker – Shane Forth Vice President – Association of Cost Engineers Manager of Project Controls – AMEC Power and Process Europe Siberian Regional Cost Estimating Centre International Research and Practice Conference 10 th – 11 th November 2009 – OMSK, Russia
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International Approach to Predicting Construction Labour Hours
Presented 10th November 2009 at International Research and Practice Conference, Omsk, Siberia. Participants included ACostE, Union of Russian Builders, Government of Omsk Region, FSI, OJSC, Siberian Regional Cost Estimating Centre
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International Approach to Predicting Construction Labour Hours
Speaker – Shane ForthVice President – Association of Cost Engineers
Manager of Project Controls – AMEC Power and Process Europe
Siberian Regional Cost Estimating Centre
International Research and Practice Conference
10th – 11th November 2009 – OMSK, Russia
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Shane Forth FACostE, FAPM
Power and Process Europe– Project Controls Strategy – Operational Excellence– AMEC Project Management Academy– Project Support
Whessoe Oil & Gas– Bid Manager and Project Services
Kuwait Santa Fe Braun– Scheduling Engineer
Other Experience – Kvaerner, ICI, Simon Carves, John Laing
Association of Cost Engineers– Vice-President – Chairman, Planning & Scheduling SIG
– Chairman Project Control Managers Working Group
– Various Working Groups, Graduate & Apprenticeship Schemes Occupational Standards
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Estimate Accuracy
There is no merit in attempting to achieve a level of accuracy that is inconsistent to the amount of information available, particularly as this could lead to the Estimate being given a ”perceived” credibility it does not deserve
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Estimate Accuracy Est
imate
Acc
ura
cy
Completeness of Design0% 95%
1 Feasibility (- 25% to + 50%)
3 Basic Design (- 10% to + 15%)
4 Detail Design (- 5% to + 10%)
+
_
2 Concept (- 15% to + 25%)
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Information for EstimatingGeneralised scope definition
Required capacity of plant
Approximate Weights
Preliminary project schedule
1 Feasibility
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Information for EstimatingPlant Location
Preliminary process diagram
Main statutory requirements
Equipment list
Outline engineering specifications
Preliminary “block” plot plan
Offsites and utilities by system and capacity
Budget quotes for Equipment
Preliminary equipment data sheets
Preliminary process and instrument diagram
2 Concept
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Information for Estimating3 Basic Design Firm quotes for major equipment
Detailed scope definition
Finalised heat and mass balance calculations
P & ID’s for process and offsites
Detailed plot plans
Detailed engineering specifications
Preliminary Material Take Offs
Operators requirements
Local authority requirements
Project master schedules
Information on site conditions
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Information for Estimating4 Detail Design Local availability of labour and materials
Detailed equipment list
Completed and approved plant layout
Electrical single line diagrams
Detailed equipment specifications/data sheets
Detailed material take offs
Firm quotations from potential vendors
Quotations from potential contractors
Commissioning and operating information
Installation and fabrication specifications
Construction subcontract enquiries
Production design phase continues
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1 Feasibility - Factors
Cost x 6.0
Cost x 5.0 Cost x 4.0
Cost x 3.0
Estimated Total Installed Cost (from which construction manhours can be estimated)
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1 Feasibility - Factors
Construction % of Total Installed CostAverage Labour Manhour Rate
= Estimated Construction Manhours
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1 Feasibility - Order of Magnitude
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1 Feasibility - Order of Magnitude
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2 Concept - Principle Quantities
Piping
Pipework
Supports
Tests
Valves
Metres
Tonnes
No off
No off
75000
200
40
300
E & I
Electrical cable
Instrument cable
Electrical devices
Motors
Instruments
Control Systems
Metres
Metres
No off
No off
No off
I/O Count
100000
50000
800
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400
6000
UnitQty
Unit of Measure
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Onshore 1 Feasibility(typically - 25 % to + 50 %) In house Estimates for Equipment and
Tagged Items Factored from Equipment and Tagged
Items for Bulk Materials Order of Magnitude from historical data on
similar projects Estimate for Project Sanction
2 Concept(typically - 15 % to + 25 %) Preliminary details from suppliers for Major
Equipment and Tagged Items Principle quantities (approximate) for
bulk materials Base norms adjusted for location factors
and productivity assumptions Estimates for Optioneering
3 Basic Design(typically - 10 % to + 15 %) Firm details from suppliers for 80%-90% of
Equipment and Tagged Items Preliminary MTO – in house, forced detail Base component norms adjusted in house
for location factors and productivity assumptions, or as provided by subcontractors
Target Cost Estimate
4 Detail Design(typically - 5 % to + 10 %) Firm details from suppliers for 90% -100%
of Equipment and Tagged Items Intermediate and Final MTO’s Base component norms adjusted in house
for location factors and productivity assumptions, or as provided by subcontractors
Definitive Estimate
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Offshore 1 Feasibility(typically - 25 % to + 50 %) In house Estimates for Equipment and
Tagged Items Estimated Weight Order of magnitude from historical data on
similar projects Estimate for Project Sanction
2 Concept(typically - 15 % to + 25 %) Preliminary details from suppliers for Major
Equipment and Tagged Items Estimated Weights for Bulk Materials Base norms adjusted for location factors
and productivity assumptions Estimates for Optioneering
3 Basic Design (typically - 10 % to + 15 %) Firm details from suppliers for 80%-90% of
Equipment and Tagged Items Preliminary MTO – in house, forced detail Base component norms adjusted in house
for location factors and productivity assumptions, or as provided by subcontractors
Target Cost Estimate
4 Detail Design(typically - 5 % to + 10 %) Firm details from suppliers for 90% -100%
of Equipment and Tagged Items Intermediate and Final MTO’s Base component norms adjusted in house
for location factors and productivity assumptions, or as provided by subcontractors
Definitive Estimate
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Shutdown Rough Estimate 500 Jobcards
7000 Activities = 140,000 Manhours 20 Manhours per Activity
Improved Estimate- Lump Sum, must exclude emergent work- For repeat shutdown at the same plant,
estimate manhours using historical data- Visit site during tender period for preliminary
discussions and assessment - especially important for unfamiliar plant
For Poorly Defined scopeEstimate in manhour ranges+ management fee
116
89
75 71
49
30 3023
17
0
20
40
60
80
100
120
VesselsInspect
Control Valves
Exchangers Drums NRVs FinFans
Pumps Towers Other
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Shutdown Preparation (typically 6 months)
B Assess Workscope
A Preliminary Turnaround list
E Prepare Jobcards (activities, manhours, etc)
D Prepare Work Packs
F Preliminary Plan
C Outline Plan
G Review Preliminary Plan
H Final Plan and Manhours Agreed
Tender Period (typically 2 months)
Shutdown Event (typically 3 weeks)
J Shutdown Event
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Shutdown
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Estimate - Base Norms Location Factor Adjustments
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Estimate – Base Norms Project Specific Adjustments
Considerations Climate
Site Layout and Access
Site Location – How Remote ?
Clock In and Walking Time to Workface
Work Days and Hours
Labour Density
Industrial Relations
Availability of Skilled Trades (Competing Projects, use of Local & Travelling Labour)
Use of Equipment, Working Methods (eg.Machine or Hand Excavate)
Permit to Work on Brownfield Sites
Contract Conditions
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Engineering Material Cutting Construction
Growth Take Off & Waste Increase Allowance Allowance Allowance Allowance
Estimate - Quantity Allowances Certain quantity allowance may also be applied to the base estimate for expected but unidentified work:
Anticipated design growth due to internal design changes
Anticipated amount of materials that is cut and wasted (eg.due to standard pipe lengths, loose flanges
Applied to construction labour, equipment and services due to anticipated Engineering Growth Allowance
Applied to for additional materials to be supplied due to anticipated Engineering Growth Allowance
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Component Norms - ConstructionINDEX
1
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Component Norms - ConstructionINDEX
2
1
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Component Norms - ConstructionINDEX
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1
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Component Norms - ConstructionINDEX
4
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1
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Construction Manhours PredictionINDEX
1 Estimated Manhours = Component Norms x Estimated Quantities
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Construction Manhours PredictionINDEX
1 Estimated Manhours = Component Norms x Estimated Quantities 2 Revised Manhours = Component Norms x AFC Revised Quantities
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Construction Manhours PredictionINDEX
1 Estimated Manhours = Component Norms x Estimated Quantities 2 Revised Manhours = Component Norms x AFC Revised Quantities3 Achieved Manhours = Component Norms x Installed Quantities
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Construction Manhours PredictionINDEX
1 Estimated Manhours = Component Norms x Estimated Quantities 2 Revised Manhours = Component Norms x AFC Revised Quantities3 Achieved Manhours = Component Norms x Installed Quantities4 Actual Manhours = Expended Manhours
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Construction Manhours PredictionINDEX
1 Estimated Manhours = Component Norms x Estimated Quantities 2 Revised Manhours = Component Norms x AFC Revised Quantities3 Achieved Manhours = Component Norms x Installed Quantities4 Actual Manhours = Expended Manhours5 Predicted Manhours = Actual Manhours + Productivity Forecast for Revised to go
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Construction Manhours PredictionINDEX
1 Estimated Manhours = Component Norms x Estimated Quantities 2 Revised Manhours = Component Norms x AFC Revised Quantities3 Achieved Manhours = Component Norms x Installed Quantities4 Actual Manhours = Expended Manhours5 Predicted Manhours = Actual Manhours + Productivity Forecast for Revised to go
This is part of Earned Value Analysis (EVA)
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Estimating – Historical Data
The Solution
Key Aspect Production of accurate estimates from high quality estimating base data
Past projects close-out information and statistics Bulk material quantities, weights and costs Engineered items details and costs
Project Controls Information (documents, changes, man-hours and costs)
must be processed promptly at project completion to maintain factors, norms etc.