Overview of BOCC Approach*

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Overview of BOCC Approach
International Comparison of Cost for
Construction Sector, Walsh and Sawhney (2004)
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BOCC Approach
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Concrete Footing Component
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Concrete Slab Component
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Roadway Component
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BOCC Hierarchy
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Components of Systems for Residential
System Name System Explanation
Site-work Construction components related to site preparation of a residential construction project
Substructure Structural components and related work items below the ground surface that are part of a residential construction project. These components are load-bearing and transfer all the loads from the superstructure to the ground below
Superstructure Structural components and related work items above the ground surface that are part of a residential construction project. These components are load-bearing and provide resistance to live and dead load on the building
Exterior Shell/ Building Envelope Construction components that form the exterior shell of a residential construction project. They are non-load-bearing members that rest upon the superstructure of the building
Interior Partitions All interior walls and opening in the building
Interior and Exterior Finishes All construction components in place for the purpose of satisfying a cosmetic function, including for example paint or plaster.
Mechanical and Plumbing All construction components related to providing climate control or water services such as heating and cooling systems, hot and cold water systems, fire fighting systems etc.
Electrical All construction components related to distribution of alternating current and direct current including electrical fixtures for a residential construction project
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Components of Systems for Non-residential
System Name System Explanation
Site-work Construction components related to site preparation of a non-residential construction project
Substructure Structural components and related work items below the ground surface that are part of a non-residential construction project. These components are lo-bearing and transfer all the loads from the superstructure to the ground below
Superstructure Structural components and related work items above the ground surface that are part of a non-residential construction project. These components are load-bearing and provide resistance of all types of live and dead load on the building
Exterior Shell/ Building Envelope Construction components that form the exterior shell of a residential construction project. They are non-load-bearing members that rest upon the superstructure of the building
Interior Partitions All interior walls and opening in the building
Interior and Exterior Finishes All construction components in place for the purpose of satisfying a cosmetic function, including for example paint or plaster
Mechanical and Plumbing All construction components related to providing climate control or water services such as heating and cooling systems, hot and cold water systems, fire fighting systems etc.
Electrical All construction components related to distribution of alternating current and direct current including electrical fixtures for a non-residential construction project
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Components of Systems for Civil Works
System Name System Explanation
Site-work Construction components related to site preparation of a civil engineering project including earthwork, earthmoving, and surface treatments such sidewalks and pavements
Substructure Structural components and related work items below the ground surface that are part of a civil engineering project. These components are load-bearing and transfer all the loads from the superstructure to the ground below
Superstructure Structural components and related work items above the ground surface that are part of a civil engineering project. These components are load-bearing and provide resistance to live and dead loads
Mechanical Equipment Equipment installed on civil engineering projects such as pumps, turbines, boilers, air handling equipment, cooling towers, vessels etc including all connecting pipes and valves. Mechanical includes utility systems (steam, compressed air, and refrigeration), process systems (rotating pumps, compressors, agitators, filters, etc.) special vessel design (tanks, pressure vessels), etc.
Electrical Equipment Equipment installed on civil engineering projects for power distribution systems, substations, power distribution panels, motor control centers, lighting, communications, etc.
Underground Utility Any underground line, system or facility used for producing, storing, conveying, transmitting, or distributing communication or telecommunication, electricity, gas, petroleum and petroleum products, coal slurry, hazardous liquids, water under pressure, steam, or sanitary sewage. These include wires, ducts, fiber optic cable, conduits, pipes, sewers, and cables and their connected appurtenances installed beneath the surface of the ground
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Construction Components
Construction Component Residential Basket Non-Residential Basket Civil Engineering Works Basket
Aggregate ? ? ?
Aggregate Base ? ? ?
Column Footing ? ?
Culvert ?
Drilled Shaft ? ?
Earthwork ? ? ?
Electrical Service Point ? ?
Exterior Paint ? ?
Exterior Wall Cement Plaster ? ?
Interior Ceiling Plaster ? ?
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Construction Components
Construction Component Residential Basket Non-Residential Basket Civil Engineering Works Basket
Interior Painting ? ?
Interior Wall Plaster ? ?
Portland Cement ? ? ?
Reinforcing Steel ? ? ?
Roadway Lane ?
Round Bridge Pier ?
Sand ? ? ?
Sand Filter ?
Structural Column Round ? ?
Structural Column Square ? ?
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Construction Components
Construction Component Residential Basket Non-Residential Basket Civil Engineering Works Basket
Round Bridge Pier ?
Aluminum Frame Window ? ?
Bridge T Beam ?
Bridge Spread Footing ?
Concrete Airfield Pavement ?
Exterior Sidewalk ? ?
Masonry Interior Wall ? ?
Concrete ? ? ?
Structural Steel ? ? ?
Unskilled Labor ? ? ?
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Construction Components
Construction Component Residential Basket Non-Residential Basket Civil Engineering Works Basket
Skilled Labor ? ? ?
Backhoe ? ? ?
Vibratory Plate Compactor ? ?
Centrifugal Pump ?
Plywood ? ? ?
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Advantages of BOCC Approach

• The BOCC provides a much simpler and better
  defined price comparison tool.
• It drastically reduces the resource and expertise
  requirements in the price collection process.
• It underlines the importance of the various
  components comprising different sets of labor and
  materials as well as equipment use. It thus
  captures productivity differentials by accounting
  for labor and equipment trade-off.
• Allows reasonable flexibility to compare
  different construction projects by identifying
  core components that are common across countries.
• Many countries have shown interest and asked for
  technical support to adapted the BOCC approach
  for use as a national inter-temporal price
  comparison tool to build their capacity.

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Labor Equipment Trade-off
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Price Collection Process
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Overview of Price Collection

• BOCC uses the SPD/PS methodology for price
  collection
• Identified components are representative and
  comparable
• Components are converted into SPDs for price
  collection purposes
• Country resources such as public works department
  and published schedule of rates can be used for
  pricing

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Price Comparison Under BOCC

• In the BOCC method 34 Components are identified.
  They include
• Two types of labor skilled and unskilled.
• Four types of equipment for hire a back-hoe, a
  centrifugal pump, a vibratory plate compactor and
  a sand filter.
• Five kinds of building material Portland
  cement, sand, plywood, reinforcing steel, and
  aggregate. Aggregate is gravel which,
  together with cement, water and sand, is used too
  make concrete.
• Complete components including a mix of labor,
  equipment and material.
• Prices for the 34 components are used to obtain
  PPPs for Systems.
• PPPs for systems together with expenditure
  weights are then used to obtain PPPs for
  residential buildings, non-residential buildings,
  and civil engineering works.

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Who collects the data?

• Building engineers, architects, quantity
  surveyors or other experts have to be involved
• Most statistical agencies do not have the
  necessary expertise
• Some countries may be able get the help of
  specialists from public works departments
• Other government agencies responsible for
  building regulations may also be useful
• In other countries the work has to be contracted
  out to construction firms or freelance engineers

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When and where data are collected

• In principle the prices should be national annual
  average.
• This means data collection should be across
  regions and should cover all year (quarterly),
  but this would be excessively costly.
• In practice some simplifications are necessary
  for construction sector.
• Prices should only be collected in 2 or 3 three
  cities that would give a close approximation to
  national average.
• In smaller countries this may not be a major
  issue. In large countries the scope of coverage
  should be extended to cover major cities and
  regions.
• Price collection in mid-year is recommended.

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How many observations?

• For building materials and for equipment multiple
  pricing is recommended
• Ideally, prices should be collected from at least
  four or five outlets again with the objective of
  providing an approximation of national average
• Again this may not be a major issue I relatively
  small countries with low price variations. In
  large countries the scope of coverage should be
  extended to cover major cities and regions
• For skilled and unskilled labor the number of
  observations required depends on the data sources
  used

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What is in the cost estimate?

• For the completed components the price is the
  total of the cost, at purchaser prices of the
  materials, labor and equipment.
• The price reported for completed components does
  not include any profit margin or any fees for
  architects, quantity surveyors and other
  construction specialists
• The purchaser prices of the materials and hire of
  equipment includes only non-deductible product
  taxes.
• Value added taxes are often fully deductible for
  goods and services that are considered to be
  investments and so will usually be excluded from
  the purchaser price.

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Expenditure Weights
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Expenditure Weights in BOCC
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Sample System Weight W2
Cost Breakdown for Construction in Canada for
Year 2000
Systems Multi Level parking Garage Light Industrial Warehouse Commercial Office Building Elementary School High rise office complex
Substructure 9.1 8.7 6.4 2.1 1.8 3.7
Structure 58.3 21.2 18.9 16.2 11.5 20.1
Exterior Closure 7.0 19.3 36.4 14.2 16.4 16.0
Partitions and Doors 0.7 0.9 7.0 5.0 7.4 4.7
Finishes 4.0 7.8 0.6 8.4 10.3 9.3
Fitting and Equipment 2.8 5.6 0.0 5.3 8.8 9.6
Mechanical 6.2 17.7 20.9 26.5 25.6 19.9
Electrical 4.9 12.3 2.4 14.9 10.7 9.3
General Requirements and Fees 7.0 6.5 7.4 7.4 7.4 7.4
Total 100 100 100 100 100 100